Low Compression w/ Rocker Arms - Maintenance and Repair Forum

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Low Compression w/ Rocker Arms
Sunday, May 27, 2018 7:35 PM
Alright, so I've got a peculiar issue (to me).

My girlfriend and I did a head gasket on a 99 2.2l cavalier. Twice.

The first time we did it, we had low compression all around (around 70 psi) except for cylinder 3, which was about 35 psi. A wet compression test yielded the same results.

Yesterday we tore the thing apart and swapped it with a known good cylinder head, new gasket, new head bolts, and everything. I should mention that we followed torque specs in the Haynes maual, I believe it was 43 ft-lbs for the shorter bolts and 46 ft-lbs for the longer ones, and a quarter turn on each of them. Before putting the intake and exhaust manifolds back on, we did a compression test again. This time, cylinders 1 through 3 had right around 75-80 psi, and cylinder 4 had 0, nada, zilch. No compression at all.

I had a buddy tell me to pull the rockers off and feel for leaks around the intake and exhaust ports and I did so, but I didn't feel any leaks, and compression went up on that single cylinder, although only to about 40psi or so after 5 or 6 cranks. Torqued them back to 19 ft-lbs, and had zero compression again. Honestly I'm stumped, I'm thinking I might send one of these cylinder heads out to a machine shop in my area and pay them the $300 to completely go through and rebuild it, but I'm not sure that it's my problem and I honestly have no idea where to look next.

As always, any help would be appreciated, and thanks so much for reading. This vehicle's been in my driveway for way too long to not be running, so I'm sure some of you can understand my frustration

Re: Low Compression w/ Rocker Arms
Sunday, May 27, 2018 8:00 PM
Does this vehicle have hydraulic lifters? Could they be stuck on that one cylinder? Could they be stuck on all cylinders maybe?
Re: Low Compression w/ Rocker Arms
Tuesday, May 29, 2018 8:43 AM
Have you checked the timing to make sure its right? This is not an interference motor, so it's almost impossible that you have bent valves. The lifters are hydraulic, but it shouldn't cause compression this low. You may end up having to do a leakdown test to see where the compression is actually leaking from. Did the cylinder walls look good when you had the head off?



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