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MG TD TF 1500 - Head Banjo bolt orifice 51TD

I'd like to hear from some experts.

I discovered that the oil feed banjo bolt on my head had been filled with solder and drilled with a hole maybe 1/32 inch. Obviously this seriously reduces the amount of oil getting to the head. Based on opinions stated on this forum, I drilled it out.

But now I'm worried that perhaps MG realized that the head was being overlubricated and began reducing the banjo orifices to keep oil pressure in the big end and send less to the head. What do you think? Below is a quote from another current thread on one users experience....
Please weigh in, I need to know if I should resolder the banjo and reduce the orifice! I would hate to think I may now be starving the crankcase and camshaft of oil because too much is going to the head!

Quote :
... in 1961 when I was 19 years old and had my first MG - a 1953 TD - I recall taking it in for a service to a BMC specialist (Geelong, Victoria, Australia). The first thing he did was fill the top oil feed bolt with solder and drill a smaller hole.
I have had my TC for 25 years and have no idea as to the hole sizes but have a constant 70psi oil pressure and drive at 4000rpm all day
Peter
Geoffrey M Baker

Geoffrey - it wasn't a "factory" fix - if it had been there would have been a service bulletin. It's obvious your car was played with in the past, i.e., had some shade tree mechanics working on it. Buy new hardware and swap the oil takeoff back to the block where it belongs.

JMHO..
Gene Gillam

My car is similarly modified. Since I've known him (1979).

Works fine.
Dave Braun

Some people do that. Yes the head is probably over-lubricated, but if you have sufficient pressure in the system then I don't see how the lower end could be starving. Too much oil at the rockers may cause increased oil consumption but I doubt it's that serious. If I were to reduce the size of the oil delivery hole to the rockers, I wouldn't go so small. Maybe 50% at most. But considering the engine was in use by MG and others for 15 years or so and they never felt it necessary, I tend to leave things as designed. Just my opinion.
Steve Simmons

With the epidemic of failed lifters and camshafts, the more oil running down the better IMHO. The bolts were modified and restricted to make up for badly worn rocker shaft/bushings and likely worn lower end bearings in an attempt to raise oil pressure in a worn out and shot engine. Period. George
George Butz


-- Geoffrey, Your referenced Quote doesn't make much sense to me. It refers to a 1953 TD and a TC----Well, the 1953 TD had an integral adapter on its copper oil line to the head. It took gage pressure from this integral adapter at the lower banjo area. The TC has an early type straight banjo bolt but it is installed in the lower oil gallery port where the pressure gage is connected. So, What is the point in putting a soldered restriction in these examples that didn't exhibit pressure gage problems? It certainly had nothing to do with pressure gage readings, but would have killed oil flow to the head/cam. Further, Can anyone really think the MG factory would ask dealers to clean that oily line and pull out their soldering iron?
Like Gene Gillam said, I would suggest that those soldered restrictors are modifications individuals did to accomplish a false logic cure for low oil pressure readings on cars that used the upper banjo for gage connection. The inventors might have thought "there's plenty of oil getting to the head so it won't hurt to reduce the oil flow". I bet at the time, some just didn't realize that the gage problem could be solved by moving to the lower banjo with their gage connection.
For those who still advocate doing this restrictor mod, let me point out a few things they might consider first. While the banjo bolt hole might be 3/16", Recognize that the inside diameter of the copper oil line going up to the head is already a restriction because it is less than 1/8" ID. Adding more restriction up there by a solder orifice is severely chocking things down. finally, Since a large part of the oil for the lifters and cam faces comes from runoff from the head down through the push rod holes, restricting that flow doesn't pass the good sense test. Moss and Peter Edney for example charge over $300 for special lifters designed with oval holes or grooves to improve the oil flow to their cam. But at the same time, some "shade tree" is advocating putting a restrictor in the oil line-- WHAT?
Richard Cameron

My concern is the possibility that the restriction became common because people realized that not enough oil was getting to the big end so they restricted oil to the head to increase flow elsewhere... I wish there was some "official" MG bulletin that addressed this issue...
Geoffrey M Baker

I welded up the oil holes in my XPAG rockers 20/30 years ago on the advice of a period MG mechanic.He said they used to drive in a small bearing ball and peen over the hole. I have had no cam/follower/rocker wear more than is normal. I still can't run the engine with the cover off because of the amount of oil splashing about.
On the TA MPJG engine which is not that much different than the XPAG the rockers were not drilled. I don't remember any wear problems when I had mine in the fifties.
Ray TF 2884
Ray Lee


Lack of oil flow or adequate pressure to the bottom end of the XPAG/XPEG has never been an issue discussed anywhere because it isn't an issue period. Even engines with worn out oil pumps, partially clogged filters or pick up screens in the pan survive.
There are a lot of areas of the engine that could use improvement, but this isn't one of them!
Richard Cameron


Ray, your right--- Even with the rocker holes closed, enough oil escapes out the sides to splash around and run down on the followers/cam.
Richard Cameron

Well, it's interesting to discover two totally different sides to this argument.
For better or worse, mine is now drilled out and I look forward to seeing the effects and the resulting oil pressure.
Geoffrey M Baker

"I wish there was some "official" MG bulletin that addressed this issue."

There isn't one because there is no issue.

Shadetree mechanic modifications were not something the factory cared to keep track of. The engineers at Abingdon were very bright people with a lot of experience. Besides, if they were to put out service bulletins for every "improvement" that owners made, the world would have run out of paper before they were finished sending bulletins that simply read "Don't!" ;)
Steve Simmons

This thread was discussed on 16/10/2015

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