[64speed]

Which one am I gonna have better luck getting not to leak? Which one are you guys using? I need success and failure stories, do's and donts, that kinda thing. I am buying the one piece pan gasket.

[mysticmissle]

the one piece pan gasket will not work with an IA2 just fyi
if you have a factory 455 N crank, i am a fan of 'the best rope seal' they seem to work real well. On my IA2 i have used KRE and BOP 2 piece seals successfully. I usually put the seam where it does not fall at the parting lines, however others seem to have success with normal installations

[lust4speed]

If you are replacing a seal in an assembled engine then you use the two-piece seal, otherwise use the one-piece. The one-piece has one less joint to leak and it is also at the top of the groove which helps. The one-piece also has two lips as opposed to the single lip on the two-piece seal. Follow the included instructions and if you have any questions call them. We had a machine shop bore into the block .027" in cleaning up the mains. Obviously operator error on the machinist part, but we were stuck with the results. Through Wade's guidance we matched the seal to the new journal height and it's been a year without leaking.

[Bill Eveland]

Ive had better luck with a 1 piece on my 455, 2 piece and graphite seal both leaked on that engine. On the 389 2 piece was fine.

[Murf]

I have factory 455 block & crank. Used Best graphite seal. Pretty pleased. Been together a long time. Seal will leave a little spot when it sits over the winter. When the car gets driven, no problem.

Murf

[Goatracer1]

I replaced a leaking new rope seal on my 428 with the 2 piece seal. I followed directions carefully and it leaked less than the rope seal but it does leak some.

[Verdoro 68]

I've been fighting this on my stroker build. I thought a one piece would be an easy deal but during the "tip test", the one piece seal leaked so I installed a two piece meticulously - which is also leaking. Butler and BOP tell me not to worry about the tip test as the crank serrations will have some leakage when the block is tipped. When I have the block at a less extreme angle there's no leakage at all.

Debating giving the graphite seal a shot, but I've heard the serrations on aftermarket cranks can eat them up.

[tom s]

posted many times.Im 100% with the BOP 1pc seal,100% with the Bestgasket rope seal and 50/50 with the BOP 2 pc seal.FWIW,Tom

[Gary H]

I've used both the 1 piece and 2 piece seals but prefer the 1 piece since there's one less parting line. The key, by far, to getting them to seal is proper measuring and installation. You absolutely have to measure the seal grove diameter, and then whether the groove is equally deep in the block and the cap, as measured from the parting line surface of the block. If any of these measurements are out of specification, then you need to take material off the backside of the seal to adjust. I use A TON of these in Pontiac engines and have very few to no issues when properly installed.

[kingbuzzo]

I bit the bullet on the two-piece BOP this summer and my buddy put it in for me...still leaking but I'm getting used to it...it's a pontipig lol

Gouged me for shipping too...ah well...built in oil change

Stock block/crank.

Good luck!

[chuckies76ta]

Originally Posted by mysticmissle

the one piece pan gasket will not work with an IA2 just fyi

I read that also, that the BOP one piece pan gasket doesn't work with the IA2. Well I made it work and so far it's been great. I made a metal spacer for the front area of the Canton 15-452 pan. Been 2 seasons and it's held up very well. I had to use the right stuff in the front and rear to help seal it up. No leaks to date.

[slowbird]

Originally Posted by Gary H

I've used both the 1 piece and 2 piece seals but prefer the 1 piece since there's one less parting line. The key, by far, to getting them to seal is proper measuring and installation. You absolutely have to measure the seal grove diameter, and then whether the groove is equally deep in the block and the cap, as measured from the parting line surface of the block. If any of these measurements are out of specification, then you need to take material off the backside of the seal to adjust. I use A TON of these in Pontiac engines and have very few to no issues when properly installed.

On my block the groove depths for seal was different (cap was shallower than block) and man what a pia trying to get the 1 piece seal to kind of work.

[djustice]

I installed the 2 piece BOP seal this spring, measured 3 times, assembled with torque. Took it apart again, measuerd and installed again.
Hooked engine up in hoist and adjusted tillt on levler til i had a heavy angle backwards, and filled 5 quarts of oil. Let it hang for a day, not a drop, turned the motor over , still not a drop.
1 week after i got the engine in and have been driving it was leaking. Dont know what black magic i have to to do to make it seal up.

[dataway]

1 piece seal here .... no leak during the tilt test, few hours of run time so far, not a drop yet.

[lust4speed]

Originally Posted by slowbird

On my block the groove depths for seal was different (cap was shallower than block) and man what a pia trying to get the 1 piece seal to kind of work.

The Teflon rope seal can move around and seal up with just setting them in place. The problem is a shorter life than the lip seals. My Teflon/graphite seals have been allowing a drop or so of oil to pass after a year or two where the some of the older Viton seals are going on five or six years without seepage.

The Viton seals require some checking and then corrective work if necessary as slowbird says. The old way of cutting some material off the end of the seal to allow the lip to not curl isn't recommended by BOP anymore. Guess sort of a live-and-learn adjustment. Now they recommend sanding the exterior of the seal on the shallow end so the seal ends up concentric with the journal. New method requires measuring from the flat of the journal to the bottom of the groove for both the block and cap and sanding the seal where needed. The seal used in the deep cut block I mentioned above had to be sanded to where the metal support was showing to center the seal. No fun, but is leak free after over a year.

[geeteeohguy]

Have done 3 with the 2 piece BOP seal, now it is 12-15 years later on each engine and still no leaks, have done one 1-piece BOP about 8 years ago and it started weeping in the first year of service. It passed the tilt test.
I never tested the other 3.
The asbestos rope seal I installed in my '65 GTO 41 years ago is still leak free. The new rope seals in the overhaul kits do not seal well at all. I hear good stuff about BestGasket square rope seals. Never used one, though.

[grivera]

Does an NOS asbestos seal have a shelf life?

[TedRamAirII]

I would not think so.

[lust4speed]

Also, any way to tell them from later seals? I've got bags of seals all mixed together and bet than there are some older ones in there. Unfortunately all the old unmarked bags look the same.

[NeighborsComplaint]

I did the dance with the 2 piece neoprene seals (pre-BOP) twice and failed both times. First time was with a Ford 460 neoprene seal and the second time was with the '63-'67 Cadillac neoprene seal which I believe the current BOP one is based on.

On the first build, I trimmed the ends .010" proud of the block dry, set it in silicone clocked with the ends away from the block/cap interface. Leaked like a sieve. When I removed the seal, it looked like the crank never even touched the seal even though it took noticeably more torque to rotate the crank after installing indicating it was sealing.

On the second build I used the Cadillac neoprene seal per the late Jim Taylor's (Pontiac Guru not the forumite) recommendations. I hand-cut radial anti-rotation slits in the block groove for retention, installed the top and bottom seal in separate operations, trimmed meticulously, meticulously set it in silicone making sure to fill the retention holes in the block first and siliconing the ends and out across the caps before torquing. Looked perfect, tilted with no leakage overnight and then leaked like a sieve within hours of running.

I pulled the motor, installed a graphite Best Seal and never had another leak.