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MG TD TF 1500 - Oil Geyser...

Decided to check/re-adjust the valves on my 54TF. Did it cold. Engine is rebuilt with a few hundred miles on it. Rocker shaft is new. When I finished with the valves I started it up with the valve cover off to see what the oil flow looked like coming through the rocker arms. From #7 rocker arm oil shot up close to a foot while very little came from the other arms. What would cause this? Should I peen over the hole in #7 rocker arm to restrict its flow and maybe force more oil to the other arms? Any ideas, thoughts, advice, etc. greatly appreciated.... John
J OSTERGREN

John, it's hard to picture just the oil would be coming from. My first move would be to assure that the rocker arm assembly is assembled correctly. Is the bushing in that rocker arm? Bud
Bud Krueger

You could check the bushing of No 7 again?

Do the shaft oil holes point directly in line with the rocker oil holes?

I have not looked at mine for 40 years and can't remember

Would rotating the shaft a tad help this issue.

The WSM shows the oil holes in the shaft lean away from the rocker drip exits?

Just a thought.

Rod

R D Jones

Rod, the shaft is keyed to the tower. It cannot be rotated. Regards, Tom
tom peterson

Rod

I will stand corrected however I am reasonably certain you can assemble the shaft 180 degrees reversed.

I believe I did this whilst attempting to sort out my problems with the inability to adjust tappets correctly. I wish the memory was better however I seem to think that all rocker arms receive no lubrication if you do this.

Might be worthwhile investigating.

Graeme
G Evans

Rod. Hi.
I agree with Tom, there is only one way to correct assemble the rocker shaft.It is keyed to one of the towers with one of the
distance washers in the front and rear towers.
see section A 8 in the workshop manual
Section general description in section A 4
shows the oil flow.
Thoralf. Norway TD 4490.

Thoralf Sorensen (TD4490)

Well, it is good to know the shaft is keyed and can only be assembled one way. I need to check mine anyway - to make sure the noise I am getting in the valve train is not the tapers wearing or the cam.

This does no help John, who started this thread and has oil squirting out of one of his rockers?
I presumed it was from the hole in the top of the rocker arm as he said it shot up a foot high. There is a lot of oil delivered to the rockers but one only should not present this behavior.

What else could get oil under pressure shooting out of the rocker arm?

Even if the shaft could go in 180 out - The oil would presumably shoot out of all the rockers? Not just one.

I can only think there is a problem with the bushing on that rocker. Or damage to the shaft.

I do know that at tick over with my rocker box remove I only get the odd drip thrown off and it will makes a mess if left for any length of time but no vertical squirts of oil from the rockers. I would definitely not recommend penning over the hole in the rocker. It is there for a good reason. The problem must be caused by something else.

Rod
R D Jones

I remember a poster here who welded the holes shut on his rockers. Not endorsing, just repeating info posted here earlier.
I do get a fountain out of each rocker on my car. Regards,, Tom
tom peterson

I noticed you said the rocker shaft was new.

I wonder, is the rocker shaft oil drilling completely through the length of the shaft, and aligned to allow a full flow?

A friend of mine with an 'A' (sporting use so hard driving at high revs) had a rocker shaft fracture in use, completely through the diameter, though irregular in line - well offset from the centre, though I don't recall whether forward or rear.

When we investigated we found that the oil drilling had been done from both ends and was offset at the point where the shaft had fractured (suggesting the meeting point of the two drillings). We presumed that created a weakness in the strength at that point.

If that can occur in production one can imagine a case where the two drillings did not meet at all, or in a way that seriously impedes the flow of oil.

That might explain a jet at the 7th rocker if that was the major point of flow available to oil under pressure.

If the front of the shaft has the screw-in stud seal, removing that and the washer split pin would allow you to check the length of clear oil run with a length of stiff straight wire. Have the front valve fully closed to take the pressure of the front rocker arm and it should not spring off in the process.

Perhaps worth exploring?

Regards
Roger

R Taylor

Tom,
I welded up my rocker holes about 25 years ago.
I was told that the TA engine did not have these holes and that they were only added to splash oil on the rocker cover for cooling purposes.
I gained 10 psi oil pressure and nothing has worn in the valve train in the 70,000 miles travelled since I did it.There is plenty of oil splashing around in the cover running down to the tappets.
Ray TF 2884
Ray Lee

...back in town. Thanks for all the thoughts. Not sure what the problem is. I did not do the rebuild so don't know much about how the whole rocker assembly hangs together. Can you put a bushing in the wrong way? Don't see how you could do that. What I did do was to tap the hole in the #7 rocker arm and plug it with a machine screw. Now I have good oil flow coming out of all the other rocker arms. There is obviously little or no oil flow restriction on the hole in the #7 arm and it just blows out of there. The rocker arm 'feels' ok. That is, it does not wobble or feel lose in any way that would suggest the bushing is worn or not there. Think I will just run with it with the #7 plugged up. If Tom has run 25 years with all of his welded shut then I guess being 75 that I shouldn't worry about it too much. I am in the process of moving from Chapel Hill, NC so when I get settled in new home I will take the rocker assembly apart to see what is going on... Thanks again for you input... John
J Ostergren

I'm foggy on what car it was, but I remember reading a factory bulletin that reported that there was excessive rocker flow, and that shops were supposed to weld up the rocker holes after break-in!

Tom Lange
MGT Repair
t lange

This thread was discussed between 03/10/2013 and 08/10/2013

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