rear main seal/ v cover leak???

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Johnny Mac

Johnny Mac

www.blueprintengines.com
FABO Vendor
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OK fellas, apparently my 408 (LA 360 base/mag heads) has managed to spring oil leaks in every direction just from sitting in a garage all winter. the engine has probably 20 quarter mile runs last year and maybe 150 street miles, then it got garaged up for the winter. my problem is when i started it up this year. it began smoking on the pass side pretty good so i shut it down to find some oil drips on the headers...almost looking like it came from a leaky filter, but it was dry. upon further inspection there was a few drops up on the block behind the pan. so i wiped it all off, and tightened the pan bolts pretty good. and it seamed to fix it.
today i go out to adjust my shift linkage, and lone behold more drops in the exact same spot, smoke and such...so hoping it was just leftover from last time. i did some full stall launches at 4000 and then parked the car. now not only were there definite drops every time i back the car up...but the TOPPP of the motor is also covered on the pass side...there was spray on my alternator...heater hoses...and valve covers. i swear that these mopar cast aluminum valve covers, with their cheap *** foreign oil caps are a leaky nightmare. so i'm hoping i find a broken/torn gasket when i pull them off...but the leak on the rear i'm most concerned about...do you guys think it can be my valve covers leaking and dripping down out of the junky oil cap...or could it be the rear main seal? or even just the pan gasket... i don't want to pull the motor again...but are the rear seals on a 360 LA block prone to leaking? anyone else had nothing but trouble with sealing cast aluminum v covers?

thanks guys
 
"Tighten it pretty good" might just be the problem. My strategy (let the flame war begin) over the years is this:

On the intake, I use composition gaskets, and throw away the end seals, use silicone only on the front/ rear of the intake Use high-tack around the water passages only

I use ONLY cast aluminum valve covers. Use "high tack" (Aviation 300 or something?? Sloppy red, like contact glue) glue the cover gaskets to the covers, screw them down LIGHTLY to plywood overnight, then OIL the head side of the covers if you have adjustable rockers. If not, high tack 'em to the CLEAN head side

Oil pan, high tack, Silicone on front / rear, NO rubber seals. Engine/ sheetmetal MUST be absolutely clean, and let it set for 2 days TWO DAYS before starting engine.

Use teflon/ sealant on oil gallery plugs, and oil sender.

Engine MUST be well ventilated. If something in engine is generating excessive pressure, such as lots of blowby, then PCV/ one breather may not be enough.

Most important thing is DO NOT OVERTIGHTEN tinwork. I used to use a screwdriver handle on valve cover bolts, and the pan does not need to be much tighter. Once you "dimple" the sheetmetal with the bolts, you create a wavey line, the gasket will compress, and it will not seal.
 
oil press gauge is fine, looked right at it and examined the line...and yes the blowby on this thing is ridiculous(hope it subsides with break-in), my best setup so far has been to use 2 evac style breathers with simple rags zip tied on the end. there is soo much valve train oil slosh that thats all i can get by with..come to think of it i did swap one of them out today for a PCV breather...that must be where the valve cover blow came off of..so back to evac breathers for me... now for this rearish leak....? i'm gonna have to jack it up again and lay under there with it running and just watch...i thought it was the pan but i really hope its not the seal
 
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