Guest Ryan A Posted December 5, 2004 Share Posted December 5, 2004 hey guys, im in the midle of restoring my 74 260z and now that winter is coming its time to work on the engine. I've been trying to figure a good set up and I could use some feed back! so far .... L26 block and crank, with a L24 con rod and L26 piston, and for a head the early e31 with larger valves, now this IF it works... its puting compression to around 11.3:1, so i'll be doin some work to the head and hopfully bring it to 10.5~10 to 1. anyways let me know what you guys think, Thanks Ryan Quote Link to comment Share on other sites More sharing options...
johnc Posted December 5, 2004 Share Posted December 5, 2004 http://hybridz.org/phpbb2/search.php FYI... 10 or 11 to 1 is not normally considered high compression. Quote Link to comment Share on other sites More sharing options...
technicalninja Posted December 6, 2004 Share Posted December 6, 2004 Will increase piston deck height 2.65mm (.100in). With out mods pistons will hit head. Start with a 280Z/ZX (75-81 dished pistons) and the E31 will produce 9 to 9.5 depending on surfacing head. This will be easy to work with for a street car. A flat top 280ZX block might also be used but it would take some chamber work to reduce comp. Quote Link to comment Share on other sites More sharing options...
Guest blusty Posted December 7, 2004 Share Posted December 7, 2004 A flat top 280ZX block might also be used but it would take some chamber work to reduce comp. you mean with the P79 head? seems like he could use the E31 on the flat top piston/280zx block. If he did that he could use a 1mm head gasket and get 10.5:1 ratio right? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 7, 2004 Share Posted December 7, 2004 Flat top and P79 gets you 8.5:1 IIRC. Use a 1mm headgasket and you will bump that up to 8.7. 1mm = .040, and stock headgasket thickness is .050 or somewhere right around there IIRC, so it doesn't have a big effect on compression. The 8.5 and 8.7 come from the Lengine program, so that's not relying on my faulty memory. After running flat tops and an E31 I can say that you have to do A LOT of work to the E31 to make it worthwhile (installing bigger valves, unshrouding them, etc). Much better idea is to get the P79 or P90 and shave the head .080 then shim the cam towers up equally. That gets you a better chamber shape than the E31, with the big valves and all that good stuff, and you don't need to do as much work. Search for P79 or P90 if you're interested in that setup, I personally think its a better idea than the E31. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 7, 2004 Share Posted December 7, 2004 Moderator Pre-emptive Strike: The great N42/P90 debate will not be allowed in this thread. Quote Link to comment Share on other sites More sharing options...
GabeRoc Posted December 7, 2004 Share Posted December 7, 2004 Moderator Pre-emptive Strike: The great N42/P90 debate will not be allowed in this thread. *sets down popcorn* awww, c'mon. the fireworks were just about to start Quote Link to comment Share on other sites More sharing options...
Drax240z Posted December 7, 2004 Share Posted December 7, 2004 Moderator Pre-emptive Strike: The great N42/P90 debate will not be allowed in this thread. Argh, you beat me to it! Quote Link to comment Share on other sites More sharing options...
Clifton Posted December 10, 2004 Share Posted December 10, 2004 You are obviously looking for a little more power than stock. Why not start with an L28 block? Quote Link to comment Share on other sites More sharing options...
Guest iskone Posted December 14, 2004 Share Posted December 14, 2004 I don't know if it helps but here is my setup. L28 1mm(.040) overbore 240Z rods E88 w/ oversized valves 11.5 to 1 forged pistons I can run 92 and it seems fine, right now my timing is off so I've got octane boost in just incase. Can't tell about the gasket though. Isk Quote Link to comment Share on other sites More sharing options...
v8wannabe2 Posted December 21, 2004 Share Posted December 21, 2004 In the technical section there is a Z engine calculator program. It may help sort this out for you. http://www.zcarclub.com.au/ Quote Link to comment Share on other sites More sharing options...
Mack Posted December 22, 2004 Share Posted December 22, 2004 I remember this one time I took a maxima N47 (40cc combustion chambers) head and put it on my L28 flat top block..... it was pretty sweet. actually, it is pretty sweet. it runs great and I can even run 89 octane on it if need be. this is a daily driver. I deliver pizzas with it. I had the valves slightly unshrouded and installed larger 280ZX N47 intake valves. I am using a fel-pro gasket that is supposed to have a compressed height of .8mm, so that helps attain proper quench, this is the only reason I can come up with as to why it survives day to day on somewhere around 11:1 compression and 15 degrees initial advance, all stock electronics. If you go this route, dont be dumb like me, I screwed up and used the maxima valve springs, they are much weaker and I get REALLY bad float at 5500RPM. Mack Quote Link to comment Share on other sites More sharing options...
z-ya Posted December 23, 2004 Share Posted December 23, 2004 I was waiting to see the word "quench", but I'm glad to see that it didn't appear ! 8^) Quote Link to comment Share on other sites More sharing options...
Mack Posted December 24, 2004 Share Posted December 24, 2004 I am using a fel-pro gasket that is supposed to have a compressed height of .8mm' date=' so that helps attain proper [b']quench[/b], this is the only reason I can come up with as to why it survives day to day on somewhere around 11:1 compression and 15 degrees initial advance, all stock electronics. Mack HA ha! ya missed that one, you must be getting old! Quote Link to comment Share on other sites More sharing options...
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