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Wore one spot in my band new rear main seal???? #752674 07/19/10 04:57 PM 07/19/10 04:57 PM
Joined: Oct 2003 Posts: 1,409 Ont. Canada 10.90 Racer OP super street
10.90 Racer OP super street Joined: Oct 2003 Posts: 1,409 Ont. Canada	This is a S.B. 408. I just put this engine together and have never used the block before. The rear main seal wore out in one spot(1/2" area), just below the parting line, in the lower half on the drivers side. The seal is still good everywhere else even just above the parting line where it is wore out? What gives??? BTW The seal was installed properly as I have been building engines for 20 years and never seen this..........

Re: Wore one spot in my band new rear main seal???? [Re: 10.90 Racer] #752675 07/19/10 05:13 PM 07/19/10 05:13 PM
Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY HEMIFRED master
HEMIFRED master Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY	what did or could have touched it. converter balloning ? too much end play in the crank ? ? home of the Sox and Martin Hemi Duster

Re: Wore one spot in my band new rear main seal???? [Re: 10.90 Racer] #752676 07/19/10 05:24 PM 07/19/10 05:24 PM
Joined: Apr 2006 Posts: 3,675 Akron, Ohio U.S.A. roadhazard master
roadhazard master Joined: Apr 2006 Posts: 3,675 Akron, Ohio U.S.A.	Well I've been specializing in oil seals for 20 years so lets see if we can figure out what the heck went on. Do you have a pic of the seal? Was the seal in the block or main cap side? Also was the seal installed in an "offset " position? Was the block line bored? If the crank is out of the block, install the main cap and measure the seal groove to confirm concentricity. Should be the same diameter vertical as horizontal. Greg

Re: Wore one spot in my band new rear main seal???? [Re: roadhazard] #752677 07/19/10 05:36 PM 07/19/10 05:36 PM
Joined: Mar 2006 Posts: 9,910 Eighty Four, PA B G Racing master
B G Racing master Joined: Mar 2006 Posts: 9,910 Eighty Four, PA	Usually a defective or damaged seal will show spot wear or something behind it caused it to distort in the area. [IMG]http://i430.photobucket.com/albums/qq21/ajcasini/max_zpsdppwd9km.jpg[/IMG]

Re: Wore one spot in my band new rear main seal???? [Re: B G Racing] #752678 07/19/10 05:38 PM 07/19/10 05:38 PM
Joined: Nov 2004 Posts: 3,544 Syracuse,NY CompWedgeEngines master
CompWedgeEngines master Joined: Nov 2004 Posts: 3,544 Syracuse,NY	Like Bob says. Sometimes people put silicone behind the seal, and I have also seen where the cap rail is dented in, and cause weird seal wear. You will ( or should) find something that casued it. RIP Monte Smith Your work is a reflection of yourself, autograph it with quality. WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.

Re: Wore one spot in my band new rear main seal???? [Re: roadhazard] #752679 07/19/10 06:00 PM 07/19/10 06:00 PM
Joined: Oct 2003 Posts: 1,409 Ont. Canada 10.90 Racer OP super street
10.90 Racer OP super street Joined: Oct 2003 Posts: 1,409 Ont. Canada	Quote: Well I've been specializing in oil seals for 20 years so lets see if we can figure out what the heck went on. Do you have a pic of the seal? Was the seal in the block or main cap side? Also was the seal installed in an "offset " position? Was the block line bored? If the crank is out of the block, install the main cap and measure the seal groove to confirm concentricity. Should be the same diameter vertical as horizontal. Greg The block is not line bored. The damage is in the cap side. The seal was not offset. I can send pics to your email. I don't think I can post them. Engine is in the car. I'm going to set a depth mic and see if the seal bore runs with the bearing bore. I sure would like the find a root cause. Last edited by 10.90 Racer; 07/19/10 07:48 PM.

Re: Wore one spot in my band new rear main seal???? [Re: 10.90 Racer] #752680 07/19/10 08:21 PM 07/19/10 08:21 PM
Joined: Apr 2006 Posts: 3,675 Akron, Ohio U.S.A. roadhazard master
roadhazard master Joined: Apr 2006 Posts: 3,675 Akron, Ohio U.S.A.	PM sent Measure across the seal groove in the block and the cap, (dial calipers will get you close enough)then compare measurements to verify they are at least the same width across the parting line. Also was this motor together before and if so all the same components except the rear seal? Last edited by roadhazard; 07/19/10 08:37 PM.

Re: Wore one spot in my band new rear main seal???? [Re: roadhazard] #752681 07/19/10 11:09 PM 07/19/10 11:09 PM
Joined: Oct 2003 Posts: 1,409 Ont. Canada 10.90 Racer OP super street
10.90 Racer OP super street Joined: Oct 2003 Posts: 1,409 Ont. Canada

Re: Wore one spot in my band new rear main seal???? [Re: 10.90 Racer] #752682 07/19/10 11:13 PM 07/19/10 11:13 PM
Joined: Oct 2003 Posts: 1,409 Ont. Canada 10.90 Racer OP super street
10.90 Racer OP super street Joined: Oct 2003 Posts: 1,409 Ont. Canada	Greg please see image above. The actual depth measurement is very close the the previous block .............approximately .004 " in that same area area.

Re: Wore one spot in my band new rear main seal???? [Re: 10.90 Racer] #752683 07/20/10 09:30 AM 07/20/10 09:30 AM
Joined: Apr 2006 Posts: 3,675 Akron, Ohio U.S.A. roadhazard master
roadhazard master Joined: Apr 2006 Posts: 3,675 Akron, Ohio U.S.A.	Pic's too blurry Back up and post a clear pic of the seal lip where the crank makes contact. I need to see the helix lines. So this is a different block but the same crank?

Re: Wore one spot in my band new rear main seal???? [Re: roadhazard] #752684 07/20/10 10:16 AM 07/20/10 10:16 AM
Joined: Oct 2003 Posts: 1,409 Ont. Canada 10.90 Racer OP super street
10.90 Racer OP super street Joined: Oct 2003 Posts: 1,409 Ont. Canada	I'll try for another picture. Same crank different block. BTW there is no damage at the parting line. The damage starts about 1/4 in below the parting line. Is the a possibility there was a just a flaw in the seal?? Last edited by 10.90 Racer; 07/20/10 10:19 AM.

Re: Wore one spot in my band new rear main seal???? [Re: 10.90 Racer] #752685 07/20/10 10:46 AM 07/20/10 10:46 AM
Joined: Oct 2003 Posts: 1,409 Ont. Canada 10.90 Racer OP super street
10.90 Racer OP super street Joined: Oct 2003 Posts: 1,409 Ont. Canada	I sent you an email. Please take a look. There is no helix lines in this seal?????

Re: Wore one spot in my band new rear main seal???? [Re: 10.90 Racer] #752686 07/20/10 10:47 AM 07/20/10 10:47 AM
Joined: Apr 2006 Posts: 3,675 Akron, Ohio U.S.A. roadhazard master
roadhazard master Joined: Apr 2006 Posts: 3,675 Akron, Ohio U.S.A.	Yes there is a possibility the seal was defective. Check the undercut on the back side of the primary lip to see if there's a split in the rubber. What brand seal was it?

Re: Wore one spot in my band new rear main seal???? [Re: roadhazard] #752687 07/20/10 11:40 AM 07/20/10 11:40 AM
Joined: Oct 2003 Posts: 1,409 Ont. Canada 10.90 Racer OP super street
10.90 Racer OP super street Joined: Oct 2003 Posts: 1,409 Ont. Canada	It was a fel-pro.

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