69 Fury Sport with 383, 2bbl develope massive blowby last fall so we parked it for a while to get past the holidays and prepare for paying our taxes to the kingdom on april 15.

The problem seemed to occur very quickly during a 3 week period when my teenage son was driving it everyday while repairng his normal ride. I don't know if he flogged it to death or if it overheated. There was a coolant leak issue that occured at this time which I repaired but maybe too late.

I built a leakdown tester, removed the rocker arm assembly so all valves would be closed and not have to worry about TDC. Blowby seems to go thru the lower end and not the intake or exhaust as long as the pcv valve is not connected. Air blows out the valve covers. I figured after the #1 cylinder test I probably had worn out rings but then I checked the rest last night. Following are test results.

1=65%, 3=99%, 5=70%, 7=99%
2=99%, 4=99%, 6=98%, 8=98%

Seems to be great numbers for an old engine except for #1 and #5.

No air is blowing into the coolant. It has been suggested by a local mechanic that a blown headgasket or warped head is allowing air into the oil return holes in the block/head?

Any ideas would be appreciated?

Thanks in advance.

 

well if you have air coming out the valve covers, it's valves/guides/seats.
They way I do a leakdown is pressure the cylinder and then I take a piece of fuel line and listen to carb, listen to the tailpipe and listen to the oil fill/dipstick tube. That will definately narrow down the problem. Hope it helped.

 

Excellent advise.

 

yeah it may have gotten hot and broke a ring or something . Or a piston land (what the ring sits on). If that is the case, the pressure would bypass into the case. Valves could do the same thing.
Check your valvesprings just for the heck of it. If you can push them down by hand, they are weak [like bad].

BTW, 40 year old Mopars and teenagers don't always mix well.