Which head is best..

[skyline_stu]

This head is off a L20ET (2l, 6cyl turbo efi) motor. Runs 7.8:1 comp. can make 350RWHP, but the stock rods are prone to snapping. Don't worry about the numbers, they were an experiment.

[Nigel1943]

Hi,

sorry i still dont get it. too deep for me. the way i see it is we cut the head on the mating surface with the block, so to me the only thing affected is the thickness of the head. we did not touch the block nor the piston travel, nor the cam rotation (it still rotates at 360 degrees at the cam tunnel, so basically nothing was altered but the bowl on the head. sorry i am no mechanic i am just talking logically.

thanks,

hf

The only reason I can see for using cam tower shims on a skimmed head is so that you can realign the standard crank and cam sprockets utilising the factory holes in the sprocket. Skimming will only minimally affect the tension in the chain tensioner. Cam tower shims will alter the camshaft geometry ie, the angle of the rockers. The proper answer is to time the cam accurately using a multi-hole sprocket.

[blue_leaf]

So what do people think of the E30 head?

I also read somewhere that since it has smaller chambers it will give me a higher compression, is it true?

[jjones-lg]

Better look at the ports if you're not planning on making chips. Compression isn't everything. It's gotta breath man.

[MAX]

Hey Guys,

Very intesesting discussions on the various head and block combinations. However, it is a bit confusing with all the variations...

Can someone come up with a chart that shows the different head and block combinations as the came OEM....And include the year, engine type (L24, 26) etc, which models they came on, and what were some of the characteristics of each, like valve size and etc......

I know that is a lot to ask for but that would be a huge help in understanding all this...

Thanks

MAX

[jurven240z]

Try the link below.

http://www.geocities.com/zgarage2001/z.html

[MAX]

Jurven240Z,

Thanks for the link. That is a great explanation of the various head and block combinations.

Very helpful....

[MAX]

I replaced the E88 head on my 73 L24 engine with the E31 head. The engine guy replaced the valves with the larger ones from the L28 engine. Well, this caused another problem which I didn't find out about until it was too late.

After running the engine for a while I noticed this loud clicking noise coming from the upper part of the engine. Upon tearing down the engine I found that the larger valves (both intake and exhaust) were contacting the insides of the cylinder walls. Later on I found out that the cylinder walls should have had some relief cut into them at the top to accommodate the bigger valves.....I subesquently was told that the L26 and L28 blocks aleady had such relief already cut into the top of the cylinders..

I was just wondering if anyone else has experienced this problem and can verify if the L26 and L28 blocks do indeed have some relief at the top of the cylinders for the bigger valves.

Thanks

[Zedrally]

Hi MAX,

Yes, the block is notched, I'm surprised your engine guy wasn'rt aware of this.

Maybe, it's time to find someone who knows the "L" series....

MOM

[silvey19k]

hmm i then have to ask about the n47 seems like there are no numbers or anything on this one.

[Jeff G 78]

The N47 is fine. It was thought that the liners restricted flow, but that has been debunked for the most part.

[d240zx2]

Six years?