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MG TD TF 1500 - No Oil Pressure!?!?!?!

I checked the archives but couldn't find much on this specifically or on stupidity!

To start out I have totally rebuilt the XPAG in my TD.
After some coaxing I managed to get the oil pump primed and oil to the lifters. Gauge showed no pressure but I convinced my self that it was the gauge since there seemed to be good flow to the lifters(and I was tired). So I started the car. Ran quietly as near as I could tell at 1500 RPM for about 10 minutes then I heard a little noise (not at all sure where from). Decided to do what I should have done in the first place and shut it down and pulled the oil pressure gauge. Sadly the gauge seems to work fine.

I suspect that the problem may be the oil pump but I checked the end clearance when I rebuilt it and it seemed okay. I have rebuilt a number of motors over the years all with good success. I was VERY careful with this one until I ignored the pressure gauge.

I'm really not sure what to check first or how to procede - any ideas?

As always thanks for you help!
Jim

Jim Budrow

I'm scared for you Jim. Start with the easy stuff first. pull the valve cover and have a look. See lots oil ? If yes thats good. Turn the engine over with the key off and see if your squirting any oil out the rockers. If you pull the cover and don't see much oil thats bad. Take the cover off the oil pump and have a look. Did you pack the gears with vasoline? If not try now. I pre-oiled my block with a pressure tank. If you can borrow or rent one I'd push some oil through the block before continuing. With the pump cap back on I'd try turning the engine over again with the key off and look for squirting oil. Next easiest check is the fittings on the pick up through the sump. I check for suction leaks there. If still nothing I'd pull the motor out of the car and check the rear camshaft plug which can easily be pushed out the back of the block if you didn't get the keeper on the back of the camshaft. (Don't ask me how I know.) If that was the problem you wouild most like know already because of the oil slick on the floor. Next step for me would be to pull the pump and see whats going on there.

LaVerne
LaVerne


Hi Jim
Have you checked if oil is comming out of the tube to the gauge if not check that the tube is open very thin tube

Thoralf
t g sorensen

Okay, I had a beer, picked up the garage, got a hair cut and took a less stressed look at the situation.

-I do have lots of oil at the rockers. I observed oil coming out of the rocker holes prior to starting the motor.
-Oil was also leaking out from around the gauge and tube fitting (I should have soaked the gasket. No carpet yet so no problem!)
-Oil was leaking out the rear 'seal'. Dip stick showed I was overfilled about 1/8" not sure I should have had a 8" diameter pool though.
-Found that I had not tightened generator sufficiently.

Still need to check the rear camshaft freeze plug.

My hope at this point is that what I heard was the loose generator - it probably loosened more when running. I still need to identify why there is no oil pressure so my plan is to remove it and check it out. Rear seal leak seems excessive so I may end up pulling pan and checking bearings and seal area anyway - not what I wanted to do but...

Thanks LaVerne and Thoralf for you thoughts!

Cheers!
Jim
Jim Budrow

Jim, I squirted in every hole I could find or open up on the engine for a couple of days before I did anything. Some of the holes would look dry when I rechecked so I fllled 'em again each time until they didn't drain out any more.
Then, with the spark plugs removed, I ran the starter for a while unitl I saw a reading on the oil pressure guage. This took several attempts for fear of overheating the starter motor.
In your case, just put a can at the end of the tube for the pressure guage and look for an oil flow.
Good Luck.
Jim Merz

jim, interesting timing on your note. i too am trying to track down why i have low..zero pressure at my oil pressure tap off. after overhaul, when i pressure preoiled i had great oil flow up to the rockers. the oil pump, like yours was rebuilt and was packed/primed before start. i eventually get oil pressure as she warms up. i am going to pull the pan and see if the pick up has and holes/leaks etc. that would keep the oil from, or allow air to, the pump. regards, tom
tm peterson

Should the flex oil line to the gauge be at the banjo fitting on the block (lower fitting) or at the banjo fitting at head (upper fitting) where the hard copper oil line directs oil from the main oil galley in the block to the head. Mine is connected to the upper fitting as that's what I've seen in photos on the www.mgcars.org.uk/mgtd/ site. I'm sure the pressure would be lower at the head. Which is correct?

Getting smarter - I think?

Jim

Jim Budrow

Sounds like we need to start a club. Owners of Rebuilt XP engines with low or no oil pressure I had exactly the same issue. Only difference was I had very low oil pressure. My pump was rebuilt by John Twist.

I have done a good six months worth of looking over the oil system and trying to figure out what was causing this issue. I found that the primary cause of low or no oil pressure has to do with the relief valve.

You did not say if this was an early or late engine. Mine is an early engine. I purchased one of the Moss adjustable oil relief valves, new spring and new ball. This drastically changed the oil pressure issue.

I also checked my gauge against a new one. I found the old one was not reading anywhere near the new one.

If you have good oil pressure at the rockers, probability is you have good oil pressure elsewhere, especially if you are comfortable that your bearing clearances are good and cam bearings are new.
BEC Cunha

Jim, connect gauge to the bottom fitting. I think there was an article by Bob Graneu (sp?) in the TSO this month about that. He even mentions that the early photos/diagrams show that may have been how they did it at first, but didn't work. If the gauge is at the top take-off, you are only reading the pressure at the rocker shaft via restricted, small passageways through the pipe and bolts. You need to know the pressure in the main galley. I'm a member of the low pressure club on my own and a friend's car- mine was loose bearing clearances, friend's was gauge on head deal. My own motor left a huge puddle when driven hard. I had carefully fitted the slinger, core plug, etc. I evidently did not seat the tabs of the lower pan to cap seal, or did not use sealant in the "corner" area of the cap to pan- put it back together with now minimal leakage. Same friend with low pressue had an increasing rear leak. It was the rear main alley plug! After reassembly, that is when he had lousy oil pressure- we switched the upper and lower block to head banjo bolts- the lower one had been brazed shut, with a tiny restrictive hole drilled in it by the DPO to make up for worn rockers! This same cursed engine that previously ran great then ran really lousy. That turned out to be the air filter feet being bent, etc. There is more from that car, but for another time! George
George Butz

Thank You!

I don't feel quite as 'stupid' as I did few hours ago!

I'll move the gauge take off from the top to the bottom tomorrow and let you know what I learn.

Again, thanks!
Jim
Jim Budrow

Jim
Good luck with the change. I also had low pressure(20LBS) when the TD was purchased about a year ago and, after reading the archives, I changed mine and went to 40lbs. This did not change the pressure just the reading but is more comforting while driving.

tim
tim

I think Tim says it all,,, >>This did not change the pressure, just the reading, but is more comforting while driving.<<

SPW
Steve Wincze

Switched the gauge input location - gauge still reads zero. Blocked off flow to head with guage input from bottom banjo connection and it still reads zero. Finally took the pump off and headed up to University Motors. John Twist said there was nothing wrong with the pump or check valve. Bottom line is, the pump is probably sucking some air. As it's compressible I'm still getting some flow but not building any pressure. When I get the oil pump reinstalled I will check and see if there are any air bubbles in the oil flow to confirm this.

Also, John recommends (as many of you do) that the pressure gauge input come from the bottom (engine block) connection!

It will now be a while before I can get bcak to this. In the mean time thanks for all of the help!

Jim
Jim Budrow

This thread was discussed between 28/02/2007 and 02/03/2007

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