240Z setup

I am building a 240Z for a possible combination of running in IT, and in Vintage. (I may end up going with Vintage only, because I know the vintage rules are much more liberal), but to start, I need some basic information.

My biggest looming question at the moment is in regards to a Cam.

Some basic background info:

I am running the stock L24, but plan on updating with new performance pistons, and bumping compression a half a point to 10:1, I already have the header and exhaust laid out. I would keep the stock Hitachi SU carbs and intake. I am running a mallory distibutor, with MSD ignition, and for fuel, I have the cell, twin pumps etc. (What fuel pressure should I set, I could find no spec on what the carbs can handle?)

So back to my main question regarding the top end, and head setup. What cam specs should I run (lift/duration)??? What about valves? I also see things like different lash caps, etc. What exactly should I get to set up?

I have tried Nissan Motorsports, and some of the big cam manufacturers, and no one can give me any kind of difinitive answer, so I figured I would come to the source. Any thoughts would be appreciated.

In addition, originally when I made the purchase, I bought a 72' 240, a 73' 240, and a 74' 260. I have the entire drivelines from all 3. What combination of engine, transmission, and rear end, do you recommend, I know the gearing is a bit different in each. I will be running Florida tracks only (sebring, Daytona, Moroso).

Lastly, some additional research pointed me to using an L28 head because of valve size etc. I dont have one, but do have the L26 head from the 260Z, do you recommend using that one on the L24 bottom end, instead of the entire L24 setup?

I know these are a lot of questions, but I need to start somewhere hehe!

Some additional overall info, I have Eibach stage 3 springs, Tokiko 5 way struts, Hawk brake pads on the stock brakes (all new parts though, rotors, calipers, hoses etc. on the front, new drums, wheel cylinders, hardware, hoses etc. on the rear).

Strut tower stabilizer on the front between the towers, all new urethane suspension bushings everywhere, Centerforce clutch assembly, and front lower air dam to run to front brakes.

Any other additional parts suggesions, tips or tricks would be greatly appreciated.

[This message has been edited by mechboy (edited January 07, 2004).]

mechboy,

I have limited experience with the Datsun Z cars. However, you need to be sure to purchase and read the GCR. Much of what you ask or propose would be excellent performance enhancments but would not be IT legal. As an example, IT rules require the use of stock cams (Stock for the head being used). Also the mixing of engine or other components from the 240, 260, and 280 models would not be allowed under the update/backdate rules as those vehicles are on separate lines on the spec list. You will need to use the L24 head on the 240Z, although I do know that there were two variations on the head for MY's 70-73 and one is prefered over the other.



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I see,

It had been quite a few years since I had read the GCR for IT cars, and didnt recall anything specific about cams, etc. but I pulled my copy (I know its kind of old 1996), but you are correct, bascially most engine components are to be stock specs. (Cant even use the 300.00 Mallory distributor i got pffft, guess i can send it back)

I guess that means I either go Vintage, or I figure out how all you Datsun IT guys make go fast, while staying "stock".

I think as far as the tranny, and rear ends are concerned, it seems a bit gray. Mainly because the only real way to tell a 260 rear end from a 240 rear end, is in the slight difference in the final gear ratio.

Thanks for the info, I look forward though to any tips or tricks to make the car go fast, also is there a Vintage board like this one somewhere?

Thanks!

I'm going off the top of my head here, but to answer your question about tranny's, I think that all Z 4 speed boxes were the same from '70 to '78, the last year they were available.

As for rear ends, gear ratios are free, as long as you keep an R180 housing you're within the rules. Solid diff mounts are not legal, but there are a lot of them out there.

I too drive vintage as well as SCCA, mainly because my home track hosts one SCCA race per year and six vintage races. I'd race more often with the SCCA, but the other tracks in my area are a seven to ten hour tow from my house. I still make a few, but I'm not up for it twice a month. I'm not aware of a board like this specifically for vintage, probably the closest thing is the RMVR board. I don't recall their URL right now, but if you Google 'RMVR race' I'm sure it will turn up.

Ty

Thanks X

I think I am actually going to do a nice stock rebuild on one of the L24's and do the other L24 as the vintage motor, that I can freely beef up.

Thankfully, I have 24 hour access to a lift and nice electric hoist set up, so swapping engines is easy. Just have to plan out my year and see!

Soooo, what cam do I run? hehe

For a 240z, use the E31 head. There are several different heads, the E31 will probably be the easiest to find and one of the best. The 4-speeds are similar throughout the years, early models having a funky shifter setup. Get a set of real SU's from z-therapy. The cam has to be stock, there are variations and there is no definitive answer unless you pay for the dyno time. Go with Sunbelt Performance Engine's cylinder head setup, E31 or E88 with port matched intake. I use a R180 with nismo lsd 3:90 ratio at Road Atlanta. Some have used a 4:11 but you'll probably be replacing valve springs. The 3:73 has been tried and found wanting at some places.
Go to zhome.com and read up on katman's dyno research for a 240z. And try to get some answers out of him before he gets too deep into germany or mazda-land. Get some info out of David Spillman too.
Tom

[This message has been edited by Tom Donnelly (edited January 08, 2004).]

Quote:

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Originally posted by mechboy:
I would keep the stock Hitachi SU carbs and intake. (What fuel pressure should I set, I could find no spec on what the carbs can handle?)

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No more than 4.75 psi.

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katman

Quote:

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Originally posted by mechboy:
Thanks X

I think I am actually going to do a nice stock rebuild on one of the L24's and do the other L24 as the vintage motor, that I can freely beef up.

Thankfully, I have 24 hour access to a lift and nice electric hoist set up, so swapping engines is easy. Just have to plan out my year and see!

Soooo, what cam do I run? hehe

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For IT you run the stock cam. To compete in vintage you need about 100 more horsepower than you get out of an IT motor (remember you're probably classed with old American cars with V8's), and what cam you use depends on about 50 other things (including compression ratio, piston dome shape, induction system, exhaust system, combustion chamber mods, valve sizes, blah blah). Collect about $16,000 and send it to Sunbelt. A vintage Prod motor needs to be done as a system. In other words, we can't answer that question without the entire engine build plans.

Or, for vintage on a lot less money, you cheat by starting with an L28 block that you grind the serial number off of and engrave "L24" on, and send $5000 to Sunbelt for an E88 head prepped with their latest cam.

Better start by getting current rule books for both vintage and IT, derive a budget, and then get back to us. Be glad to help, but right now the answers are way too involved without a refinement to the questions.

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katman

Ok,

I just took inventory of my engines and what not, and the end result is, I have two E88 heads, and one N47 Head.

Of those two models, I take it, the E88 is the recommendation?

Thanks

Mechboy,
N47 not for 240...it would be great...well,no not great,try to swap it for something of value "it has a really big chamber" with the larger valves,unless from a maxima.....but not allowed. Your E88 could be a small chambered unit if from 71/early 72? Larger chambered E88 head is not desirable,but will work,but lower compression
Later E88s from late 72 to 73 cars,then another E88 for the 260 with larger exhaust valves another "No-No".
Find a decent E31,or the much rarer small chambered E88.....if you gotta have the max right out of the gate.
What you have will work "E88" just fine to get on the track. Enjoy the ride
ZHOME.com used to have a some pictures of the different head chamber shapes...
David Spilman

Quote:

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Originally posted by mechboy:
Ok,

I just took inventory of my engines and what not, and the end result is, I have two E88 heads, and one N47 Head.

Of those two models, I take it, the E88 is the recommendation?

Thanks

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Instead of running IT, you may want to consider running E-production. E-prod is a little more open with their rules, off the top of my head, I believe you can run a custom cam up to 0.5" lift and compression ratio up to 12 by milling the head. Also you can convert the rear brakes to 280zx discs. This may be more in line with the vintage rules. Also, 240's took 2nd and 3rd at the 2003 runoffs after many lead changes, so that shows they are still very competitive in that class. Get a new GCR and compare rules before you spend lots of $$ and can't legally race in any competitive class.

You would be well served to contact Joe Harlan at [email protected] if you are on the West Coast...

He builds the motors for the fastest ITS 240Zs in this part of the country, right up there with Rebello. He has an extensive knowledge base and experience with these cars.

The 240Z is an excellent EP car as well. In my opinion, one of the few cars that has a shot at actually beating the Miatas at the Runoffs one of these years...

ITS or EP... either way, it's tough to lose with this car...

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Darin E. Jordan
SCCA #273080, OR/NW Regions
Auburn, WA
ITS '97 240SX
http://home.comcast.net/~djjordan/Web/DJ_AV1.jpg