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I recently rebuilt a 70 455 engine for my 65 Goat. The engine leaked at the Rear Main Seal very bad prior to the Rebuild. The engine had the old rope style seal. I installed the Viton Seal when I put engine back together. First few hours of run time I only had a couple of drops leaking but after a few drives it is leaking terrible making a mess of the underneath and dripping along the length of the car. Hate to do it but I have to remove the engine and I am going to try the "Graph Tite Seal" from the "Best Gasket Co." I sure hope this does the trick. I had used the Viton Seal on the 350 Engine in my FireBird and it seals good. I agree that The serations on the crank in the area of the seal are probably why a Rubber Lip Seal like the Viton could very well leak. I had followed the instructions on install of the Viton Seal to the letter. I even had a tech from "BOP" who makes the seal walk me through the install over the phone. I think it is a good seal, however it appears that it just doesnt seal in all cases.
 

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.... and if the engine has been align honed or align bored in the mains, the viton seal will have an even tougher time of it because those operations both result in the seal groove no longer being round, but sort of elliptical. I'm having the same issue with my car. The next time the motor comes out, I too will be going with the Graphtite seal.

Bear
 

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I have got my 455 engine ready to come out in the morning. I will then proceed with removing the pan, crankshaft, etc. When I got my car, the Rear Main seal leaked terrible. It had the rope style seal. I removed the engine and replaced with the Viton seal which I had a tech from BOP walk me through the process of installation. The Viton seal leaked worse than a sieve. Tomorrow I will start the process again of replacing the Rear Main Seal, thus removing the Viton Seal. I am going to replace with the new Graph Tight Seal from Best Gasket Co. I was wondering does anyone have any tips or experience with the Graph Tight Seal that I should know about when installing this Rear Main Seal. I so want this seal to do the trick and not leak. I do not want to go through this again. Is there any thing I should be looking for on the Crankshaft in the area where the Rear Main Seal goes that may be causing the issue, or should I just assume that the previous seals simply did not work. I was wondering if there could possibly be a thrusting issue with the Crank that could be causing the issue. Does that sound possible?? The engine is a 1970 455 HO. Crank has 10 under Main Bearings installed. As always, any advise is appreciated.
 

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BOP seal is great

After having a 455 with a leaking rope seal I switched it out to a BOP Engineering seal and not a drop. I just build a 400 and used the same seal and agter 1,000 miles still not a drop. Why take a chance with anything else? I k=just followed the install instructions fronm BOP and it was quite easy. I had the engine builder who originally built the 455 do the first install in with the engine still in the car and I thinni he did it with the mains loosened up and the crank dropped down a bit. I did the 400 install myself and it was a snap.
 

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I have JUST recently done this! It went extremely smooth... did not even have to remove the crank. Used a vitron seal from Tin Indian. can upload a few pics if wanted...
 

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I have JUST recently done this! It went extremely smooth... did not even have to remove the crank. Used a vitron seal from Tin Indian. can upload a few pics if wanted...
Yes...pics please. Remove engine?? or raise and take the pan off?? OR?? Comments on how you got the old one out and new one in, any sealant at the joint etc. Since crank still in, did you loosen caps to raise it slightly or?? Tx:eek2:
 

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You will hear from folks who've successfully re-sealed Pontiacs without having to pull the motor, but you won't hear from a lot of them. The safest way is to pull it. BOP has a new 1-piece seal out now that seems to have a lot going for it. Installation requires you to cut it in one spot in order to fit it around the crank and at first that seems wrong... but when you think about it, if you make the cut then you can be sure that both "sides" are going to mate up with each other perfectly. The crank and seal assembly are then installed into the block with the cut facing up (center of the block portion of the seal groove). This new seal also has two sealing lips, not just one, and the instructions say to fill the valley between the lips with a heavy grease. Everything about this new seal just sounds 'right' to me. Jim has probably built a motor or two by now with this new seal, so if he likes them and gets good feedback on them, then that's what I'll be using in mine whenever I get around to replacing it.

Bear
 

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My '70 and a fellow club member's '67 had the seals replaced by jacking the motor up while on an overhead lift. The right tools made it as easy as could be. The motor mounts were removed and engines carefully jacked up. My trans was out of the car at the time being rebuilt so that made the job a lot easier. The '67 I believe had the cross member removed and the tans disconnected. Both mine and his had vitron seals installed and sat untouched on a lift, mine for 2 days and his a week (until our A Team could get back to it) so the sealants would set proper. No leaks from mine after 5 years and his 1 year........ Although I thought mine may have begun when I saw some drops on the floor last mongh but after removing the fly wheel cover and checking the oil pan bolts, all were in need of tightening. After 3 years they needed re-torqued. (We tore the engine apart for inspection and internal cleaning) and repaint etc 3 years ago when I was restoring it and the engine bay. That stopped the drip from that area.

IMO: Before assuming the RMS is leaking one may want to double check the torque on the oil pan bolts or the oil pan seal itself. Turned out, both mine and his were NOT leaking from the rear main seal, mine was fine with a graphite seal, both mine and his had oil pan gaskets in need of replacing but since the RMS was now exposed, it made sense to replace since it was disturbed. We had similar issues, oil was shooting out the back of the oil pan giving the illusion of a rear main seal leak.
 

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The first time I rebuilt my 400, I used the viton seal. I siliconed at the areas specified in the installation instructions, ... result .... leaked like a bad diaper on a baby. The following winter I installed a new forged crank, so naturally, I installed a new viton seal from a different supplier, it was slightly different from the first one I installed. I even made sure the seal mating surfaces were not on the same plane as the bearing cap. The result was the same. IT LEAKS badly. I'm seriously considering trying the graphite rope seal mentioned in a previous posting. I seriously wish you good luck, and if you accomplish a leak free seal, please let me know how you did it.

THANX
JeffW
I had the same experience with a Viton seal, followed directions and it leaked bad, real bad. Sounds like this new Graphtite seal is the way to go. I'm doing a teardown this winter and based on all the good press I'm definitely going that way. Glad I looked on tech forum today.
 

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How come I cannot see any pics on this thread. It would be helpful as I am on the same boat with oil dripping from the engine
 

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This may be the wrong place for this question but this is my first post and am not computer literate. '70 GTO with 400 engine, automatic trans. Front engine seal blowing oil so bad that other cars are backing away when driving. Do I have to pull the engine to replace the seals, both front and rear?
 

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This may be the wrong place for this question but this is my first post and am not computer literate. '70 GTO with 400 engine, automatic trans. Front engine seal blowing oil so bad that other cars are backing away when driving. Do I have to pull the engine to replace the seals, both front and rear?

I am not being evil here, but if you have to ask a question like that I assume you have never worked on an engine. So the first thing I highly suggest is to begin by purchasing a Factory Service Manual for your '70 GTO. The manual will answer your question as well as others.

Front seal can be done with engine in the car. You want to make sure that the snout on the balancer hub is not worn/grooved due to an old hardened seal wearing into it. They do make a repair sleeve that goes over the snout to make it smooth again, so you want to look for this or you may have the same leak with a new seal. You could also go with a new balancer if funds allow - which is a good investment and not too expensive.

If you are talking about the rear main seal, you would want to pull the engine to make things easier.
 

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Um, isn't the front sealing surface the balancer hub? :grin2:0:)

Bear
That was just a test to see if your would catch it. LOL DUH, you are correct. I wrote the response with one foot out the front door going to the mall, so got it wrong. Will edit my post. Thanks for the catch. :wink2: :thumbsup:
 
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