Rear Main Seal 250 I6???
 

Don't know why but I can't find a rear main seal for my 66' 4.1. I get listings for the seal but non fit. I've checked the year on the motor, checked 2 others I have for parts (all the same seal) and still cannot find one to fit the motor. Any help would be greatly appreciated. I'm about ready to put the old one back in with a whole tube of rtv to seal it up.

Re: Rear Main Seal 250 I6???
 

What does yours look like?

Re: Rear Main Seal 250 I6???
 

It's two peice rubber one half is U shaped and the lower is the same but has ears on it that sick out about an inch and a half and go around the nearest bolt holes. It has about a 3 or 4 inch diameter but I can quite remember off hand.

Re: Rear Main Seal 250 I6???
 

Like this one? https://m.summitracing.com/parts/fel-bs13241

My 250 is from the '70s and has this rear main seal: https://m.summitracing.com/parts/fel-2900

Re: Rear Main Seal 250 I6???
 

I know the first one listed doesn't fit it's about half the size. I'm not sure on the second one I've tried 8 or 9 different seals now. Basically anything listed I could find. I'll check that one tomorrow.

Re: Rear Main Seal 250 I6???
 

http://www.rockauto.com/en/catalog/c...haft+seal,5604

I bought a complete closeout set quite some time ago from Rockauto. I don't know if the seal fits yet but the set says 66-67.

Re: Rear Main Seal 250 I6???
 

Try the Felton 2900 rear main seal. It is a higher quality product and only about 5 bucks more. Sharpes40 had excellent results in his 250 so I tried it also and have been pleased.

Re: Rear Main Seal 250 I6???
 

Didn't think that seal would be that hard to find. The seal is the same for all 4 and 6 cyl motors up to 1967. O.E.# 3792463. After 1968 the 6 cyl used the same seal as the small block motor O.E.# 473424

Re: Rear Main Seal 250 I6???
 

I'll try looking some up under the 4cyl but the seals I was getting were listed as the same for the V8s basically as a match for all motors but the closest size I found was still about 2 inches to small and that was a seal from a 6.2 1980's diesel. I'm not sure if it's a cataloguing issue or something but it's been the same issue at multiple stores. This afternoon I'm going to order the Felton 2900 and see.

Re: Rear Main Seal 250 I6???
 

The FelPro BS13241 looks correct and it cross references to the O.E. part number. It has the two little tangs off the side like yours does. Rockauto has it if you can't find it locally.

Re: Rear Main Seal 250 I6???
 

The bs13241 isn't even a close fit. I ordered it from two separate stores to see it it was mispackaged because it comes up as the correct part but it's about 2 & 1/2 inches to small in diameter and about an 1/8th of an inch to slim.

Re: Rear Main Seal 250 I6???
 

Does it have the tabs off each side? Sounds like a bad batch they manufactured. Basically only 2 seals ever used in the 6 cyl, the early one with the tabs going out sideways or the later one that the V8 used.

Re: Rear Main Seal 250 I6???
 

Mine has tabs that have bolt holes in them. The ones I got that were to small didn't have the holes either.

Re: Rear Main Seal 250 I6???
 

The seal with bolt holes is the rear oil pan seal and not the rear main bearing seal which goes inside the rear main bearing cap. That seal you are looking for will come in a oil pan gasket set that you order for your motor.

Re: Rear Main Seal 250 I6???
 

I was wondering if he was talking about the rear oil pan seal. I bought two oil pan gasket sets as I could not get the rear seal to fit; it never fit the rear bearing cap groove. I said Eff it and used Permatex's The Right Stuff. That has sealed great and has not leaked any in a year.

Re: Rear Main Seal 250 I6???
 

Ok, I'll have to find that seal then. Sorry if it's I stupid mistake but I haven't pulled many motors apart. How exactly does the rear main sit in this motor then?

Re: Rear Main Seal 250 I6???
 

No problems. Not a stupid mistake. Best way to learn is to ask questions before you make the mistake. The rear main seal comes in 2 halves. One half pushes up into a groove in the block and the other half sits in a groove in the rear main bearing cap. When the cap is torqued down the two halves form a tight seal around the crankshaft to stop any oil from going outside the block. These are known to wear and cause oil leaks. They are tricky to change when in the truck as you need to push the one half in the block groove around the crankshaft to get it out and same with putting new one in. But it can be done. You should order an oil pan gasket set for your motor and it will come with 2 cork side gaskets and a rubber front and rear seal. The rear seal is the one you are describing. As was mentioned installing it with a little sealer will help hold it in place. Let us know how you make out.

Re: Rear Main Seal 250 I6???
 

Ok, thanks I'll try and get everything tonight and have it installed by tomorrow since the motor is out of the truck hopefully it'll be fairly easy.

Re: Rear Main Seal 250 I6???
 

That was a pan seal I needed. In hindsight I probably should have picked up a manual in from the beginning instead of just having someone give me a quick explanation and try to figure it out. Thanks for the help.

Re: Rear Main Seal 250 I6???
 

Get your oil leak stopped?

Re: Rear Main Seal 250 I6???
 

The Enginetech gasket set P/N for 66-67 194, 230, 250, 292 is C250-15.

Re: Rear Main Seal 250 I6???
 

The rear main seal is an easy swap. Jack up the engine by the balancer pulley and drop the oil pan. Remove the rear main cap and use the plastic tool that is included (at least they used to be) to push the upper half of the seal out. Put a dab of RTV on the seal ends and torque the main bolts.

While you have the pan off, it is a good time to update the gasket setup. Instructions were included when I did my last swap 30 years ago. There are two bolts that hold the front main cover that are inside the pan. You need to remove the bolts and tap the holes so the front cover can be removed without dropping the pan. Beyond those instructions, I have lost too much memory. Getting old ain't easy.

Re: Rear Main Seal 250 I6???
 

Interesting, I just looked at that P/N on Rockauto and it says rear seal not included. On my box it says it is included.

Re: Rear Main Seal 250 I6???
 

I sealed it all up a few weeks ago and put the motor back in the truck. Seams to be good all good now. Haven't fired it up yet. It's a 66 motor in a 81' c10 so I've been chasing wires going a little crazy. Should be firing it up within a week if all goes right.