On my 400 SBC in my COE (new built engine to semi-stock specs - 100 miles / 10 hours running time - on engine) I have oil being pushed out of the engine. Based on the spray patternm I think it is being pushed throught the front seal on the timing cover. I swapped my solid filler cap for a vented cap and that helped a lot but it still leaks. I run a PCV valve connected to the front port of a quadrajet and it has good suction at idle and at RPM. There is no leaking at idle, just under load on the highway. I replaced the seal already with no improvement. The balancer is also new, so no groove.... ANone have any ideas what I should do to fix this? Dual PCV valves, run it into the manifold...??? I need Help...!!!!!!
It's probably blow by From the ring still trying to seat. If the vented cal Didn't help completely you might want to do a leak down test
When you replaced the front crank seal, how did it look? Did you replace the timing cover gasket? Posted using the Full Custom H.A.M.B. App!
It has a cheap chrome timing cover. The old seal was sticking out by 1/8". I could only get the new seal in almost flush, but noticed it too is starting to move out, the top feels like it is sticking out by 1/16". I bought a new steel timing cover and am thinking of replaceing the cover tonight to try and eliminate the slippery chrome. I wonder if the seal being out by a slight amount is contributing to the leak?
Bolt is in the block. I pulled the balancer off again and discoivered the new seal I put in last night, is damaged. the edge of the seal is torn off. It may be my fault, I did not oil the balancer shaft as I installed it, so it may have been too dry causing the damage. I also see where the seal had in fact slipped out of the chrome timing cover as I thought. SO...it will be a late night tearing the front end of the engine down to replace the timing cover and install a new seal. Maybe I'll just install the new seal in the chrome cover and deal with swapping out the timing cover later after I get the COE moved to KC.
Some of the cheap chrome covers have the seal off center. I've had to oversize the dowel holes in the cover and use the balancer to center before snugging it down before.
I put the new seal in (Fel-Pro) and it fit better than the Timken. Before I installed it, i sanded the inside of the hole to give the seal a better chance to hold in there and cleaned it with thinner to remove any oils. I also lubed the rubber of the seal and the balancer shaft and rotated the balancer as I installed it. I kept double checking to see that it wasn't binding up or twisting the seal edge inwards. It seemed to go in smoother than the Timken did last night. I think I caused the damage by installing it dry. It probably "folded over" as I installed the balancer. Too late to test it tonight. Man I hope this works...! I am really not into engines. I'd rather fab parts and brackets, wire cars and do bodywork. I'll replace the chrome cover when I have more time.
Sounds like the seal got burnt from being dry on start up. I had a cheap chrome cover with the hole off centre also. JW
Most of the chrome plated timing covers available have 5 to 8 spot-welds for the pan lip seal. The oil seeps out between the welds. This has ALWAYS been an issue with these covers, it isn't new. The factory pieces from G.M. have "hermetic" electronic weld (see below) along the entire lip. If you have an old G.M. cover available you can see the difference. Another issue with the chrome covers was the seal actually "popping" out while driving. Thanks, Gary in N.Y. P.S. You'll never stop the oil from seeping past the spot welded area, there is no "pressure" against this piece! See the photos below here.
How does the crank snout look? I have used a lot of crank savers over the years because the cranks get worn where they meet the oil seal. It is a little sleeve that slips over the crank snout.
I am still fighting with my oil leak issue. I took another look today and discovered the front pan seal was split down the center with a large part of it just hanging out away from the pan. I am not convinced this is the leak. I do not see how oil could jump from this seal into the balancer and be thrown everywhere. Also, there is no tell-tale leaking down the front of the pan. As for the front balancer seal, it is still firmly seated in the chrome timing cover. I tried high revving the engine in the garage for a few minutes...no leakage anywhere. ??? My plan is to tear off chrome cover and replace it with a new steel cover and re-seal everything. Sounds simple until I realized that the engine needs to be removed to get the oil pan off. If I have to go to that extreme, I plan on painting and cleaning everything. I really hope it does not keep leaking after I do all that work... I checked and the bolt is in the block by the fuel pump, I will replace the timing cover and seal, the balancer is new and I will re-seal the oil pan... I checked and the manifold and valve covers are not leaking. What am I missing?
One other detail is that I always smear some RTV on the damper where the end of the crank goes into it, to keep oil from running out the keyway. This generally won't be a big leak, just seepage.
If you take the pan off you might replace the gasket with one of the one piece blue silicone ones (felpro) with the metal rings so the pan bolts can't tightened down too tight. I've had very good luck with these. Shit can the chrome cover and use an original.
Uhhhhhhhhhhhh guys,I`m not the sharpest tool in the box,BUT kscarguy said that he was trying to not let the seasl lip fold back when he was installing the balancer. Now it seems to me that he MIGHT have installed the seal backwards.The taper of the seal is supposed to face the block,not the back of the balancer.If I`m wrong,fire up the flame throwers,I`m ready. Good luck.Have fun.Be safe. Leo
Could be...but also there is a small lip on the outside of the seal. If the chrome timing cover is as crappy as some of them I've seen, the seal hole is offset, so the little lip on the outside will fold over on one side as you install the damper.
There are two different thickness rubbers that go around the bottom of the timing cover. If you put the thick one where the thin one belongs it will eventually split like the one in the pic then leak like hell. If you put the thin one where the thick should be it will leak like hell from the get go. The early SBC's used the thin one. Sometime in the late 70's or early 80's is when GM change the timing covers to start using the thick ones. All of the new GM brand chrome timing covers require the thick ones.
^^^^^I was about to post exactly this, it depends upon the spot welded groove in the timing chain cover as to which front rubber you use, compare it to another once your cover is off. The difference is obvious.
Ugh....I hate how the pan/timing cover is sealed on the SBC. The best thing I've found to fix that front pan seal is the one piece Felpro gasket. It's pricey, but it works.
I believe the difference is in the oil pans not the timing covers. 1955 to 1974 pans used a thin seal, and 75 to 85 used the thicker seal. This info came from John Lingenfelter's book on SBC's. You can measure the depth of the front sealing lip on the pan to verify this. It is either 2 1/4" or 2 3/8" The post about the spot welds on the timing cover causing leaks is spot on as well the one about the timing cover being off center. in relation to the crank snount.
I have dispute the last post. I just put a new Chevy crate motor in a 65 Chevy 2 for a customer. It had the stock front sump pan and a new GM chrome timing cover. I first installed the thin rubber and I could slide a seal pick in the space between the pan and rubber so I had to remove the pan and put the thick one in.
If you're having trouble figuring out which oil pan or front seal you have, or need, '74 and earlier models used the thinner front seal. '75 and later models used the thicker front seal. If my memory serves me correctly, which it does occasionally. I think many of the aftermarket gasket kits are likely to contain both style front pan seals.
I pulled the timing cover off today and took pictures of the Aftermarket chrome vs. the stock GM cover. The chrome fits like "crap" and has the spot welded inner seal support. Sealant actually came up between the spot welded seam, meaning oil could get out. The curve at the bottom does not match the curve of the oil pan and the alignment vertically down the front of the engine was off. I think someone pulled it off a motor without loosening the oil pan and bent it. Here are pictures of the chrome vs. stock cover fit.
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