Guest Blue02wrx Posted August 10, 2003 Share Posted August 10, 2003 are the valve sizes the same in an n42 head and a p79 head. also how do the valve size compare with the p90 head maybe it will be easier if i say this...i hvae a n42 missing some intake valves and i have some p79 heads and some p90 heads, i need to know where to get some valves. Quote Link to comment Share on other sites More sharing options...
j260z Posted August 10, 2003 Share Posted August 10, 2003 check out this site http://www.geocities.com/row4navy/head2.html from what i can find intake valves are the same from: 70 240z - 75 260z 75 280z - 80 280zx 81 - 83 280zx exhaust valves are the same from: 70 - 73 240z 74 260z - 80 280zx 81 - 83 280zx Quote Link to comment Share on other sites More sharing options...
Guest Blue02wrx Posted August 11, 2003 Share Posted August 11, 2003 so can i use the valves from my p79 head? when you say is has a bigger valve, is it a taller stem or bigger head? Quote Link to comment Share on other sites More sharing options...
Guest Blue02wrx Posted August 11, 2003 Share Posted August 11, 2003 ok, i got all the valves out and the p79 valves and the n42 valves have different stem lengths. i have a whole set of p79 intake and exhaust valves, but only the intake valves of the n42 head...here's my question should i hunt some n42 exhaust valves or use all the p79 valves. i am planning on getting all new springs and retainers and valve seals when i put it together. what would the longer stem l;ength do??? i am using the f54 block with flattop's in it. if i use the longer stems am i going to have some valve - piston clearance issues. anyways, thanks, brian Quote Link to comment Share on other sites More sharing options...
Guest Blue02wrx Posted August 13, 2003 Share Posted August 13, 2003 can anyone help me out??? or at least give me an email of someone to ask. i have the whole set of p79 valves that are ready to go into the head, unless i am going to have clearance issues, then i need to find/buy some n42 valves. i am running flat tops. when i order a cam and springs/retainers will i need a different setup with the p79 valves? Quote Link to comment Share on other sites More sharing options...
Guest DaneL24 Posted August 13, 2003 Share Posted August 13, 2003 Valve seat diameter for both intake and exhaust valves is the same for any head from years '75-'83 (N42, N47, P79, P90). The valve stem width is also the same...so they will physically interchange into the valve guides as well as fit the valve seats. N42 heads have valve stems that are .080" longer than P79/P90 valves...so if you were to use P79/P90 valves in an N42 head you would have to use lashpads that are .080" thicker than stock with P79/P90 valves. You must also realize that by putting P79/P90 valves in an N42 head, the valve springs will be compressed an extra .080", which I think will be beyond their limit. One possibility is to install the springs without lower spring retainer seat to reduce the spring compression...but I would be wary of that as I have never tried it and have never heard of anybody else doing it. Maybe the spring retainer seats could be shaved a little to reduce they're thickness...or aftermarket retainers of a different thickness could be purchased (don't know who would sell them, but its worth a shot.) I have a feeling you'll be interested in this site: http://www.geocities.com/zgarage2001/head.html You don't need to use an N42 head for high compression (although it is the easy bolt on way)...there are other alternatives. Quote Link to comment Share on other sites More sharing options...
Guest Blue02wrx Posted August 13, 2003 Share Posted August 13, 2003 i already have everything to put the head on. i am not using the p79 head. everyone raves about the n42 so i got one, and hardly paid anything for it. i only gave 25 bucks for it. i am going to blast it, and try to get it together with stock stuff. Quote Link to comment Share on other sites More sharing options...
ianz Posted August 13, 2003 Share Posted August 13, 2003 Just go find more valves for the N42 (I think the N47 uses the same valves but do yourself a favor and check out the Geocities site) Even if you have to buy new valves, they are still available and not too terribly expensive..... that is DEFINITELY or best bet!! good luck, Ian Quote Link to comment Share on other sites More sharing options...
Guest Blue02wrx Posted August 13, 2003 Share Posted August 13, 2003 oh i have read that site many times over. it was very helpful. Quote Link to comment Share on other sites More sharing options...
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