Compression Test

Cylinders #1-#4 in the 120-130psi range, #5-about 10psi and #6 about 120psi. All measured dry (no oil squirted in).

Hmmmmmmmm. Seems to be a problem here.

Time for a stroker!

I guess for now, I'll pull that piston and rod and see if I can fix it (JB Weld? ). Then this fall, I'll put together a stroker. Probably the budget 4.5. Not a lot of money to spend. Billet crankshaft, di-lithium pistons and neutronium rods would be nice but spendy.

I did find I have the AX15 tranny in there. Didn't know if it was the AX15 or the Peugot. Now I know. At least I have that.

Eliminator89 said:

Cylinders #1-#4 in the 120-130psi range, #5-about 10psi and #6 about 120psi. All measured dry (no oil squirted in).

Hmmmmmmmm. Seems to be a problem here.

Time for a stroker!

I guess for now, I'll pull that piston and rod and see if I can fix it (JB Weld? ). Then this fall, I'll put together a stroker. Probably the budget 4.5. Not a lot of money to spend. Billet crankshaft, di-lithium pistons and neutronium rods would be nice but spendy.

I did find I have the AX15 tranny in there. Didn't know if it was the AX15 or the Peugot. Now I know. At least I have that.

Click to expand...

Well what is it with oil squirted in?
BTW 10# sounds like a broken valve spring, with a broken ring you could expect to see 50# 75#.

langer1 said:

Well what is it with oil squirted in?

Click to expand...

A valid question as the problem could simply be a burnt valve. It won't stop you from building the stroker, but sometimes budgeting can slow down life's little pleasures. A valve job now may give more time to build the good block cast from unobtanium.

Otherwise, go for it.

Yeah, definitely try that again with the squirt of oil. It be a shame to do all that work for a bad valve. Although a stroker would be reeeeeal nice...
Jeep on!
--Pete

ComancheClub.com

Well, when I pull the oil cap off while idling, it puffs smoke out the valve cover like an old locomotive. Poof! Poof! Poof! Poof!

Holy piston! Batman!

I believe that symptom eliminates (pun intended) a bad valve and the bad gasket idea. Seems to me the only easy way to get combustion pressure into the crankcase is through the piston. If its a bad ring, seems to me it would have to be both compression rings. I see having both rings wrecked as unlikely.

In any event, I plan to replace the engine. During some previous work, I saw damage to the bearings that made me think the PO ran it low on oil.

I'll probably buy a junkyard engine and do the stroker later this fall or this winter.

Why could that not be a bad valve spring? Either problem means a hole in the chamber that allows pressure to escape out into the rest of the engine, both running and during the test. Or am I simply not understanding things?
Jeep on!
--Pete

Bad valve would let the combustion pressure into the intake or the exhaust. I have it coming out of the valve cover which means its getting into the crankcase.

Couldn't the pressure cause it to escape past the valve seals?
I'm definitely out of my element here. Quick, somebody ask me how to open the hood when the cable snaps. :laugh3:
Jeep on!
--Pete

OK, its a bad valve.

About the hood: Can opener?

Eliminator89 said:

OK, its a bad valve.

About the hood: Can opener?

Click to expand...

Do a search for the hood, but to start you need to remove the head lights and baskets, you can the get at the bolts for the hood latch .http://www.naxja.org/forum/showthread.php?t=62063&highlight=hood+latch

Large amount of blowby can only be caused by a couple of things. A hole in a piston or rings that have broken, been ground up and basically migrated away from the side of the piston, or a bad head gasket (not real common), or a cracked head. Unless the rings really got hosed, my money on a 10psi reading is a hole in the top of a piston. Gasket and cracked head normally won't drop it that much.