seeking 455 rear main seal advice

[skymark]

Hello,

I'm new to your site and was wondering if some kind soul could give me some good advice. I have a 1972 Skylark Custom Convertible. I picked up a 1973 455 and did a complete rebuild. I bought one of the TA Performance "NO Trim" rear main seals. Within 5 minutes of starting the new motor, the rear main was gushing. We assumed that something just got screwed up in the assembly process, so I bought another "NO Trim" seal from TA, we checked the crank and all the area around the seal for burrs, etc., installed the new seal and put the motor back in. Twenty minutes after startup, the rear main is gushing again.

I'm wondering first if others have had problems with these seals, or if maybe there is some trick that we are missing in getting it to actually seal? My second question is if there have been problems with these seals, is there an alternative other than the old style rope type seal, or is that my best bet? I certainly don't want to have to pull this motor a 3rd time.

Thanks very much for any advice that can be provided.

Mark

[The Old Guy]

Mark

I have used the TA rear seal numerous times, and have experienced NO problems. The directions that are supplied were followed,and they worked fine. Maybe there is a problem with the block or crank.

[Guest imported_Thriller]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">My second question is if there have been problems with these seals, is there an alternative other than the old style rope type seal, or is that my best bet? I certainly don't want to have to pull this motor a 3rd time.

Thanks very much for any advice that can be provided.

Mark </div></div>

I don't know specifically about availability for the 455, but if you can get a neoprene seal, it is much more likely to be trouble-free than the rope type.

That being said, I just wonder if installing a rope seal is perhaps a lost art...I can't imagine these cars leaked that much new (my '62 was using a quart about every 100 miles of driving this summer). Just a thought.

[The Old Guy]

Derek'

The TA seal is a neoprene seal.

[skymark]

Thanks guys very much for your input.

When the first one leaked, we were really careful with the second one. I guess I'll have a better idea once we pull the motor and get the seal out, but I'm really hesitant to just replace this seal again unless we actually find something wrong. This motor project has been an 18 month marathon. Now I'm finally this close, the motor runs fantastic, and I can't get past what I think should be a minor issue. If anyone has suggestions as to problems of this nature that they may have seen in the past, I sure would appreciate their sharing. The surfaces of both the block and the crank have been gone over thoroughly (although I'm sure we will do so again when we get this seal out), no burrs or imperfections were found.

Thanks again for your responses, and I sure would appreciate any suggestions on other things to look for. I dread pulling this motor again, and want to make this the last time for a while if at all possible.

Mark

[Roadhog]

Skylark, before you pull the engine again, make SURE of where the leak is coming form, clean the underside GOOD, dry it, run the rngine at idle and shut it down as soon as you see a drop. Then thourghly inspect the area with plenty of light to make sure or the location! You stated it took twenty minnutes for the leak to appear. If something was installed wrong it seems the leak would be almost instant, 20 minutes sounds like the seal was being "chewed" up? Look at it good sometimes the problems are so evident we tend to overlook them! Also a good trick to find an oil leak is to paint the area with silver spray paint, when the oil runs down the paint it will wash it off and leave a nice trail!!!! If you would state your location in you profile maybe some one close can come by and take a look!!!!1

[skymark]

Thanks Roadhog. When we removed the first seal, the edge of the seal looked uneven all the way around, which is why I looked for burrs or imperfections on the crank, but it was almost as if it was, like you said, chewed. I will do my best to pinpoint the exact location of the leak before I start taking anything apart, but I don't have a ton of experience to fall back on, so if anyone can help with suggestions of other things to look for I sure would appreciate it.

P.S. I took your advice and added my location to my profile...Thanks

[NTX5467]

On many rear main seals, there are some cast-in "knurlings" on the seal where it will contact the crankshaft (other than the "lips"). If, perhaps, the seal is installed "backward", the knurlings will actually deflect or "pump" oil out of the back of the seal rather than deflecting it back into the crankcase area. I'm not sure if it's possible to install the Buick 455 rear main seal in the incorrect direction, but it's a thought you might keep you eyes open to. I read about that in an old "Popular Science" vehicle troubleshooting column back in the 1960s.

Of course, the rope seals didn't need knurlings as such. The newer neoprene seals are supposed to be better than the earlier rope seals, but that could be debateable.

On the seals you are getting from TA, you might be able to source them locally if you can determine what the correct application for them might be. As which later model Buick they fit. That could decrease your downtime, possibly.

Also, it seems like I recall seeing where the neoprene seals need an initial lubrication for installation and initial start-up. For example. on the one-piece seals which GM has for the small block Chevy V-8s that went to the one-piece rear main seal, they come with little globs of a thin, gelatin-like lube on them, which will also serve as assembly lube. Perhaps "no assembly lube" could be an issue with the seals you are using? Just a thought.

Happy Holidays!

NTX5467

[jimtil]

Don't feel bad ive been trying to solve the leaking buick mystery for 2 years now. i have the same problem. after 20 minutes or so the leak begins. longer if i am at idle, faster if i get on it. I have tried Ta performance, Poston and BOP's neopreane seals none have made any difference. i've rebuilt the thing three times, block magnafluxed,cranked checked, "mic'd" and polished with no success. The more i read about Buick the more i find that their oiling systems were flawed. not enough oil in some places. (cambearings) too much in others (rear main bearing) Good luck. Please let me know if you figure it out.

[NTX5467]

From what my machine shop associate has told me, on some Buick engines you can reposition where the "hole" is in the cam bearings to help some oil passages get oil better than if they were put in the factory-spec location. Something about the factory location putting oil after where the main load on the bearing was rather than before where the main load area was (with respect to the direction of rotation). Perhaps this repositioning situation could balance things out somewhat?

BUT, the issue remains that if the factory could put them together and they'd last, why's that not possible now?

Just some thoughts,

NTX5467

[skymark]

Thanks to everyone for your thoughts. I'm confident that we installed the seal correctly, so I've been leaning toward going to the old rope seal. Even if I leave a couple of drops here an there, I can drive the car, which I can not do now. I stumbled onto BOP Engineering that offers a rear main seal that is supposed to be specifically designed for the Buick big blocks, as opposed to the retrofit that TA and others are selling (it has FORD stamped on it). I was wondering if anyone has any experience with BOP. The seal is $35 or $40, but if it doesn't leak and allows me to keep my engine where it's supposed to live, then that is a small price to pay. Thanks again and Happy New Year.

Mark

[RocketDude]

I don't have much experience with Buick engines, but when I was building engines at an Olds dealership in the mid 80's, we used 460 ford rear main seals. Olds only used the rope seals at the time, and we always changed them to the Ford neopreme seals. They worked like a charm. Not sure if they would do the same for a buick. I always put a tiny spot of silicone sealer where the two halves butt together. Have never experienced a leak.

The rope seals were OK, but the neopreme were far better. I would check the seal with some grease, to see if it is making contact all the way around, on the crank. There is no reason for that seal to leak like that. I'm wondering if if could be something else dripping down there and looks like a main seal? I don't know where your oil sending switch is located on that engine, but on SB chevys, the switch was on top of the block, by the distributor. They had a habit of developing cracks in the plastic, and leaking down the back of the block. There have been untold numbers of rear main seals changed, only to find out it was the oil switch. Your switch may not be located there, but the point is, I would be looking to make sure it is the main seal.

You can always buy some dye and add it to your oil, then with a special light, you can see exactly where the oil is coming from. That is the path I would follow if it came into my shop.

[Gasonit]

Skymark, I think you will find that you are putting the rear main seal in bekwards. This seal appears to be a lip seal when in fact it is not. It is a compression seal the same as a rope seal. If you put it in with it facing the way a lip seal would go, it puts the contact point riding on the oil grooves cut in the crank shaft journal. Turn it around and it rides right behind the grooves. A lip seal has a sharp edge and a compression spring, this seal does not have that. It has a flat contact simular to the rope type, just not as much contact surface.

 Put the seal in they way you would a lip seal, put dirty oil on the journal and spin the crank and look at where it makes contact. You will see what I am talking about.

  Then flip it around and put it in the way that does not look right and check it. There is a Cadillac seal from mahle that will fit to. I dont remember for sure but I think the part number has a 600 or 602 part number. It is a rope seal replacement. I realize this is an old post but maybe it will help the next guy.

Edited July 28, 2018 by Gasonit (see edit history)