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Discussion Starter · #1 ·
Just got my 393 stroker falcon going. I ripped it down road a few times and was impressed by no leaks of any kind. So I leaned on it a little harder tonite Runs like a scalded dog. Had oil leaking from rear of the pan when I pulled it in the shop. I'm wondering if I'm building crankcase pressure. I have m/t valve covers with non breathing caps. But I do have breathers one in each valve cover. No Pcv valve. Does anyone have any insight??? Thanks in advance. RS59:confused:
 

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Did the builder put a dab of silicone sealer in each corner of the pan where the pan meets the rear bearing cap
 

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Discussion Starter · #4 ·
I have run the motor on numerous occasions. But just got car ready to drive last week. I have done a few burn outs and hole shots with it but never wound it up much till last night. I was wondering if the higher revs are building pressure in the crankcase that is more than the breathers on the valve covers can vent It leaked at the back of the pan where it meets main cap. Ford is front sump pan. Maybe the pans not sealed I'm a stickler for that stuff though. And it did not leak till last night right after I drove it.
 

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It's certainly possible that it needs more ventilation for higher rpm work. It's a simple fix, and not too spendy to try that first. I have two breathers and a PCV valve on the BBC in my Falcon, and no problems with breathers puking, or gaskets leaking. I just have two breathers on the SBC in my Austin, and no gaskets leaking, but do get a tiny mist out of the breathers when cruising at high rpm's on the freeway. I think a PCV valve would fix it, but I need to do major surgery to add one, as my carbs don't have a large vacuum port.
 

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I'm wondering are you talking a drip of oil or a puddle of oil. Reason why is the back of the block on my motor up top at the Intake seems to leak oil where the head meets and it will run down the pan making it look like my rear main is leaking. Especially after a good run down the road. I'm using the Moroso evacuation checkvalve system and I think it works. It's not gasser era but I was concerned with high revs when I did that. Although I don't have enough compression to need the evac system I think the negative pressure helps prevent oil blowing out in weak areas.
 

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Just a thought, if the oil sending unit is on the back of the engine like a MOPAR, if it isn't tight you can get a pretty good leak down the back of the pan/transmission area.
 

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Your not running the one piece silicone oil pan gasket are you ? I tried one of those on the 302 I built for my wife's mustang. Had to pull it and put cork back in. Or I've noticed with headers the right bottom corner of the right side valve cover gets super hot. I thought I was leaking at the main till I tightened the cover.
 

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Your not running the one piece silicone oil pan gasket are you ? I tried one of those on the 302 I built for my wife's mustang. Had to pull it and put cork back in. Or I've noticed with headers the right bottom corner of the right side valve cover gets super hot. I thought I was leaking at the main till I tightened the cover.
Amen! I'm not a fan of those one piece silicone pan seals. Leaked like a sieve!
 
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