SAAC Forum

The Cars => 1968 Shelby GT350/500/500KR => Topic started by: RSOHC on July 10, 2021, 01:17:00 AM

Title: Rear Main Oil Leak Repaired
Post by: RSOHC on July 10, 2021, 01:17:00 AM
My persistent rear main leak no longer exists.  Here is the process I used.  (1) Cleaned the read main and engine block with brake cleaner, (2) I changed to a MAHLE brand of seal, (3) Torqued the main cap to 105 ft-lbs before installing the side seals,(4)  lubricated the side seals with Melling assembly lube, (5)  installed nails without points using a 3 pound lead hammer, (6)  Installed new black Fel-Pro gaskets on the oil pan and windage tray, (7)  Covered with silicone the area where the nails were installed.  (8) Torqued oil pan bolts to 9 ft-lbs, (9)  Waited one day for the silicone to dry, (10) Primed the system and it did not leak. 
Title: Re: Rear Main Oil Leak Repaired
Post by: 6S1568 on July 10, 2021, 07:36:17 AM
Thanks for your tips, and I hope your problem is completely solved. Good to be drip free!
Title: Re: Rear Main Oil Leak Repaired
Post by: sg66 on July 10, 2021, 01:09:21 PM
Nails? Also, why type of windage tray are you using that needs a gasket? The B302 style I've used bolt to the main caps only and have no gasket.

Whenever I've done rear mains, I always offset the ends so they butt up against each other about 1/2" inside the cap/block. That way there is no possibility for oil to seep out through a seam which is flush with the block.

Another thing I've seen many people miss is that the 2 larger oil pan bolts in the rear do not go into a blind hole, meaning the threads in the block go all the way through to the crankcase and if not sealed can be another source for oil drips.
Title: Re: Rear Main Oil Leak Repaired
Post by: Bob Gaines on July 10, 2021, 03:54:46 PM
Quote from: sg66 on July 10, 2021, 01:09:21 PM
Nails? Also, why type of windage tray are you using that needs a gasket? The B302 style I've used bolt to the main caps only and have no gasket.

Whenever I've done rear mains, I always offset the ends so they butt up against each other about 1/2" inside the cap/block. That way there is no possibility for oil to seep out through a seam which is flush with the block.

Another thing I've seen many people miss is that the 2 larger oil pan bolts in the rear do not go into a blind hole, meaning the threads in the block go all the way through to the crankcase and if not sealed can be another source for oil drips.
In this category  the OP could be referring to a big block. Although 68 GT500 or KRs did not use a CJ windage tray from the factory 69/70 GT500's did. It is not uncommon for owners to add the BB CJ windage trays to  their engines even though they did not come with them from the factory .Those windage trays use two oil pan gaskets to sandwich it between the oilpan and the block.
Title: Re: Rear Main Oil Leak Repaired
Post by: sg66 on July 10, 2021, 04:39:06 PM
Quote from: Bob Gaines on July 10, 2021, 03:54:46 PM
Quote from: sg66 on July 10, 2021, 01:09:21 PM
Nails? Also, why type of windage tray are you using that needs a gasket? The B302 style I've used bolt to the main caps only and have no gasket.

Whenever I've done rear mains, I always offset the ends so they butt up against each other about 1/2" inside the cap/block. That way there is no possibility for oil to seep out through a seam which is flush with the block.

Another thing I've seen many people miss is that the 2 larger oil pan bolts in the rear do not go into a blind hole, meaning the threads in the block go all the way through to the crankcase and if not sealed can be another source for oil drips.
In this category  the OP could be referring to a big block. Although 68 GT500 or KRs did not use a CJ windage tray from the factory 69/70 GT500's did. It is not uncommon for owners to add the BB CJ windage trays to  their engines even though they did not come with them from the factory .Those windage trays use two oil pan gaskets to sandwich it between the oilpan and the block.
Ahh my bad, small block on the brain today
Title: Re: Rear Main Oil Leak Repaired
Post by: RSOHC on July 10, 2021, 06:10:31 PM
Here is a picture of the windage tray that fits a Ford FE.