Posted on: March 9, 2009

by Steve Finberg

Of late, Alpine engines have exhibited a chronic tendency to leak oil from the front timing chain cover set. As has been explained in an earlier tech tip, this seal is designed as a slinger. The oil is spun off the crankshaft back into the timing cover by a spiral groove and disk.

Russ O’Brien published a tech tip in the October 1984 TE/AE Newsletter (Vol.9, No.8) describing a modification to the front oil seal. He brazed in a custom adapter and used a standard American rubber oil seal. The installation required a special jig and some fancy machining.

Having owned an Alpine since 1967, I had doubts about the need for a modification; the front seal did not leak when new and I did not see how the slinger mechanism could deteriorate.

Recently, while transplanting an engine into my Series V Alpine, I had occasion to pull the timing chain covers of three different 1725cc engines. All had chunks of rubber lodged in the oil drain area at the bottom. A quick reference to the factory service manual and parts book showed the missing rubber seal. A close examination of the parts book shows a rubber “o” ring-like gasket near the timing gears, but it was not obvious where it went. It fits in a well in the front timing cover where it seals the gap between the slinger disk and the cover plate. See illustration.

Replacing the seal

It is my guess the “high quality” English rubber will last only a few years as it is under constant pressure, but it is fairly easy to replace. To replace the seal, first drain and remove the radiator, then disconnect the fan belt. Next remove the starting handle (hand crank) castellated bolt. The right tool to do this is a 1 5/16″ 12 point deep socket (Snap On P/N S421) and a breaker.

I have seen it removed with a pipe wrench, but you will never be able to retighten it adequately without the socket.

Early engines (before S/N B395005604) had a tab type lock washer, which must be bent clear before loosening the castellated bolt.

Next carefully remove the damper pulley with a steering wheel puller, using the two tapped holes in the center section. Be careful, as new dampers are not available. Remove and save the woodruff key.

Before removing the timing cover, clean the encrusted grime from around the cover to keep it out of the engine.

Remove the timing cover by removing 13?3/8″ bolts. Once open, clean out any loose rubber fragments and inspect the condition of the timing chain, rubber tensioner, and the timing gears.

When new, there is virtually no slack in the chain; but the gears are quite a bit pointier than expected in most American engines. My decision was to replace all the pieces, as I did not want to go back in later.

Remove the old cover gasket by thoroughly scraping. Inspect the timing cover for flatness as over-tightened bolts could have distorted the flange. Straightening the sheet metal will allow the new gasket to seal better. A light coat of gasket cement on the new paper gasket is appropriate. Be careful, as too much will ooze out and could get in the oil supply and cause serious damage.

Clean the inside of the timing cover and install the rubber gasket in the well after giving it a light coat of oil for initial lubrication. Be sure the slinger disk is oriented properly and replace the cover. The factory calls for a special tool to properly center the cover hole on the damper shaft, but who has it? An alternate technique is to place a piece of 3 to 5 mill shim stock (1/2″ x 5 1/4″) around the damper shaft and use that to centralize the cover.

Assemble with the shim in place and tighten a few of the hold down bolts.

Remove the damper and shim and tighten the remaining bolts.

Tighten only until the compression lock washers flatten-over tightening will only distort the cover (WHAT? You have not installed lock washers on all the engine cover bolts?)

Reinstall the woodruff key and damper; tighten the crankshaft nut as tight as you can. Use a socket and a breaker bar and secure with maximum force you can muster, short of breaking bar. It will be necessary to secure crank by holding flywheel. Reinstall the fan belt and radiator.

After 2500 miles in 3 months, I am very satisfied with the results. Absolutely no seepage is evident and oil consumption is running about one quart per 1500 miles.

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