Felt or new style crank seal?

[Reno Speedster]

I needed to take the pan off a engine built (too) many years ago to check things and get it ready for installing my Rajo BB head. In the process, I mangled the new style crank seal I had installed. I have both felt seals and a new style seal that I could install. Can’t make up my mind which to use. The new one would probably seal better, but seems a bit fiddly and,as I have just proved, a pain to get apart. The felt is easier, but might leak. On the other hand, what is a T without a drip and with an original Muncie transmission, it’s guaranteed not to be the only one. The end of the crank was ground slightly undersized to make a clean surface so I should get a good seal either way.

[Allan]

I always use the white rope seal used in A models. The two halves are longer than needed. I fit the seal to the pan, forming it into round with a socket of appropriate size, and trimming off the ends, leading them a little long. Same s=fitting in the timing cover. The pan gasket is cut around the proud part of the gasket. When the pan is fitted , the extra crush on the proud sections of the gasket make for a firm seal.

others will have different ideas.
Allan from down under.

[jsaylor]

I have always used the rope seal installed the same a Allan with no issues.

[DanTreace]

Comparison of felt (lower) and rope seal (upper)

Install of rope seal in timing cover

[KWTownsend]

In my experience I have found the early pans and timing covers have a narrower slot and the rope seal can't be forced into it. On my 1915 I used a "modern" one piece seal which worked great until I had to remove the timing gear cover...

[Dennis Prince]

There is a reason that a lip seal was invented and used ever since, with all of the effort that it takes to replace that seal why not use the best seal that you can get?

[TXGOAT2]

The rope seal is superior to felt. The white-colored rope seal is probably impregnated with white lead or teflon. It needs to be snug, but not jammed extremely tight. Oil it before putting the pan on. Care in installation will give a good result. The surface finish of the crankshaft will affect how well the seal works and how long it lasts.

[RajoRacer]

A smaller rope seal used to be readily available but apparently harder to locate now. Steven Lang is supposed to have a similar substitute.

[speedytinc]

There is a reason that a lip seal was invented and used ever since, with all of the effort that it takes to replace that seal why not use the best seal that you can get?

There are advantages & disadvantages to the rope & modern seal.

The modern seal is very narrow. The crank seal surface must be great. If you remove the timing cover in the future, you are very likely to destroy the seal. Then you have a massive leak. Then the pan has to be removed to replace. Or a narrow external seal has to be glued to the front of the motor.
The rope seal, being split will allow the timing cover to be removed & replaced with no damage. The wider seal surface is more forgiving, but still must be nicely polished/ground for a long term seal.

[Reno Speedster]

I notice no one has mentioned using the felt seal. What is wrong with it?

[Scott_Conger]

It's less of a seal and more of a filter...

felt is as effective in keeping engine oil "in" as felt is effective in keeping axle oil or grease "in" an axle.

[DanTreace]

Here is some info from a felt seal mfg. website.

Agree with these generalizations too, have found wool felt as a crankshaft seal is marginal, why Ford used cotton rope seal one on the new Model A.

As for other uses, like the large round felt seal in rear hub recess, or Hyatt bearing cap , have always greased the felt prior to install to reduce wicking of the lighter lubes in the rear axle. Same at the fan bearing too, felt seals should never be dry installed.



“Felt seals are usually pre-saturated with lubricants of a higher viscosity than the bearings offering positive bearing protection. If the seal does run dry it will tend to protect and polish the shaft rather than cause damage. Through normal operating temperatures and conditions the felt seal is highly economical, normally requiring replacement when the machine is overhauled.
Felt Seals are not suitable for oils with extremely low viscosity or the lubricant is pressurised.”

[Allan]

Good, dense felt can be an effective grease seal. Think front wheel hub seals and LH rear axle seals. It is not so effective as an oil seal. Think timer seal, land in which T crank seal fits and RH axle seal, often diluted with engine oil.
Modern lip seals require an accurately machined land into which they are pressed. T front camshaft seals often need to be deformed or shimmed to fit. The receiving land in the pan and timing gear cover is not such a machined land, and using a modern seal in this application comes with its own set of fitting requirements. The lip may seal well but the outer diameter of the seal in the cast-in grooves of the pan and timing cover present their own work-arounds. There are no such requirements when using the white rope seals .Each half can be fitted in separate operations and there is no chance of damage negotiating a somewhat experienced crankshaft snout when fitting same.

Allan from down under.

[Dan Hatch]

Here some NORS seals I listed. Still have some left. Dan
viewtopic.php?t=33401

[RajoRacer]

Will those fit in the early, narrow pans & timing covers, Dan ?

[Dan Hatch]

I am sure they will but when I get a chance I’ll try on a 7 rivit pan in the shop. Dan

[TXGOAT2]

Back in the day, a felt crankshaft seal may have been more effective than one would be today. After a few hundred miles, the original felt seals probably accumulated enough carbon and gum to make them less permeable to oil. Modern oils and gasoline would have some tendency to keep the felt cleaner, and thus more permeable.

[Allan]

The felt seals provided in the gasket kits today is not up to snuff. It is way too loosely felted. Fit one to a timing cover and fit the cover to the block. Then see just how much you can punch the felt tighter on each side of the crankshaft. Just another repop part not fit for servise. No such problem with a trimmed A model white seal.

Allan from down under.