The Stovebolt Site Forums The Shop Area Engine Shop Front crankshaft seal on a 235

I have a '50 4100 with a really good running 235 in it. The front seal is leaking profusely. I have never installed one on one of these engines before. How big of a can of worms am I going to open if I attempt this with the engine in-frame? It appears that the balancer/crank pulley is just pressed on. I have no doubts about being able to get it off - I'm just worried about how in the hell I'm going to get it back on.

I see now that this engine uses the same front seal as a small block V8. Interesting.

(actually - the small block V8 uses the same seal as the stovebolt 6)

Later this summer I'll be replacing the rear seal on my '59 235, which is a rope type. Is the front seal also the rope type for the 235's?

Front seal on a 235 is a one piece rubber lip seal with a metal retainer. Pulling just the balancer may let you change just the front seal. If you have to replace the timing cover gasket you will have to pull the oil pan to get to two screws that enter the timing cover from the back.


The 59 235 should be able to use the two piece rubber seal on the rear.

Front seal leak fix can really benefit from using the balancer sleeve kit to renew the sealing surface.

Like this one ( example)

https://www.summitracing.com/parts/...BsaAv868P8HAQ&ibanner=MobileSwitchNo


Picture of worn sealing surface ( example not 235)

It is not as easy as it may look. You have to pull the oil pan to get the timing cover off to change the seal. There is a Tech Tip on how to solve that problem, but in the meantime, removing the HB, oil pan to get to the two screws that are holding it in from the inside, then slide it out. Personally, I like the idea of the stainless steel speedy sleeve to ensure it doesnt leak again. Going to all that trouble, why not have the extra insurance?

It is also important how you put the timing cover back on. You need to leave all the bolts loose and tighten them slowly moving across from the one you just tightened. Let the crankshaft be in the center of the seal. If you center the seal on the crank, you won't have leaks.

It's been 30 years since I rebuilt a 235 / 261 so I figured I better look about the front seal.

On ebay is about 26 or so 235 timing covers, some look new, some are dirty and old.

But all appear to show the seal goes in from the balancer side of the cover, so the oil pan and cover should not have to be removed to replace the front seal from what I can see.

If the timing cover gasket has to be replaced, then the oil pan has to come down to get to the two screws that hold the timing cover on from the inside.

If he plans to replace the rear seal he will have the pan off anyway and I think it would be a good idea to go ahead and replace the timing cover gasket as well as the seal.

Using a micro sleeve on the balancer would be a good idea too especially if there is a groove worn in the balancer where the seal rides.

Good advice about how to center the seal before tightening all the bolts. And some fix the timing cover so that they can install the two hardest to get to bolts from the outside rather than having to pull the pan to get to them.

I have seen stovebolt timing covers made both ways. I do believe the ones where the seal installs from behind are the really early model covers - that probably utilize a rope type seal. Covers that use the typical lip type seals have the seal installed from the front side.

I have contemplated doing the whole shebang when I get ready to do this - pull the balancer, drop the pan and pull the timing cover, etc. Replace the rear main seal as well. This thing sat for almost 40 years with the fuel pump removed - so there's no telling what might be in the pan. lol I did flush it out good before I started running it and it does have good oil pressure. However it would be a good idea to clean it out.

it would be advisable to pull the pan anyway to clean it. The regardless you'll be able to remove the timing cover for whatever work you need to do.

You don't have to remove the cover to change the seal. I just use a pair of side cutters to tear the metal lip a bit and then yank it out with large pliers. I use a large pipe nipple to drive in the new one. A speedy kit should be used if the seal surface is worn.

My main question still hasn't been answered - how much of a pain in the [censored] is going to be to re-install the damper pulley with the engine still in the frame? I suspect I am going to have to pull the radiator support and the front grille out in order to get better access to it.

To pull it off you need a puller with the two bolts. In my 51 I had to raise the front of the motor a bit to get clearance. To put it back on you simply drive it on with a big heavy hammer. I use a large pipe nipple to interface with the pulley. One important thing is to measure the distance between the pulley and the front cover before you remove it. That way you will know when it is seated all the way when you are installing it.

Some folks warm the balancer to help it expand while they drive it on.

Best way is to drill and tap the snout of the crank shaft so you can pull it on with an installer.

it was pressed on at the factory.

Thanks for the input. I'm sure I won't have any trouble getting it off. I have a wide selection of pullers. I was just wondering how in the hell I was going to be able to get it beat back on with the limited clearance on the front of the engine there. I suspect I am going to end up taking the front grille and radiator support out...and that splash pan.

Replaced my front seal on Saturday. Man that balancer was stuck on there tight. I wasn't sure I was going to be able to get it off. Just about the time I thought the threads on my puller were going to strip out it popped loose with a loud crack. I was able to drive it back on with an air hammer, worked good. Now it looks like the front of the oil pan is leaking also, but the worst leak was definitely coming from that seal.

We used an old single-eye electric hot plate for a lot of years to get balancers ready to install. A 1/2" thick piece of aluminum plate was placed over the heating coil, and the snout of the balancer was placed on it. After about 10 minutes of heating the balancer would slip onto the crank snout more than halfway and it could be driven home quickly with a BFH and a block of hardwood. When the balancer snout hits the timing gear it's at the right depth- - - -no need to measure.
Jerry

If you have a leak between the curved front of the pan and the front plate of the motor, you can seal that externally with RTV. You just have to get it really clean, run a bead and work it in place with your finger. It is not under pressure and is above the sitting oil level in the pan.

Yeah, I really need to drop the pan though. This thing sat up almost 40 years. I need to clean the sludge and dirt daubers and god knows what else outta there.

Thanks! Sage advice!