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Bad compression, or something else?

Posted: April 20th, 2006, 11:47 am
by corbanbrook
Had compression tested and it ran in at 140, 135, 95, 140. Sooo not so hot.
Even with the bad compression.. the car still could haul some a--. and idle sounded pretty smooth.

Drove the car to montreal and back.. put about 1300 kms on it and now the car engine sounds like a motorcycle. *put put put put* puttering when idleing. and when i accellerate the car it really growls loud like a muscle car.. its embarresing because people on the street are starting to look at me.

Now.. I know my clutch to be almost toast as well.. and it slips a lot so im guessing either my road trip to montreal killed the clutch even furthur so that its causing the growling noises. or i worsened my compression to the point where im noticing a big loss in power and causing the loud growling noises.. or its a combination of the two.

Im not very mechanically inclined and at the moment only have enough cash to get this clutch replaced. What should my course of action be?

Have I diagnosed the problem correctly? your thoughts?

Posted: April 20th, 2006, 12:03 pm
by hobbypete
Your compression should be 175 to 180, so 135 is the lower limit at 75% of max. If I was you, I'd focus on that first - the clutch can wait. Put some oil in one spark plug hole at a time and re-test the compression. If it improves, you probably need new rings. If not, it looks like a head gasket at the very least, because 3 is so low. Because all values are below spec, you may need valve work as well. It's going to be a great learning experience. Good luck.

Posted: April 20th, 2006, 2:29 pm
by corbanbrook
heh.. And a lot of cash im guessing.

Mechanic told me it would be about $1000 to do the valve work on the engine when I had him test the compression.

Posted: April 20th, 2006, 3:00 pm
by hobbypete
With some carefully chosen tools and some courage, you can do more than you think you can. Someone else will still do the valve work, but not the disassembly/reassembly - saving you a 2-3 hours of labour minimum. We all started somewhere.

Posted: April 20th, 2006, 3:10 pm
by Custommx3
If you put oil in your cylinders and do a comp test and it doesnt increase, it could be a stuck or bent valve also...