Compression test low on #2&#4

[Lorna c]

Ok new day but I have a stumble . So I've checked spark plug wires with my timing gun they seem to be firing just fine going down each one looking for a stutter in the light.. next to the compression test 2 and 4 are low 12 .
1 and 3 are I think normal about 130-140 .. so what should I be looking forward to cause this problem probably my headgasket huh ? My new head gasket that was $50+

[Lorna c]

120 or less on #2&#4. Typo above

[redroadster]

Do it completely cold
May have a seized ring but you can still use it that way

[Lorna c]

Nooooo .noooo nooo I vote for gasket please .. I can change the gasket .. plus rings r new , but new don't stop a seize huh .. how does one tell the difference ??

[nismou20]

Do you have a lot of blowby? Blue smoke or excessive oil consumption? Compression looks to be on low side. Recommend doing a dry and wet compression test, and it's more about consistency among cylinders. I think 10% variance can be acceptable. It does look low though. Think a healthy engine should be showing about 150-180

[Lorna c]

Do you have a lot of blowby? Blue smoke or excessive oil consumption? Compression looks to be on low side. Recommend doing a dry and wet compression test, and it's more about consistency among cylinders. I think 10% variance can be acceptable. It does look low though. Think a healthy engine should be showing about 150-180

Yeah I've heard that too . Not too bad . This tester may be a bit off too . The air doesn't sit right where you leave it , leaks down .. not too sure about wet & dry compression test .. I'll Google it .. thx . It's getting better as I fix some spark wires . Thinking of a new set with color next .. but the stumble I'll see if new wires fix that somewhat .. I do want to learn about wet dry tests though

[Lorna c]

Got it . Watched a video that explains it . And I didn't open the gas either . . Just turned key over .. ill do a better test tomorrow ..

[SLOroadster]

Adjust your valves first. Pull your spark plugs, crack your throttle open and crank till the needle stops. Record the number repete on the rest.

Will

[Linda]

Usually they say block your carbs open, so air filter off and lift piston up to fix it open.
Linda

[jamesw]

Also consider doing an "Italian tune-up." Google it here or do a search. If you really do have a seized ring, this can pull it loose. It moves the rings up and down in their seats. And it's fun!

HTH
James

[Lorna c]

Also consider doing an "Italian tune-up." Google it here or do a search. If you really do have a seized ring, this can pull it loose. It moves the rings up and down in their seats. And it's fun!

HTH
James

lol ok ...

[Lorna c]

Usually they say block your carbs open, so air filter off and lift piston up to fix it open.
Linda

oh really . thanks

[Lorna c]

I need to open throttle too .