SBC 400 leaks oil

[67weimann]

SBC 400 unknown miles or time on motor... leaks oil from the timing cover seal around the balancer. Dude said he replaced it, while it was in the truck, and put a chrome timing cover on it. Says oil didn't leak after swap but after romping on it, it started to leak again but "not as bad"...What could the problem be? I am looking for a junkyard motor to throw in the boat while I build the new mill. I would rather take a chance from someone who owned it and knows what's wrong, to a certain extent, with it. What does everyone think? Buy for 3 bills or look elsewhere?
I'm set up for SBC so BBC or BBF are not an option.

[obnoxious001]

If that leak is the only issue you want to take care of, pull the balancer and see if it has a groove worn in it. If that is the case, for about $5 you can get a sleeve that fits the balancer to eliminate the leak, or you could replace the balancer. If there is no groove, look closely at the seal. If the rubber of the seal looks ok, perhaps it was installed in the cover with no sealer which would also be an easy fix.

[Moneypitt]

Those seals aren't made to hold liquid oil above them. If it has too much oil it could cause it to leak...Also, what type of breathers does the engine have? A breather tube to the airfilter, AND a PCV valve are needed to evac the pan corectly. Other than that it would/could seem to be too much internal crankcase pressure from blow by......Also, balancers do wear in the seal area. There is a gasket/seal kit called a "sleeve and seal".....A very thin sleeve that slips over the balancer to re new the sealing surface. I have used a few in the past and they do work............MP

[67weimann]

Also, what type of breathers does the engine have? A breather tube to the airfilter, AND a PCV valve are needed to evac the pan corectly. Other than that it would/could seem to be too much internal crankcase pressure from blow by......MP
It had a push in breather and I'm assuming it had a pcv valve. Does it have to have both?
He said when he replaced the seal he used the "sleeve". So a faulty install may be the problem?
I'll pull the balancer and inspect tomorrow. Anything I should be aware of on the crank snout that may be a problem? Looked at it tonight but had no time to inspect...

[obnoxious001]

He said when he replaced the seal he used the "sleeve". So a faulty install may be the problem?
I'll pull the balancer and inspect tomorrow. Anything I should be aware of on the crank snout that may be a problem? Looked at it tonight but had no time to inspect...
Look closely at the seal, inspect for any small tears. Make sure you lubricate the seal and balancer when you put it back together. As long as you are taking it apart, I would say buy a new seal. I use gasketcinch on both the seal and timing cover when I put a seal in. You should be able to see where the seal is running on the balancer or sleeve.
I suppose it is possible that the sleeve is not on the balancer correctly, and is allowing an oil leak?
You should have a better idea once you pull the balancer and take a close look at everything.
Any chance your leak is the corner of the oil pan, not the front seal?

[steelcomp]

This is an age old problem with Chev engines. The front timing cover is located with two dowel pins. If the hole in the timing cover isn't exactly in the right place, (which few are) the seal and crank are not concentric, and no amount of repair sleeves are going to fix the problem. There are a few ways to fix this, but if you can't get it to stop, try a new timing cover.
Edited to add...lose the chrome Tiawanese cover. I can just about guarantee that's your problem.

[Rexone]

Edited to add...lose the chrome Tiawanese cover. I can just about guarantee that's your problem.
Yeah no shit. There's a reason they're cheap. They're cheap shit. Thin metal and I've heard of seals being out of concentric. GM cover only is good advice, even if not chrome.

[502 JET]

The motor is worth 3 bills all day long as long as you don't blow it up.:jawdrop:
Make sure there is not excessive crank shaft thrust clearance.
Loose the 30 year old balancer and the $2. cover. You can buy a new replacement balancer from the parts store for around $65.

[pocketchange 22]

What a bitch, I had problems with a timing cover drips. After taking apart fe times, the chrome plating is your problem, gaskets nor sealent will stick 2 the plating. Scrap the chrome, and buy a stock GM, or a quality aluminum.:devil:

[Moneypitt]

This is an age old problem with Chev engines. The front timing cover is located with two dowel pins. If the hole in the timing cover isn't exactly in the right place, (which few are) the seal and crank are not concentric, and no amount of repair sleeves are going to fix the problem. There are a few ways to fix this, but if you can't get it to stop, try a new timing cover.
Edited to add...lose the chrome Tiawanese cover. I can just about guarantee that's your problem.
The guide pin holes may be keeping the cover off center....As mentioned...Open them up to clear the pins, AND install the balancer BEFORE tightening the bolts......This allows the balancer to center the seal while the cover can move around a bit...............MP

[steelcomp]

The guide pin holes may be keeping the cover off center....As mentioned...Open them up to clear the pins, AND install the balancer BEFORE tightening the bolts......This allows the balancer to center the seal while the cover can move around a bit...............MPFord trick.
Dammit Ray, ya can't be givin away all our old guy secrets! It's all we got left!
Sheesh!
LOL! :D

[Moneypitt]

Ford trick.
Dammit Ray, ya can't be givin away all our old guy secrets! It's all we got left!
Sheesh!
LOL! :D
Hey, if the engine leaks oil it goes in the bildge, what goes in the bildge will eventually wind up in the water.........Just doing my GREEN part for the month.....After all, fish **** in the water. Would you like to be ******* and have dirty, oily water all around you?.........Ray
PS, I got a few "old guy" secrets left.......Like how bad do cracked heads have to be cracked, before you can't get 20 or 30 more miles out of them!!!!!!

[Beer-30]

Flimsy chrome cover as previously mentioned several times. Dump that and get a nice aluminum one. Tighter clearance and won't warp when the seal is being pressed in.