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L series Buildup


Mr.INSANE

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Alright so im planning on building a monster N/A l Series, After doing substantial reading ive came to the conclusion that with an E31 head my compression will be very high. But if i ever detonate the rings or head gasket will blow instantly. So i plan on having an HKS 2mm headgasket and some other stuff to lower the C/R slightly

 

This is going to be a race motor and i want to run Triple Mikuni's, Solex's etc whatever i find first. Im on a budget and so far it looks like 1k is a really low price for these with manifold carbs etc,

 

Now i was thinking i just might be able to get them from a Junkyard (i will rebuild them ofcourse) Ive heard they come on Toyota's what else do they come on? would it be better to just spend like 1k on them?

 

The motor will be a 3.1 or 3.0 l stroker as well. So i plan on having everything balanced.

 

What do you guys thing of a setup like this? How well would this perform without porting and with porting? Just give me your thoughts :P

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Just keep looking... you can occasionally find a rebuildable set of triples for $500.

Use the E31 head...just get custom pistons with a dish to match the combustion chamber shape.

Don't use the 2mm HG... that is the cheap-scape way out of CR. On the contrary use a 1mm metal or 1.2mm felpro and dish the pistons more.

 

Unfortunately you can only get the junky Cali. gas and you probably don't want to buy high octane (race) gas all the time. That means you need to keep the CR at or below 10.5:1. Around here a couple Z guys run 11.2:1 with our 93 octane gas and they run fine.

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Just keep looking... you can occasionally find a rebuildable set of triples for $500.

Use the E31 head...just get custom pistons with a dish to match the combustion chamber shape.

Don't use the 2mm HG... that is the cheap-scape way out of CR. On the contrary use a 1mm metal or 1.2mm felpro and dish the pistons more.

 

Unfortunately you can only get the junky Cali. gas and you probably don't want to buy high octane (race) gas all the time. That means you need to keep the CR at or below 10.5:1. Around here a couple Z guys run 11.2:1 with our 93 octane gas and they run fine.

 

Thanks, Ill keep looking.

 

Octane is not a problem 100 Octane race gas down the street from my house. Im just worried that ill blow my motor really early which i dont want.

 

I want a high C/R though for power

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If a budget 3.0 motor is in your sights I would use a shaved P90 head. With a quality cam. 3.0 street car should be just fine with a set of 44 or 45 carbs. Standard 1.2 metal headgasket and a quality balancing job. I have a friend if Florida with a H/C L30 and nitros. Has to use only race gas and while his engine is cool I would hate to keep worrying where I could drive my car and if there is gas there. Just a thought.

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If a budget 3.0 motor is in your sights I would use a shaved P90 head. With a quality cam. 3.0 street car should be just fine with a set of 44 or 45 carbs. Standard 1.2 metal headgasket and a quality balancing job. I have a friend if Florida with a H/C L30 and nitros. Has to use only race gas and while his engine is cool I would hate to keep worrying where I could drive my car and if there is gas there. Just a thought.

 

Any Hp numbers? i want to make atleast 200hp but it seems that its not possible without porting

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I think you can make 200 whp without porting. Cam selection has at least as much to do with it as the porting does in my opinion and most people go way too conservative with the cam selection. If you're not using the stock FI, you can get away with a pretty big cam. I'd suggest something in the .500/300 range and that should flow enough to get your 200 whp. BRAAP's favorite .520 lift cam would be a good one too. If you're not doing any porting, I'd also start with a L28 head because it will have the larger intake valve (and marginally larger exhaust) than your E31, and it seems to me that the P heads just look to be cast better. I agree with greenmonster80, a shaved P90 or P79 would be my first choice. And if you're going to do triples, get 44's or 45's and don't waste your time with 40's.

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Ditto on Jon's comments, 200WHP is achievable without head work.

 

I recently built a 0.020" over L28 that makes almost 190WHP. 10:1CR, untouched N47 head, and 460 lift cam. I'm running a conservative timing of 25deg, and power doesn't start dropping off until 6500RPM or so. Running a 6:1 header, ZX intake, 60mm TB and Megasquirt.

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no diff. P90 will be (arguably) best for the quench. but the N42 is a great all around head. highest compression in heads that have large valves. that means less work, no milling to bring the compression up, and still a decent quench area. my favorite NA head (if you don't want to do more work)

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If you've got them both then you have the valves you need from the N head to go into the P head when you shave it, if you want to go that way. There was a website by a guy named Bryan Little that had the whole procedure and it is apparently now gone, but basically you shave .080 off the head, shim the cam towers up .080 and use the N42 or N47 valves. That restores the valvetrain geometry and keeps the timing chain tight. If you're going with a new cam (and you should with your goals) you'll still need to mess with lash pads and all that crap.

 

If you're going to try and push the hp limits on pump gas, the P head is in my opinion superior due to it's better combustion chamber design and will allow you to run more compression and timing without pinging. This is an argument that has been gone over many times, so if you want to get the other side of the story, just search quench. The subject was positively BEATEN TO DEATH a few years ago so we really probably don't need to do it all over again.

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....... This is an argument that has been gone over many times, so if you want to get the other side of the story, just search quench. The subject was positively BEATEN TO DEATH a few years ago so we really probably don't need to do it all over again.

 

 

And the lords good people said..

 

AMEN!!!

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If you've got them both then you have the valves you need from the N head to go into the P head when you shave it, if you want to go that way. There was a website by a guy named Bryan Little that had the whole procedure and it is apparently now gone, ...

 

I was just reading through Bryan's site last night: http://www.datsunzgarage.com/p79/

 

This is an argument that has been gone over many times, so if you want to get the other side of the story, just search quench. The subject was positively BEATEN TO DEATH a few years ago so we really probably don't need to do it all over again.

 

Classic HybridZ stuff there. Informative and entertaining!

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If you are online right now there are some 44mm mikuni tripples for dirt cheap on ebay...

HERE

1 hour left and at $507

Those have the nice rubber insulators and the Nissan Comp (good) manifold. Haven't seen that air cleaner before. I wonder if it's impossible to get filters... Nice setup overall. Killer price (with 45 minutes to go).

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