346 flathead front main seal

[pauldridge]

I'm in the final stages of completing overhaul of my spare 346 engine.  I opened my gasket set, expecting to see a front seal with a rubber or neoprene lip as on most cars, even older ones, but after closer inspection of my timing chain cover, it appears that the complete front seal consists of a cork "donut" that fits inside a spring-loaded metal carrier.  I do have the donut in my gasket kit, just wanted to make sure that this is all there is?

And then, do I just glue this cork seal into the metal carrier, or is it held there automatically by the spring tension once the cover goes on?

Appreciate any experienced comments

Phil Auldridge  austin

[harry s]

Phil, That's all there is. The cork donut just fits into the carrier and rides on the inside of the timing chain cover. I put some lubricant on the cork to hopefully retard wear. There was an article a few years ago showing the conversion to a modern neopreme seal. As I recall the biggest problem with the conversion was finding the crankshaft center in the center of the timing cover opening. I don't recall where the article appeared. I'm sure someone will know.     Harry

[pauldridge]

Thanks Harry,

I guess the nice thing is that if the thing starts leaking, it should be a pretty trivial exercise to pop that timing chest off and replace it with another!

Phil

[Steve Passmore]

As Harry said Paul, thats all there is, They usually work very well though. To make a conversion one would have to line bore through the main bearing journals.

[Tom Beaver]

I replaced the front oil slinger with a modern seal on my 38 LaSalle.  The front seal I used is a NAPA 18548.  It is for a mid 90's Ford 302.  Shaft size listed for the seal is 1.875".  The seal surface on the Cadillac harmonic balancer I have measured 1.873" and on the Ford measured 1.875", which is close enough I think.  Diameter of the hole for the seal in the Ford front cover measures 2.558" which is something like 0.010" smaller than the OD of the seal itself.  The seal is designed to be compressed a bit when driven in, so I milled the hole in the Cadillac front cover to be the same as the Ford.

Since the Cadillac front cover is positioned by dowel pins I assumed that the original crankshaft hole was concentric with the crank and so centered the new hole on the old one.  I am within 0.002" as there was a little eccentricity in the old hole.  When I installed the harmonic balancer on the crank with the front cover in place it fits into the seal well and visually appears to be centered.

To allow all of the front pulleys to line up as before, I placed a spacer washer on the crankshaft between the timing chain drive gear and the end of the harmonic balancer.  I made the spacer approximately 0.040" thick which is the same thickness as the sheet metal on the old Cadillac seal/wiper which I had removed. 

To date, there has been no hint of an oil leak from the front cover or seal.

Tom Beaver

[harry s]

Tom, The fact that there are no leaks certainly speaks well of the conversion. If I had not just put the engine in my '37 I would have tried it. At least if I have any leaking I know what to do. Thanks for the info.      Harry

[Ron Parker]

Harry, Should the seal be sealed or glued to the carrier? Thanks ,Ron Parker

[harry s]

Ron, It just sits in the carrier and the tension keeps it in place. I like to put a film of grease on the outer face of the seal.  It's not part of the instructions but just seems to make sense.      Harry

[Ron Parker]

One last thing. The cork seal has 3 notches on one side. Do they go toward the front or engine? Thanks Ron Parker

[harry s]

I haven't seen the notches but would guess they would  be inward on the holder.      Harry

[Ron Parker]

Thanks Harry, I will be installing those heads soon.