to block or not to block rocker hole that is the question

[JUANRAF]

Hi,

I have decided to buy all new rocker arm shaft parts. But now I don't know if I should block the rocker arm holes or not.
a Morris Engines Service Sheet published in March 1938 that told dealers to blank these holes off by hammering 1/8 inch ball bearings into the holes.
I am very lost on what to do.
Pedestal shims, yes or no?
rocker arm holes, yes or no?
25 hot pressure at 2000 rpm, ok or not ok?
cause of low oil pressure due to rocker arms and rocker arm shaft, yes or no?
My wife will ask me for a divorce soon if I continue like this
I'm going crazy!!

[Steve Simmons]

I've not blocked the holes on my own car, but have seen it done many times. I like the idea of oil being delivered to the rocker tips from the top holes, but that's just my own opinion on the subject. To my knowledge, those who have done it haven't noted any issues with increased rocker wear. Whether it will increase oil pressure isn't certain, but I suspect it would not make a notable difference.

I would not use pedestal shims unless they are needed to correct the rocker geometry. I would definitely NOT use them to adjust for push rod length.

25 PSI hot @ 2K RPM sound ok to me. Anything over 10 PSI at idle and over 40 PSI at highway speed is good. The old rule of thumb is 10 PSI per 1000 RPM. I prefer a bit more than that, but I consider it a safe minimum. These engines don't want or need very high pressures. I feel that quantity of flow is far more important.

Rebuilding the rocker assembly can increase oil pressure, but only if they are significantly worn. I rebuilt an engine once and the only thing not done was the rockers. Oil pressure was not as high as I wanted, so I had the rockers rebuilt. It made no difference whatsoever. Your experience may be different of course.

Regarding the wife, maybe she just needs a vintage car of her own!

[Tom Lange, MGT Repair]

Havr you considered having your rocker apparatus professionally re-done? Rocker Arm Specialists does an excellent job: they clean everything, build-up the rocker tips with Stellite material and re-grind them back to standard profile, they have an original shaft (nothing from Overseas) hard-chromed and centerless-ground back to spec, new rocker bushings, re-lube and re-assemble everything.

My suspicion is that thre quality of used, original parts will be superior to new parts you buy today, and the cost of rebuilding will be less than buying new.

Tom lange
MGT Repair

[Kenmgtc]

A few weeks ago I discovered my rocker shaft was installed backwards and there was no oil flowing to the rockers at all, just oil mist for at least the last 7000 or 8000 hard miles I’ve driven the car, and who knows how long before that. I rebuilt everything but was very surprised at just how little wear there actually was. My oil pressure did drop a bit with the rocker path now working.

My point is, the xpag rocker assembly is surprisingly robust, and anything you do to slow the flow of oil up there is probably ok. Don’t worry about it otherwise.

[Ray White]

What surprised me was how much the actual shaft wears and yet the the brass bushes seem to show very little attrition. I would have imagined the cheaper expendable bushes would have been knocked out first.

Just goes to show you don't know what you don't know.