How high do you rev your Z? My 260 is ill.......

[Ron Earp]

Well I we mangaed to get the car down to Roebling to race this weekend but things went badly. The car had not been running well as I was re-wiring everything, but I attributed it not running well to having sat in the garage for three weeks with a weak battery and little starting.

I got it off the trailer at Roebling Thursday night and drove it around the paddock a bit and didn't like the way it sounded. It was flat, idled rough, and seemed to be getting a little worse.

I took it out for the first session on Friday morning but it wouldn't pull much over 4k and really ran poorly. I bought it in after a couple of laps. Had a look and the engine didn't have the plug I had on the drivers side that seals that tube that goes down into the block. It used to have one, but it blew the plug off. Hmmmmm.

After fiddling some more with it things were definitely worse - there was a plume of smoke coming from my oil can that was definitely under pressure. We borrowed a compression gauge from Gerald Potts (has a nice 325 ITR car BTW!) and found compression was pretty bad across the board:

1- 0 psi
2 - 20 psi
3 - 1XX psi (can't remember but was the strongest)
4 - 120 psi
5 - 90 psi
6 - around 90psi

Damaged rings. Might as well check valves too so we pulled the cover - 12 operating valves and no stuck ones with good oil flow (This check would have made a good Bevis and Butthead episode. All we needed was Mr. Anderson to walk up and say "What the hell?" in the middle of the flying oil scene). Actually, oil pressure is good all around at 40-50 psi when hot and above idle, about 20 psi at idle. Motor has 20 hours on it and was reported to be just rebuilt as new when we bought the car two years ago.

I think I killed the motor at CMP a few weekends back. It was strong at CMP, but I might have been too rough on it. I was running it regularily to 7k and sometimes a bit more in the AutoX section to avoid a shift to fourth. Probably a dumb idea. And, I now can recall the last couple of laps I backed off the motor because it didn't "feel quite right" but couldn't find anything wrong. It still ran well right after that weekend but then the stuff I described at the beginning of this post started happing.

So, now that I've got to pull this thing and re-ring it (as well as bearings, head check, etc.) what do you Z guys recommend as a standard shift point?

Anything you can recommend for the future or for my impending rebuild that can help?'

Ron

[zchris]

If you need pistons you should buy forged as they are now allowed and the cast piston is probably on its performance edge at 7k. 0 compression usually means a holed piston or a missing valve head.
Chris

[Ron Earp]

I agree with you on the holed piston. I might very well have one because I've never seen this amount of blow by before on an engine with cracked rings.

How high do you turn yours?

R

[MMiskoe]

From what you've said here any thoughts that you might have bumped the valves on the pistons? You've got two cylinders that are good, two are fair. One that's dead and another that just moved into a hospice house. I'm just skeptical that the rings care about being over rev'd whereas the valves certainly do. Any ability to do a leak down? It will tell you much more than a compression test as you can hear where its leaking. Its possible you only need head work.

BTW my dad's 280 get upshifted at about 6k (but I've found it at 6500 sometimes when I drive though).

Matt

[Ron Earp]

From what you've said here any thoughts that you might have bumped the valves on the pistons?
[/b]

Maybe, but the valve train does seem intact and operating quite well.

But the amount of gas/fuel/air in the crank case is staggering. More staggering is the amount of metal trapped in the Olberg filter. I popped the top off it last night and the screen is covered with metal

I don't have leak down stuff but I might be able to borrow one.

I thought about some sort of fueling problem that might have caused a leak condition and led to a holes piston or cracked rings. But 1/2 are dead, while 3 is solidly healthy - all fed by the same carb. 4/5/6 are all sick.

[kthomas]

What's the factory redline on a 260Z?

On a 240Z a junkyard stock motor will run 7000 all day long. With forged pistons we went to 7400 when necessary. The weak link is the ring lands on the stock pistons, but the mode of failure is usually just wear leading to higher leakdowns.

To have that much damage sounds a lot like detonation or seriously overlean on one carb. For a long period of time. Rather hard to destroy an L series motor in IT trim. Sorry to hear about that.

[Joe Harlan]

Katman is spot on here. The only other thing I will add is that valve damage can happen on these motors at 7400 but it happens on forced decel. If you were overreving to get through a quick section sometimes the tach gets higher when you are useing the engine for brakes.

[JeffYoung]

One other symptom to add to the diagnosis before we pull this thing apart.

You can turn the crank pulley about 10 degrees in either direction although it appears the cam pulley does not move when you do so. Last, you can also move the crank pully towards the block by about 1 to 2 degrees -- it has that much play in it.

Really crazy that this car ran great one weekend and then went pop this quick. Par for the course with our racing efforts I guess.

[Ron Earp]

One other symptom to add to the diagnosis before we pull this thing apart.

You can turn the crank pulley about 10 degrees in either direction although it appears the cam pulley does not move when you do so. Last, you can also move the crank pully towards the block by about 1 to 2 degrees -- it has that much play in it.

[/b]

I don't know Z motors, but am about to get to know them, but this front crank pulley - is it a dampener too?

If it is a dampener along the design of a Ford SB or similar then this could be explained if the rubber innards that connect the hub to the pulley are degraded in some way.

The crank pulley does indeed turn left or right about 5 degrees. And, as Jeff says you can lift it fore or aft a couple of degrees out of the plane of rotation. The hub bolt is solidly tight. It might have 3 or 4 bolts that hold it to the hub that are loose, I'll find out when the motor comes out.

Joe, I don't think I hit 7400 or so, but there could be some tach error. Definitely hit 7k on occasion. Any tips you fellows can share on Z rebuilds would be appreciated. At this point I think we'll just try and put the motor back the way it was (and I'll take advantage of anything in the rules that the motor didn't have - compression etc.) and get it back out on track. I don't learn about driving working on cars.

Katman, I have some dyno data from one of the motors that was in the car at one time. The data has the dyno shop's name, if I pass that along maybe you could clue me in as to the probably builder in the past in Atlanta?

Just cleaned out my basement for spares to sell on Ebay! Must fund motor rebuild.....

R

[Ron Earp]

To have that much damage sounds a lot like detonation or seriously overlean on one carb. For a long period of time. Rather hard to destroy an L series motor in IT trim. Sorry to hear about that.
[/b]

That is what I think would be the normal cause. And it might be, although the EGTs didn't show anything like that. They definitely showed a difference in temps, the rear three were about 75-100 cooler than the front, but the front EGT that is in #1 never got over 1350 to 1400.

I re-wired the entire car and I made a new panel for it as well re-wired the EGTs. They "seem" to be working, but I've never been all that confident in those gauges. They are some expensive pieces that came with the car and according to the checkout procedure for them they are okay. But I'm still not sure. They'll be getting new probes on the new motor.

Joe or Katman, what do you recommend for forged pistoned?

R

[Joe Harlan]

Ron, couple of notes here, EGT's are a tool. you can have high temps and be to rich and you can have low temps and be too lean. Basicly they are only good if you are inside their window of operation. Read your plugs. Your eyes will not lie to you. 10 degrees of chain movement is excessive. you could tag valves on decel at 7k easy. remember that when you decel you have all the valve spring pressure and drag pulling the cam backwards (whip in the chain. that means if you have 10 degrees of crank slack the cam is retarded and the piston chases the exhaust valve closed. At this point your best bet is just to take the head off and post pictures. That will get you the fastest answers to your questions. The rebuild will not be that hard as long as the bore aren't all beat up from being leaned out. Also i am not sure your hauling situation but let me run one by you. I was the last race of the day several years ago. We came off track and had to travel 4 hours home. Car went straight into the enclosed trailer and the doors were closed. Got home had loads of business so i just left everything in the trailer for about a month. Car went into trailer running the best ot ever has. Month later took the whole thing to the track charged batt and drove it out to change the oil and service it...(at track is bad) Anyway after oil change I went out and noticed the engine was smoking and pushing oil into the breather. When I took it apart there was damage to the rings and a couple of broken ring lands. After a complete autopsy we discovered that moisture was the cause of the failure. There was signs of rust in the bores but the gaskets were fine. the real signs were surface rust on the interenals of the engine components. The race oils we use do not have the same moisture inhibitors as street oil and combined with being locked in an oven for a month I am sure that I was the cause of the engine failure. Good luck. Pictures always help

Edit: As far as pistons go I am still a hold out for OE stuff. These days if you want to run a forged piston any of the big manufactures are good. the down side is most of that is custom and this time of year you need 6 to 10 weeks to get them built.

[JeffYoung]

The plugs did not show an overly lean condition at all -- I just don't think that is what happened although I agree it would appear to be the most likely cause.

Joe, you know my technical knowledge is lacking -- can you help me with a question? Why would the crank pulley turn 5 degrees or so, and the cam pulley NOT turn the same amount? Is it possible something happened to the crank and the pistons and valves did some smacking?

We'll get pictures up as soon as it is apart.

Thanks guys.

[Ron Earp]

Joe, you know my technical knowledge is lacking -- can you help me with a question? Why would the crank pulley turn 5 degrees or so, and the cam pulley NOT turn the same amount? Is it possible something happened to the crank and the pistons and valves did some smacking?

We'll get pictures up as soon as it is apart.

Thanks guys.
[/b]

Hey Jeff the crank pulley is simply bolted on the end of the crank and has nothing to do with the cam gear, cam, or valve timing. The cam gear it secured on the crank and does not have play in it, and neither does the cam. Chain is properly tensioned too. I have not checked cam timing, but the pulley is independent of all that.

To be clear the crank pulley is what has about 5 degrees of play in it, and in the current state it allows one to turn the water pump and alternator a slight amount. I think the crank pulley has an inner and outer section (I've not checked yet) and the inner section has somehow become slightly detached from the outer section which allows some play in the plane of rotation, and, allows you to pull it fore and aft a couple of degress too.

Joe in between the CMP race and this race three weeks elapsed. But the car came straight off the trailer Sunday night from CMP and into my garage, which is at a nice 70F. I worked on it for three weeks, intermittently starting it from time to time to verify my wiring work. During this time it ran poorly, but I thought it was due to the frequent starting and shutdown and lack of revving. Where I live I can't fire up race motors much and definitely can't rev them over 1.5-2k or so, just when moving the car around. So, I figured all the rich starting and idling was causing the motor to sound poor and run badly.

I'll get lots of pictures up, I like pictures. Probably later in the week we'll have some photos of motor out and parts.

R

[Joe Harlan]

Actually Ron you were probably correct about the poor running and rich fuel being what started the issue. You could have fouled the plugs enough that forcing the engine to run on very dirty plugs and raw fuel in the system could have led to the possible detonation you may have experienced. Now as far as the crank pully goes. Yes it is 2 part and yes they fail. You need to turn the crank by the bolt one direction and then the other direction to confirm chain slack. These engines will have slack from no oil pressure to the tensioner unless it has been properly installed. Jeff, Excess Slack in the chain will allow the valves to make contact under decel and I have seen it a bunch of times in IT engines when you add soft valve springs to it(valve float)you can make contact on up shifts. The 2.4 engines it is not uncommon to see little smiles on the piston tops from the exhaust valves.

[Ron Earp]

Now as far as the crank pully goes. Yes it is 2 part and yes they fail.
[/b]

That explains the crank pulley then. Fords are two part too, in some applications, and do the same thing.

We'll have to check everything else when the motor gets opened up. It'll be interesting to see what we find - holed pistons, cracked rings, broken valves, bent valves, or all of the above! Maybe we need a lottery and a $10 prize!

R

[Joe Harlan]

Ah, Now I will also save you some future money...Before you take the engine apart take the head off rotate to TDC and check your timing mark alignment. It is not uncommon for the outer ring to rotate before these balancers fail. If all is good then scribe a mark across the two part so you can have a qucik look with a mirror before every race..

[kthomas]

"Katman, I have some dyno data from one of the motors that was in the car at one time. The data has the dyno shop's name, if I pass that along maybe you could clue me in as to the probably builder in the past in Atlanta?"

PM me and I'll see if it rings a bell, but if it was a chassis dyno it most likely won't help. I'll be at TGPR tomorrow flogging the BMW but I'll be back in touch tuesday.

We used JE for the forged pistons. Stockers were up to $73 each last time I looked, which was quite a few years ago, and the factory quit shipping groups of 6 from the same casting lot, so we bought a bunch of pistons to find 6 we like last time we used OEM.

Most EGT gages are too hard for a driver to read, they're really dsigned for aircraft applications. We eventually replaced our dual EGT gage with blinking lights o2 sensor. You know, something the PITA carbon lump in the driver seat could understand. :eclipsee_steering:

[Ron Earp]

I'll get that data out, it is from a flywheel dyno and you might know the shop.

Dang, pistons are not cheap, and forged will be a long time to get it looks like. Maybe, just maybe, we'll get lucky and have some pistons that can be re-used. But I doubt it. I think we'll be in for an overbore with damaged pistons.

Jeff and I will sort something out and look this week while checking cam timing, tension, and timing. Thanks for all the help and replies on this one.

R

[[email protected]]

Everyone else has covered this well, the one thing I can add is that the valve springs won't last forever. Change then every 3-4 races depending on how high you rev. If you are regularly going over 7000, like running a 4.11 at Rd Atl, change them every weekend. This will save you a lot of trouble down the road.

As you get ready to build back, if you are building yourself, I have a torque plate for the Z engine. I am in Shelby NC. I was amazed the first time I measured a block that had been done with a torque plate. The difference is huge.

Mike

[Ron Earp]

Jeff and Jeffery came over and got the engine out for me last night. We tore it down til the head came off and stopped. Timing was good, chain good, etc.

But, two of the pistons have have chunks out of them and I think a third is about the go as well. That will definitely explain the compression issues. In looking through the truck load of spares that came with this car I also notice that there is a set of "dead" pistons attached to rods. One of those pistons shows exactly the same little half moon burn through that looks like these. I've enclosed a picture of the piston that it out of the spares, but it looks like mine from the top (mine are not out of the block yet).

I've not inspected the head yet. All the pistons have little smilely faces on them, just as you said they would. Looks like it was built using ARP stuff throughout and with OEM pistons. I'll get more pictures up once I work out this time limit and global attachement size thing on this board.

Ron

[x-ring]

Ouch!

To answer your original question, I usually shift at 6700 - 6800, with the MSD 'pill' at 7K.

Hope mine doesn't look that bad, but I have different symptoms than you. Got all the external stuff off last night, all that remains is to unbolt the transmission and motor mounts.

I'm thinking of saving the oil drain pan full of metal chunks to remind me not to let someone else work on my car...

[JeffYoung]

Sorry to hear that Ty. I didn't realize you lost a motor as well?

We took Ron's apart last night. Big chunks out of the 2 and 4 pistons, valve contact marks on all pistons.

Other than that everything looked great!

I assume the valve marks on the pistons are from an overev?

[Joe Harlan]

Sorry to hear that Ty. I didn't realize you lost a motor as well?

We took Ron's apart last night. Big chunks out of the 2 and 4 pistons, valve contact marks on all pistons.

Other than that everything looked great!

I assume the valve marks on the pistons are from an overev?
[/b]

Yep but most under downshift over revs. More photos will help and Ron you can Email them directly over to me if you like. Measure the bore and check for scratching int he walls. I may have some pistons around here that would help to get you by.

[JeffYoung]

Got it, thanks Joe. I think Ron is going to take a bunch of pictures of the pistons, valves and the mystery header for Keith.

I assume valves smacking into pistons means we need to take a hard look at the valve train as well?

[Joe Harlan]

Yep, you should buy 6 new exhaust valves cause your gonna need them. Get a set of springs and inspect those old retainers.

If you don't have this book its a good investment.

http://search.ebay.com/search/search.dll?f...tsun&category0= (http://search.ebay.com/search/search.dll?from=R40&satitle=how+to+rebuild+datsun&category0=)

[Ron Earp]

Bought that book Joe, thanks!!! And thanks for the offer on the help with pistons too. Haven't got any of that apart yet and the pistons you see that are out of the car were in the pile of bits that came with the car. That half moon piece out of the ones you can see in the bore looks a lot like the one I'm holding in my hand there....

http://www.gt40s.com/images/Z/IMG_2631.JPG
http://www.gt40s.com/images/Z/IMG_2633.JPG
http://www.gt40s.com/images/Z/head.JPG
http://www.gt40s.com/images/Z/header.JPG
http://www.gt40s.com/images/Z/no2.JPG
http://www.gt40s.com/images/Z/no3.JPG


http://www.gt40s.com/images/Z/ex1.JPG
http://www.gt40s.com/images/Z/ex2.JPG

[Joe Harlan]

Stahl race header or a knockoff.

Detonation sucks....What are you runing for timing and fuel? The amount of oil on the piston tops is an issue also. Hard to tell int he photos but the vertical scratches in the bores look pretty deep.

Joe

[JeffYoung]

It needs a rebore. The scratches can be easily felt with a fingernail. Deep in several places. Block has been bored once, the pistons in it are +10.

We think it ran rich until about 5,000 rpm. after that, we thought it was ok. Plugs did not show a lean condition, but it sure looks like detonation in the chambers, I agree with you there.

We are told by a local engine builder with Z experience that the #2 cylinder on L24/26s run hot due to the intake manifold design.

[seckerich]

I would say the fuel pump problems at CMP did more damage than you thought. Sorry to hear you need a rebuild.

[Ron Earp]

It is a bummer, but as Jeff says do the vice and pay the price. Some comments:

*The header isn't optimal, but it'll do for now I think.

*Head has excellent IT legal max port work and matching, very nice.

*Block has good attention to detail with some safety wired bits and ARP harware throughout.

*Fueling is done with two electric pumps, back flow valves, and external regulator. Never had problems before, it has always run well. BUT - at CMP I had a voltage regulator go bad and we were having problems keeping fuel pressure where it should be as well as the car running. 18V at the pumps can cause the regulator to be over powered etc. - to make a long story short Steve is right, it might have run a race with fuel pressure less than optimal but I'm not sure. It did run the CMP race well, but on the last couple of laps it behaved a bit odd. I attributed it to the car having to run on battery only, but I imagine that wasn't just it.

*It'll need a re-bore, new pistons, all new bearings, and we're going to have the head gone through and new springs installed. I'll need a source for some 0.010" or 0.020" pistons and good rings. Also need new valves, I can't imagine them not needed to be replaced, as Joe says, after leaving that smilely mark on there.

So, to recap on the revving thing:

*If I like to replace springs every race, or close to it, then I can run to 7400 RPM (providing my fueling is good and I'm not running into trouble there)?

*If I don't wish to replace springs that often I need to stick to 6800 RPM or so?

I'll need suggestions on good bearings, good rings, pistons, springs, etc. I've not talked with my Nismo man yet, so I'm not looking for cheater stuff, I'm just new to Z's and don't know what you folks do for parts sourcing. Remember, I'm just off the Jensen bandwagon and I'm used to sourcing my own and scrounging from an old dude that lives in a bus - this being able to pick up a phone and call a Z Parts place is cool! JensenWorld went out of business long ago because their last racer was cut in half.

R

[JeffYoung]

Shit man, we need to race. I wouldn't shift that thing past 6800 for a year or two if that.

[Ron Earp]

Shit man, we need to race. I wouldn't shift that thing past 6800 for a year or two if that.
[/b]

I agree. That CMP race was my second ITS race since my rookie X. And I had intentions of keeping it below 6.5k. But then I got out there (after Steve E's wife graciously brought me a tool to get the car running on the grid!!! Thanks to both of you!!!!) , the green flag dropped, and I got around a couple of people with torque on the start and said "whoa, this is fun, I gotta get more of that!!!!!". And more of that meant some 7k+ shifts......and look where that got me. You know the story, you warned me it would happen.

7k pill for a bit.

R

[Joe Harlan]

OK now lets look at this whole deal.

6800 is fine on tracks that are 3rd and 4th gear stuff. The the split will keep you in the powerband just fine. on tracks that you see second gear you need to run the motor to 7200..NO big deal . You do not need to change springs every race even at 7200 rpm every shift. 7400 makes no power so I really don't get why anyone would be up there other than maybe pullng a low gear down hill and over running. As as far as the rebuild goes. the only ARP stuff needed in these engines is the rodbolts. I believe all of the L26 rods are 9mm bolts anyway so your not going to save any real big end weight on them. Mainstuds and headstuds are not needed on these engines and I actually had more failures with headstuds on GT motors than just using the good factory bolts. As far as pistons go off the shelf OE if they are sill around our even some of the best buildlers in the country have been seen putting repco pistons in these things. I believe the L26 uses the same piston as the late L24 which I have only been able to find in .020 over. The early piston displaces 3cc less if I remember correctly again. Deaves or hastings or sealed power gold rings. all are good I have a mixture of rings that I use in these engines. Factory bearings are the way to go here especially on the mainline. OE timing sets are also of the best quaility. I have a ITS 240 customer with 4 seasons on the sme engine. We have taken the head off every year and freshened it. DYno numbers indicate there shouldn't be a 5th year on the bottom end but it's not by very much. The header you have there looks like a Stahl header and I have 2 cars with them and 3 others with the Nissan part. bottom line the header is not hurting you at this point. The real deal is you need to get this car back on the track so worse case is find a good running used engine freshen the head and get back out there while you do this one back up. Good luck if I can help let me know.

[Ron Earp]

Joe,

At least for this motor and my experience with it I agree with your rev limits. It made good power to like 6.8k or a bit more, but signed off after that. However, at this CMP track we drive there is a four turn complex that is all in-between 3-4 and one doesn't want to shift to fourth, so, one holds third and ends up with some over rev. At least the way my car is geared.

I don't have any OEM bolts etc. so I'll use what is in the motor. L26 is the same piston as the L24, so that should be no problem. I like those Sealed Power rings but didn't know if they had them for Z's, should be possible to find them if you've used them. I swear I saw some 0.030 and 0.040 over sets but that might have been for a 280Z, which it seems easy to get forged sets for.

I'll give Riley Curtis, Lynchburg Nissan (1-800-443-2117) a call. He's the guy that Katman suggested and set me up with the Nimso clutch etc. I assume he could source pistons, bearings, and a timing kit per Nimso? Anyone have other suggestions for good Z suppliers?

R

[[email protected]]

On the piston size, the markings on the top are in mm. so if you have a 1.0, it is .040" already. I don't remember if Nissan made anything but .5 and 1.0mm over.

A few weeks ago, David Spillman had a wrecked 260 that has been behind his shop for a few years loaded up on a trailer looking like it was going to the metal yard. I looked longingly at it, but I have a good engine in the car and a good spare L26 block and two others that are usable. If he still has it, it may be something to get you back on track until you get your primary back up.

I have some stock head bolts and some aftermarket equivalent to the diesel main cap bolts I can hook you up with cheap. I also have a torque plate you can borrow to get it back right. Really makes a difference.

Mike

[x-ring]

At least for this motor and my experience with it I agree with your rev limits. It made good power to like 6.8k or a bit more, but signed off after that. [/b]

That's pretty much what mine does too. There's only one track around here that requres second gear, and it seems like sometime every race somebody will get me there.



I'll give Riley Curtis, Lynchburg Nissan (1-800-443-2117) a call. He's the guy that Katman suggested and set me up with the Nimso clutch etc. I assume he could source pistons, bearings, and a timing kit per Nimso? Anyone have other suggestions for good Z suppliers?[/b]

Around here most of us use Courtesy Nissan out of Richardson, Texas. Finding a dealership that still has some parts guys from the old days isn't easy anymore. If you tell them you're a member of the IZCC they give you, I think, an extra 10% off.

Don't have their number handy, but their web site is: http://www.courtesyparts.com/



Sorry to hear that Ty. I didn't realize you lost a motor as well?
[/b]

I've been pretty backed up the last few months. Kid stuff and travel for work (I'm off to Europe tomorrow for 10 days) mostly. Since I never could find the time I had a local prep shop install a new oil cooler and accusump for me just before our first double of the season last weekend. When he installed the oil lines he reversed the pressure and return off the filter adapter, meaning the oil pump was pumping against the check valve. Surprisingly, the (brand new) valve leaked enough to give me about 40 lb/in2, at least until the oil warmed up some, then it sealed tight.

The engine is out but I haven't done a full disassembly yet, just pulled the oil pan. The rod bearings look fine, but I've never seen a crank bearing that particular color. Not sure why one would overheat and not the other.

Next race Memorial day weekend. I already tell it's going to be a thrash getting ready.

[kthomas]

Nyet on the Stahl header- its a Interpart/BRE header sold as part of the "Whisperpower" system many moons ago. If you collect the 2-1 in the right way in the right place it's actually a pretty damn fine header for IT. I didn't think there were any of them around any more...

Where you need 7400 rpm is with a 3.90 gear at Road Atlanta to win the ARRC. A 3.90 rear and 3rd gear is the fastest way out of turn 7 and 10b, but it means you're twisting it down the hill to 10a. Otherwise Mr. Harlan is correct.

If you're shifting at 7k or below you can run a set of valve springs all season, unless of course your cheating on your cam. :018:

Even going to 7400 at RA the earliest I might have changed springs is..... beginning of the next season. Of course it helps to cam doctor about a jillion stock camshafts to find one which A) has all the same lobes at all the same timing (harder than you think), and B) has worn enough over the nose to to be a little smoother on the valvetrain harmonics.

[[email protected]]

Thanks Keith, when I saw that header, it looked like a Motorsports Auto header to me. I ran one for several years. Everyone was so confident that it saw a Stahl, and it does look kind of like his header that I didn't comment. I think it is a Motorsports Auto header.

Mike

[kthomas]

"I think it is a Motorsports Auto header."

Nope, I'm right. :D I got a picture of it that will convince you. Monday I'll see if I can get it posted somewhere.

[x-ring]

Are you sure? It looks like a Pacesetter to me.

:D :D

[Ron Earp]

Well, I'm not sure what the header is but I'm going to coat it for preservation. Got an antique!!!!

Now, bad news on my block - it is 1mm over now as Mike says. So what are my options? I'm not finding greater than 0.040" pistons, 1mm over, and I've got to have this thing cleaned up. Do I have it sleeved? Or do I toss it to the curb and find another one?

If I have it sleeved, what do I go with, stock bore? I suppose that would make the most sense to get more use out of the sleeves. If that is the case then I can go ahead and order up the parts at standard bore.

R

[JeffYoung]

You can't go more than .40 over per the GCR. Not sure about sleeving, will check when I get home.

[Joe Harlan]

One sleeve OK but six you mayas well start with a fresh block. Std pistons will be hard to find anyway so find what pistons are out there and bore to fit. I know you are not into short cuts but you need to find a running short block and get this hot rod back on the track so you can take you time and build something nice over the winter. Seat time seat time will benefit you more than an extra 20hp. I can check around and see if there are any 260 engine laying around.

Katman, I bow to your memory, you are correct on the header 100% I had one of those and a Stahl on my GT2 car years ago.

[Ron Earp]

I hear you guys and through a stroke of luck Jeff found that a local racer, Rex D. from IT7, has two 260 blocks squirrled away at Happy Japs, his car repair business. So.......I bought them and will pick them up Monday. One engine is complete and we'll do a leak down on it, the other is a short block. I hope to use the complete one as a spare motor to get back running, and use the short block to build a new race motor out of, depending on bore. Might switch around depending on what is going on with them.


I don't think this block can be used. It is definitely 1mm over, which is legal limit. I'll take it to the shop for evaluation, but I don't think there is much help there.

I could be back up and running in as little as a week if all works according to plan. Having a spare "stock" motor that runs would be a good thing. They can be swapped in 2-3 hours and would be a cool thing for failures like this or other unforeseen accidents.

Tell you one thing, having a lot of people that know about a car/motor is a fantastic thing. There was no way to get this sort of info on the Lotus motor or buy two engines locally for a couple of bills. And, help in the paddock is available - I've lent parts to other Z racers to get them on track and have borrowed as well, another nice feature. Any future race cars I race/build will be known quanities for sure.

Hey, when you guys do the mains on the Z do you use two sets to make a 360 grooved bearing? Common Lotus 907 trick to help with oiling, do the Z guys do it too? I noticed I have a spare main bearing set in the spares that came with the car, but only half of them are grooved. Could buy another set and only use 1/2 for each set.

R

[Gary L]

Hey, when you guys do the mains on the Z do you use two sets to make a 360 grooved bearing? Common Lotus 907 trick to help with oiling, do the Z guys do it too? I noticed I have a spare main bearing set in the spares that came with the car, but only half of them are grooved. Could buy another set and only use 1/2 for each set.

R [/b] I have two comments on this procedure. First, aren't bearing halves supposed to be mated for life? I guess the procedure could be beneficial, but couldn't one also end up with a mis-matched pair of halves that might be more detrimental than beneficial?

Second, someone may correct me (and that's okay :D ), but I would consider this to be well into the grey area WRT the IT ruleset. Aren't you essentially creating replacement parts that don't meet OEM spec when you do this?

[Joe Harlan]

Ron, on the bearing question.
No I do work on the bearing but I don't use full grooved all around.


Gary, I have never read or even considered bearing to be in specific pairs. Nissan used to sell (maybe still do) bering half of different thickness so you could get proper race clearence on OE cranks. While i would never have an issue with using full circle bearings I have to agree under the current writing of the book that would be of questionable legality.

Anyway good luck on your plan. When you get it back together get some help setting the carbs up and get back to the dyno just to be sure the motor is getting proper care and feed at high rpm.

[Parrish57]

"I think it is a Motorsports Auto header."

Nope, I'm right. :D I got a picture of it that will convince you. Monday I'll see if I can get it posted somewhere.
[/b]


I hate to throw doubt on the subject, but just in case there is someone looking for one of these headers I thought I'd provide this link. http://www.blackdragonauto.com/icatalog/z/0066.asp Black Dragon used to be Victoria British. More than likely Monza has copied the older header that you were refering to.

[kthomas]

That ain't the same header, and as far as a copy- well it has 6 into to at approximately the same place but that's it.

[Ron Earp]

Sort of looks like a cross between that one and one of the others. It has six EGT bosses that were added, and I'll be moving the probes around, you can bet that. I know I'm keeping it!

We might have a ace in the hole though with a motor in the car before long......some options have popped up, or shall I say started up.....

R

[[email protected]]

Steve, I think you are right, I was thinking of the Victoria British header. They have two versions. One is 6 into 1, and the one posted. I had one on my car prior to building the stepped header that Ty has now, or I hope has by now. Not a bad header, fit reasonably well, but the Y-pipe could be a pain sometimes and it was too low. Rubbed on the banking at LMS and over the curbs at Atlanta.

[pballance]

It has six EGT bosses that were added, and I'll be moving the probes around, you can bet that. I know I'm keeping it!

R
[/b]

I am fairly new at this but I don't think the "bosses" you mentioned were meant for EGT(I assume EGT=Exhaust Gas Temp used in todays ECU setups). They were Air injection ports to aid in the engine passing the smog regulations "back in the day." The orginal exhaust manifold had them as well and the air pump was mounted on the opposite side of the block from the alternator. I have a working air pump if you would like one :P .

Good luck on the new motor. I have located several parts cars around North Alabama if you get into a bind and need another block.
Paul

[Ron Earp]

Ah ha! Good to know. I've never seen a stock working 260Z. Let me check out these two engines I have and I might come back to you on a block. Thanks for the offer!

Ron

[Joe Harlan]

Actually, back in the day isspro egt probes used a screw in type bung just like that...:)

[Ron Earp]

Hey Joe, it is back in the day! :P

Have a look at my panel, ISSPRO gauges that you can't get anymore - the big 3 3/8" ones. They work great and are very readable, even at speed. Jeffery and I just made the panel new to replace the old junk that was in there and the extremely poor electrical system. The new system uses aircraft circuit breakers for protection, all new switches, and properly sized wire to deal with current loads. In fact, the metal panel up top is a C152 surplus from the aircraft breakers and works great in the Z.

R

[Joe Harlan]

Just so happens that isspro is here in town and I have a good contact there should you ever need it...:) The thing I never liked about those probes is they were to big and really filled up a 1.75 header tube.

[Ron Earp]

Just so happens that isspro is here in town and I have a good contact there should you ever need it...:) The thing I never liked about those probes is they were to big and really filled up a 1.75 header tube.
[/b]

Dang, wish I'd known, I just ordered new ones, but small ones. They have the Type Ks in a 1/16" package that don't do much in the way of blocking flow, although they are not cheap. These gauges I have are not made any longer and have been surplanted by small 2 1/16" models that are still over $400 each retail. Tech told me that these olders ones are somewhat in demand on the used market for replacement in various applications.

I'll get them fired up on the new engine. Still now sure what will happen there, but if this stock block I'm looking at tonight checks out it is going in the car while I build a race motor.

Will a stock block and stock oil pan survive (with Accusump) in a race car? I know the rods/crank will, just not sure about the oiling with a stock pan - I've never seen a stock pan.

R

[JeffYoung]

Accusump SHOULD be good enough to survive. But I will let the Z experts weigh in.

[Parrish57]

I ran my first two years with a stock pan and accusump. No oiling problems. Then I went to the NISMO pan and ditched the sump. Still no oiling problems. I'm looking at this pan for the future. http://www.arizonazcar.com/pan.html Has anyone used one of these for any length of time in race conditions?

[[email protected]]

Wow, that pan is a beauty!

I did see or hear about a deal where the BRE guys tried an aluminum pan and started breaking oil pan bolts. So they went to larger and stronger bolts. Then the started cracking and breaking pans. They ended up back with the steel pan and stock bolts. That big ol' 6 flexed too much at high rpms for the aluminum pan. Now they were running revs that we only have nightmares about. Might be fine for us.

Mike

[Butch Kummer]

I just caught up on this thread and I don't drive a Nissan, but in reading I noticed something that hasn't been mentioned here. If the timing mark is on the outer ring of the harmonic balancer and that ring has shifted relative to the crankshaft, you have no clue what your timing is set to. That could be the cause of the detonation moreso than an overrev situation.

Back to regularly scheduled programming...

[Joe Harlan]

Actually I think I did mention checking mark against TDC several pages ago. Yes the stock pan will work at most track even without accusump but I don't recommend not running an accusump without a good pan. Good luck on your stocker cause seat time in a race car is far better than seat time in the grandstands....:)

[Butch Kummer]

Joe, Yes you did mention checking the timing mark (and scribing across the entire balancer to quickly tell if it's correct) but if you set the timing without knowing that it's incorrect you can run severe advance without realizing it. We found that out when we were running a SBC at about 65 degrees advance because the timing mark had moved and we didn't realize it when we set it. Luckily we found it before holing a piston when we checked the timing again and it had moved dramatically.

YMMV...

[Joe Harlan]

You are completely correct on that. I don't sned an engine out or even set timing on a Z motor with out establishing TDC and matching the mark. I have seen those balancers slip or be marker wrong to many times. over the years. It just is not that hard to pull a plug and check, Even on an SBC...:)

[Ron Earp]

While the marks did move a bit in relation to the crank, the dizzy did not and and ignition timing did not.

The car is well marked where the locked distributor should be on the bracket and it has never moved from that point. We also never adjusted timing over the course of this "issue" so as far as ignition timing goes everything was cool. Yes, there was a slight difference in TDC in reality and what was shown on that damper/crank pulley, about 8-10 degrees, but the crank markings were never used to adjust timing.

Rebello sells an aluminum crank pulley nowadays that is about 1/2 the price of the NLA Euro dampner that I just tried to buy. Anyone used on of these? They don't have an inner and outer piece, so that slippage situation can be eliminated. I also thought to use a stock on and machine the AC pulley off of it.

That is a really nice pan there! Mine doesn't look like that, I think I have the NISMO comp pan if that is the one with kick outs. Still kicking, so I'll use that.

Bore on the used engine is stock!! And the bores look good. Engine had head damage and head is MIA, but the block/bores I can see look okay. I will tear it apart of the next couple of days and have a look.

R

[Joe Harlan]

Ron, I have used the single groove unit before and until the recent rule change on balancers I always just machined the outer groove off the stock unit to match the euro part. I am sure there are better balancers out there but I have not spent the money on them.

[Ron Earp]

Well, things are looking up. 0.040" and even 0.060" (illegal I know), plus 0.020" pistons are in stock and available, $42.04 to $38.07 each, so not bad. All from Riley at Lynchburg Nissan, that guys knows his Z motors well as well as the local builders of Z motors and what they use.

I can get together some good rings sets and of course the Nissan bearings are good pieces and available as well. I just need to get busy and look at what I have and get stuff ordered.

R

[x-ring]

On the Arizona zcar pan, one of the 240 guys here has one on his car, but he hasn't had it long, maybe one or two race weekends. I haven't heard any complaints.

I have a similar pan from MSA that I've been running for at least four or five years. The one from MSA isn't quite as nice, but the difference is in the small details. I think the MSA version costs more, so now that Arizona zcar pan is back there is no reason I know of not to get it. Of the tracks I race on around here, there is one corner, a tight slow (40 mi/hr) right hander, that makes my oil pressure idiot light flicker. I think I have a 20 lb/in2 switch.

Do check the bolts though. I think that maybe the different expansion rates between the aluminum pan and the iron block causes, or allows, the bolts to loosen.

It might pay to check the hole in the sheet metal part the end of the dipstick is supposed to go through. On the MSA one the hole was in the wrong spot and the dipstick wouldn't go all the way in.