Leaking tins

[Steve Little]

Hi.
I have had a problem with my 37 EL rocker tins leaking large amount of oil every time I rode it. When the engine was rebuilt, the lifter blocks had to be oversized to bring them into service.
Unfortunately the oversize was .010” and this meant that we were restricted to one manufacturer.
We had not heard of any bad stories at that stage so we decided to use them.
The engine is as quiet as a kitten and runs beautifully with plenty of power but from the outset, I was unable to stem the flow of oil that was pushing out between well sealed rocker tins.
The heads are genuine 37 but had been retro fitted with genuine 38-39 tins and covers. The covers are not distorted and the gaskets were sealed with Aeroquip non hardening sealer.
Kyle had heard a story that the ventilated top of this particular brand may be the problem so he suggested blocking the holes, but I have not been able to make time to do the job.
I rode the 37 around the block this morning after washing off the oil from the previous ride.

When I got back, I left it idle a minute and then had a look at the front rocker box tin.
Oil was running out and dripping on the exhaust so I decided it was time to fix it.
I removed the front lifter block, and walked around the workshop with one of the lifters looking for some material to fill the holes.
After unsuccessfully trying some wire, I picked up an electrode and it measured 0.127" which is 002" over the hole size in the lifter...good enough.
I ground a lead chamfer on one end and cut the first dowel about 3/16 long, cleaned it with Acertone, coated it with Loctite, got a pin punch and drove it in.
002" interference fit, and Loctite......its never coming out.
I decided to make the next pin shorter as I was concerned that the adjuster may make contact with the dowel on the inside when it was fully adjusted down in the lifter.
I made the rest fo the dowels 1/8" long.

After fixing the front lifters I decided to ride the bike around the block, but it still leaked like a sieve on the front rocker box tin, so I put the bike back up on the lift and pulled the rear lifter block out and did the same thing.
Put it back together and rode the bike around the block, and it was perfectly dry, even though I had not changed the previously leaking rocker tin gasket.
I just got back from a 3 hour ride to Melbourne and back...not a drop of oil.
I finally fixed this very frustrating problem.

Analysis.
Even after blocking both holes on the front lifters, the front rocker tins still leaked like a sieve...3 drops per second at idle.
The combined area of the 2 unblocked holes in the 2 rear lifters, is enough to drop any vacuum away, and both rocker boxes will fill with oil and leak.
I think that even one un-blocked hole will cause enough vacuum drop to allow the rocker boxes to fill with oil...but I did not try that to prove it.
I have done nothing else to the rocker boxes, nor did I replace the rocker tin gaskets that were leaking and it is now dry, which proves it is the holes.

I have located another set of early lifter blocks, so I will see if I can fit some S&S or Jims into them so that I can get away from the ventilated top lifters. The top of the front exhaust lifter came loose some time back and I re assembled it with Loctite, but I don’t want to run into this problem of loose tops in the future.
Hope this experience helps some one else.

[ricmoran]

Steve, are the rocker arm shafts the type that you can adjust for the amount of oil or are they the later type that does not require adjusting?

I had to seal the holes in the lifter only on one side of the lifters in my 39, which I believe was on the intake side to allow the vacuum to work better on the exhaust side and had not had the problem your having.

Was getting a lot of noise that was driving me crazy which I thought was related to under oiling.

I discovered the right fuel tank resting against the front cylinder intake fastener that is used to secure the rocker shaft.

My 39 is a mutt, and after finding this problem I realized the chase for the noise was not at all related to under or over oiling of the rocker shafts. That investigation lead to the discovery and tips provided by club members about the early rocker arms with there oiling adjustment that the shafts could be adjusted for more or less oil.

Another issue was hapenning, issues with the top of the lifter seperating from the lifter base.

The result of this would be a lifter going out of adjustment and causing a lot of racket.

After having this happen to 3 lifters, I used JB weld around the top of the lifter and then the lifter base where the 2 seperate parts are pressed fitted together.

Did not want to use heat on this because I was afraid that the heat would warp the lifter in some way causing other issues with wear of the lifter block.

Once the JB weld cured, I had to chuck the lifter into a drill and used sand paper to cut the edges back of the ill fit of the top to the bottom, otherwise when running the lifter would of caused binding in the lifter block and ultimately damaging the lifter block.

If you look closely at older lifters and see where it looks like someone had grabbed the top of the lifter where the male lifter thread shaft and cup where the bottom of the push rod rests, where this assembly threads into the lifter base (the top of the lifter actually) you may see grab marks that may have been caused with vice grips.

That reveals that the lifter had come apart at some point. That is the only way I found to be able to hold the lifter to loosen the adjustment nut to be able to retreat the shaft far enough to remove the push rod and ultimately the lifter itself.

If you have lifters that go out of adjustment frequently, the ill press fit is the culpirt behind the issue. With that and after installing 2 new repop lifters and having the both come apart I grew frustrated with the issue, thus used the JB weld to aid in holding the works together.

It's been about 6 - 7,000 miles with zero issues from either of the lifters coming apart. To seal the holes, I used JB weld for sealing the intake lifters.

I also must say, was advised not to use JB weld, but to braze the holes closed. After reading the info at the JB weld page, I felt quite confident that this would hold for the 2 tasks. So far the results are what I expected, everythign is working as it should.

Over oiling is a nuisance, but at least you know your getting the lube where it is needed.

One last tip, and that is to get an pushrod tube and braze a fitting to it where a vacuum gauge can be used. With this you can test each head for how much vacuum is present if your into removal and installation of each tube and the related work to find out what is going on.

[Chris Haynes]

Could it be that you are using the wrong oil pump drive gear and are over reving the oil pump? Which pinion shaft are you using? If you are using the -39 Pinion shaft you must also use the -39 oil pump drive gear. if the -36 gear is used you have problems. Also putting a small aluminum rivet with a .060 hole thru it in the top end oil line at the the fitting in the timing gear cover will help control oil flow.