no compression #2 cylinder

[70twocan]

1977 Bronco with a 1977 302 that has serious blow by. I did a compression test and the #2 cylinder is ZERO. I preform a wet test (add oil to the spark plug hole) and the compression jumps up to 110lbs.

The PO let it sit for a couple years then pulled the Bronco out of a barn and said that's when the blow by started.

I put some off the shelf cleaning solution on top of the pistons and will let it sit overnight.

I'm thinking I have bad piston rings on the #2 piston. Before I tear it down, I thought I would ask if anyone has had this problem before and if so what was the fix? (replace piston rings?)

 

[70twocan]

Any thoughts?

 

[darkmagus]

Well if it went up on a wet test then it's almost certainly rings. Valves or something like a hole in the piston wouldn't change during a wet test.

 

[70twocan]

Looks like the oil pan will come off tomorrow then.

 

[73azbronco]

Uh, how about do some more soaking with kerosene ?

Or I'd say throw some gas in it, use some 30wt oil with seafoam in it and run it for 30 minutes.

 

[Blue Bastard]

^^might get lucky and have a ring free up. Nothing to lose there except some time.


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[Broncobowsher]

My guess is that is the reason it was really parked in the first place, then forgot about. Most of the time when something is parked it is parked for a reason (or multiple reasons). Or that cylinder got some rust when stored and that broke a ring or two when it was started.

Maybe it is just stuck, but I am not counting on that.

How much has it been driven since it was woken up?

 

[hucklburry rev2]

I'd probably pull the valve cover on that side first just to see what the valves are doing, its easier than the pan, so its where I would start, despite the oil test. Make sure the valve(s) aren't sticking open, it doesn't take very long to pull a valve cover off.

 

[ledslinger29]

I've never heard of a ring 'freeing up'. Valves however, they can free up fo sho.

 

[wildbill]

;D;D;D I had one like that took 3 days to fix I used liquid wrench. Run the motor till warm and put down the carb. with the motor running fast idle about 1/4 can and shut motor off and let sit over night. Do it the next day morning and night then the next day do it and go for a drive. This worked on the one I did and it would smoke for a couple of days then ran very good. I sold it and the drove it about 30 days and it passed cal. smog. I wish you good luck with your's. ;D;D;D; Bill%)

 

[70twocan]

Truck sat for a couple years and I have now ran it for a couple hours. I soaked the top of the piston with seafoam last night, Valve covers came off, valves have proper movement, and compression test jumps up when I add oil to the spark plug. I am going to repeat the same process a couple times. Fingers are crossed. I've been able to revive rings before, but I started the process with low compression(not ZERO).

 

[Justafordguy]

I've had the same luck as Wild Bill but using ATF instead of the liquid wrench.

 

[blubuckaroo]

Lacquer thinner or Berryman's Chem tool.
Nothing breaks up varnish better.
Using this stuff will leave the cylinder walls dry, but if anything will free it up, this will.

 

[70twocan]

After last night the compression jumped up from ZERO to 40psi. Ill try the ATF tonight.

 

[Rustytruck]

Warm up the engine and then put the piston at the bottom of the hole then put put in a fair amount of ATF and let it soak for several days. A turkey baster through the spark plug hole works pretty good to get the liquid in. Then turn over the motor with the plug out to pump out the excessive liquid and then put the plug in and fire up the engine. Putting the piston at the bottom of the hole, the bore is less tapered there and have a greater chance of keeping the Atf in the cylinder long enough to do some good. Any time you soaking a cylinder always pump it out with the spark plug out so you have no chance of hydraulicing the motor and blowing up a piston or bending a rod.

 

[73azbronco]

Yeah thats why I said 30 minutes for seafoam then i did leave out the remove it part by draining the oil. Directions say drain it right after you use it, the volatiles evaporate. If your leaking out seals they would leak with 30wt anyway. Then I'd use the ATF method.

 

[70twocan]

Thanks for the advice on the ATF. Ill be trying it tonight.

 

[70twocan]

Cylinder pressure up to 70psi. ATF in it. Now I wait until tomorrow. Slowly but surely I'm hoping the psi continues to climb.

 

[70twocan]

Ugh, 1 step forward and 2 steps back. The cylinder pressure was down to 30psi and I found a large amount of tiny metal shavings attached to the magnetic oil drain plug. I think it may be time to pull the head.

 

[rjrobin2002]

Just pull the oil pan and then piston/ rod and have a look see.