compression test on engine stand
#1
compression test on engine stand
hello all, i am mechanically inclunded but not entirely sure what to expect of my results on my 2jzge i just bought
1-100psi
2-50psi
3-0psi
4-50psi
5-100psi(after adding oil) (75psi before)
6- 25psi (before and after adding oil
my readings were so erratic that i am suspecting the gauge itself but with the variety in my readings it should also be noted that i am turning the crank by hand to try and build compression. all the spark plugs were removed and the engine appears to have factory cams and intake/exhuast manifold are removed anyone with a better mind than mine have any input or suggestions. thanks
1-100psi
2-50psi
3-0psi
4-50psi
5-100psi(after adding oil) (75psi before)
6- 25psi (before and after adding oil
my readings were so erratic that i am suspecting the gauge itself but with the variety in my readings it should also be noted that i am turning the crank by hand to try and build compression. all the spark plugs were removed and the engine appears to have factory cams and intake/exhuast manifold are removed anyone with a better mind than mine have any input or suggestions. thanks
#3
Super Moderator
iTrader: (34)
A leak down test is better than a compression test. Do not tear it apart till you have done that test so you are not guessing what the problem is. You will be able to pinpoint whether exhaust or intake valves or rings are your problems. Before you know it, you might not even have to touch your short block if piston rings are good meaning no pressure leaks coming from your crankcase.
#4
Gerrb the only issue is I am doing this in the basement of my apartment complex and dont have access to shop air for leakdown test. I also got a known good gauge so I will retry the compression test. My main issue is that im trying to crank by hand on a cold engine
#5
me again, with an update! i got a known good compression tester and retested
cold engine, hand cranking
1-120psi
2-30psi
3-90psi
4-100psi
5-150psi
6-30psi
cold engine, hand cranking, W/ OIL ADDED
1-165psi
2-30psi
3-90psi
4-120psi
5-180psi
6-65psi
seeing as i had a healthy mix of both blowby passed the valves, and rings i pulled the head. gasket seemed to be in fine shape with no obvious signs of cylinder to cylinder cracking or any signs of coolant to oil contamination. cylinder walls had nice cross hatching. from the looks of it i might be able to get away with a hone and new rings. but i will get exact measurements to be sure
cold engine, hand cranking
1-120psi
2-30psi
3-90psi
4-100psi
5-150psi
6-30psi
cold engine, hand cranking, W/ OIL ADDED
1-165psi
2-30psi
3-90psi
4-120psi
5-180psi
6-65psi
seeing as i had a healthy mix of both blowby passed the valves, and rings i pulled the head. gasket seemed to be in fine shape with no obvious signs of cylinder to cylinder cracking or any signs of coolant to oil contamination. cylinder walls had nice cross hatching. from the looks of it i might be able to get away with a hone and new rings. but i will get exact measurements to be sure
#6
Lead Lap
iTrader: (1)
make sure at minimum you lap your valves as well. I wanted to do a valve job but I didn't have the money so I just did a really really meticulous lapping job over and over. I really wanted to be sure they seated right so yeah. haha. but I did both methods, the suction cup, and the drill with a vacuum hose attatched to both the drill bit, and the valve.
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#8
Grumpi I plan on pulling the valves to replace valve stem seals so they will be done and if I cant find a straight edge I plan on sending the head out.
Matt you a correct I could only spin it as fast as you would a scissor jack if youre in a hurry. You are also right that starter is the best method but im working with what I have.
Matt you a correct I could only spin it as fast as you would a scissor jack if youre in a hurry. You are also right that starter is the best method but im working with what I have.
#10
im looking for 500- 600 wheel i havent decided what the engine is going in, i kind of want to put it in a '70 nova cuz i like to **** off purists ill actually be starting another thread to document my process i currently have the engine torn down with just the crank still in the block so im deciding on what kind of rod and main bearings to go with
#12
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Join Date: Jan 2015
Location: Colorado
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By hand there's no way to get an accurate compression test, the only accurate test you could do on a stand is a leak down. But with no compressor you're a little sol.
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