All Small Six Rear Main Seal search problems and solutions (I hope)

This relates to all small sixes
Dr_Dan_WWW

Dr_Dan_WWW

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There was quite a FordSix discussion in Feb 2022 about finding scarce FELPRO rear main seals for 200ci. I tried to find a FELPRO but no luck. I bought the Mahle JV703R because eBay vendor said it fits "200, 250, etc etc). I took a chance and lost. The Mahle JV703R is too big. But my short block machinist at Mann's Speed Shop here in Kansas City found a BOP RMS02 rear main seal. The BOP RMS02 is for "421, 428, 455 CID Pontiac V-8, and 400, 430, 455 CID Buick V-8" according to the package. I put a few photos here. Bubba showed me that it looks like FELPRO will continue to make the correct rear main seal. But they are taking a while to get in.

BOP:
Rear Main Seal BOP RMS02 1 IMG_7158.png

BOP package
Rear Main Seal BOP RMS02 package IMG_7160.png

BOP vs Mahle:
Rear Main Seal COMPARE JV703R TO BOP RMS02 7159.png
 
Always have the ends meet at 10:00 & 4:00. That prevents leakage where the rear main cap seats in the block.
 
This is second hand info. I have not installed it.
"For anyone looking for a RUBBER rear main seal for a 144, 170, 200 or 250, and can't find the Fel-Pro BS30135, Best Gasket makes 5341S. Just installed one and it is a great fit."
I found a link to the Best Gasket 5341S rear main seal.
www.olsonsgaskets.com

Ford 6 cylinder 144, 170, and 200 ci Rubber Rear Main Seal - Olson's Gaskets

Rubber rear main seal for Ford 144, 170, and 200 cubic inch 6 cylinder engines. Equivalent to Felpro BS30135 and Victor JV730P.
www.olsonsgaskets.com www.olsonsgaskets.com
 
I'll add that the last Fel-Pro oil pan gasket set in an overhaul gasket set I bought about 3 years ago had a rear rubber was too long. One cork gasket had an oil pan bolt hole or 2 that didn't line up. The rear rubber was listed on the gasket set box as being made in China. I used the rear rubber and one cork gasket from an older Fel-Pro overhaul gasket set that Autozone sold me years ago when they did not have a head gasket set.
 
78_200_C4 said:
This is second hand info. I have not installed it.
"For anyone looking for a RUBBER rear main seal for a 144, 170, 200 or 250, and can't find the Fel-Pro BS30135, Best Gasket makes 5341S. Just installed one and it is a great fit."
I found a link to the Best Gasket 5341S rear main seal.
www.olsonsgaskets.com

Ford 6 cylinder 144, 170, and 200 ci Rubber Rear Main Seal - Olson's Gaskets

Rubber rear main seal for Ford 144, 170, and 200 cubic inch 6 cylinder engines. Equivalent to Felpro BS30135 and Victor JV730P.
www.olsonsgaskets.com www.olsonsgaskets.com
Click to expand...
I ordered 2 of these. Supposed to be arriving tomorrow. A little on the pricey side at 55.00, but since the Felpro is likely discontinued, I thought having a spare would be good.
 
Is that $55.00 for 2?
Fel-Pro maybe discontinuing the seal as a separate part.
Rockauto lists the FEL-PRO 2601002 engine gasket set with a photo which includes rear main seal. Price is $52.79
FEL-PRO lists the 2601002 as a Full Gasket Set.
(FS 7916 PT-2 is the Engine Complete Overhaul Gasket Set) This was the set that had the rear oil pan rubber that was to long
 
Thank you very much "78_200_C4", for posting that info, it's certainly some very good news on the new Best Gaskets Ford Small Six Rear Main Seal I am going to being needing one real soon for a new Performance 200 Six build. There were some site members reporting that the FelPro Rear Main Seals weren't fitting well and not sealing for about 3 or more years back. "Please Also Note" that the FelPro #2601002 Ford 144, 170, & 200 Six Full Engine Gasket sets "No Longer Come with a BS30135 Neoprene Rear Main Seal in them" so no mater what the pictures in the adds show's for the included items or where ever they are being sold this is wrong. It's very disappointing for me for sure as the FelPro brand was such a good one for so many years of my working career that I used them for everything I was working on. I will not be buying any of their 200 Six gasket sets for the foreseeable future or recommending them to anyone if ever again unless someday they might fix this problem but it isn't looking very good after this many years. By the way "Also Note That" the 1969 up Ford 250 Six Neoprene Rear Main Seal and its Oil Pan Gasket Sets are very different than those used on the Smaller Six's, the Neoprene Rear Main Seal is of a much larger diameter with a different part number save yourself some frustration because "They Will Not Fit" in the 144, 170, or 200 Small Six's PERIOD!, plus they can't be cut down to work. By the way if you were wanting a very good Rope Seal then I found out that "Best Gaskets" also has the very Best Rope Seal made too. Best of Luck
 
That's bad news that the FelPro 2601002 Ford 144, 170, & 200 Six Full Engine Gasket sets "No Longer Come with a BS30135 Neoprene Rear Main Seal in them."
I have a new in the Fel-Pro plastic bag BS30135 rear main seal from a Fel-Pro overhaul gasket set that I bought many years ago.
The last 200 I ran for 28 years never leaked oil. I still have this 200 and would install it in a car today and run it if I was more than one car guy.
I'll buy another brand of gaskets from now on after getting a too long rear oil pan rubber in my last Fel-Pro gasket set.
 
I found out that the so-called full gaskets sets without the rear main seal are short block installation gasket sets. I saw many of those for sale on eBay which were listed as including a rear main seal. The Enginetech set was one example. I checked at Enginetech and no seal was included.
I also read that it's not just the small six that has rear main seal problems.
Some of the seals never get past a dyno test of a newly rebuilt engine.
I read about problems going back to 2012.
A Youtube video showed how certain rear main seals are too long.
Some of these bad seals leak before the engine is started.
There are even problems with some rope seals ends threading when cut.
 
I may try machining the block and cap for a one-piece seal, but i do not like the idea of the bore being larger that the crank slinger part, making it not able to help keep the flywheel in place in case the crank breaks at the last journal.
 
do not discount the rope seal (as above). They last very long, due fine...
Learn the tricks, just like the modern (nothing is a "slam-together").
 
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