MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

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 - oil pressure at idle

Today I started the car up and ran her for about ten minutes, the first time she's run in several months.

I noticed that oil pressure rose up to 20lbs and stayed there. Manual says 25-40, but I never ran her above an idle, so does this sound reasonable?

Otherwise everything looks good except that she cut out after a few minutes. A little smoky in the exhaust, but there's probably a bit too much oil in the engine now, I added a quart and she's above the fill line, so I will drain some soon.

Time to put the steering wheel back on, windshield on, bolt the dash back down, and get the paperwork so I can put her back on the road.
Geoff Baker

I should add that I started her again twice, and ran her up to a fast engine speed and in both cases I could not get the gauge to go above 40; at a reasonable speed (cant tell the rpms as the rpm gauge reads either 0 or about 1500 rpms, nothing else) it stays at 38.

Hope this sounds good to everyone, I'm cautiously optimistic.

Geoff Baker

On a cold engine, i have 55/60 when i start it up and rev a bit...at idle its probably around 20/25...when its hot at idle .. around 20 or so
gblawson(gordon)

Down here in Tucson, there's no such thing as a cold idle :)

The pressure gauge never jumps up, just calmly climbs from 0-20 on idle. 0-38 when I run it up to speed.

I guess it's good, I won't worry about it.
Geoff Baker

Geoff.
Where are you taking the oil pressure from. If the flex line goes to the top connection on the head it might explain the lowere reading. Exchange positions and take oil pressure off the lower fitting. The attaching fitting are interchangeable. Be certain to anneal the copper washers or replace with new. It's easy to anneal them. Just use a small torch heating them cherry red and let cool or if you wish quench them in oil.10 minute to do that at most.
Sandy
SANDY SANDERS

geoff, all of what sandy said is true, to add to sandy's comment..to me the real use of the oil pressure indication is when it changes from what you normally read..yes there is a minimum (you are well above that) and a level that is so high you have a concern about blowing seals,(you are well below that) but beyond that all you have is bragging rights. so whether you read it at the block as on later cars, or at the head above the metering/supply tube what will tell you trouble is brewing is when there is a drop from your normal pressure. whether you pick up at the block or at the head you will be able to monitor the relative health of your engine. my two cents and then some i guess. regards, tom
tom peterson

Conventional wisdom calls for about 10 psi for for every 1000 rpm the engine is running at as a minimum with the engine hot. Cheers - Dave
David DuBois

There doesn't seem to be any standard pressure for any T-Seres engine. And these gauges are not snubbed, but the capillary is very small, so your response is not immediate.

Operating oil pressures while driving, will range from 20psi to 50psi and occasionnaly higher. If its a particularly warm or hot day, expect that to drop by 10 psi.

However the key to oil pressure is at idle. If you're looking at less than 5 psi under any conditions, then you should a) check your oil pump, b) as noted above, check your connection to the gauge, c)make sure that the oil is not restricted by a clogged line in the valve gear and, God forbid, d) listen for rod bearing rattle. Its not a difficult job to drop thwe sump and carefully remove a rod bearing. Take only the bottom half and inspect it. If the surface is a nice clean grey, carefully put it back. Do not disturb the shell; and while you've got the sump off, re-torque the big ends while the engine is warn, not hot or cold.

Gord Clark
Rockburn, Qué.
Gordon A Clark

We have this discussion on a routine basis. Easy answer. Take the valve cover off. If you have oil at the lifters, you probably have enough oil pressure. If it slightly spurts above the rockers, all the better.
Bruce E Cunha

What weight oil are you using?
George Butz

George, I'm planning on changing the oil soon. My dad normally used to put 10-30 weight in, so that is what is in there, I imagine.

Haven't decided what oil to change to, seems like there are plenty of opinions about which oil is best :)
Geoff Baker

That is very likely why the pressure is a little low. Switch to 20-50, especially in your warm climate. The XPAG bearing clearances are really loose compared to a modern engine. Make sure the oil has plenty of zinc- search the archives for that issue. George
George Butz

Also in Tucson area, and have had this same discussion in previous threads you can read below. My '53 (Myrtle) consistently runs at 20psi warm at idle and 45 psi warm at road speeds. I recently changed out the oil pressure relief spring and ball assembly and did gain some pressure, especially at cold temps. The glovebox manual that came with the car sttes 40 psi warm at road speeds and 20-25 psi at idle, so I guess we're right where we need to be. My engine was completely professionally rebuilt (stock specs) before I bought it, so am confident all is well inside the engine. In this warm climate I usually use 20-50 Castrol motor oil and with the stock oil filter assembly, I use the felt replacement element. (By the way, Ernie did the rebuild, so I am confident no problems there.)
Robert Agar

This thread was discussed between 02/03/2010 and 03/03/2010

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.