burned valve?

It's not ignition. Related I've ruled that out the carve is working fine. I do have a whistling noise through the garb and it has recently got louder.when I crank the engine with the distributor unplugged it turns over. But gets about 3/4 of the way around and feels like it gives up. When tweaked the timing the other day I got a loud screaming noise through the darn when I retarded or advanced the timing. I'll do a comp check today if I get time

Ok, so ignition is ruled out.

Compression check time then. I'm not entirely convinced that the carb isn't at fault but the comp check will point the way.

Be sure to set the throttle wide open to get accurate results, and remove all the spark plugs.

I've seen people run compression tests with just one cylinder and the throttle closed, you will get abnormal and low results.

Are you talking about a compression test or a cylinder leak test

compression gauge, start the car run for a second with gauge on 1 cylinder then check, its more of a cylinder pressure check, should be over 150 depending on cam, 150 is on the low side tho, Ive got an s10 at the shop with 120psi cyl pressure on number 6 that shows a miss at idle.

billy-ray wrote:Are you talking about a compression test or a cylinder leak test

Compression test.

A leak test would be great if you've got access to all the parts needed to check it. otherwise a cheap $30 gauge and a buddy will do.

A leakdown test will help pinpoint which valve wether its intake or exhaust. a Compression test will just tell you which cylinder is suspect.


The key is that all the cylinders be within 10% of each other otherwise it will run rough. it could have 60psi on each cylinder and still run smoothly and be incredibly worn out.