is 10% leakdown acceptable?
Generally speaking up to 20% on a cold engine is acceptable, and up to 10% on a running-temp engine is acceptable. Ring end gaps vary as a function of their temperature as well as the block's temp. Valves, however, shouldn't leak at any temp.
If you want to diagnose the source of your leakage, whip out a mechanics' stethoscope ($10 at Sears) and listen at the following locations, while the cyl is pressurized and the piston is at TDC:
1.) Throttle body or injector base: intake valve leaking (not good)
2.) Exhaust manifold: exhaust valve leaking (not good)
3.) Oil dipstick tube: rings leaking (OK)
If you want to diagnose the source of your leakage, whip out a mechanics' stethoscope ($10 at Sears) and listen at the following locations, while the cyl is pressurized and the piston is at TDC:
1.) Throttle body or injector base: intake valve leaking (not good)
2.) Exhaust manifold: exhaust valve leaking (not good)
3.) Oil dipstick tube: rings leaking (OK)
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The reason why I ask is not a question of the rings really, I recently had a problem with a dealer breaking a valve spring, i was concerned about the valve being bent, now I am all paranoid that I have blowby UGH
lol
lol
TECH Junkie
Joined: Dec 2001
Posts: 3,242
Likes: 0
From: Lakeland, FL
I wouldnt worry about it too much but you are towards the worse side of things. On the cylinder that had 10 percent where did you hear it coming out of? For a comparison I had 90% blowbuy and I was blowing my dipstick tube out due to crankcase pressurization,, you are nowhere near this and probably just have normal wear on the motor. Don't sweat it.
Originally Posted by ls1jimmy
I have got 25 % in one cylinder and the rest is at 2 and 3% i would like to know to because i had a cam installed and gained 25 hp from long tubs and cam ..
Was the leak down check done with the motor hot or cold? This can have a big effect.
The LS1 (after re-ring) going into my RS had 42 & 35 percent leak down in cylinders 1, 3 cold. The another cylinder was a 25 percent and all the others were at 10 percent. I don't think 10 cold is too bad.
The LS1 (after re-ring) going into my RS had 42 & 35 percent leak down in cylinders 1, 3 cold. The another cylinder was a 25 percent and all the others were at 10 percent. I don't think 10 cold is too bad.