MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - TF oil pressure

Mostly on start up and when running the oil pressure on my car was pretty average, I wasn't too worried as I checked the mains and big ends when I had the sump off to put a new gasket on and a new front seal in and they looked good.
I suspected the oil gauge, however today I took the small copper pipe that attaches to the Head off and started to clean it out, I would say it was 30% blocked
Start up on completion showed 55lb pressure on the Gauge.
Happy man
G Mills

Curious was the overhead gear light on for lubrication prior to unblocking the line? Lots of controversy regarding where the gauge should be connected, in your case if the gauge was connected to the block you surely would have higher oil pressure with the capillary line blocked.

Making the gauge connection at the head will provide an indication that there is low oil pressure to the overhead gear.

A difficult choice to make where to connect the gauge.
G Evans

The flexible braided oil line comes from the bottom banjo fitting.
The last time I had the tappet cover off there was plenty of oil being pumped to the rockers, another reason why I didn't worry about the low oil pressure on the Gauge.

Regards
G Mills

Reading your post again I understand what you are saying, one would think that if the line to the gauge came off at the lower banjo then it should not effect the oil pressure at the gauge, well in my case there was a definite restriction at the point where the pipe fits into the lower banjo continuing up the pipe for a bit.
Why this has made a difference at the Gauge beats me.
G Mills

What did you use to clear the line George? Something like a long pipe cleaner? Cheers
Peter TD 5801
P Hehir

First up I heated the pipe and banjos then dipped it in water a lot of oily crap came out then I pushed some thin wire through twisting it and working it in and out then blew it out with air, the banjos had been bronzed on so didn't want to take them off, if I could get some new fittings I would make a new pipe, the flexible line was clear.


cheers mate




G Mills

As long as there was ANY opening in the tube the pressure will be the same..there is no flow so a restriction..not complete blockage will not affect pressure reading..just volume flow..and seeing as there is NO flow in a gauge line your pressure reads accurately . Regards, tom
tm peterson

Sorta understand that Tom, all I know is I had average oil pressure at the Gauge, cleaned the line put it back and the oil pressure went up to 55 Lbs.

I would sure be interested in getting another Copper line if anyone has one to spare as mine has had a hard time, been bent and squashed etc in places.
Moss has them I know but the shipping cost is nearly twice the price of the pipe.

Regards
G Mills

Here is some theory behind what could be occurring within the line that is restricted, how applicable it is is above my level of comprehension, it does not take into account that the line contains elbows and bends;

https://www.youtube.com/watch?v=nW421UQa7as
G Evans

George,
I'm sure I could make a small batch of them and sell them cheaper than Moss. The international postage would be 5€.
I would need to know the length if the car is RHD.

I also make a pressure switch adapter to replace the union on be bulkhead with a union with a pressure switch and the electric module for buzzer/ oil pressure lamp. Individual parts or a complete kit.


Regards
Declan

Declan Burns

I seem to remember that some people have fitted a restrictor in cylinder head oil banjo bolt to reduce the oil flow to the rockers.
Putting this in the block end of the pipe would give a lower pressure at the gauge. The gauge measures a flow pressure and not a static.
In an open ended oil system a restrictor always reduces pressure downstream but not in a closed system.
Ray TF 2884
Ray Lee raybar2(at) tiscalidotcodotuk

This thread was discussed between 12/03/2016 and 13/03/2016

MG TD TF 1500 index

This thread is from the archives. Join the live MG TD TF 1500 BBS now