compression test help

[SLOWJOE]

Ok i bought a compression tester did some testing and just need someone to verify what i think is the problem.

1 dry wet
145 210
2 20 30
3 152 210
4 138 190


what i believe to be the problem is the head/valve area, the manual said standard compression numbers should be 205 ish on a new engine and not less then 150 on a used. my number do confirm that my rings are definitely worn but the searches i have pulled up here those are about the average from used engines. Know should i just pull the head and get a rebuild or should i just go ahead and try to do a re ring. The engine has aprox. 215000 miles.

thanks!

[Damkid]

the one thing i'd look at is how much it'll cost to fix the one you got compared to getting a new motor

[mooseheadc]

Re: compression test help

Ok i bought a compression tester did some testing and just need someone to verify what i think is the problem.

1 dry wet
145 210
2 20 30
3 152 210
4 138 190


what i believe to be the problem is the head/valve area,

if #2 had shot rings, you should see all kinds of blowby from the oil fill
or other gaskets, and the add of oil didn't help with the wet check, so its
probably valves, as cracked head would probably show other trouble
like oil/water interchange in the crankcase/radiator

get a rubber hose the size of the spark plug, and jam that it in,
and hook to air compressor.

turn motor over by hand, you should hear the hiss change
and intake and exhaust valves close from tailpipe and throttlebody

But anyhoo, you got to pull the head to know for sure.

Unless you do that yourself you need to decide if you want to think
about a different motor. Fine time to find a B6

[SLOWJOE]

thanks for the help, i did have massive amounts of blow by it was pushing it past the valve cover area, so i wasn't sure if it was the rings or the valve stem seal. I pulled the head everything looked ok. I wanted to do the hissing test but I didn't. The head gasket looked fine. A re ring kit from summit is like 250. I don't wanna put a b6 or anything else in. I have a turbocharged mustang so I really don't need anything else for power. a head job is gonna be right around 200 bucks. I just don't wanna pull the block out if i don't have too. If the ring were really shot in #2wouldn't the wet test showed higher? I really just wanna fix the head and be done with it.

[Festy46]

If you still have the camshaft in the head, rotate it until both valves are closed. Turn the head upside down and fill the combustion chamber with kerosene or empty a can of WD 40 into it until the valves are completely covered with fluid. If the fluid leaks out the intake and/or the exhaust ports in a few minutes, the valves are bad. If it doesn't leak out, then you probably have stuck or broken piston rings.

[mooseheadc]

If the ring were really shot in #2wouldn't the wet test showed higher? I really just wanna fix the head and be done with it.

even a busted compression ring will show a little more improvement
with oil on them than that 10 psi difference. Most cylinders I seen
that read that low from bad rings showed a lot of wall scratching and
gouges, and you can't oversize bore the B3 much-- time for a
different block.
Any if you have to pull that, dropping a B6 in is so easy.Depends on your local yards, but it seems Festys go right to the crusher, while
capris stick around for awhile.

Though if you try that drip test, all you might need a need is a new
valve

[SLOWJOE]

I already disassembled the head so i can't do that test. the valves are burnt and full carbon big time i don't see how the head was sealing. So your saying that i can't bore the block and put new pistons if i had too? the walls on the block still show some crosshatching so their definitely not scoured up. it has some carbon on the top part where you have to use the ridge reamer to get the pistons out but i usually pus them out the bottom.

[mooseheadc]

the valves are burnt and full carbon big time i don't see how the head was sealing.

Or breathing all that well. hope that is all it is, new valves and even a quicky home suction cup valve spinner and some lapping paste
might be all it takes, with a new head gasket for cheap repair

So your saying that i can't bore the block and put new pistons if i had too? the walls on the block still show some crosshatching so their definitely not scoured up.

I don't recall seeing anything in oversize pistons for the 1300 motor,
just stock, not like the BPs where 2mm aren't uncommon.

[SLOWJOE]

thanks for your help