what should the compression be on my 70 firebird w/a 350? my engine compression readings are 1-130 2-130 3-130 4-125 5-120 6-135 7-120 8-165? Are these good readings?
2007-11-01 16:42:32 · 4 answers · asked by tazmanjr1 1 in Cars & Transportation ➔ Maintenance & Repairs
They are very good reading depending on why type of compression test was performed. was this a dry or wet test? the number are fine for the most part. but I would retest #8.
2007-11-01 16:52:08 · answer #1 · answered by gearnofear 6 · 0⤊ 0⤋
I certainly would say you got valve problems. The only good cylinder is #8 The compression should be 165 in all cylinders. That's a bit much to ask in an oldie like this. Compression should not vary by more than 10 psi from the high to low cyl. Does this thing run ? the 130-130-130 almost suggest head gasket problem. You definitely need some work. Should check valve clearances first off.
2007-11-01 17:14:04 · answer #2 · answered by tronary 7 · 0⤊ 0⤋
normal compression for that engine should be around 150 pounds per cylinder,when reading compression you don't worry so much about the numbers as you do the difference in the numbers from one cylinder to another,you have a really big difference in the one cylinder,and the rest of them are a little low,id be more concerned about getting a number that was within,10-15 pounds of each other that would be more normal,you have to large of a difference in the one cylinder,id be checking all of them out,its probably just an old engine and in need of an overhaul,those are good readings but the big difference in no-8 is really a lot,good luck with it.
2007-11-01 17:02:54 · answer #3 · answered by dodge man 7 · 0⤊ 0⤋
You don't need to worry unless you find one below 110
2007-11-01 16:48:45 · answer #4 · answered by ASE_mechanic 4 · 0⤊ 0⤋