1989 SOHC zero compression from cyl. 2

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seafoamdream
Posts: 1
Joined: Thu Sep 16, 2010 2:00 pm
Car: 1990 Maroon Hatch with RB20
1989 Silver Green Two Tone SOHC

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Hi guys, so I'm pretty much at a loss on what to do right now and I would really appreciate anyone's input.

I picked up an 89 sohc 240sx with the engine not running. After inspecting the car, I knew the timing was off. Looked like it jumped two teeth. We reset the timing and did a compression test and the first two cylinders were bad.

So we pulled the head off to check it out. The valves for 1 and 2 were bent and had hit the pistons slightly, but overall the pistons looked pretty good. I took a picture of the pistons, so let me know what you think.
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We went and got another head from a friend that looked good and put it onto the car. Set everything up, and it wouldn't start. My friend realized he 180'd the timing. So we did the timing again and it started right up.

Now the car is running slightly funny, so we did another compression test and sure enough it's only running on 3 cylinders. The number 2 cylinder reads ZERO compression.

So my question is, do you think that the piston rings are bad? Was it possible that one of the valves in cyl. 2 got bent because of the timing being 180'd? Or maybe the valves on the new head that we got were already stuck?
Check out the pictures and let me know what you think. Thanks guys! :ohno:

Image


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zachattack_5491
Posts: 641
Joined: Sun Jul 13, 2008 8:00 am
Car: Pignose S13 Redtop SR
Location: Albuquerque, NM
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I'm pretty sure having it 180 degrees off is okay. It just opens the exhaust and intake valves at the opposite times. Not 100% on that though.

To get zero compression you would have to have blown ring lands on cylinder 2. Even with pretty bad rings you'll get a small reading.


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