front crankshaft seal number

[Cav Trooper]

Anyone have a National seal number for the front crankshaft timing chain cover seal on an 230 engine?
Thanks,

CT

[T. Highway]

CR21820 or Victor 49521

[MSeriesRebuild]

National #6636S, I don't know if this is a direct cross over to the numbers given in the above post or not. This is a special seal for this specific application, it has a deflector on the case to eliminate direct oil splash against the seal lip. These do not leak provided the crank hub is not grooved or pitted, if it is, the redi-sleeve # is 99218. An ordinary seal can be had that fits the bore, but will leak unless a good oil slinger is in place. The 6636S seal eliminates the need for the oil slinger that we find missing in most of the engines we tear down. The original oil slinger cannot be used with the 6636S seal because of the deflector that is on the seal case, there is a clearance issue. We have found it best to eliminate the oil slinger from the assembly and use the 6636S seal. It last longer and is much more leak resistant due to its advanced design.

The timing cover seal or 2- piece rear main seal is no longer included in most overhaul gasket kits these days such as Victor and Fel-Pro, and must be purchased separately. The rear main seal is part #3675.

[Cav Trooper]

Thanks, all. Just like the transfer case and rear differential, PO replaced some of the seals, all NOS but didn't bother to replace or repair the hubs so, the seals, as bad as they are being leather, didn't have a chance on the worn and pitted mating surfaces. The front crankshaft hub had actually been painted on the od. so the seal had to wear through the paint then onto the pitting. This has been a long journey to stop the leaks and find all of the poorly done work. I think I can see the light at the end of the tunnel though. Knock on wood, the rear main doesn't appear to be leaking so far and just a minor drip out of the front diff. I may be premature on my optomizium but, it's looking like a winner.

[Lifer]

Well...I have heard it said that an M37 is a lot like a Harley. If it's not leaking, it's time to add oil.

[MSeriesRebuild]

Well...I have heard it said that an M37 is a lot like a Harley. If it's not leaking, it's time to add oil.

Lifer, I know you are just kidding around, but with the price of good oil, and the fines that can be levied for oil spilled on the ground these days; I'd just as soon not go there. One more thought also, if you are going to make an effort to repair it, why not just do it once and be done.

A leaking component in our eyes here is a direct give away for a job not done right.

[SOTVEN]

Well...I have heard it said that an M37 is a lot like a Harley. If it's not leaking, it's time to add oil.

HAHAHAHA!!! IT SEEMS I GOT ME THE WRONG KIND OF HARLEY THEN, MINE DOESN'T LEAK LOL