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MG TD TF 1500 - slow oil pressure 53 TD

I know I know I asked about this before but I still cant find out whats going on ..The oil drains out of the oil filter can back into the sump after sitting a day or so . When started it takes 5 or 6 seconds to fill the can before I get oil pressure . The oil pressure is fine once up 60+ lbs. I replaced the regulator ball and spring with no improvment . There are no external leaks at the oil pump or filter can. The oil guage line is clean. I tried cranking the starter to prefill the oil can but boy that takes a lot of cold cranking .
A.L. Gerstle

A.L. - That is about the same time it takes the oil pressure in our TD to build up after it has sat for some time. There is no anti-drain back valve in the filters for the T series cars unless you convert to a spin-on filter, so there is not much that can be done to stop the oil from draining out of the filter over time. While 5 or 6 seconds seems like an eternity, Realize that there is still oil in the bearings and the engine is not turning high RPM, nor are the bearings hot during those 5 to 6 seconds, so the amount of wear occuring is negliable. As I said, I have experienced that for the past 29 years (and nearly 100,000 miles)on our TD. During that period of time I have rebuilt the engine twice and never observed excessive bearing wear. I have quit worrying about it. Good luck - Dave
David DuBois

The delay is probably partly due to the time it takes the pressure to travel up the capillary tube to the gauge. Mine takes about 5 seconds to drop to zero after the engine stops. I have fitted an oil pressure switch on the filter outlet. The light goes out as soon as the engine starts, but it takes 5 secs for pressure to show on the gauge. So I agree, nothing to worry about!
M T Martin

I like the idea about the switch and light since I'm about to put my engine back in after an oil pressure problem. I really think the self inflicted problem was due to low oil level. About 3 1/2 - 4 quarts drained out but the dip stick was in 1/2" of oil (you know the part of the stick that says "EMPTY"). The failure came as I was demonstrating the newly sleeved brake cylinders to a friend's wife. I pushed in on the clutch when I saw the oil pressure at zero, about 10 or so seconds after the hard braking. The result was #3 & #4 rod bearing gauling but not spinning. The middle cam bearing also gauled. Crank cleaned ok. Put in new rings and resized rods. Bad luck (stupid) - I don't want this to ever happen again.
Question is what oil pressure switch did you use? What does the group think if connecting it to the ignition as a kill switch? This would have to be done through a relay and a start delay or start override push button, but I don't think that is a big deal.
Thanks in advance - I read opnions your faithfully.
Dave Dunlavy

Dave - I don't believe that a "kill" switch would be a very good or safe idea. There are times when it is better to spin a bearing or damage a crank that to be without power on the road. As to a switch to be used, The late MGB has a oil pressure switch used to activate a anti-runon system that I use to activate an audible alarm when I run out of oil pressure (I did this after loosing oil pressure and running a bearing on the Tacoma Narrows Bridge and backing up trafic for some 10 miles). The switch requires that the adapter between the flexable oil pressure line from the block and the simi-rigid line going to the oil pressure gauge be changed to the one used in the late MGB, which is a 'T' connection for mounting the switch into. The only problem with this switch is that it is a normally off switch (on with oil pressure, off with no pressure), so I had to build an inverter circuit to go along with it (one could do that with a single pole double throw relay). Also, since it would then have the alarm screatching at you when you first turned on the ignition and before the engine built up any oil pressure, I also incorporated a delay circuit, which turns everything on to the circuit about 30 seconds after the ignition is initially turned on. This is a rather convoluted means of rigging an alarm, but it works quite well. Good luck - Dave
David DuBois

Dave,

Just thought that you should know that the indication on the oil dipstick of an XPAG engine (at least on a finned sump version) is not to be taken literally. Next time you change oil try an experiment. See how many quarts of oil have to be poured in before it even shows on the dipstick. I think you'll find that it takes five (5) quarts before it reaches the 'EMPTY' mark. It then takes two more quarts to reach the 'FULL' mark.

Using a piece of thin dowel to measure after adding each quart I found the following: Quart #1 - 5/8" in sump, #2 - 1.25", #3 - 1.75", #4 - 2.5", #5 - 3.25"(@EMPTY), #6 - 4"(@ 'AL' in 'HALF"), #7 - 'FULL'.

I've not tried this on an early sump.
Bud Krueger

Alan, I have thought some about this since your last posting -- I hope others more technical will read my comments and add or correct.
I wonder if you have all the parts and seals for the oil filter in place. There are two different style horizontal filters, Tecalemit and Purolator, which incorporate different seals. I have a spin on replacement so must ask someone else to identify all of the components or if you have the Abingdon Spares catalog it shows them. The normal oil flow from the pump is through the outside of the filter and from inside the filter back through the pump body into the block -- missing washers or seals might allow faster drain back to the sump.
Regards,
Dennis
D F Sexton

How do you know the can is draining? The gagues do tend to stick at zero. I suggest buying an inexpensive gauge at a parts store and adapting to check the true pressure in the galley. You can temporarily adapt at the "Y" or banjo bolt at the bottom of the line to the head by removing the flex line. Also make sure it is feeding off of the bottom banjo and not the top (head). If it still takes 5-6 seconds, then I would check things out as Dennis suggests, and if no problem found, just crank it until you show pressure, and forget about it.
George Butz


I always use either Wynns or STP in my cars [ MGA, MGB and TD }, and have been doing so for several years,
although there is no way of actually proving that it works I am convinced that that it gives the engine added protection.
H.E.W. Walker

This thread was discussed between 14/02/2004 and 17/02/2004

MG TD TF 1500 index

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