J LT1 TA

iTrader: (6)

I did a compression test on a car I bought awhile ago, previous owner ran nitrous. Engine started to smoke, shop told them that #7 cylinder sleeve was cracked. This is my first time doing this test and these are the numbers I got, I believe my problem is on the other side. #6 gave me nothing, it made noise like it was the starter, but didn't give me the sound of the motor turning over like the others. I took a pic of the spark plugs. I believe my firing is correct.

first pic bottom plug is #1 then 3,5,7, second pic left is #2 then 4,6,8

8 - 180 ---------7 - 200
6 - 0 ------------5 - 175
4 - 155----------3 - 175
2 - 160----------1 - 175

Darth_V8r

iTrader: (4)

I'd bet on a bad valve on number 6

ElkySS

iTrader: (6)

Agreed. Probably bent

J LT1 TA

iTrader: (6)

ok is that what is causing 2 and 4 to have a lower number? Also everything else looks good? They where told #7 had a cracked cylinder sleeve, that's incorrect right? based off the numbers? First time messing with an engine. Thanks for the tips

ElkySS

iTrader: (6)

Can't tell for sure but the motor clearly needs to be torn down anyway so I'm sure you'll figure it out during.

J LT1 TA

iTrader: (6)

ok Ill probably end up removing it and take it to a shop and have them look it over to be sure.

Darth_V8r

iTrader: (4)

Ok so in 2 and 4, shoot a squirt of motor oil in the soarkplug hole and retest. If it comes up, its rings. If not, it's one of the valves in 2 and 4 also

farmington

iTrader: (14)

#6 is very clean, a sign if a water leak, either from a head gasket or cracked cylinder wall