Re: Installing Front Crank Pulley Rope Seal in the Timing Cover - Reply to Joe

Posted by Gordon Biggar on March 11, 1998 at 11:10:05

In Reply to: Re: Installing Front Crank Pulley Rope Seal in the Timing Cover
posted by Joe on March 11, 1998 at 08:02:13

Joe --

Again, I appreciate your thoughts.Because of the difficulty that I am experiencing, I would think that your first suggestion (i.e., installing cover first, then crank) might cause the main bearing clearances -- especially at the front main -- to be larger than spec, particularly if the bearings had recently been line-bored.

I had contemplated your second idea (installing the pulley after the cover and seal were in place), but one of the machinists here "thought" that such a procedure "might" place undue stress on the timing cover, possibly causing it to crack.I like the concept, though, and will be interested to learn if anyone else has tried it.

The clearance between the pulley and seal groove (without seal) must be abnormally tight, in my situation, since I don't find that too many other rebuilders have had such a problem.Maybe the shims installed under the main caps -- on a newly babbitted block -- are significantly greater than the .018-.020" shims that I have on mine.

I might try Marco's method initially.I'll keep you posted!

Gordon
: Well, hate to differ with Marco, but I have done it via another way and have cut the seal with no resulting leaks.Perhaps Marco is using a more modern replacement seal rather than the braided type "packing" that was available about 10 years ago when I did my engines.

: The methodology I used was to change the order of assembly.
: It requires the engine be in an engine stand and rotatable (and disassemblable) and is normally done during a "build up" after rebuild.

: I put the timing cover in place and bolted her up before placing and locating the crankshaft.Once the seal is in place and hammered down as far as possible into the groove, I bolt the crankshaft in place and then cut off the excess seal level or slightly above the mating flanges.By locating the excess material of the seal to primarily one side or the other you only have to make one cut.If it's cut a little high (1/16th inch), this is not a problem.

: Then I do a similar operation to the oil pan half of the seal (sans the crankshaft, of course) and bolt the oil pan in place.I place a dab of permatex type compound at each end of the seal where the "mating faces" touch together and then bolt all together.

: Actually, what Marco says about prying on the bolt holes of the timing cover or using a punch to force seal material down into the groove accomplishes exactly what this method does as well: establish a "compressive preload" to the somewhat elastic material of the seal.

: The methodology I describe gives me what I think is some control or degree of feel as to the tightness of the seal that I want.Marco's method probably does too, it's just a different "feel".I guess it's whatever you're comfortable with or can do easily.After all, we're not talking rocket science here.

: I have three engines done as I described above and none leak any oil at the front.

: Alternately, I would be interested in anyone's thoughts regarding leaving the crankshaft front pulley off and assembling the engine with the front seals in place but not compressed around the crankshaft.The small taper usually found on the trailing (rear) edge of the front pulley hub seems just right for forcing down into the hole with the seals in place and establishing the "compressive preload" as the seals "ramp up" this taper onto the flat portion of the pulley hub.An interesting concept and one that Henry might have used when the engines were originally assembled in the factory.

: While I didn't do this on mine (no guts), I would be interested to know if anyone has, or knows how it was done by Ford.

: Thats one of the intriging aspects of the Model A.There is more than one way to do most anything and provided it works, it's o.k.Conversely, it's sometimes hard to get a definitive answer on the correct way to do something.Respondants naturally feel that "their" way is the best and hope that everybody will do it as they do.The best thing to do is to research opinions via this board and in the end do what you think is best for yourself.

: Best regards,
: Joe


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