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Opinion/Experence Rocker Shaft Wear

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glemon

glemon

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The one thing I didn't do when I rebuilt my TR250 motor was replace the rocker shaft or rebush the rocker arms. It is not in too bad of shape, but since it was a 90,000 mile engine with no prior rebuild I have to assume some wear.

Anyway I am trying to decide if I want to just order a rocker shaft or send it to Rocker Arm Specialsts for a full rebuild, anybody have any thoughts on whether it is the shaft or the rocker arms that wear more on the TR 6 cylinder?

I know I could take it off and take it apart (tried to just push the rockers to the side, but not enough clearance to really check) and do some checking, but I am having to much fun driving the car in the mild (so far) midwest winter.

I guess if the concensus is the rocker shaft wears more I might try to go the cheap route and just get a shaft.
 
Not specific to the TR6, but I've heard that the softer bushings can accumulate bits of worn metal, which is what causes them to be able to wear away the harder shaft. Putting rockers back on a new shaft will wear it again quickly. Now this might have been unique to certain types of rockers, and not apply to the TR6.
 
I bought my 1958 TR3A brand new and have 182,000 miles on the original rocker shaft, original rockers and pushrods. I have measured a bit of wear, but never had an issue with the wear.
 
On our GT6 (engine currently being rebuilt) I replaced the rocker shaft and several of the arms about 20 years ago when refreshing the engine. What I did not know at the time was that my father-in-law (the previous owner) had installed some killer valve springs that put way too much load on all the rocker gear. The old shaft was severely worn as were several of the arms. I guess all I am trying to say is that you should take the time to inspect what you have and address the problems you find.
 
My understanding is that the TR6 does not use bushings inside the rockers; instead the cast iron rockers run directly on the steel shaft. I would guess that leads to the rockers wearing faster, but it likely depends on how well cared for the engine has been. The oil moves very slowly inside the shaft, so it's common for sludge to build up and eventually block the flow.

If the engine is together and running well, then I'd just leave it alone. A modest amount of wear in the shaft won't hurt anything, since you compensate for the clearance when you adjust the valves. And once the wear has gotten bad enough to do something about, then it makes sense to me to refurbish all the worn components, not just one. The tips of the rockers also wear.
 
To check shaft wear, just slide #1 or #2 rocker down the shaft. Heaviest wear is under these two rockers. If it doesn't want to slide, it's probably due to wear. If it does slide, just feel the underside of the shaft for a wear ridge.

Rocker wear happens on the face of the rocker. A groove forms from the contact with the valve. A heavily worn rocker can make it challenging when trying to adjust the valves properly.

I sent my rockers out to Rocker Arm Specialists for rebuild. I would recommend going that route. The shaft, I purchased the upgraded unit from Moss.

The engine has much less valve clatter now.
 
There is not enough room to push the rocker down the shaft to really check shaft wear, the separator spring doesn't allow that much movement. But the general guist of the comments are 100% correct, it is probably OK as is, but I get a little valvetrain clatter, a buddy came by a while back with his TR6 and it the engine was whisper quiet, and I decided I coveted his silky smooth sounding motor.

it went from warm to winter again in the last 24 hours, so I will do what I should do and take the thing off and take it apart and check for wear, easy enough to do, and go from there.
 
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