mainboyd Posted June 10, 2014 Share Posted June 10, 2014 Hello everyone, So I was given a free P90A head that only had the hydraulic lifters, valves, and valve springs. Nothing else is on the head. My goal is to try to save this head and use it on my F54 block as a turbo engine. I dont want to spend much money on it so ill be looking around in the junk yard for anything that I can find and of cores work. A couple weeks ago I found a 280zx in the junk yard but i forgot if it was a N42 or N47 head in it. Ill take a look at it tomorrow to know for sure. So now for the build. After doing some research (correct me if im wrong) I found out that all solid lifers are the same on the L28 heads but the P90A head that has the hydraulic ones. So I will be swapping out the hydraulic lifters with solid ones and I know its not a direct swap into the P90A and will be needing an adapter to fit the solid lifters in replacement of the hydraulic. Next would be the cam and cam towers. What are the possible cam and cam towers that i can use to put in the turbo P90A head? I read that the N47 cam could work on the P90/P90A head... is this true? I also read that some camshafts have internal and external oiling and that the P90 and P90A have the internal oiling. Is there any other cams that have the internal oiling that I can use? Next would be the rocker arms. If I find a cam in good condition then would it be safe to take the rocker arms too? Am I missing anything else? Any help would greatly be appreciated. Thanks Quote Link to comment Share on other sites More sharing options...
Leon Posted June 10, 2014 Share Posted June 10, 2014 Pull the rockers and lash pads along with the cam, and keep each pad and rocker with its mating lobe. Quote Link to comment Share on other sites More sharing options...
mainboyd Posted June 10, 2014 Author Share Posted June 10, 2014 Leon, Ill make sure of that. Thanks. I also forgot to mention that the head did not come with the sprocket. Are all sprockets the same on L28 motors? Quote Link to comment Share on other sites More sharing options...
Leon Posted June 10, 2014 Share Posted June 10, 2014 Essentially. I'd just buy a new timing kit, should only run you $100 or so. Quote Link to comment Share on other sites More sharing options...
mainboyd Posted June 21, 2014 Author Share Posted June 21, 2014 So I found a 280zx that has a P79 head with an F54 block. I took the solid lifters, pad, and rocker arms. However im am still in need of a cam. The cam that is in the P79 head is stamped with a k. I cant find any positive answer to where its from or the specs on it. Some say its a maxima cam. If so can this be used on a P90 head? Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 21, 2014 Share Posted June 21, 2014 A lot of the P79/F54 ZX engines have the K cam. It seems to have been neglected when someone put the specs. out on the internet (specs. which may or may not be totally correct anyway). It's the standard NA cam for the ZX engines. The specs. in the FSM are probably as close to right as you'll get. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 22, 2014 Share Posted June 22, 2014 Should have pulled the P79 head and run it...same in all respects to the P90 save the liners in the exhaust Quote Link to comment Share on other sites More sharing options...
mainboyd Posted June 22, 2014 Author Share Posted June 22, 2014 The liners in the exhaust and its exhaust port are round for the P79. I thought that the square exhaust ports flowed better then the round... Would it be ok to basically put all the P79 internal parts, besides the valves, and put it in the P90a head? So it would be a P79 internals in a P90a head. Can this work? Tony, if your saying that the P79 head is the same in all respects to the P90 but the exhaust ports then this P90a/P79 head should work right? Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 22, 2014 Share Posted June 22, 2014 (edited) Nope, no meaningful performance nor flow differences. The P79 takes the turbo exhaust manifold just fine. You're making a lot of work nd introducing variables in assembly for nothing with all the parts swapping, IMO. Edited June 22, 2014 by Tony D Quote Link to comment Share on other sites More sharing options...
mainboyd Posted June 22, 2014 Author Share Posted June 22, 2014 If thats true then why do people choose the P90 over the P79? Also, why would nissan create two different types of head for the L28? Why didnt nissan then just use the same head on both the turbo and non turbo and have the only difference be that one had dish pistons for the turbo and the other flat? I mean they take the same F54 block... Quote Link to comment Share on other sites More sharing options...
Xnke Posted June 22, 2014 Share Posted June 22, 2014 Stock for stock, there is no difference in flow. The turbo cars got squareport heads because the additional heat will burn the liners out over time. The K stamp cam specs have been posted here, the cam is short on duration and a little short on lift compared to some of the others. 222* seat to seat, 219* at 0.050", and 0.300" valve lift were what I measured last time I had one installed in a head. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 22, 2014 Share Posted June 22, 2014 Because they're internet dweebs stuck on what everybody else tells them and can't figure out the data that shows them what I say is true. As for 'why didn't Nissan' do this or that, I'm not getting into an in-depth engineering discussion on why the liners are there, but suffice to say the glowing hot liner markedly helps the HC Emissions if the ECU farts at all, and normalises the O2 Content by combusting those HC's before they hit the N/A O2 Sensor. Keep in mind they didn't have P79 heads on the JDM Cars... Why? Uh...because the emissions requirements weren't there? Why were there N42 CLOSED CHAMBER heads overseas, with NO EFI Bolt Pattern on them? Don't use false logic based on incorrect thinking to justify a parts choice. I simply said you are making a LOT of work when there was a perfectly good head complete (from what you say in your posts) that you could have had off, and on to your car already without all the interim steps and failure points introduced. I'd need to SEE a head with a 'burned out liner' from turbo use, because the ZXT I got had a P79 on the ET Bottom End, and the owner told me he replaced the head at around 150K when the original turbo went out and they found cracks in the P90 that was on it. He put a USED P79 on it and when I bought it there was 225K on it and those liners looked JUST FINE...and were in there same as any other. So in at least 75K of turbocharged application on a P79 that started with 150K, those liners were holding up darned good. I just haven't seen it. I've seen loose liners but not one that came out and went anywhere, nor one that 'melted down' or 'burnt out' as some tout. Doubt it would do much if it did. It's a Nissan Hotrod Book root...and the guy writing it may have simply wanted to steer people towards stuff that was easier to modify---though Bryan Blake's work on the P79 showed very good results comparable to the P90 in terms of ultimate flow. "The Restriction of the liner just wasn't what everybody seemed to think it was..." Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 22, 2014 Share Posted June 22, 2014 The title of the post was 'JUNKYARD BUILD' -- It was not '1,000 HP Electramotive Replica Turbo Build' so I'm betting any amount of money you would like to wager you will not get to a point with this build that the Exhaust Liners will in any way come into play, nor will your cam selection amongst the stockers you seem intent on using. I think the proper word to use on the 'burn out over time' should be more like "was feared that they MAY burn out over time" -- Remember Engineers were looking at 300,000 mile reliability and the elevated temperatures of the turbo engine on the exhaust side MIGHT cause an issue. But... for most people not running in Europe...they weren't on boost long enough to damage anything! Quote Link to comment Share on other sites More sharing options...
mainboyd Posted June 23, 2014 Author Share Posted June 23, 2014 Well first off I would like to say thank you Xnke and Tony for the info. I just started working with these engines so whatever info I get off the internet or from forums or even from this specific forum I take in and study or do more research on. Also, I would like to make clear that no where on any of my post did I say I was wanting to gain any performance on this head but just save it because I thought it was a better head to use. I dont mind the swapping of heads because this is the first time I have worked on the internals of a piston engine. I have way more experience with rotary engines because I have owned and rebuilt a twin turbo RX7. Also I have not paid a dime on this head because my friend is the manager of the wrecking yard that I have been going to for the P79 head. Only thing I have "waisted" would be time but I have for sure gained a lot of experience with these head (not as much as you guys for sure). Just be patient with me and my questions. I try to do all the research before posting. As of right now im going to use the P90a head sense I already took everything off the P79 head... yea it probably wasnt a good idea to pull all that out but it has already been done and there is probably no point to going back. Im going to pick up the P79 cam and do some measurements on it sense there is not much for this "k" stamp cam Quote Link to comment Share on other sites More sharing options...
mainboyd Posted June 23, 2014 Author Share Posted June 23, 2014 FYI, Junk yard build is probably the best title for what im doing because thats where im getting all my parts from and it might be a junk head once its all done... Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 23, 2014 Share Posted June 23, 2014 (edited) "The only thing I have waisted would be time." Not only yours, some people are taking time to answer your questions. Don't ever forget that! Personally, I don't have the time to waste with that kind of minutiae, I'd have done a head swap and have been driving the car learning about it...while I made a 'good head' out of the P90 to be used at a later date. Different paths, but understand not driving the car sucks. Edited June 23, 2014 by Tony D Quote Link to comment Share on other sites More sharing options...
ozconnection Posted June 23, 2014 Share Posted June 23, 2014 I'd need to SEE a head with a 'burned out liner' from turbo use, because the ZXT I got had a P79 on the ET Bottom End, and the owner told me he replaced the head at around 150K when the original turbo went out and they found cracks in the P90 that was on it. He put a USED P79 on it and when I bought it there was 225K on it and those liners looked JUST FINE...and were in there same as any other. So in at least 75K of turbocharged application on a P79 that started with 150K, those liners were holding up darned good. Oh, I seem to remember that you said Nissan would never ever use a linered head for turbos from the factory Tony. In my particular case, the Y70 head "must have been changed over at some point, couldn't have possibly been assembled that way from the factory". Remember our Y70/l20A discussion Tony? Low powered L series engines with factory boost levels could do it...we're not talking stepped up hot rod motors, although dare I say the liners would probably hold out pretty well by my measure and more recently yours! Willing to change your opinion on the linered heads for factory turbo engines Tony? Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 23, 2014 Share Posted June 23, 2014 Read what I wrote, it is exactly as stated and there is absolutely no disparity in the two statements. They are congruent in every way. You are mixing up what someone in the field does with what an OEM would do in an ultra-conservative planning session with lawyers present. THERE WERE NO LINERED TURBO ENGINES FROM NISSAN ON THE L-SERIES, PERIOD. What someone changes out of expedience EXACTLY makes the point I was making: on stock engines it's likely not going to make a difference. But From a LIABILITY STANDPOINT the OEM just isn't going to do it. The function of the liner is defeated by the turbo! Linerless Heads are CHEAPER to make as well...BTW. I'm not arguing with anybody on this point. You want to pick pepper out of flyshit and make an argument twisting things areound you can go hop the flying express to buggerville. I'm not having it. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 23, 2014 Share Posted June 23, 2014 It's not that Nissan wouldn't ever...it's THAT THEY NEVER DID! Your Y70 is a NORMALLY ASPIRATED HEAD. Period. End of story. If there was a turbo hung on it, it was done ex-factory. Period. End of story. Move on. Quote Link to comment Share on other sites More sharing options...
mainboyd Posted June 23, 2014 Author Share Posted June 23, 2014 "Not only yours, some people are taking time to answer your questions. Don't ever forget that!" Hahaha all I can say is that thats on you. I didn't twist your arm to answer my questions or look into this forum. However, I do appreciate the time that people have put in to answering my questions. Don't ever forget that!! Also, I ran into this today which was insightful: http://forums.hybridz.org/topic/109877-cylinder-head-flow/ http://datsunzgarage.com/p79/ However, it seems like the only difference would be the amount of porting you can do to the P90 exhaust port compared to the P79. Might be wrong but ill be looking into it a lot more. Even though im not looking into performance gain for my personal use between the two heads, I would still like to know if there is any other difference between them when modded. FYI, I already have a complete L28ET with a P90 head so all this "work" I have been putting into the junkyard build is not stopping me from enjoying my car. Quote Link to comment Share on other sites More sharing options...
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