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Replacing Front oil seal in timing chan cover on 400 big block

Replacing Front oil seal in timing chan cover on 400 big block

Old May 4th, 2018, 10:50 AM
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Replacing Front oil seal in timing chan cover on 400 big block

Well, I took off the timing chain cover and the front oil seal came out with it in the bottom, inside a cut grove in the cover, Can I replace this seal without removing the oil pan?

Thanks!

Barry
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Old May 4th, 2018, 01:04 PM
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Originally Posted by barryrsmith View Post
Well, I took off the timing chain cover and the front oil seal came out with it in the bottom, inside a cut grove in the cover, Can I replace this seal without removing the oil pan?

Thanks!

Barry
Yes, but...

This is one of the biggest challenges on an Olds motor. Normally, the front cover is installed before the pan, and thus the pan easily compresses that seal. Your problem will be to get the cover started over the two dowel pins while simultaneously compressing that seal against the leading edge of the pan. This is not an easy task. If you can pull one of the dowel pins, it's much easier. Then you can grind a chamfer on the end of the pin and force it back into place to compress the pan.

I've also had some success with using screwdrivers in two of the bolt holes to lever downward on the cover to compress the seal. Basically you angle the cover into place, starting with the seal. Use the screwdrivers to push down on the seal while tilting the cover into position. Sometimes you can get the bolts to the block started and then use them to pull the cover home. I haven't tried this yet, but you might consider getting a couple of pieces of threaded rod to go into the block bolt holes. The bolts are a little short to get them started easily. Once you get the threaded rods started, use nuts to pull the cover in.

Of course, you need to trim the "ears" off the ends of the new seal. These are designed to be clamped between the pan and the block to close out the oil pan seal, but obviously that isn't going to happen if the pan is in place. Instead use RTV to seal the ends.
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Old May 4th, 2018, 01:37 PM
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THANKS JOE!

That gives me a few ways to try and get it on there.

Man I worked up a sweat something fierce yesterday trying to line up them pins and compress that sucker into the pan.

I did not remove the ears so that may help.

I was thinking about just loosening the front oil pan bolts and see if I could separate it a little then put the cover on, put rv on the pan and bolt it back up.

But would rather not brake the seal if I can, so I will try the for mentioned.

Barry
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Old May 6th, 2018, 04:00 PM
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I did that job once upon a time and did what Joe suggested plus I let the front seal warm up in the sun before the fun started.
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Old May 6th, 2018, 09:08 PM
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I did the same job on a 351/M400 in a Torino once and it was just about the same. It was about a 3 hour wrestling match trying to get everything just right. Thought I had it several times only to find some aspect of the rubber seal was not exactly right. Lots of wiping things dry and re-applying silicone in the corners each time I pulled the seal and put it back in for another try. Don't give up 'cause if you put it back together with something not perfect, it will leak and you will hate yourself for not getting it done properly the first time. Taking the front cover off a second time because you didn't get it right the first time sucks! I found that using a pair of scratch awls to lever the cover into place worked better than screwdrivers because they are smaller on the ends and will stay in the block holes better. They will also pivot farther and the tapered shafts make the cover a bit more willing to slide into place. Good luck!
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Old May 7th, 2018, 03:46 AM
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Yes not a fun project – IMO - Installing a seal and cover w/o fully dropping the pan on 350/400/455 is big waste of time and money. Modifying the seal may just cause a leak now or later on. This is just one of those projects that should be done correctly, per manual. I replaced the seal, did the loosening of the front pan bolts trying to get clearance for the cover seal etc…Tried shaving the seal ends etc. Took hours of messing around trying to get the cover/seal on, damage one seal, messed up the clean cover repaint. In the end got a slight leak on the pan/cover seal, so again was not worth it to me. Next time I would just drop the pan.
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Old May 7th, 2018, 07:24 AM
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Well it's in there, I THINK!

Is the seal suppose to go all the way in or just the rear halve?

The bolts are all tight and the cover is flush against the block but the seal is like halve way inside the pan, if that makes since.

I uses the all thread about 4 inches long and nuts to pull it in once the pins where lined up, and plenty of silicone helped it to slide in.
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Old May 7th, 2018, 07:31 AM
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Originally Posted by barryrsmith View Post
Is the seal suppose to go all the way in or just the rear halve?
The seal is supposed to be completely inside the lip of the oil pan. The metal front cover should be flush with the leading edge of the pan. As is, you are bending the bottom of the cover, which can distort how the crank seal rides on the balancer and cause premature wear. This is not an uncommon situation, as I have exactly this situation with the 307 in my wife's car, and it leaks. I suggest you loosen the bolts on the pan, remove the balancer, and use a block of wood and a "fine adjustment hammer" to drive the seal and cover into place.
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Old May 7th, 2018, 07:31 AM
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The seal should fit in the groove at the bottom of the timing cover in such a way that the ends (along with silicone) fill the gap where the pan meets the block and the main body sits directly on top of the rolled edge of the pan. If it is sticking out in an awkward way or too far inward anywhere, it needs to be corrected. If it looks smooth and uniform all the way around the bottom of the timing cover to pan gap, then it is correct. Post a pic and you'll get lots of advice and armchair quarterbacking to let you know.

Last edited by cjsdad; May 7th, 2018 at 10:09 AM.
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Old May 7th, 2018, 09:49 AM
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ARRRRRG!

I had a feeling that was not correct

Back to the auto parts store to rent the puller again.

Honestly think I will drop the pan slightly and try that if the hammer doesn't work.
Thanks for saving me all the work of having to take of all the stuff to get to this again!

Barry
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Old July 2nd, 2018, 05:41 PM
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Damn...wish I'd seen this thread a couple days ago. I've fought it into place, time will tell if I was successful. Hopefully it will be good enough to last another couple months...that should be all I need.
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Old July 2nd, 2018, 05:57 PM
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I ended up looseningg the front three bolts, getting a chisel wedged between the pan and block on the very outer edge on both sides at the same time and it finally sit all the way back and cover fit smooth against oil pan.
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Old July 2nd, 2018, 07:10 PM
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Okay guys u drop the pan, your breaking the pan gasket seal to the bottom of the block right? Is that not issue too? Or please tell what I'm missing. Just chiming in because I may have encountered the same issue on a 400E. I was going to pull the motor this late fall or winter....
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Old July 2nd, 2018, 08:02 PM
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Originally Posted by barryrsmith View Post
I ended up looseningg the front three bolts, getting a chisel wedged between the pan and block on the very outer edge on both sides at the same time and it finally sit all the way back and cover fit smooth against oil pan.
I used red silicone gasket sealer between the existing gasket and pan , also around the outer edges, cleaned the area with a thin screw driver with a disposable blue rag and degreaser a few times to remove oil residue, tighten it up a little till it squeezed out slightly, waited about an hour then tighten it up to torque specs, I have 30 lbs pressure at idle and 50- 6p,trying, no leaks
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Old July 2nd, 2018, 08:05 PM
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Originally Posted by barryrsmith View Post
I used red silicone gasket sealer between the existing gasket and pan , also around the outer edges, cleaned the area with a thin screw driver with a disposable blue rag and degreaser a few times to remove oil residue, tighten it up a little till it squeezed out slightly, waited about an hour then tighten it up to torque specs, I have 30 lbs pressure at idle and 50- 6p revving, no leaks
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Old July 2nd, 2018, 08:36 PM
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Never thought a 400 was a big block.
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Old July 2nd, 2018, 08:47 PM
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Yes sir,in 69
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