83zed owner Posted August 12, 2009 Share Posted August 12, 2009 so pulled the head out of my 83 and called a shop to see if they had a p79 but they only have a n47 can i use the n47 head without any problems? my block is the original f54, motor is bone stock so is the car. Reason why i pulled the head is because i wanted to get all new seals and resurface the bottom. thanks for your help. Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted August 12, 2009 Share Posted August 12, 2009 A N/A F54 is a flat top and your compression ratio will be really high for the stock EFI and cam. Is there any thing wrong with your P79 or did you just want to drive the car while the work is being done? Quote Link to comment Share on other sites More sharing options...
83zed owner Posted August 12, 2009 Author Share Posted August 12, 2009 no i am rebuilding my motor and wanted to change the seals and resurface the bottom of the head.he said he has the n47 to exchange for my p79 Quote Link to comment Share on other sites More sharing options...
woldson Posted August 12, 2009 Share Posted August 12, 2009 I'm thinking you might want to stay away from "that guy". Quote Link to comment Share on other sites More sharing options...
blue72 Posted August 12, 2009 Share Posted August 12, 2009 Yeah, flat tops + N47 = 10.0:1 - 10.5:1 compression ratio. For comparison, stock is 8.8:1 Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted August 12, 2009 Share Posted August 12, 2009 For clarification, stock meaning late L28E F54/P79 with stock head gasket. There are different sources, these numbers are from L Engine: 8.52:1 for the N/A F54/P79 and 9.82:1 for the N/A F54 and N47 Quote Link to comment Share on other sites More sharing options...
Guest Rolling Parts Posted August 12, 2009 Share Posted August 12, 2009 People swap heads all the time (this is a hybrid site after all) so it's not unusual around here. If you're otherwise staying stock, just have your original head reworked since the reason you're doing it is just to "refresh" what you have. Quote Link to comment Share on other sites More sharing options...
83zed owner Posted August 12, 2009 Author Share Posted August 12, 2009 correct that's what am doing refreshing what i have but ,i also want more kick, now am not trying to bring the famous "HOW TO GET MORE HP ON MY N/A" questions lol but what you guys are telling me is that it will raise compression,now the question is will i be needing to upgrade injectors and blah blah blah etc.now if that is the case then i will just stay p79. sorry for just saying stock .now the car is an 83 zx with f54 block, and p79 head ,and flat top pistons . now lets say i go n47 would i i need a thicker head gasket to lower compression? thanks all for the questions and the advice. Marco P. Quote Link to comment Share on other sites More sharing options...
Lazeum Posted August 12, 2009 Share Posted August 12, 2009 I do currently have F54, Flat top and N42 (same as N47 regarding Compression chamber), with stock cams and stock ignition settings you will detonate. the way to avoid that is to lower timing (with MSA stage II, I've got total timing setup at 28-29°). Doable for a short period of time under certain circumstances (can the stock distributor handle decent timing at idle and total timing at the same time...?) Obviously premium gas would also be mandatory. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted August 12, 2009 Share Posted August 12, 2009 more camshaft,premium pump gas,being able to have the vacuem advance retard timing,run a 160 thermostat.alot of modern cars are running 10/1 compression.a good high compression engine has better throttle response.back when my car had the old l28 original engine i put in new injectors,new injector connectors,and built a custom distributor from 2 dizzys.the plug on the vacuem can has an adjustment under it.the is a plastic piece under the base plate that is usually broken the the centrifical advance is usually inop.any way after some fine tuning the old l28 was a very surprising engine.if i didnt have all the turbo stuff around i wouldnt mind having a nicely built n/a motor with aftermarkit efi. Quote Link to comment Share on other sites More sharing options...
bmarchuk Posted August 13, 2009 Share Posted August 13, 2009 ive also been thinking of doing this swap, i have a n47 just sitting in my parts car ive been thinking of swapping... so to answer some more specific questions for the poster and myself.. With the msa stage 2 or 3 cam in mind, can the car run on stock efi, and be "fine" if yes or no, what are the drawbacks? basically i wanna know if im going to ruin something by not getting megasquirt or something right away.. and will the gains still be greater than the losses? Timing can probably be taken care of in some way with the stock distributor as the last user posted, correct? Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted August 13, 2009 Administrators Share Posted August 13, 2009 Those of you with broken keyboards may want to read this... http://forums.hybridz.org/showthread.php?t=139500 Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted August 13, 2009 Administrators Share Posted August 13, 2009 You veteran members should know better! Shame on you! SHIFT Nazi, hath sprecken! Quote Link to comment Share on other sites More sharing options...
Scott_M67 Posted August 13, 2009 Share Posted August 13, 2009 With the stock ECU and EFI you will be hard pressed to run a stage 2 or 3 cam. The stock system doesn't like much more than 260 advertised duration. Now Megasquirt is a different animal, you can use whatever cam you would like. Quote Link to comment Share on other sites More sharing options...
83zed owner Posted August 13, 2009 Author Share Posted August 13, 2009 thanks for all of you that helped. Quote Link to comment Share on other sites More sharing options...
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