TwinTurbo.NET: Nissan 300ZX forum - Ok. Good.
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Subject Ok. Good.
     
Posted by ZTurboFan on December 20, 2009 at 11:49 AM
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In Reply To Timing posted by Andrewhuffman on December 20, 2009 at 11:18 AM
     
Message Ok, well, I guess if it were my car and I was trying to save money and not concerned with time, I'd just tear it down in the car. Mostly because I'd want to do a compression test after a lifter swap ... and I'd want to use the starter motor for that compression test...and pulling the tranny sucks and is not proven necessary yet.

So you gotta tear the top down. Plenum, fuel rail, etc etc etc. Valve covers, etc etc.

Remove the timing belt and cam gears.

Remove the cams.

Swap the lifters.

Replace the cams.

Put on and set the timing belt.

Then I'd do a compression test as bare as possible. Wouldn't even bother with the valve covers. None of the top of the motor needs to be hooked up. So basically you can do a compression test at that point.

If the compression numbers travel with the lifters. I think you've probably got it sorted out and you might be able to prove the rings are actually OK despite your concerns. If the numbers don't travel with the lifters, then you're stuck pulling the motor out and apart because either valves are damaged (though we think they shouldn't be because timing was correct) or with this new information, rings - which would really suck - but hey, if you have to rebuild the short block, so be it. It's actually quite easy to assemble. The problem is always going to be machine work if it needs to be done. Finding someone you can trust = PITA.

I hope it's not your rings. Complete rebuild if it is.

Did you assemble the short block yourself or did the machine shop do it? I'm hoping it's lifters because everything else is obviously a full tear down scenario. Good luck and let us know what you find - or at least how you plan to proceed as obviously you could just rip it right out now and take it apart. If it is the lifters, you'll see it in the head once it is off. Valves stuck open when lifters installed. Valves shut tightly when lifters removed. Valves open when lifters removed = bent.

     
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