Hey z drivers, I just bought a 1983 280 zx 2+2turbo with 5 speed, My question is how do I adjust the valves there is no place for a wrench to loosen or tighten. And my fsm does not say any thing besides bleedind off air. Bleach you know the way this is done could you or any one else explain . I figure the rocker might have to come off for access buit I am not sure thanks I searched first but gave up. Will have pictures soon take care everyone.The pivots are different then other non turbo heads.

 

the 83 turbo head have hydraulic lifters? i think thats what there called, anyway.....i think you should fallow the procedure in the FSM..

 

hydraulic pivots they are not lifters I guess & they need no adjustment is this the story people

 

yup you are correct, it is the only hydraulic type head that nissan ever made for the l28, no adjustment ness. you should see a p90 stamp on the right front of the head.

 

P90A to be exact. The P90 was the non-hydraulic type. And yes, if it's the original 83 head then it's non adjustable and they are indeed valve rocker pivots.

 

Well that sums it up gentelman. Is the mechanical pivot p 90 a better head choice on a turbo engine ?. I know for hi perf use solid is the way I assume it is the same in the z engine arena . I like to adjust the valves it gives you a sense of involvement with the engine just shy of getting too deep with it.

Thanks for the replys you guys rock

 

While we're on the subject, my Hayne's only lists one set of valve adjustment numbers. Am I to assume it's the same #'s for both NA and Turbo (.007 intake, .009 exhaust, if I remember correctly)?

 

.25 intake .35 exaust non turbo. what are you smokin?

 

??? .25 inches? you mean a quarter inch of gap!?

I thought it was more like 0.008 and 0.010 inches gap. Different L-series call for different specs. I think some are 10 and 12 but I always ran them tight and had no issues in my NA engine. LWW noticed my cam ran very quiet.

There's nothing wrong with the P90a, but when I had the option in my buildup I chose to use the P90 head with manual rockers.

 

the hydraulic head has two disadvantages. First and foremost is if one of the hydraulic pivots goes bad they are NLA. So you'd have to source another used one. The other disadvantage, and this only applies to super high RPM race motors, is that the lifters can bleed down. But this would never be a problem with healthy lifters on these motors. The L28 doesnt see high enough RPM's to affect the lifters. That aside there really are no other negatives to this head. I consider the fact that replacement pivots are so hard to find a good enough reason to opt for a P90 over the P90a though.

On the other hand the motor is much quieter. Alls you can hear (unless you have an exhaust leak) is the injectors clicking away and the fan.

 

I just wanted to clarify that these numbers are in mm.

The rest of you were quoting clearances in inches

So technically everybody is right so far

 

yea bleach it is the latest new thing, people are seting crazy big valve clearances just to be cool and get emaginary horse power or somthing like that . I don't know I couldn't think of any thing funny to say to that.