240Z_Master Posted July 30, 2003 Share Posted July 30, 2003 I have been puzzling myself over this topic for quite sometime. If anyone can tell me the advantages of each and what not that would help. L24 Motor E31 Head... (Stock 240Z) with Mikuni Intake Manifold and Triple Solex DCOE 40mm Carbs... or a N47 Head and F54 Block with the fuel injection? Quote Link to comment Share on other sites More sharing options...
johnc Posted July 30, 2003 Share Posted July 30, 2003 Use the search function. This topic has been covered a few times. Quote Link to comment Share on other sites More sharing options...
DAW Posted July 31, 2003 Share Posted July 31, 2003 Why not go with the F54/N42 combo AND the triple sidedrafts? I've got this set-up on an autocross Z and it works well...very quick throttle response (nice feature for autocrossing). DAW Quote Link to comment Share on other sites More sharing options...
240Z_Master Posted July 31, 2003 Author Share Posted July 31, 2003 Good idea, that's probably what i'll be doing. The Intake manifolds are the same I take it? Quote Link to comment Share on other sites More sharing options...
Guest NorCalZ Posted August 4, 2003 Share Posted August 4, 2003 from what I understand from 70 to 83 the intakes are the same but after i think 78 or something the exhausts ports changed to round. They were square before or something like that. but I think intake never changed. Quote Link to comment Share on other sites More sharing options...
240Z_Master Posted August 4, 2003 Author Share Posted August 4, 2003 Can I match a F54 Block to an E31 Head on this? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 4, 2003 Share Posted August 4, 2003 That's what I have in my car Watch the compression if you're not serious about running race gas. Unless you have owned that E31 since it was new you're probably not sure if the head has been milled. Mine was a virgin, but I ended up milling just enough to make it flat, like .004 or so, and I seem to be able to get by on 96 octane or so. I figured the octane out by cutting 112 octane leaded with 92 until it started to ping, then bumping it up a little from there for a little safety margin, ended up at 96. Also your E31 has smaller intake valves, so you would probably want to have the seats changed to fit the bigger 280 valves. If you run dished pistons compression is way too low, like low 8's. My machinist also told me not to run a 2mm head gasket, because in order for quench area to work the head and the piston need to be within .060 or so. I also polished the combustion chambers A LOT! There were lots of sharp spots in there, those are going to increase the tendency to ping, so you may want to do the same before you slap the head on the block. With polishing and unshrouding the valves I added about 4cc to 6cc to the chamber volume, made them all even within .5cc and improved the flow. The N42 would be a lot easier, just slap it on, and it would run on 87 octane. I love my motor, but I miss driving my Z. It really only comes out on special occassions or to go to the races. Used to be my daily driver. Jon Mortensen moderators - is it bad form to give this info after you've told the guy to search??? Quote Link to comment Share on other sites More sharing options...
240Z_Master Posted August 4, 2003 Author Share Posted August 4, 2003 Just a reply, it's freakin' insane to do a search with so many pages of forums to go through. Sometimes I search before and never come up with aynthing. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted August 4, 2003 Share Posted August 4, 2003 There was a recent thread on E31 heads, like in the last couple of weeks. The E31 use to be the hi-po head, but apparantly it has smaller valves and/or a more restricted intake to match the smaller L24 bore. According to some the (I believe) E88 head is now the head of choice. BTW, I wish people wouldn't get so uptight about telling people to do a search. It is not like anyone's income is dependent upon answering every post. If you don't feel like answering a repeat question, then hit your back button and go on. Besides, the search engine took a definite turn for the worse with the software switch. Quote Link to comment Share on other sites More sharing options...
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