rear main seal leak

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May 3, 2008 | 10:53 PM

excessive81

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From: indianapolis indiana

rear main seal leak

i built a forged stroked ls3 for my blown 05 vette. problem is rear main seal is leaking(second time). i have the complete gm j tool kit for these motors so i am using the rear cover install tool and the rear main seal installer tool as well. i thought i had it fixed as it started and ran with no leaks but when we came back from eating to finish it up there was a little puddle on the floor. so i started it agian and it was dripping of course.....sounded bad *** though...open lg headers...lol... any way is there a trick or somthing to this

May 4, 2008 | 08:02 AM

SpinMonster

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From: Colorado Springs, CO

St. Jude Donor '08-'09-'10-'11

Last motor I did, I put the seal in the cover and slowly centered it on the crank since the seal points toward the motor and makes it hard to get on without a wrinkle. I didnt use the J-tool since the oil pan was off and it centers itself in that case. The cover is then tightened down and the oilpan is then attached without affecting the z-axis on the rear cover which is what mandates the use of the tool when the pan is in place. My point for the long winded explanation was to ask if you used the J-tool with the oil pan on or if the cover could have centered itself without the tool the way I do it? Also did you add RTV to the corners?

May 5, 2008 | 07:33 AM

excessive81

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From: indianapolis indiana

well last two times motor has been in car so i used the j tool for centering the cover not the one for the bottom since pan is in place. the new seals have a reverse lip ie the lip faces out. i had a guy on ls1 tech say with blower cars i should install it backwards...with lip slanting towards crank. it a callies dragonslayer crank by the way (apparently there is a issue with the eagle cranks). they also mentioned adding more crank case ventilation. what you think about tieing the drivers side valve cover fitting that is plugged into my catch can system.
thanks

o and yeah rtv'd the corners

May 5, 2008 | 11:25 AM

andreas g.

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From: laguna niguel ca

Quote:

Originally Posted by excessive81

I vent the valve cover to my catch can from the top of the oil fill cap with a 90 degree fitting. The pipe from the valve cover is pluged. So I have both the PCV and the breather going into my can. I've been flamed for not having a fresh air into my crank case at idle. Yet after 12,000 miles, no leaks, great neg pressure which gives me great ring seal, with forged pistons in @ .055 clearance, and no oil in my intake.
It works for me. I could care less what the forum mechanics think. With blown motors it's even more important to have neg pressure in the crankcase. I know it looks right to have the seals in backward the way the lip is but it doesn't work. Put it in the way GM says and simply create neg pressure in the crank case. I've herd from some that you can actually suck air pass the seals into the crank case with high neg pressure, how high I don't know. My LSA is 112 so at idle my vacume isn't very high. Maybe that's why I haven't had any problems in over 12,000 miles with my set up. A&A corvette did my forged motor give them a call and talk to Andy green. I'm sure he can help.

Last edited by andreas g.; May 5, 2008 at 11:35 AM.

May 5, 2008 | 12:45 PM

Zig

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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)

i suspect, as long as none of the gaskets are leaking, which, btw i prefer to install as 'recommened' not backwards, but then again, that would have to also include, if they don't seal properly one way then yep, turn them over.

i suspect you've got too much pressure and not enough vent.

try opening up the 'pcv system' a bit. i'd be tempted to open up the 'fresh' air vent and the pcv outlet (into a catch can, of course

) . that should help get more 'flow' through the pcv system.

if you build too much pressure you will blow. same thing happens when there isn't any pcv flow or vent cap. the engine continues to build pressure until there is relief. if there isn't a 'pressure release' the seal, which are weakest fresh, blow/leak.

i'd put her back together and try her with either a 'vented oil fill cap', or a larger flowing pcv system.

May 5, 2008 | 09:02 PM

SpinMonster

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From: Colorado Springs, CO

St. Jude Donor '08-'09-'10-'11

Quote:

Originally Posted by excessive81

I'm not sure what you mean by 'new seals'. The 2005 seal lip faces toward the crank which is why its hard to put on. Did it change on 2006+?

May 12, 2008 | 05:54 AM

excessive81

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From: indianapolis indiana

yeah it is a revised seal

May 13, 2008 | 10:55 PM

excessive81

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From: indianapolis indiana

well i not sure what the o5 seal is but i built a ls3 for my car. the new sel leans towards the clutch....seems that the issue. i put it on backwards...aka like the old ones and no leaks