Shelby Block Rear Main Seal Leak

[A98Coupe]

Originally Posted by Barry_R

Sorry I am sooo late in finding this thread. I assembled the engine in question. It was "dry" on the dyno, but FEs rarely seem to stay dry for long.

The comment on dye is spot on - - I have seen leaks from all over the place get diagnosed as rear seal because that is where it ends up dripping from. Liquids will do an amazing job of following along edges in the castings and gaskets to find the way to the rear. I usually find tiny leaks at the junction of the intake and the cylinder head to be the hardest to trace down.

The Shelby block used should be OK - its not that old and should not have the rear drainback issue - that was from a very long time ago. If I recall correctly it has the complete Aviaid pan and screen kit. I use the TF-31 gray Motorcraft silicone on assembly on all pan & tray surfaces. Still possible for stuff to go wrong there - but the pan gasket is usually OK.

On aluminum blocks it seems that every fastener needs a turn or two after some run time & then they are OK for a long time. The pan gaskets are especially bad since they are sandwiches of gasket, tray, gasket and you cannot really tighten them much with damaging & distorting things.

Check the oil level - and get the dye kit. Fix it when its cold and wet - - enjoy the car and the weather while you can. It was 34 degrees F here in Detroit right now...

Barry,
Thanks for the comments. Still haven't had chance to set timing & idle mixture yet due to work, but today I got right up close to the pan gasket and checked all around either directly or using a mirror. The passenger side from front to rear is actually wet looking and looks worse as it gets further back. I think you are probably correct in diagnosing the pan gasket as the source of the leak. I've nipped the pan nuts up a bit more and will give her a run next weekend if the weather holds out. I'll get a dye kit if the leak persists.

Stuart

[jetblue69]

Originally Posted by A98Coupe

Barry,
Thanks for the comments. Still haven't had chance to set timing & idle mixture yet due to work, but today I got right up close to the pan gasket and checked all around either directly or using a mirror. The passenger side from front to rear is actually wet looking and looks worse as it gets further back. I think you are probably correct in diagnosing the pan gasket as the source of the leak. I've nipped the pan nuts up a bit more and will give her a run next weekend if the weather holds out. I'll get a dye kit if the leak persists.

Stuart

Probably the pan gasket. Before you condemn the rear main don't forget the oil return from the rear bearing/seal is right there. Hopefully you checked to see if the pan rail/tray covers it as I had to grind mine. I had a leak, created several new swear words thinking it was the rear main, tightened the pan fasteners (the Canton came with studs) and bye-bye leak. I even used TA-31, torqued it to factory specs when I installed it and the S.O.B. STILL LEAKED after a few runs on my break-in stand!