L28et Variations
09-06-2005 | 11:18 PM
#26
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Joined: Apr 2005
Posts: 5,485
From: Temecula, CA
The E88 had smaller valves than any of the heads you'll find on an L28. The largest L24/26 valve was 42mm while all L28 came with 44mm. Thats of course intake valves. It was 33mm to 35mm on the exhaust valves, once again with the L28 having the larger valves. As far as the difference between the N42 and the P90: The only drawback to the N42 is it was before the days of unleaded gas, but that's an easy fix. Both heads had square exhaust ports and flow very well. However, the P90 has a far superior combustion chamber design then all of it's predecessors with the exception of the P79. In my opinion, the P79 and P90 are the two best heads for the L28 simply because of the better chamber design. The P90 has the edge due to its square exhaust ports over the P79's round w/liner exhaust ports.
09-08-2005 | 01:06 AM
#28
Thread Starter
Registered User
Joined: Aug 2005
Posts: 126
From: St. Petersburg & Orlando Florida
ok so the P79 was made from 81 to 84...but the P90a was made in 83 & 84... so which models had which heads? Thanks alot for that last post JFairladyZ...really really helpful man!
09-08-2005 | 01:08 AM
#29
Thread Starter
Registered User
Joined: Aug 2005
Posts: 126
From: St. Petersburg & Orlando Florida
Originally Posted by Captain caveman
hmm, how about a carb setup with turbo. I've seen people do it on their 510s, I wonder why it isn't common to do that on an L6
09-08-2005 | 08:53 AM
#30
The Evil Twin
Joined: Mar 2001
Posts: 9,296
From: Seattle, WA
1984 was the first year of the 300ZX V6 so the P90a was only 1983.
The only L-series head in 1984 was from the Nissan Maxima which was an N47(?) on an L24 block. (smaller displacement) but that head has smaller valves like a 240Z.
P79
1981-83 non-turbo 280ZX
P90
1981-82 turbo 280ZX
P90a
1983 turbo 280ZX
Head casting is on the right (passenger) side of the head down at the base of the head where it meets the block. Always check the head casting when pulling from a used car or buying used. People make mistakes in listing an item for sale and heads get swapped all the time in Z-cars without people knowning so don't just trust the year in a junk yard.
The only L-series head in 1984 was from the Nissan Maxima which was an N47(?) on an L24 block. (smaller displacement) but that head has smaller valves like a 240Z.
P79
1981-83 non-turbo 280ZX
P90
1981-82 turbo 280ZX
P90a
1983 turbo 280ZX
Head casting is on the right (passenger) side of the head down at the base of the head where it meets the block. Always check the head casting when pulling from a used car or buying used. People make mistakes in listing an item for sale and heads get swapped all the time in Z-cars without people knowning so don't just trust the year in a junk yard.
Last edited by Bleach; 09-08-2005 at 08:56 AM.
09-09-2005 | 12:41 AM
#31
Thread Starter
Registered User
Joined: Aug 2005
Posts: 126
From: St. Petersburg & Orlando Florida
oh yea...sorry...i was just looking at the timeline somebody posted...wasn't thinkin about the 84 change...sad thing is that i had an 84 300z once lol. Thanks for the specifics man, helped me out a lot.
08-14-2006 | 08:08 AM
#32
Registered User
Joined: Mar 2006
Posts: 271
From: florida
There was also a P99 head of which I owned one off of a late 1983 zx turbo.
It seems identical to the p90a in every way so not sure why they even used p99 but there are a few out there.
I gave the l28et I had to Datsun Dynamics with that head on it.
It seems identical to the p90a in every way so not sure why they even used p99 but there are a few out there.
I gave the l28et I had to Datsun Dynamics with that head on it.
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