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MG TD TF 1500 - TF Oil Pressue

I'm going to look at a TF1250 today for a prospective buyer. He test drove it, and said the brakes were terrible (not a problem), but the oil pressure was zero at idle. Could be any of the following: bad gauge, bad rod/main bearings, oil pump problems, etc. Any other ideas or TF specific issues? Also, how to diagnose without any tools? Thanks, George
George Butz

George - For comparison, check the oil pressure on cold start-up, and hot running. Low oil pressure at idle is not necessarily awful; some cars get away with it, some don't. But low when hot running is a problem - check the viscosity of the oil. A car I had here recently was running so rich that un-burned gas was thinning the oil, causing low oil pressure indication.

Make sure the oil pressure line goes off the block end of the oil line, not the head end

Worn rocker gear is also a cause of low oil pressure

One way or another, low oil pressure is usually a sign of a tired engine and/or worn parts inside the engine with excessive clearances.

Tom Lange
MGT Repair
t lange

I would say that the engine should be rebuilt, period! Mine runs 55 lbs cold and 52 lbs hot at idle. Now there are a lot of "depends" in there. Depends on how much the owner wants for the car, how nice is the car for the money, how much work other than the engine is needed to be able to drive it. Bottom line, it would depend on how much money the buyer wants to spend to get what he wants out of the car, he's already looking at 5 to 6 grand beyond the purchase price for an acceptable rebuild. JMHO. PJ
Paul sr

Pj, I assume your comment comes with the caveat that the indication is correct. Before I tore the engine down I would determine that the indication is correct, I would determine what the lower oil galley pressure is with the oil line to the head blocked off(hate to overhaul an entire engine if it is only a severely worn valve train), what is the condition of the oil relief valve, drop the pan and remove a few caps, etc. not all per purchase stuff, but at the least a master oil gauge to see if the reading is correct and a peek at the oil relief valve and a peek into the oil fill cap while running to see how much oil is spraying around in the rocker cover. Regards, Tom
tom peterson

Well, yes Tom I agree, naturally a proper engine diagnosis would be in order. Problem could be, the seller might not go for it. PJ
Paul sr

Good ideas, thanks. I'm taking another gauge with me. I don't know if they will let me use it, or exactly what I can or cannot do. Flat zero idle pressure without diagnosis would either be a deal breaker or $5K off I would think? I'll report back after I see the car later this afternoon. George
George Butz

$5K off is a bit much unless they're asking top dollar for it now, George.

If they're familiar with the TD's workings though they'll probably be happy to let you try the spare gauge...only 5 minutes or so to see if it changes anything. Too bad you don't have a spare tubing run so you could eliminate that too (see recent thread on cleaning one http://www2.mg-cars.org.uk/cgi-bin/or17?runprog=mgbbs&mode=thread&access=&subject=8&source=T&thread=2013082822305210207).

Gene
Gene Gillam

George.........on my original engine, (45,000 miles) using 20-50, my start up is 75 psi. Warmed up it runs at 60 psi @ 3000 rpm. Idle is about 25 psi.
I know that some of the rockers shaft bearings are a little on the loose side of spec., but it does not seem to effect the OP.
colin stafford

George,I have a fitting the threads right into one of the oil galley plugs on the side of the block...less than 5 min. And your master gauge is installed...no need to disturb anything else. Regards, tom
tom peterson

George, a long time ago I rebuilt the lower end of a TD engine and the oil pressure was terrible at hot idle. To see what the problem was I temporarily blocked off the oil line to the head - instantly the oil pressure was right where it should be.
Hugh Pite
H.D. Pite

con't. For some reason the rest of my post was cut off.
The low oil pressure at idle would not concern me but if the engine is also burning oil then it is probably time for some attention.
If this TF was for sale nearby and the selling price was in the $15k range I would purchase it with very little hesitation. Depending on the condition of the wood, interior and the chrome I might even go to $18k.
Hugh Pite
H.D. Pite

To detail just the oil pressure: it was more like 10 at slow idle, much higher at higher RPM, remembering TF gauge is rather crude in scale. Engine sounded fine and was strong. I suspect the issue may be the 1/8" copper line run off of the lower banjo to the firewall , half way across the bottom of the battery, to a piece of rubber fuel line, to the correct adaptor mounted on the bracket mounted on a firewall bolt below the bottom right of the battery, the correct tiny copper tube runs up the right side of the battery through the firewall. No earthly idea what they were thinking!!
George Butz

Check the dipstick.
JIM NORTHRUP SR

This thread was discussed between 30/08/2013 and 31/08/2013

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