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Saturday Night Racer >> RACE TECH >> Help needed reading cylinder heads
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Message started by dirt33 on 10/03/09 at 6:56pm

Title: Help needed reading cylinder heads
Post by dirt33 on 10/03/09 at 6:56pm

The following link contains 2 pictures of a head off of a 2.2L Chevy 4 cylinder that is raced in a front-wheel drive class. When you click on each picture, click on it a 2nd time and it will bring the picture up in a very large size so that you can see the chambers in close detail.

Earlier in the summer this motor burnt up the #1 piston and head real bad. I replaced the pistons and the head. This head that is pictured was fresh from the machine shop about a month ago, has maybe 30 laps on it total (2 nights of racing).

The problem is that the last time out, the motor developed a miss. It acted similar to the time before when it had burnt a piston. However, when I pulled the head off today, all pistons look fine. If you look at the #2 cylinder on the head (3rd from the left in the pictures), it is obvious that that cylinder is not firing like the other 3. The other 3 cylinders look good, both valves on each cylinder are burned clean and are the same color. On the #2 cylinder, however, the exhaust valve is a much lighter color, and the intake valve is very black and has a lot of carbon deposit on it. The scrape through the middle of that valve is from my finger nail running over it to see how bad the deposits are. Also note that the spark plug in the #2 cylinder looks different than the other 3 cylinders.

I have very little knowledge when it comes to reading the burning characteristics of a cylinder and determining if it is too rich, too lean, or just right. I am wondering if you guys can take a look and tell me what side of the equation this particular cylinder seems to be. Not getting enough gas which would possibly be an injector bad, or not getting spark in which case the coil pack could be shot?

Thank you if you can help.

http://s279.photobucket.com/albums/kk153/wesgames/CylinderHead/

Title: Re: Help needed reading cylinder heads
Post by miniguru27 on 10/05/09 at 10:43am

Looks to be running lean.Check injectors and check for vacume leaks.A coil not firing the cylinder would be wet with fuel.Just a thought.