260Z Headgasket, Z Gaskets

[Ron Earp]

As some of you know I lost a dampener off my 260Z motor at VIR and cooked it late last year. The damage to the head was extensive. I had a deep channel cut in the head between cylinders 3-4, pitting, and severe warpage.

My head man was able to salvage the head and press it straight. They had to do a lot of welding to the head and then cutting of the head to make it all correct. The net result is a good head BUT the combustion chambers are tiny, like 35cc tiny. If I bolted the head on the Z with a normal head gasket I'd end up with something like a 12:1 compression.

So, what to do?

Riley at Lynchburg Nissan turned me on to these guys:

http://www.headgasket.com/gaskets.html

Who will make you a head gasket in whatever thickness you need. Did some calculations and found out what was needed to get back down to the legal 9.X:1 ratio and ordered one up.

Just thought I'd put this out there as an FYI. I'd have tossed the head but I'm out of E88 260Z heads. This tired old motor is now going to become my spare motor since Sam Neave is doing me a new 260Z race motor.

[tim240z]

As some of you know I lost a dampener off my 260Z motor at VIR and cooked it late last year. The damage to the head was extensive. I had a deep channel cut in the head between cylinders 3-4, pitting, and severe warpage.

My head man was able to salvage the head and press it straight. They had to do a lot of welding to the head and then cutting of the head to make it all correct. The net result is a good head BUT the combustion chambers are tiny, like 35cc tiny. If I bolted the head on the Z with a normal head gasket I'd end up with something like a 12:1 compression.

So, what to do?

Riley at Lynchburg Nissan turned me on to these guys:

http://www.headgasket.com/gaskets.html

Who will make you a head gasket in whatever thickness you need. Did some calculations and found out what was needed to get back down to the legal 9.X:1 ratio and ordered one up.

Just thought I'd put this out there as an FYI. I'd have tossed the head but I'm out of E88 260Z heads. This tired old motor is now going to become my spare motor since Sam Neave is doing me a new 260Z race motor.

12:1... I dont see a problem with that :D

I would do a search over at hybridz... I know I’ve seen several HG threads regarding this very problem

[kthomas]

Riley should have told you that clarkcopperheadgaskets.com has a custom fit L24 gasket designed by yours truly that he can whip out in just about any thickness.

We had an engine that ran all season with no problems with a solid copper gasket, and another that we just couldn't stop from leaking even with a couple coats of copperkote on each side (newly surfaced head and block, I dunno what was wrong). We used solid copper gaskets because it's the only way I could control repeatability in the compression ratio calculation in Tech. Normal head gaskets are all over the place dimensionally.

That said, if you need a thicker gasket to get legal compressionwise you must be "out of compliance" somewhere else. I tried to get Topeka to approve a thicker gasket to correct comp ratio when the head was shaved too much and they said throw the head away. Oh spare motor? No problem, just don't accidently win the ARRC with it. :)

[JeffYoung]

Yeah, the shop had to cut the head down too much after the damage. We know it is technically illegal using the gasket to get the compression back to where it should be, but in my view that would be a weenie protest if someone did it, and the motor is only going to be in the car for a weekend or two anyway until the "pro" motor goes in.

[spawpoet]

As some of you know I lost a dampener off my 260Z motor at VIR and cooked it late last year. The damage to the head was extensive. I had a deep channel cut in the head between cylinders 3-4, pitting, and severe warpage.

My head man was able to salvage the head and press it straight. They had to do a lot of welding to the head and then cutting of the head to make it all correct. The net result is a good head BUT the combustion chambers are tiny, like 35cc tiny. If I bolted the head on the Z with a normal head gasket I'd end up with something like a 12:1 compression.

So, what to do?

Riley at Lynchburg Nissan turned me on to these guys:

http://www.headgasket.com/gaskets.html

Who will make you a head gasket in whatever thickness you need. Did some calculations and found out what was needed to get back down to the legal 9.X:1 ratio and ordered one up.

Just thought I'd put this out there as an FYI. I'd have tossed the head but I'm out of E88 260Z heads. This tired old motor is now going to become my spare motor since Sam Neave is doing me a new 260Z race motor.


Ron, was the dampener that failed on you the Professional Products dampener you talked about using in 2007 when you built your motor? If so I'm curious to know more about how it failed on you, as we are using the same unit.
Do they not hold up well in racing applications? Also if you need an extra 260 E-88, I think he have one on one of the 260 motors we have. It has an E-88 on it, I'm just not absolutely positive it's the head that originally came with that motor.

chris

[JeffYoung]

Chris, we think those dampers are crap. Ours failed, and we've heard of other failures as well. The rubber delaminates from the metal innards and then you are done.

We are now looking at getting some billet ones made as this cost us two races, and a motor.

[quadzjr]

with all this talk about balancers.. Aren't we required to run the stock damper?

Also, we used custom copper gaskets in our old roundy round motors without failure. I wonder if the copper gaskets would be more likely to fail with dis-simmiliar metals from head to block? Interesting thought..

[JeffYoung]

Nope, pulleys are free except for the cam pulley.

[betamotorsports]

Pulleys are free in IT but I don't think the damper itself is. I seem to recall a successful protest ages ago about a 240Z running a European damper, but I could be mistaken. Do you recall anything Keith?

[quadzjr]

Dampers are not pulleys. I wouldn't think dampers would be open in IT or you would see more people running billet super dampers.

[JeffYoung]

Damper is an integral part of the pulley, at least on my motor (and pretty sure it is on the L24/26 motor too).

On Edit: Note rule. Crankshaft pulleys of any diameter or material may be used. If your damper is integral to the pulley, I think the whole assembly is free. Don't know if I know of any Z cars that run the stock damper at this point.

n. Alternate water pump, alternator, power steering, and crankshaft pulleys of any diameter or material may be used. Type of accessory drive (e.g., V-belt, toothed belt, etc.) shall remain as stock.

[Ron Earp]

Regardless of your feelings on the dampener/pulley rule DO NOT USE THE UNIT shown at the top of this page:

http://www.thezstore.com/page/TZS/CTGY/PEM06

It is shit and I have had two fail. I don't know about the one at the bottom of the page, it is new.

I think Keith used the stock dampener and never had any trouble. Problem with that, for me at least, is I never got a stock dampener with my 260Z. My engine came with a Euro dampener, it failed and I replaced it with one of the Professonal Products units. It also failed with about 45 hours of use.

I'm now having a batch of dampener/pulleys machined out of billet in a 33% underdrive diameter. Should have the first one for test fitting next week.

Best,
Ron

[Ron Earp]

Dammit. Gasket arrived, it looks great. Unfortunately, it is for a L16 motor. Yay. They are happy to fix the problem though and since I don't have the other engine parts no harm done.

R

[kthomas]

I think Keith used the stock dampener and never had any trouble. Problem with that, for me at least, is I never got a stock dampener with my 260Z. My engine came with a Euro dampener, it failed and I replaced it with one of the Professonal Products units. It also failed with about 45 hours of use.

I'm now having a batch of dampener/pulleys machined out of billet in a 33% underdrive diameter. Should have the first one for test fitting next week.

Best,
Ron

We did use stock junk yard harmonic balancers, and in fact I used the factory "with air conditioning" pulley attached most of the time. Don Potter was a big proponent of as much front end mass on the crank as you could get, and from an engineering standpoint any rotational inertia you save on the "dampener" pales in comparison to the difference between the 1970 model 17-18 lb flywheel versus a 21-22 lb 1972 or 73 flywheel (poor Ron, has to use that big ole honkin 22-23 lb L26 flywheel. I feel for ya buddy).

Now some of the motors coming out of Sunbelt back then had Euro dampeners on them but not ours. I have to recuse myself from a rules discussion because frankly I've forgotten, but I'm pretty sure I thought the Euro dampener was not legal. We never had anything close to a failure in 10+ seasons of racing, with any of the 12+ street Z's and ZX's I've owned, or any of the many dual purpose cars I've built and tracked or autocrossed with friends. I've often wondered if harmonic balancer failures in ITS weren't a result of lightened cranks or improper heavy metal balancing. On street cars I think that just must be bad car kharma.

We turned 7400 rpm when needed, and 7100 regularly, so the stock part longevity wasn't because we didn't twist them. And since we were stock crank pulley diameter, I machined my own water pump and alternator underdrive pulleys out of 7075-T6. Man they were some sweet, lightweight parts. I miss 'em.....

[Parrish57]

The only damper failure I've had was a stock unit. I've run the euro damper for most of a decade without incident. But going with a billet piece can only eliminate the weak spot.

[Ron Earp]

The only damper failure I've had was a stock unit. I've run the euro damper for most of a decade without incident. But going with a billet piece can only eliminate the weak spot.

I've seen four dampener failures in Zs, two of my own, since I've been racing. The other ones that failed were stock pieces so I don't know what is the norm for the stockers. Anyhow, I've suffered enough from dampeners and will fix that issue. While there isn't any real weight advantage to running a billet unit one thing is for sure there won't be anything to it for a failure mode. Hunk of metal with a pulley machined into it, pretty simple. An underdrive crank pulley ratio means no fancy making of pulleys for the water pump and alternator.

BTW, a Chevy 350 aluminum water pump pulley bolts up great to the Datsun waterpump. I got one off Ebay and it works great.

As far as L26 flywheel weight, heck, I think it is more than 22-23 lbs. Seems I remember weighing it and it was around 25 lbs or so, but of course that is with a bathroom scale which won't be that accurate. I've resurfaced it a few times but unfortunately that just doesn't really get much weight off! :)