L28 block with an E88 head good or bad idea

[legendzcarclub]

my engine blew on me the other day for some strange reason it hapened out of nowhere i was driving it all good in the night till about 3am and i wake up at 6am to go to work and my engine started making a loud noise like if a rod went out .......

so now i am taking my engine out and instaling a L28 with my 2.4 head an E88 but i was told its a bad idea cause of the high compression and then with my cam that i have installed i was told it would be worse my engine wont last over a month

and thats not even the bad part im planing on overhauling my old engine since it is the original matching block to my z ...but....i only have four pistons with the groves for the valves and two flat head pistons

so i need to know if its a good idea and what i would need to do to make this engine combo work

thanks....

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[Arne]

First - in the US there are at least three different versions of the "E88" head, which I have heard referred to as "small chamber" (very late '71 and ''72), "large chamber" ('73 240Z) and 'big valve" ('74 260Z with larger exhaust valves). I don't know which you have, nor do I know whether the L28 you will be using has dished or flat top pistons. If you have dished pistons, you'll be OK with around 8-8.5:1 compression. But with flat top pistons you'll be pushing close to 10.5:1 which is fairly risky on pump gas.

[legendzcarclub]

i have the 73 head.. cause my car was all original when i bought her off the original owner... but you know how young kids want to go fast and look good so i started adding parts to it so its not so original anymore but the engine wasnt swaped out for the fancy turbo set up or a big v8..... i wanted to keep the original engine in there for as long as i could after all we had together !!! but shes an early 73 ......

so what do you suggest run an electric pump and use a block off plate

[Phred]

Legend,

Arne had some good info, but I think compression is the least of your problems. Your pics show some of these potential killers. First, the pistons appear to show some piston to head clearence issues. The shinny areas where no carbon is present, is an indication the piston is slightly hitting the head. Not to mention the different dome styles, two with flat tops, the others with valve reliefs, indicate they came from different sets. That means they will probably have different compression ratio's, as well as possible Valve to piston clearence problems. More than likely the worst issue will be the piston weights will be different, causing a serious internal imbalance at speed. The other indicator is the red anodized valve spring retainers. Not a good idea for a street drivin engine, and questionable on a track only car. Which would make me question the springs and cam. How much lift? How much V/P clearence? How much spring pressure? How much pist./head clr.? And finally, how much compression? If you don't know these things, you have another engine that is blown up. It just hasn't happened yet. Please pick up a copy of Frank Honsowetz' "How to modify your Nissan/Datsun engine". Engine modifications can be frustrating and expensive. Once you become informed, its a lot of fun. Hang in there and do it right.

Phred

[bloxman]

For what its worth this site seems to have a lot of intelligent comments arranged in a sensible format.

Therefore you have likely been there already

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

Bloxman

[76Datsun280z]

It sounds like your engine may have blown the head gasket.

[e_racer1999]

It sounds like your engine may have blown the head gasket.

the pistons look too dirty for that IMHO.

anyway, as far as E88 on L28... that's what i'm doing.

pros of this? square port head & higher compression ratio.

cons? smaller ports = less flow.

what i'm doing is porting out the head and putting 280 valves in it.

of course everything i said here is up to speculation and opinion.

[ktm]

Here is a great engine design utility. Just input the information and you can get an idea of what your static CR will be: http://www.ozdat.com/ozdatonline/enginedesign/

Arne, I do not know where you are getting 10.5:1 CR with an E88 head (260z E88). The link I provided above, assuming flat top L28 pistons, L28 rods, L28 block, L28 cam, 1.25mm gasket and an L28 crank puts the CR at 9.7:1. Hell, even if you put an E31 head on there your CR is only 10.1:1.

[legendzcarclub]

wel i got the engine to run last week it ran good but the mechanic that fixed it didnt know how to adjust the su's but it sounds like it has good power now i just need to find out what happened to my electrical stuff cause nothing wants to work

[e_racer1999]

^i will take this time to plug ztherapy. get the videos!!!

[k5ride]

I know this is an old post but I thought this might be a helpful tool to use for determining which head to use and figuring out your compression.

lengine.zip

[siteunseen]

Is it this one? OZDAT.com Engine Design Utility

I couldn't open your zip without downloading something.