john kosmatka Posted May 28, 2003 Share Posted May 28, 2003 Will a p90 head work with the stock l28et, and if it does how much power can it net you. I don't know much about this yet, I'm just learning, but the different head changes the compression right, so what I am asking if the compression will work with the turbo will work with the turbo motor. Quote Link to comment Share on other sites More sharing options...
Mudge Posted May 29, 2003 Share Posted May 29, 2003 You'd have to get rid of the turbo cam, and any power gain IMO without porting it and rebuilding the whole thing will be minuscule if any. http://www.classiczcars.com/forums/showthread.php?threadid=1292 Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted May 29, 2003 Share Posted May 29, 2003 A p90 is the stock head on an L28et. Are you talking about putting it on an NA motor. If so, you may pick up a slight increase in power due to the square exhaust port, but not enough to make it worth the swap effort if you ask me. Now if you want to mill it some, then I would say it may be worth it. Quote Link to comment Share on other sites More sharing options...
john kosmatka Posted May 29, 2003 Author Share Posted May 29, 2003 Lockjaw I didn't know the p90 came from the l28et, due to the fact I just bought the car and still gathering some info. Iwas thinking of taking the head from a N/A z and putting it on the l28et. But I am guessing this would cause to many problems with reliability and might not even work or be worth the effort for the power gain. I was just wondering about ideas. Thanks for the input. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 29, 2003 Share Posted May 29, 2003 All L6 heads are interchangable on the L6 blocks. The N/A L28e head is a P79, and has the excact same combustion chamber design as the P90. the P90 is said to have better flow, due to its square exhaust ports. I've just purchased a P90 for my car. I have a P79 on the car, and don't really need the P90, but my car is in desprite need of a valvetrain overhual and I don't have a place to work on it. I lucked across the P90 at a good price and I figure I'll build that head then swap in on the motor when I do the timing chain. Chances are, you already have the P90, unless you have an '83--then you would have a P90a, which is a P.O.S... They have hydraulic lifters, which Nissan has stopped making, and they're no good for tuning. Look at the letters between sparkplugs 1 & 2 to find out. If this is the case, start looking for a P90/P79 pronto! Quote Link to comment Share on other sites More sharing options...
rags Posted May 29, 2003 Share Posted May 29, 2003 I'm gonna throw this out again to stir the pot. I have a P90a that is NOT hydraulic. I did not do a lifter swap on it and I seriously doubt that the original owner of the car did the swap. The car was maintained by Nissan and the owner couldn't remember having any valvetrain work performed. Does anyone else have or seen one of these? And yes, I'm sure. Joe Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted May 29, 2003 Share Posted May 29, 2003 Nope, but Nissan has been known to do some funky stuff from time to time. Be thankful it is a solid lifter head, the hydraulic ones suck. I would run a P79 befire a hydraulic. Also you can run any head on the turbo engine, its just that the N and E series heads will probably bump your compression to high, and the P series heads were a high swirl design, which is better, IMO. Some people disagree with that statement, and we won't restart that drama, but in the end the P90 was designed to be a turbo head, and is the best choice. Quote Link to comment Share on other sites More sharing options...
280Zen Posted May 29, 2003 Share Posted May 29, 2003 I've got to ask, why is the hydraulic lifters such a PITA? Quote Link to comment Share on other sites More sharing options...
z-ya Posted May 29, 2003 Share Posted May 29, 2003 I agree that if the hydralic lifters fail, it's a major pain. The P90a head is a good head if the lifter are working correctly. I've been running one for three years now without any problems. With the new T3/T4 turbo, it pulls strong all the way up to 6500 RPM. Less maintenance is fine with me. If the lifters start failing, I'll swap in a P90 or the P79 I have sitting on the shelf. If it ain't broke..., well you know. Saying that all P90a heads "suck", is a generalization that is not accurate, and doesn't really give proper credit to this head in good working condition. Just my $0.02 Pete Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted May 29, 2003 Share Posted May 29, 2003 I've got to ask, why is the hydraulic lifters such a PITA? When they go bad, there are no replacements available. Also I personally feel like the oil pressure won't keep them up in position properly when the oil gets really hot, and hence you lose a little performance due to the bleed down effect. All I know is this, a hydraulic cam does not make as much power as a solid in a V8, so I wouldn't run a hydraulic head on a datsun. I think anyone running one will find a power increase by going to the solid head, but thats just been my experience. Quote Link to comment Share on other sites More sharing options...
Mudge Posted May 29, 2003 Share Posted May 29, 2003 Solid cam will make a bit more bottom end power, and a bit more top end, most of thier advantage is revability without lifter pump up and low end power with even a somewhat largish cam. As said if they need replacement prepare to pay big time, and probably spend awhile trying to find them. I too have heard of P90a without hyd lifters, it must have either been a transition item or maybe just converted down the road by people who owned them. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted May 29, 2003 Share Posted May 29, 2003 I too have heard of P90a without hyd lifters, it must have either been a transition item or maybe just converted down the road by people who owned them. I'm going to go out on a limb here, and say the solid pivots were transitional before Nissan moved to the hydraulic pivots. Judging by the difficulty of adapting a smaller threaded solid pivot to a head threaded for a hydraulic, I think the head was originally machined for the solids. When they moved to the hydraulic, they changed the head machining to accomodate the larger threaded pivot. I have seen many P90A heads with solid lifters, more than the hydraulics. I am running a P90A with solids, and it works excellent. The junkyard motor had a sticker on it underneath the grime that said "Remanufactured by Nissan", so it came from Nissan the way it is. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted May 29, 2003 Share Posted May 29, 2003 I wonder if you could take the hydraulics out, and weld the head and redrill it and tap it for solids? I mean a half way decent machine shop should be able to handle that right? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 29, 2003 Share Posted May 29, 2003 And the fountain of knowledge flows Cool--I didn't know that. Quote Link to comment Share on other sites More sharing options...
280Zen Posted May 29, 2003 Share Posted May 29, 2003 I do know that the P90A head can be converted to a solid lifter head, ZGad had a local shop do this to one of his spare P90A heads. I just wanted to know what the big issue was against the P90A head, If the hydraulic lifters could be clean/repaired/restored/replaced would they not be the better choice for use? From the post above I see that the solid lifters provide better top and bottom end power. Now bear with me a sec, Im a novice when it comes to engines.. I've also read that the solid lifter heads need to be adjusted from time to time, Is the advantage of power from the solid lifters greater than the advantage of not having to adjust the hydraulic lifters? Quote Link to comment Share on other sites More sharing options...
yo2001 Posted May 29, 2003 Share Posted May 29, 2003 I would think the machine shop sould be able to use a sleeve, kind of like Helicoil but alot bigger, to adapt the soilid lifters on P90A. I just don't think anyone bother to try since you can get a soild lifter head pretty cheap. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted May 29, 2003 Share Posted May 29, 2003 I bet I do a valve adjustment once in a blue moon. That is more a fuction of RPM's then anything if you ask me. If you constantly flog your car and run it to redline, you may need to adjust them more frequently. I have gone more then a year without adjusting mine, and I don't worry about it. If they get really noisy, I will adjust them. 8) Quote Link to comment Share on other sites More sharing options...
yo2001 Posted May 29, 2003 Share Posted May 29, 2003 I bet I do a valve adjustment once in a blue moon. That is more a fuction of RPM's then anything if you ask me. If you constantly flog your car and run it to redline' date=' you may need to adjust them more frequently. I have gone more then a year without adjusting mine, and I don't worry about it. If they get really noisy, I will adjust them. 8)[/quote'] Are you telling me that I'm flogging my car? Even after the turbo motor, I have to adjust at least once a month. It's a habbit I think Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted May 29, 2003 Share Posted May 29, 2003 If you have the rockers that match the cam, you should not have ti adjust the valves very often, when you start mixing and matching, then you have to adjust, that has been my experience anyway. You know I flog my car, in fact that is pretty much all I do with it, besides drive it to the track. Poor car, it has such a tough life. I haven't even had to adjust mine since the new cam installation. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted May 29, 2003 Share Posted May 29, 2003 Mixed and matched here. 8) the set of rocker arms were from a same head (I assume) the cam came from another head. Quote Link to comment Share on other sites More sharing options...
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