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MG MG Y Type - rocker fountains

I recently installed a new rocker shaft since when, with the rocker box off I get an impression of the fountains of versailles. I think this is excessive and have seen some steps people have taken to reduce this effect.

Some have plugged the top rocker holes in various ways while I think the factory suggested a restrictor in the oil feed to the head. I am not keen on blocking the rocker holes but is there a standard restrictor for the feed or should I go and experiment myself? Or leave well aloe.

What have others done

Regards
Brian Hough
B R HOUGH

Brian, the top and bottom oil feed bolts have different hole sizes, the smaller of the two goes to the head. However I was told by an MG mechanic to make the top hole about 1/16", I filled the hole of mine with solder then drilled the new hole. Seems to work OK.
Regards, Don TF 4887
D J Walker

Hi Brian,

I have always done an old mod suggested to me by Tony Ohlmeyer in the late 60s. I have run this mod for about 45 years on my road TC and my race TC special.

I leave the system standard except for turning the rocker shaft upside-down. (End over end because of the keyways) Doing this puts the supply to each rocker on the bottom, which is the load side. BUT a new hole has to be drilled in the shaft to let the oil in from the rear pedestal. The surface hardening needs to be ground off locally with a small grindstone before drilling with an ordinary drill bit.

The original system seems strange to me because the oil pumps out the top of the shaft and straight out of the top hole on the rockers!

Good luck with the "fountains!"

Bob Schapel

R L Schapel

Thanks Don & Bob for your suggestions, I will give both some serious thought and may even try both to get the best results.

Thanks again and regards

Brian Hough (YB TC)
B R HOUGH

It occurred to me that although I restricted the oil feed to the rocker shaft some years ago there may have been some reason for such a large flow in the first place. Maybe spraying the inside of the rocker box cover helped to cool the oil, and that the valve stems were well supplied. Anyway since I don't live in a hot climate there has never been a problem for my car.

Bryan
B Mellem

Thanks Bryan for your input. This has been suggested elsewhere that the oil cooling is helped in this way but I think even the factory produced a restrictor so it seems even they thought the flow was excessive.

By the way I saw you go past last Sunday, I was the guy directing entrants into the Pendine Dash start from the Gardens roundabout! Hope to see you for a bit longer on a future event sometime.

Regards
Brian Hough
B R HOUGH

This thread was discussed between 31/07/2015 and 11/08/2015

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