Rear Main Seal Confusion

So I am still having issues with my rebuild. In my previous posts I noted that my engine was rebuilt in the wrong direction at the machine shop it was taken to. It has gone back to them and they think that they have everything worked out. However there is still one point of contention between the shop and myself. That is the specifics of the rear main seal. The motor is a right hand rotation 302 originally produced in 1981. The block was replaced during this rebuild with one salvaged and rebuilt from a 1988 mustang. The machine shop used a right hand cam purchased new as well as the crank from the original block. They are now telling me that the seal is a one piece that is not rotation specific, however, this is not what I have heard here. Compounding my confusion is the fact that skidim does not sell a right hand rotation main seal for a 302...

Your thoughts?

83+ with the 1-piece rear main seal is the only type that is directional... the earlier blocks had the wick lines in the crank and used a bi-directional (or rope) seal.

I was going to wait for someone else to chime in, but I'll give it a shot and let someone else correct me if I mis-speak.

Hopefully the machine shop did not reuse the old crank in the new block, as the cranks and blocks are not interchangeable between the 2 styles (older 2-piece vs. newer 1-piece). To use an older crank in a newer block would require some machining.

Hopefully they actually used both the crank and block from the newer engine (1-piece seal style). This is fine- you just need a RH seal for a newer 302. No one has them (comercially)... but if you can get in touch with ReidP and ask really nicely, I bet he'd sell you one. He had a run of them made when stock ran out a few years ago.

Remember that the 1-piece RH RMS is only good if they havent altered the geometry of the block or crank in that area. Might want to verify that they used the newer block AND crank first.

Not many applications spin the engine backwards... we're in a pretty small group. I dont know why new seals would suddenly have been developed to handle bi-directional oil control- though of course, anything is possible. At this point, I would not put much faith in your shop's reverse rotation knowledge though. Personally, Ive only seen Ford rear main seals with wick lines in one direction (either LH or RH) when used with a smooth crank (1-piece style). The bidirectional seals used on the older blocks are fine because the oil control grooves are in the crank. I can tell you for certain that a LH seal in a RH engine will pump oil into the bilge at an alarming rate!

I would not count on a 500rpm oil pressure test to reveal RMS problems... but it might. Better than nothing- but I would be pretty diligent about making sure it was put together properly before you get to that point.

I went round and round with phone cals, pics and emails to SKIDIM over the new front seal. Old one had the wick lines and a lip to hold it in place from the front. The new on is smooth and has no lip. Tried to get one at Napa and the came up with 2 that had the lip, but they had the wick line in the wrong direction.   If the crank has no wick lines and the seal is smooth I don't know why it matter which way the crank spins.