69 350 motor

[blown&0chevelle]

hey everyone. Was wondering if anyone had any tricks for my issue. I just replaced my rear main seal and someone talked me into buying that lucas oil stop leak. So I mixed 1 quart to 4 quarts like it said and now my motor is slow turning. In turn my starter moves very slow and can't turn over the motor. Got a brand new battery so power isn't the issue. Thanks.

[geezer#99]

Did you have it running after the rear main change out and before the oil mix being put in?

[truckster]

I would ask the same question. It goes to whether the seal and the main bearing cap were installed correctly. That would be my first concern.

[Wrenchbender Ret]

If you did not remove any brg. caps other then the rear, I cant see how that would cause this problem. Did you hook up all the cables? A good ground from the engine to frame?

[cdowns]

Mee too i'd check andf clean all the cables for proper condutivity

[mechanicalman]

Originally Posted by geezer#99

Did you have it running after the rear main change out and before the oil mix being put in?

X2, key issue.

[mechanicalman]

I don't see how a properly replaced rear main seal OR the stop leak oil being an issue with the engine turning slowly. I'm thinking bad starter or cable/connection as a coincidence or result of engine lifting/starter removal during the seal change.

[Wrenchbender Ret]

Another thought. Maybe you bumped the dist. & moved the timing way advanced.

[mechanicalman]

Originally Posted by Wrenchbender Ret

Another thought. Maybe you bumped the dist. & moved the timing way advanced.

Hey yeah good catch. If he bumped it on the a/c or heater housing that would advance it.

[blown&0chevelle]

turns out it was a bad ground wire. starter was working improperly

[blown&0chevelle]

got another issue. replaced my rear main seal but now it leaked again. I never had an issue until I got new edelbrock intake manifold, headers and new 600cfm holley Could I be building up to much crankcase pressure. I don't have a breather but, my pcv valve seems to be good.

[leftybass209]

I can't speak for crankcase pressure and it's specific influence on the rear main seal, but what does have a lot to do with that leak is the initial design of the seal and a super clean surface with properly placed sealant, which is not impossible, but hard to do on your back with the engine in place. Too much or not enough sealant can cause a leak, time can cause a leak, and a worn crankshaft in that area (not highly likely but probable depending on it's age and use). I also run a PCV and a breather.

[Wrenchbender Ret]

Could the oil be leaking at the rear of the intake manifold & running down the back.
You must have a vent besides the PVC valve.

[Churchill]

My truck has a 1969 TAX engine suffix 350 that I added an edelbrock intake, 600cfm carb, and headers to and has no leaks. PCV and a breather. Surely it wouldn't blow the main seal out if it was crankcase pressure before it blew something else out.

[special-K]

None of that stuff you did to the motor would create more crankcase pressure. Try a valve cover vent opposite the PCV. But, most likely it's a botched seal replacement or other leak from higher up on the rear of engine. it's not uncommon to have a replaced seal still leak. Sucks, I know

[Mike C]

Originally Posted by Wrenchbender Ret

Could the oil be leaking at the rear of the intake manifold & running down the back.

This. Did you use the rubber end seals? Those things always squeeze out and leak. Just use a bead of silicone. Black my favorite, gray seems to be flavor du jour though.

[mechanicalman]

Always start at the top and work your way down; if you don't, you can chase your tail in circles. Always use silicone to seal the ends of the intake manifold, make sure the surfaces are spotless and oil-free (brakleen) and always remove the carb from the manifold before re-installing (any amount of gas slop will destroy the silicone before it cures).

Like Special-K said, the rear main can still leak after replacement; the crankshaft can become pitted on the seal area and cause a leak. You can install an off-set seal that should last as long as the original one did. It's well worth using; be sure and use a good inspection/dust cover (leaving the cover off can accelerate deterioration). You don't need the fancy baffled kind, those let in more dirt.

Also, in addition to the aforementioned intake manifold leak, valve covers, external oil passage plugs and oil sending unit that can leak, there are galley plugs in the rear of the engine that can leak (rare) and a cam plug (less rare). I've seen them all leak in my career.

I would recommend NOT using the stop-leak oil if you install any new seals at all in the engine. That is designed to soften old, hard, dried-out seals and give them a little longer life. It would over-soften new seals and shorten their life (not the source of your immediate problem).

I've read good reviews on the 1 piece oil pan gaskets used on the pre-86 engines, but have not used myself yet. The 1 piece oil pan gaskets I have used on 86 and up have been all leak-free.

Make sure and use some very fine emery cloth and polish the seal surface on the crankshaft if you do the seal over again.

http://www.ebay.com/itm/Fel-Pro-BS11...70610639&rt=nc

http://www.speedwaymotors.com/SuperS...eal,34261.html

[frankslagoon]

I found out the oil plug hole was stripped out in the pan I used After I put the motor in. Dam. anyway I used the one piece felpro gasket. looked pretty awesome so I bought it. Seems to be working good and way easier to install under the trk. But, the rear seal is still leaking. I've had terrible luck tryin to replace em .

[mechanicalman]

Originally Posted by frankslagoon

I found out the oil plug hole was stripped out in the pan I used After I put the motor in. Dam. anyway I used the one piece felpro gasket. looked pretty awesome so I bought it. Seems to be working good and way easier to install under the trk. But, the rear seal is still leaking. I've had terrible luck tryin to replace em .

Well if you have to replace the pan you can re-use it the gasket and try the offset seals, and polish the crank area with fine emery cloth. Don't forget a dab of permatex on the flat spots on the main cap. Try to get a flex-light up there to see the cam plug and oil galley plugs.

Foot powder can be sprayed above the leak areas to check for leak trails or florescent dye can be added to the oil for use with a black light.