Triming two piece rear main seal

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Triming two piece rear main seal

Post by BOOT » Thu Oct 05, 2017 5:23 pm

How does one trim the seal w/o damaging it? I've read more than once of people having to trim them slightly and this one leaked so I'm gonna give it a shot. One I have looks metal core so can't just cut it with a razor.
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Re: Triming two piece rear main seal

Post by superpursuit » Thu Oct 05, 2017 6:57 pm

Why do you want to trim it? Is it the wrong seal for the application and you are trying to adapt it to suit? Or has the block been line bored? These are probably the only time that you would consider trimming the seal. If it is the correct seal for the application and the block has not been substantially altered to affect the seal area then you would not trim the seal.

To answer your question the normal process to trim a 2 piece Rear Main Seal would be to carefully trim opposite ends of the seal on a linisher. You do the opposite ends so that when the seal is installed the trimmed end will butt against the opposing untrimmed end of the other part of the seal.

If you have the correct seal for the application then trimming it will not help.There is some thing else wrong. I hope this helps.

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Re: Triming two piece rear main seal

Post by statsystems » Thu Oct 05, 2017 7:08 pm

superpursuit wrote:
Thu Oct 05, 2017 6:57 pm
Why do you want to trim it? Is it the wrong seal for the application and you are trying to adapt it to suit? Or has the block been line bored? These are probably the only time that you would consider trimming the seal. If it is the correct seal for the application and the block has not been substantially altered to affect the seal area then you would not trim the seal.

To answer your question the normal process to trim a 2 piece Rear Main Seal would be to carefully trim opposite ends of the seal on a linisher. You do the opposite ends so that when the seal is installed the trimmed end will butt against the opposing untrimmed end of the other part of the seal.

If you have the correct seal for the application then trimming it will not help.There is some thing else wrong. I hope this helps.

What is a linisher? I do it with a belt sander and go very VERY slow.

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Re: Triming two piece rear main seal

Post by BOOT » Thu Oct 05, 2017 7:23 pm

statsystems wrote:
Thu Oct 05, 2017 7:08 pm
What is a linisher? I do it with a belt sander and go very VERY slow.

No clue either, what grit belt or does it matter?
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Re: Triming two piece rear main seal

Post by Keith Morganstein » Thu Oct 05, 2017 7:33 pm

statsystems wrote:
Thu Oct 05, 2017 7:08 pm
What is a linisher? I do it with a belt sander and go very VERY slow.
A belt sander/ belt polisher.

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Re: Triming two piece rear main seal

Post by statsystems » Thu Oct 05, 2017 8:34 pm

Keith Morganstein wrote:
Thu Oct 05, 2017 7:33 pm
statsystems wrote:
Thu Oct 05, 2017 7:08 pm
What is a linisher? I do it with a belt sander and go very VERY slow.
A belt sander/ belt polisher.

Learn something new every day. Never hear of a lanisher.

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Re: Triming two piece rear main seal

Post by superpursuit » Thu Oct 05, 2017 9:14 pm

statsystems wrote:
Thu Oct 05, 2017 7:08 pm
superpursuit wrote:
Thu Oct 05, 2017 6:57 pm
Why do you want to trim it? Is it the wrong seal for the application and you are trying to adapt it to suit? Or has the block been line bored? These are probably the only time that you would consider trimming the seal. If it is the correct seal for the application and the block has not been substantially altered to affect the seal area then you would not trim the seal.

To answer your question the normal process to trim a 2 piece Rear Main Seal would be to carefully trim opposite ends of the seal on a linisher. You do the opposite ends so that when the seal is installed the trimmed end will butt against the opposing untrimmed end of the other part of the seal.

If you have the correct seal for the application then trimming it will not help.There is some thing else wrong. I hope this helps.

What is a linisher? I do it with a belt sander and go very VERY slow.
A linisher is a high speed belt sander. In this case it is an attachment you put onto a bench grinder.

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Re: Triming two piece rear main seal

Post by Sodbuster » Thu Oct 05, 2017 10:16 pm

I just went thru the same problem. I used a piece of flat glass with a sheet of emory cloth taped to it. By holding the ends of the seal flat against the emory cloth and then working it back and forth, I was able to make the seal fit my application. It didn't take but just a few minutes. Hope this helps. Have a Great Day !!!

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Re: Triming two piece rear main seal

Post by BOOT » Thu Oct 05, 2017 11:06 pm

Belt sander worked great and quick, thx for the info!
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Re: Triming two piece rear main seal

Post by hoodeng » Fri Oct 06, 2017 12:37 am

A belt sander and linisher are the same thing ,just remember to work from the i/d of the composition seal to the outside that way any fluff can be trimmed without marring the working part of the seal.

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Re: Triming two piece rear main seal

Post by Walter R. Malik » Fri Oct 06, 2017 12:09 pm

hoodeng wrote:
Fri Oct 06, 2017 12:37 am
A belt sander and linisher are the same thing ,just remember to work from the i/d of the composition seal to the outside that way any fluff can be trimmed without marring the working part of the seal.

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Re: Triming two piece rear main seal

Post by Fireonthemountain » Fri Oct 06, 2017 4:18 pm

Trimming the 2 piece seal fel pro sells for Olds is pretty standard, as it is actually a Ford 460 seal and almost fits right. The earlier Olds used a rope seal. Just FYI

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Re: Triming two piece rear main seal

Post by pdq67 » Sat Oct 07, 2017 4:10 pm

Fireonthemountain wrote:
Fri Oct 06, 2017 4:18 pm
Trimming the 2 piece seal fel pro sells for Olds is pretty standard, as it is actually a Ford 460 seal and almost fits right. The earlier Olds used a rope seal. Just FYI
So did the early SBC blocks. I want to say '57 and earlier blocks? Might be '58, I forget??

pdq67

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Re: Triming two piece rear main seal

Post by Fireonthemountain » Sat Oct 07, 2017 7:44 pm

pdq67 wrote:
Sat Oct 07, 2017 4:10 pm
Fireonthemountain wrote:
Fri Oct 06, 2017 4:18 pm
Trimming the 2 piece seal fel pro sells for Olds is pretty standard, as it is actually a Ford 460 seal and almost fits right. The earlier Olds used a rope seal. Just FYI
So did the early SBC blocks. I want to say '57 and earlier blocks? Might be '58, I forget??

pdq67
The later SBO 330-403 used the Ford Y block seal, if I remember right. Not sure about even earlier Olds.

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