[misterp266]

I have both a BOP and a TIP in stock. I’ve never installed either. Motor is a ‘67 400 with a Scat forged crank.
Any preference on which is better? Any tips on installing that may not be covered in the instructions?

[Mr Twister]

https://www.bopengineering.com/viton_compare.shtml

A comparison. I have used the brown ones sucessfully.

[mysticmissle]

ive used both, wo issue, as long as crank has no serrations and i don't think a scat does you should be fine with either.

[leeklm]

By no means an expert here, but I really like the BOP 2 piece seal. Motor with eagle crank with serated seal area, had 5 years with no leaks. Just refreshed over the winter and re used the seal. Still no leaks.

Only used the one piece seal once, and it had a small leak when ironically using on a crank with smooth surface. Most likely installing error on my part...

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[Half-Inch Stud]

I've installed a few 2- piece, and 1 1- piece onto the 3.25" mains. Well the 1-piece looks formidable but putting it on ONCE is pretty easy.

Just don't do it a few times, as if you gotta sort-out the Main Bearing Clearances ahead of time....like i did.

[Don 79 TA]

has anyone tried nightmare performance 1pc seal?

[misterp266]

I ended up installing the BOP seal.
How does one get a one piece seal over the crank flange?

[steve25]

The same way you get rings onto pistions, carefully!

Plus it's a two person job, one to guide the seal into the groove while the other lowers the Crank.

[67Fbird]

^^^ yes on the 2 person part..... You have to slice the seal per the instructions and as stated...CAREFULLY "tweek" it into position.

[Dragncar]

Sanding is required with that one piece. Lots of test fitting, on and off of the rear cap. Seal needs to be centered without wrinkles.
Call BOP and Mark will explain.
BTW, I used a couple of nylon straps and a come along to lower the crank. And it was still a 2 person job.

[PunchT37]

If it`s got serrations on the seal surface, I would go rope seal. Permatex #1 on parting line.

[Wade Congdon]

For the record our seals have been used on serrated cranks for 20 plus years with no issues, tens of thousands of them. The only time the serrations are an issue is on aftermarket cranks (like Eagle) where the serrations are deep and aggressive.

We have evolved our install practices over the years. It is important to realize that what varies from engine to engine is the block groove and not so much the crank. Therefore, we recommend to fit the seals (one or two piece) to the block. This is typically done by sanding the OD until either the correct protrusion is achieved (two-piece) or the cut line is fluid (one-piece). If the ends are trimmed the ID becomes smaller which is not Ideal. The instructions are thorough but feel free to call with any questions, anytime.

[lust4speed]

Can someone post a photo of a Pontiac crank with no serrations? Later modification on a lathe doesn't qualify.

[KEN CROCIE]

get the serrations polished off at a crank shop down to flush with the journal.

[Tim Corcoran]

Here you are Mike, this is a Scat crank I just got from Butler, as you can see the seal area is sooth as a baby's butt.

[lust4speed]

So pretty - and surprising...

[bluejudge]

I am curious, why are there serrations on there to begin with. Thanks, Marc.

[Joe-Touring]

Originally Posted by bluejudge

I am curious, why are there serrations on there to begin with. Thanks, Marc.

They were on factory cranks to provide some oil to the ID of the original asbestos rear main seal. Kept the RMS from grabbing the crank, lubed, pliable, etc