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MG TD TF 1500 - Engine problem

I'm pretty discouraged. I have a 1950 TD that has been sitting for many years, and I found out why - the last owner started it without oil pressure, and it ruined a rod bearing journal.

I got all the books, and read all the advice carefully, and searched thru the archives here to find all the details I should notice.

I completely rebuilt the engine, had the crank built-up, new bearings, etc - EVERYTHING!

Tonight, when I went to start it, I put in 5 quarts of oil, filled the radiator, buzzed it for 15 seconds until I had 60# oil pressure, and then startted it - it started right up, and ran strong while I broke in the cam and lifters. I noticed a LOT of smoke, but thought that was just because the engine was fresh.

Then I noticed greyish glop coming out of the radiator overflow, which seems to be an oil/water mix. I shut it off to think about this for a few minutes, but when I went to start it I noticed no oil pressure - the sump appears to be empty, with no leaks.

I've heard of glop in the sump where the water mixes with the oil (blown head-gasket, I think), but where has all the oil gone, except into the radiator? And how?

And what to do now? I'm RELLY discouraged.

Thanks. Jim,
JM Murray

That's really a tough break Jim. You're probably correct in assuming the oil is in the radiator & I would think also in the water galleries in the block. There isn't anywhere else for it to go. If so how did it get there? Hopefully it's just a blown head gasket. If not one or more of the oil galleries either in the block or the head has failed. I'd drain the radiator & have a look at the contents. Next step would be to remove the head & look for signs of a failed gasket. Did you have the head crack tested during the rebuild? If the head gasket checks out & the head is OK then I don't know how you would proceed from there. Maybe the damage was done by the PO & wasn't evident during your rebuild. There are quite a few guys on this site with loads of engine experience so I'm sure you'll get some helpful advice. Hang in there. Cheers
Peter TD 5801
P Hehir

Start with a leak down test in the cylinders, and a pressure test of the cooling system. The problem will present itself soon. How long did it run without oil pressure? Coolant will spin the bearings in short order. It needs fresh oil before you turn it over again. I am next door in Vermont if you need tools, assistance, or a sholder to cry on...
-David
D. Sander

You mentioned smoke- was is blueish oil smoke or white water vapor?
Do a quick compression test to see if there's a head gasket problem for starters. That could indicate water into the cylinder and steam out the exhaust as well as blowing exhaust into coolant, but that doesn't sound like what you described.
To investigate your unique problem, I'd take the radiator cap off, then remove the oil banjo bolt to the head and use an airgun to blow compressed air into the head. I'd leave the valve cover on for preliminary tests as oil will spray around. You'd expect air/oil to escape from the rockers only, but not bubble up in the radiator. This will either eliminate or isolate the problem at the head.
I don't have a spare head here at home to examine, but as I recall, that banjo bolt port in the head feeds a rocker stand bolt and oil eventually passes up into the rocker shaft. There should be no connection to a water passage.
If that doesn't shed light on the problem, remove the banjo bolt at the block and again use air pressure to check it out. That threaded hole leads the to oil gallery that feeds the main bearing and cam shaft bearings. Again, there should be no short circuit to a water passage in this oil circuit.
If these do not reveal your leak, then you may have to focus on the oil pump.
Did you remove/replace camshaft and/or cam bearings?
Do any work on the oil pump?
Keep us posted!
JIM
JRN JIM

Both David & Jnr Jim have offered excellent advice. The compressed air test is a great suggestion. Was the head crack tested? Cheers
Peter TD 5801
P Hehir

Thank you all.

There were clouds of white smoke, but smelling of exhaust. I did replace the cam bearings, and made sure the round plug in the back of the cam was in place.

I also had the oil pump cover machined, replaced the gears and the two shafts, and cleaned out everything. I followed the Moss sheet to measure and adjust everything.

I ran the engine fo4r5 close to 15 minutes, checking for good oil pressure all along. It held solid at 60 until I re-started it for about 5 seconds before shutting it off.

I'll do a compression test in the morning, and see what that shows. I'll go to Harbor Freight and get a leak down test kit over the weekend, and then I'm away for the next 2 weeks.

I can also get compressed air in the two fittings for the oil line - it's an early engine, so it has the oil pressure line coming off the head.

I really appreciate the help - it's my first engine, and I'm really embarrassed and disappointed that I have messed it up somehow, and what's worse, I don't know how! It's getting chilly, and I can take it apart again over the Winter, if necessary.

jm
JM Murray

There is an oil gallery plug at the rear of the head under the sheet metal cover plate. It goes into the oil pipe banjo gallery for the rocker arms. If this plug were missing the oil pressure might go past the cork gasket and right into the head water passages. It would allow all of the oil to be pumped into the coolant system fairly quickly since it is about 1/4" in size. The air pressure test described would show this problem if it exists in the head too.
Richard Cameron

Jim,
Just s thought , there is a large grub screw in the back of the head, under the rear cover plate which plugs the head oil galley machining access. If loosened during head work it will pump oil into the coolant at a rapid rate ( ask me how I know ) If you are fortunate , and this is the case, loosen four screws remove the cover, loctite the grub screw back in and your problem may be solved in a jiffy. I have known heartbreak with my engine too, more than once . Hang in there , these cars are worth it. YOU WILL PREVAIL
Fingers crossed for you !
All the best, Keith
K. McKenzie

Now I'm beginning to get scared. I just reinstalled the head on my TD and I carefully put the rear cover plate on backwards - I then pumped most of the coolant out in a torrent. I realized what I'd done, took the plate off and cleaned it up and reinstalled it correctly - no drips no runs no errors. BUT, at no time during this ordeal did I see a "large grub screw in the back of the head, under the rear cover plate." I've put 250-300 miles on the engine since reinstalling the head and I see no oil in the coolant nor any coolant in the oil. I just hope the large grub screw is still tight 'cause I don't want to delve back into that head this soon.

When you say "under the rear cover plate" do you mean covered by the plate and out of sight or below the cover plate but still visible when the cover plate is installed? Does anyone have a picture of the large grub screw? Jud
J K Chapin

Jim, Never feel bad about an issue like this. I unfortunately became an expert on removing and replacing my TD engine quickly at rebuild a few years ago. I like all of the ideas above, one is likely the problem. Did you use the correct headgasket, as there are two styles? Hopefully that is where the issue is. George
George Butz

Well, as usual, you guys were completely right. I just pulled the head (45 minutes - amazing how easy it is when everything is clean and new...), and the grub screw at the rear of the head is missing. The machine shop must have taken it out when they hot tanked the head, there was nothing like it in the box of cleaned parts that came back, so I just plain missed it. I'll have to look through the books again and see if I missed reading about it when I made my assembly list. Anybody know what the threads are? Hardware store metric or Moss/AS?

(J Chapin - the screw is under the cover, and I suppose that if yours was missing you would know it by now - my car emptied the sump in just a few minutes.)

The engine was externally clean and dry while running, and the hardest part of removing the head was removing the red Roadster Gasket that was sealing the side cover! Boy those things work well.

The head gasket is fine, the high-compression pistons that came with the car do not touch the valves, and all looks slippery and gloppy, but OK. I just hope I did no damage to the bearings; there can't be much lubrication value to anti-freeze...

Any suggestions how to clean the block, other than flushing it with the garden hose a few times? Is there a block cleaner I should use, or is it not a big deal?

Again, you guys are great, helpful and knowledgeable. Thank you.

JM
JM Murray

Thats Great Jim glad you found the issue. I received so much help from others on this forum it is nice for me to able to help someone else for a change.
Hope all else goes well!
Cheers, Keith
K. McKenzie

Jim,

Fast 'n easy.

Pull a plug. Put your finger in. What do you see?

Gord Clark
Rockburn, Qué.

Gordon A Clark

There was higher pressure in the oil side, pumping oil in to the coolant. My concern is that the oil pumped out, and the engine was running dry. Drain the sump and look for any trace of coolant. I doubt you will find any.
A thorough flush of the radiator and block is in order. It should be a Mx1.0 thread, available at your local hardware store.
Keep us posted...
David
D. Sander

The plug is covered by the gasket and sheet metal cover plate. I believe The plug is the same as was used in the ends of the original rocker arm shaft. It has a slight taper on the end, and flat screw driver slot head. If you have an old shaft laying around you could salvage one from it.
Richard Cameron

Obviously the radiator and coolant must be drained.

If you want to blast out the majority of oily mess, what I've done is remove the petcock in the front of the block, remove the radiator cap, add about a quart of water, and then hit the block (where the petcock was removed) with a blast from the airgun. You may want to wear a raincoat, cover the car in plastic and perform this flush in a remote location as there can be a nasty geyser erupting from the top of the radiator.

As for cleaning out the remaining residue, I'd fill up with a strong solution of water/dish detergent for my next few trips, draining the contents after shutting down. For probably the next year or so, the remaining traces of oil will float to the top of the radiator, where you can simply overfill the tank and float out the scum.

As for the screw, I'd first hit up the machinists. You can try the hardware store as Dave suggests or try calling Moss Motors. It isn't displayed in their catalog picture, but they may have a handle on it.
JRN JIM

Another reason I read this forum. In all the years I have owned my TD, I have never read about this issue or its cause. I learned another new piece of information about the engine.
Bruce Cunha

RE: Grub Screw -

Perhaps British Tool & Fasteners can help ...
http://www.britishfasteners.com/index.php?search%5Bterms%5D=grub&search%5Bmode%5D=any

I don't remember seeing a screw under the rear plate on my AEF118 head so I don't know if any of the BT&F grub screws is correct.

Lonnie
TF7211
LM Cook

Me to Bruce. It's a good day when you learn something new. Hopefully Jim's lobes, followers & bearings are still pristine! Cheers
Peter TD 5801
P Hehir

OK, A Picture

Richard Cameron

Picture of Steel plug , I believe 8 X 1 mm. I can't completely confirm the thread, but a 8mm TD rod bolt screws in the hole fully by hand without binding.

Richard Cameron

One more --When fully seated the plug sits slightly below the surface where the gasket and sheet metal plate covers it.

Richard Cameron

No need to source a special plug just fabricate your own from a standard 8X1 bolt and judicial use of a hacksaw to cut thread to length and create a slot.

Engine builders can be a source of all kinds of grief unfortunately sometimes quality control has to rest solely on the shoulders of the owner. I learnt the hard way with my XPAG I was fortunate I had a good tutor providing guidance before I lit the blue touch paper.
G Evans

Thanks Richard. Three more valuable pics for my gallery. Top tip Graeme. Cheers
Peter TD 5801
P Hehir

There are a lot of ways to solve problems and this is just one possibility to consider. Cleaning out the coolant system will be really messy so pick a place where drained sludge won't cause a problem. I'd remove the radiator and the thermostat housing for the initial flush. Recommend using hot water to get the biggest globs and milky stuff out of the block and the radiator. Since the home hot water heater sump should be drained of sludge occasionally, I have hooked a hose to the drain on mine and used that as a source of hot water before when I needed hot water outside. Once the biggest part of the oily sludge is out, hook everything back up and fill the system with a mixture of Dawn dish wash soap, or liquid Cascade and tap water. Run the engine till it gets up to operating temp, then let it cool just enough to safely remove the lower radiator hose to drain the system again. You'll probably have to do this several times until the system is clean enough to service with antifreeze again. I don't think the little drain cocks on the block or radiator will be of much value during the initial drains because the globs of emulsified oil will probably plug them up, but once you get the biggest part of the system clean they may work as normal service.
Richard Cameron

Just went out to the garage to look at my spare head - there was the grub screw. I live and learn.
Many thanks.
Peter
Peter Malkin

I advocate some concern at the amount of scale depicted in the head photos, there is an Ausy product that can be used to alleviate this problem.
G Evans

Scale? Where?
Gene Gillam

Gene, as usual, your right-- The head in the photo came back from Thermal Cleaning two weeks ago. However, I wish every engine part I have was rust free. If there's an Ausy product that alleviates, lets hear about it.
Richard Cameron

Richard

If I had a head professionally cleaned and ended up with the internal finish depicted in your image I would be demanding a refund.

Here is the link to the Ausy manufacturer that I can recommend from personal use, dropped my TF running temp by 10 degrees.

http://liquidintelligence.com.au/
G Evans

Flash rust is not "scale". I'm not going to be a total skeptic but any company that advertises stop leak oil and hydraulic seal expanders and liquid blown head gasket repair kits would make me think twice before I used their product to clean my cooling system.

Just saying.
Gene Gillam

You can be as skeptic as you like, until you have used this fellas products there is no grounds for criticism. If you saw what this 2 part treatment removed from my block following the useage instructions with no damage to rubber components you would be confident that it works.

I cant comment on other products than the descaler as I have not used them.
G Evans

This thread was discussed between 31/10/2014 and 03/11/2014

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