way too much pressure

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hamesdart

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Ok so i have a mild 440 in my car.
68 hp motor,10:1 compresson is what is advertised for stock.
509 cam and so on.
Now out of no were it started running choppy like the carburator was out of tune or something but then i looked and saw the valley pan "popped out" like there was so much pressure it just pushed it out. wasnt sure what it was until i saw there was a hole in my pcv valve. so im guessing it was too much crankcase pressure.... does anyone thing theres a serious problem here?
when i ripped the motor down yesterday everything looked perfect but there was very very very slight play in the piston side to side if that means something too.
any ideas? just getting worried there mite be a huge problem.
 
yah i have one breather but because of my valve cover set up is the twist style its a ford breather and it is somewhat restrictive i think and the other side is the pcv valve and it had a hole burned into it so i dont think it was even venting correctly but im wondering if the breathers alone could cause this or if there could be a bigger problem?
 
Before you tore it down would have been the time to test the ring seal. You could carefully remove the rings now and measure end gaps. It takes a lot of pressure to pop the intake backwards. IMO that is a big sign of ring seal issues when there's a pcv and/or breather in place.
 
yah,Unfortunitly the leak down test i should have done before i tore it down is out of the question.....
but from my understanding if there was that much pressure leaking through the rings to do this then i would have hear a miss or had a dead hole.
and keep in mind with a hole in my pcv valve so all i had breathing the crankcase was a small cheapy breather cap.
And if it matters any I also am at about 10;1 compression on this motor.
 
What do the tops of the pistons look like? If there's a crapload of blow-by, it'll probably show visually.
 
pistons from top and bottem are in good shape.
There is some burnt oil in the centers but not an unusual amount for original pistons.

I did a little more research and found this article and pulled this part.
"If the PCV system is not functioning
properly, the flow of crankcase vapor into the intake manifold will not be properly metered.This, in turn, will upset the fuel/air mixture for combustion and cause rough idlingor even stalling of the engine."

This sounds like an explanation to the recent rough idling as well.

See overall i only drive the car a few times a year.
Last august i raced it and parked it ever since.
maby drove 10 miles to a car show two times after that.
within those two times i drove it is when the valley pan popped out and also started running a little rough,
im not doubting anyones experience or opinions.
Im just trying to pull all the information i can on this and collect opinions.​
 
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