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"Oil Screw" on Rocker Shaft

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rlich8

rlich8

Jedi Trainee
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"Oil Screw" on Rocker Shaft

Hi All, Happy Friday!

My dad was telling me about a problem on the TR6's (maybe on TR2,3,4,4A's as well?) where there's a special little screw towards the bulkhead on the rocker shaft that has something to do with keeping oil pressure to the rocker assembly.

He said that sometimes if loose, they will fall out and fall into the oil pan and oil pressure is nearly completely lost to the entire top end.

Is this also applicable on my TR4A??

Thanks All!

Royal
 
Re: "Oil Screw" on Rocker Shaft

On the TRactor motors, there's a shaft retaining screw at the rear of the rocker assembly that also orients the shaft in the proper location so all of the oil holes are in the correct position. If it falls out, I suppose the shaft could rotate out of position.

Edit: I'm not sure if oil would pour out of that hole if that screw fell out. The oil comes up the head and into the pedestal that the screw goes into.
 
Re: "Oil Screw" on Rocker Shaft

Just saw this the other day on a car that was reawakened for a 20 year slumber. On the 6, if the rocker shaft screw is missing the shaft will eventually turn out of alignment and at oil passages will not line up. Oil will escape from the screw hole and none will reach the forward rocker arms. This is only for the TR6 engine as I don't know the rocker shaft arrangement on the tractor engines.
 
Re: "Oil Screw" on Rocker Shaft

If memory serves, the screw does penetrate to the bore in the center of the rocker shaft, so it would disrupt oil delivery to the rockers somewhat. But IMO a larger concern is what happens when the screw jams between a pushrod & it's tube.

Basically having any fastener come apart inside an engine is a Bad Thing. But lack of oil to the rockers is no big deal, I've run for literally thousands of miles that way. They wore faster, of course, but nothing catastrophic. And because the oil to the rockers is basically metered by the camshaft turning, it won't rob any significant amount of oil pressure from the rest of the engine.
 
Re: "Oil Screw" on Rocker Shaft

I've had them in the shop with no rocker oil. Yes, rockers and shaft wear out, sometimes badly, but you also get no oil for the valves, and unless it was co-incidence, the stems and guides were GONE.
 
Re: "Oil Screw" on Rocker Shaft

Yup, that too. I bought a TR3 once that had the rear cam bearing installed wrong, so no oil at all to the rockers & valves. No idea how far it had been run that way, but I drove it from Houston to LA and at least a few thousand beyond that, before I discovered the problem. (Unfortunately not until after I had transplanted the engine & OD into my 59 TR3A.) Some of the pushrods were literally rusty! Guides were certainly badly worn, I didn't check the valves. Since it was a low port "Le Mans" head, I just put it on the shelf and rebuilt a later high port head to replace it.

But my point was that the engine didn't go BANG or spin a bearing, etc.

Checking for that locating screw (and that there is oil flow to all of the rockers) is a good thing to do whenever you adjust the valves. But I wouldn't bother taking the cover off just to check the screw.
 
Re: "Oil Screw" on Rocker Shaft

Ok! Thank You all!!!
 
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