attworth Posted January 28, 2009 Share Posted January 28, 2009 I'm considering purchasing the 83T for sale in the classifieds. The current owner says it has a blown head gasket. Easy enough, right? At first, I thought I would just have the head checked and cleaned up. Then I started reading around and found what I was looking for. The head in my car should be a P79, which seems to be a good fit for the turbo application based on reading around. So I walk outside to check my 81 NA to make sure it is indeed a P79 like it should be. Nope! It somehow has an N42 in it. So unless my facts are mistaken, the motor in my car is not the right motor (at least the head...) Can I use the N42 on a turbo motor? I understand it has square exhaust ports, which is right for the turbo manifold. But what about the other aspects of the head? I hadn't even thought about this, but I assume the cam from both the P79 and the N42 aren't really going to react well with the turbo. Any advice? Quote Link to comment Share on other sites More sharing options...
Phantom Posted January 28, 2009 Share Posted January 28, 2009 If you compare the performance specifications between a 280Z motor and a late 280ZX motor you'll see that the HP and torque ratings are pretty close - EXCEPT - the torque curve on the one with the P79 head comes on around 3,000 RPM vs the N2 head engine which comes on around 4,400 RPM. If you are thinking about putting a new cam in then either head will work for you. If you're planning on keeping the stock cam that comes with the head then I'd recommend the P79. Quote Link to comment Share on other sites More sharing options...
attworth Posted January 28, 2009 Author Share Posted January 28, 2009 What about using the P90(a) cam in the N42? If it's the hydraulic lifted variety would it work? I hate piece milling the thing together but I'm on pretty strict budget as is. Wife isn't too happy with the prospect of another Z. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted January 29, 2009 Share Posted January 29, 2009 Are you're suggesting using an N42 head for a turbo application? If so, it's probably not a good idea as the N42 is an open chamber design with less quench than the P90 and P79 meaning you can't run as much timing as you will want. I've know people have made it work, but it's not the best choice. But why not go with what you originally suggested to get the head on the turbo motor (assuming it's a P90) checked out and cleaned up if it needs it? Changing a head gasket, especially when the engine is already out, is not a big deal. Quote Link to comment Share on other sites More sharing options...
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