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Discussion Starter · #1 ·
I've decided to adjust the intake and exhaust rockers since I have the fuel tank pulled off for some other work. The first thing I noticed after removing the access covers is how little oil there seemed to be on the rockers and spindles (not dry but not shiny, dripping wet like I would have expected). So I pulled off the rubber rocker oil feed hose and blew into to make sure it wasn't plugged. It was unobstructed but only a few drops of oil came out which didn't seem like very much. I will check the metal tube spindle feeds next.

My questions are:

1) Does this seem like a normal amount of oil in the rocker chamber and oil feed tube or is it starved for oil (the engine had not been run in a almost a week).

2) How much oil should I see in there if I run the engine with the access covers off?

3) If the oil flow is weak (based on advice for #2 and my own observation) can I increase it by restricting the flow back to the tank or would that cause another problem?

I appreciate the feedback in advance.
 

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I’m no expert on these engines but I can tell you that after I rebuilt my engine and started it for the first time I had the same concerns you have listed. It seemed to me that I should have seen more oil than I did in the rocker boxes.

One thing I did learn about the oil flow on these beasts is that unless you have oil down in the sump, you won’t get any coming to the rockers at all, and the oil returning to the tank will be frothy looking. Seems as though the oil to the rockers is delivered there in a mist and not in a flow.

I have had the rocker open a few times since the rebuild and I have never found a bunch of oil in the rockers. In fact I can run the engine at idle and it never makes a mess. I’m keeping my eye on them for awhile. I’m curious to see what others more knowledgeable than me have to say about this?
 

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The oil to the rockers is mostly intended for the rocker spindles. Once through the spindles, the oil flows to the pushrod tubes, through the tappet blocks, and is thus returned to the sump. The valves/guides etc don't require much oil, and the residual mist/splash/spray takes care of that. Especially after sitting, most of the oil left up there would have drained back to the sump.
 

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"some" oil in the rocker box

I've decided to adjust the intake and exhaust rockers since I have the fuel tank pulled off for some other work. The first thing I noticed after removing the access covers is how little oil there seemed to be on the rockers and spindles (not dry but not shiny, dripping wet like I would have expected). So I pulled off the rubber rocker oil feed hose and blew into to make sure it wasn't plugged. It was unobstructed but only a few drops of oil came out which didn't seem like very much. I will check the metal tube spindle feeds next.

My questions are:

1) Does this seem like a normal amount of oil in the rocker chamber and oil feed tube or is it starved for oil (the engine had not been run in a almost a week).

2) How much oil should I see in there if I run the engine with the access covers off?

3) If the oil flow is weak (based on advice for #2 and my own observation) can I increase it by restricting the flow back to the tank or would that cause another problem?

I appreciate the feedback in advance.
If you look at the 2 small holes in each tappet guide block. you will see how much capacity there is (not very much) for the oil to flow by gravity from the rocker boxes to the sump. Dripping wet should not be expected after the motor has sat idle. All you need is: not dry. The oil to the rocker boxes is not really a pressurized flow, just gravity with the rocker box feed being lower than the sump return outlet and just the size of the return tube creating enough resistance to send oil into the rockers.. If you're getting "some" oil, that's the way it was designed. Some of the oil returning to the tank goes into the rocker box feed. Bob
 

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The restriction in the return line in the oil tank (7/32" hole),causes some pressure to the rocker-feed line.It's about 0.5 psi when the oil is warm.If you held the hose a foot above the rocker shafts and oil still pumped out,that's enough pressure.

You can get more pressure if you push a coat-hanger wire into the return pipe in the oil tank.Bend it over at the top,so it won't fall inside the tube.That will give you about 25% more pressure.10 times the standard pressure will still work OK,as long as the hose stays clamped onto the fittings.

The best thing you can do for rocker spindle lubrication is put the thrust washers in the right place.'69 and later rockers should have the thrust washer against the rocker,and the thackeray washer against the rocker box casting.This was right in the parts manual,but assembled wrong at Meriden.It means buying two 1/2" ID thrust washers (as shown in the parts manual) to replace the incorrect 3/8" ID washers.
 

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Are you talking about your '72 Bonnie? The older unit 650's had an oil drilling in the push rod side of the rocker arm that allowed much better oil flow through the top end, and the 750's, I believe '73 and later had a spiral oil way machined into the rocker spindle which also allowed plenty of oil flow. If you have an original rocker set-up on a650 from somewhere between these years, I think '68 or '69 to '72, you will most likely have very little oil flow through the top end. If you take a look at your spindles and rockers, you will see that the only place for oil to flow is through the diametral clearance between your rocker spindle and rocker arm which is maybe .002".
With such a small amount of pressure, not much oil will make its way through.
 

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Discussion Starter · #7 ·
Well based on the responses it sounds like no one would have been surprised to see what the inside of my rocker box looked like.

I also recall GrandPaulZ saying in another thread that he had unintentionally raced one of his engines with a blocked or separated oil feed and no damage was done.

I will check to make sure the spindle oil tubes are clear, squirt a few drops of oil at the four corners and call it a day. If the push rod clearance isn't too bad then that probably means its getting adequate lubrication- which apparently isn't all that much.

Thanks everyone.

cheers
 

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Discussion Starter · #8 ·
Also, thanks for the coat hanger tip, Mr. Pete.

I might try that to see what the increased top oil end oil flow looks like.

A little extra oil up there probably can't hurt anything as long as the valve stem seals aren't letting it leak by.
 

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Discussion Starter · #10 ·
Stock Triumphs (classics) don't have valve guide seals.
Bad assumption on my part. Just checked the exploded diagram.

Why is that do you suppose? Pre-valve stem seal technology? Or seals are just simply not necessary with the limited amount of oil being fed to the rocker box? Probably not enough oil to keep the seals lubricated?
 
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