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 - Dead on the highway mystery

Doing about 65 mph after a lovely days drive then total power loss -engine dies, coolant blows out of overflow tube and she dead by the side of the highway. 10 minutes later it starts up immediately and runs but under load a loud ticking noise comes from the engine .More load = louder tick. No noise if you really baby it. We limp home 10 miles. Idle is fine spark plugs fine ( no. 2 a little dark ) Compression 150 to 153 across the board ( no change over normal ) no coolant in oil. i am running a roller cam with 10 degrees advance and have been for 1200 miles. Stock gasket with retorque at 500 miles to spec ( 45 ft/lbs ) valve train looks fine.
Help !!
Blown gasket? cracked head ? ( I have larger valves and hardened seats )
I am more than a little bit bummed out by this and am currently self medicating with my third wobbly pop. The pain is only slightly less, I think I see a fourth in my immediate future !
Not so Cheers, Keith
K. McKenzie

Sorry to hear of your misfortune Keith & hope it is nothing too serious. I'm in the process of installing the roller lifter/cam set up so am very interested in the cause of your problem! Shouldn't make too much difference but the head torque is recommended at 50 ft/lbs. Keep us posted & good luck.
Peter TD 5801
P Hehir

Keith, remind us of what kind of car you're driving.

Jud
J K Chapin

52 TD.
Just checked, no oil in the coolant. Looks like I only lost a quart of coolant. The rad core is not exposed and is still under coolant level.That knocking/ticking noise did not sound healthy !
K. McKenzie

keith, sorry to hear of your troubles. have you rechecked your timing since the incident? regards, tom
tm peterson

Pull your valve cover and make sure all your rocker arms are intact.
Rich (TD 3983) Taylor

Fresh engine? Water temp during the event? Dan
Dan Craig

Kaith - seems unlikely to be a head gasket, as your compression is still OK on all 4. It would be low on one or two if a bad head gasket.

Oil temp when it happened? Water temp? Oil pressure?

Tapping could well be bad bearing (more like knocking) as revs increase, or cam issue. I suspect you will have to start digging.

Check timing at idle, but a slipped timing chain happens very seldom with an XPAG.

Tom Lange
MGT Repair
t lange

Thanks for the input All
Water temp and pressure were normal before and after the event. Just got off the phone with Bob Grunau, what a great guy. Unfortunately , he had an almost identical experience and it was broken crank !!!!
He mentioned the coolant loss as a potential red herring, Highway speed engine heat+sudden engine stop=brief coolant boil=coolant overflow.
However the compete power loss then 5min restart is still a bit of a mystery
Any other opinions would or ideas are welcome!!
K. McKenzie

I had a problem that had some of the same ear marks.
Turned out to be a problem in the fuel line. Mixture would suddenly go very lean causing knocking, low power and if speed was not reduced immediately engine could stop. As soon as float bowls filled engine would run OK but any speed and problem would reappear.
Don
D Hanna

Make sure it is not a leaking exhaust manifold gasket, I recall they can make weird noises. I'
m with Bob on the coolant loss, likely nothing to do with the stoppage. When my crank broke, I had zero oil pressure, but don't know if that is always the case. George
George Butz

Checked the fuel pump, it is delivering fuel to a gas can well ( I just changed a month ago to an electronic pump upgrade for the original SU )
I put a socket on the crank pulley nut , took off the belt , put her in gear and rocked the crank back and forth with a tommy bar- no click or clunk but this is far from the definitive method of assessing a broken crank.
I just stopped all lower end oil leaks last month by adding a double lip front seal/speedy sleeve combo and am loath to remove it yet again till I exhaust all other avenues
* sigh*
Thanks for your comment George , oil pressure was normal , Bob commented to me that it was the same in his case as well when his crank broke.
K. McKenzie

If the crank is broken, it most likely would not even turn over again. They usually break at the front right by the pulley, that is where mine did. Mine would not turn over once it broke. I am assuming that you are not supercharge. THe area between two and three is where the gasket usually blows and that can be disconcerting. Been there done that also..Good luck, hope it is not the crank.
Tom Maine

Had a similar situation courtesy of a lying temp gauge(thanks MOMA). Galled a piston and stuck the engine for about 10 minutes till it cooled. Restarted well but of course had a noise from piston skirt damage from that point forward. Able to inspect cylinders with an inspection camera thru the plug hole - telltale scuff marks present on wall. Might look in the cylinders. Also see if the noise changes when plug wire removed from a particular cylinder. Dan
Dan Craig

Keith,
Not dead on the highway, just a momentary loss of life!

With your new cam, you installed larger springs? No matter. What valve cover do you have? The coffins have a habit of clattering with valves. See if you have dings inside the valve cover. Hopefully, this will resolve your ticking.

While the cover is off, doublecheck the rockers that one isn't loose. I've had that happen on 3 different XPAGs.

Today, our temps were up in the mid 80s (F) and you probably had warm weather, too.
Highway speed engine heat+sudden engine stop=brief coolant boil=coolant overflow
After pulling off the highway, we had a touch of vapor lock (I switch on backup Facet pump for better fuel pressure and keep going). Hopefully, you'll find your engine runs just fine. When the engine crapped out, was the fuel pump clicking like crazy? Avoid high ethanol gas, maybe add a wire loom onto your fuel line for insulation and keep the tank topped up to avoid vaporlock.

BUT, MOST IMPORTANT- do tell us what you find!

JRN JIM

Keith,
With your new cam, you installed larger springs? No matter. What valve cover do you have? The cofins have a habit of clattering with valves. See if you have dings inside the valve cover. Hopefully, this will resolve your ticking.

While the cover is off, doublecheck the rockers that one isn't loose. I've had that happen on 3 different XPAGs.

Today, our temps were up in the mid 80s (F) and you probably had warm weather, too.
Highway speed engine heat+sudden engine stop=brief coolant boil=coolant overflow
After pulling off the highway, we had a touch of vapor lock (I switch on backup Facet pump for better fuel pressure and keep going). Hopefully, you'll find your engine runs just fine. When the engine crapped out, was the fuel pump clicking like crazy? Avoid high ethanol gas, maybe add a wire loom onto your fuel line for insulation and keep the tank topped up to avoid vaporlock.

BUT, MOST IMPORTANT- do tell us what you find!

JRN JIM

Hi Dan
I tried your test and with no. 3 plug wire off the knock is gone. inspection through the spark plug hole shows scuffing on far cylinder wall of no.3.
Jim , the knock occurs load and proud , with the valve cover off.
So …its off with her head , tonight
K. McKenzie

OK
Here we go. Pulled the head. Score marks on no.3 AND THE WRONG HEAD GASKET!!!! They are the original banana head and block.
The engine was assemble by a LBC "expert" who refused to let me assemble the engine after his machine work.
AARRGGHH
This after the previous "expert " put the piston rings in upside down!!
And I tried to drive it and diagnose it for a season !

K. McKenzie

Bummer Keith. Hopefully the "expert" will repair the block at his cost. If so I'd be standing over his shoulder! Was it a broken or unseated ring? If that's the case it sounds like both a brand & an expert to avoid. Good luck
Peter TD 5801
P Hehir

Seems you have an abundance of experts working on your engine, Keith. Going to have to decide whether to attempt a repair in-frame or pull the lump. Cylinder condition would determine the next step in the repair. Hone and a new set of pistons would be best case scenario. Out-of round, excessive taper or deep gouging would lead to rebore or sleeving. Cause is equally important - high temperature is probable cause. Wrong head gasket, lean mix, tight clearances all need to be considered to prevent reoccurance. Sorry man - been there done that and still pissed about it. Dan
Dan Craig

Looks like something from my 2 stroke bike days in the 70's- saw engines do this from lack of oil, too tight clearance w/ bore jobs, too lean (jets/air leaks), etc. Dan is right on, sounds like you need to mic the bores/pistons, etc. What did the plugs look like? Any evidence of too lean? George
George Butz

Well
Have a look at this pic and the ones that follow see if you can spot the GLARING utterly bone headed mistake made by the rebuilder

K. McKenzie

The result of the previous photo. Only a thousand miles on that .030 piston. Wrist pin is very tight to one side. Cause for the rattle under load ?
big end bearing is .0025 clearence and looks OK . Rod looks straight to the eye. Crank seems solid , spins free , can't twist it with my hands.

K. McKenzie

Oh did I mention I am pissed? This is the third expert in 8 years who has screwed up the engine. Damn good thing I love driving this car or I give up and sell it. I feel privileged to be an owner of a TD but things like this do test my patience a tad. Not sure what to do next but Bob Grunau has been an outstanding source of advice and support .
If this is any more interest in this tale of woe , I will keep you all informed.
K. McKenzie

Keith, apart from the incorrect head gasket could it be that he has installed the gasket end for end thus totally blocking the waterway? Surely not!

Page A.11 in the WSM carries a note in italics which states "Ensure that the gasket is fitted with the elongated hole for the waterways to the rear of the cylinder head"!!!

There's no doubt it's on him. The question is would you trust him to have another go?
Peter TD 5801
P Hehir

Headgasket upside down, what a moron! Looks exactly like that piston seized. Question is why would that and subsequent overheating cause just one cylinder to seize? If the engine builder was that incompetent, it may be a good idea to go through the entire engine. He certainly owes you some $. George
George Butz

Bingo Guys!
Gasket in upside down !!!! Blocking main coolant flow to the head. It is amazing I got a 1000 miles before seizing .Tough little motor .
It did take it's first 15 min run at 110kmh ( 70mph ) to do it. I will be looking for compensation or it off to small claims court
K. McKenzie

$10,000 ought to cover it Keith.
P Hehir

Definitely need to look at all pistons, valves/guides, etc. Presuming your temp gauge bulb is in the radiator tank, with no coolant flow it just never read hot when it really was. Sorry that happened. George
George Butz

For what it's worth, I've thought it would've been wise to make the heade gaskets with the cutouts at both ends to prevent such a catastophe in the first place. I doubt this isn't the first time this has happened.
JRN JIM

Uhhh...I've done that head gasket trick myself. To be honest, it ran hotter than most XPAG's but not to the extent you'd expect - the only time it reached boiling was sitting in traffic - while moving it was not much hotter than most XPAG's.

There is water flow through the head even with the rear hole blocked but not nearly as much. I agree adding a cutout at both ends of the gasket would prevent idiots like me from screwing up though.
Gene Gillam

Keith, if you need to remove aluminum from the cylinder use Muriatic acid, but be careful, then if the bore is ok deglaze with a ball type hone. Piston to bore clearance is .001" per inch of bore size.
Len
Len Fanelli

Hi Guys. If you prod around with a bit of wire you will find that there can be almost NO water flow if the rear gasket hole is blocked in an XPAG engine. The main water gallery "log" and rear head gasket hole are NOT connected to the other head gasket holes and the water jacket around the bores. Water goes from the pump along that "log" cast into the right hand side of the block and then through the rear gasket hole only! There are one or two tiny holes (about 5 mm and must be kept clear) behind the core plugs in the "log", connecting to the water jacket around the bores but very little water would get through there. Water just percolates through the forward 16 head gasket holes. With the gasket backwards it is a wonder the car did not overheat in the first few minutes of running! Bob Schapel TC 7929 South Australia
Ian Buckley

See http://www.ttalk.info/XPAG_Cooling_System.htm for Gene Gillam's coolant trace. Bud
Bud Krueger

On rebuild do check that you have sufficient piston clearance. Remember solid skirt pistons need more clearance than split skirt pistons.... And the latter must be put in the correct way round! If you lost very little coolant it is possible that there was local heating caused by the friction of the piston seizing, boiling the water only locally. This means that even if the gasket had been correctly installed your engine might have seized anyway when it got hot. Just a possibility? Bob Schapel TC 7929 South Australia

Ian Buckley

Ian - not to hijack, but is that a modified Judson [poking its head out there? It looks shorter than the stock MG-26.

Tom Lange
MGT Repair
t lange

Tom, no it's the engine from my MGB V8. I have been using that photo for years, maybe I should change it now that I have another TC as well.
Actually the comments made on this topic using my ID are from my good friend Bob Schapel. I don't actually know how that happened but it doesn't matter.
Bob is a lifelong TC man who has developed and raced a supercharged TC special for decades very successfully. He also has had a road going TC since his teens.
cheers, Ian
Ian Buckley

Tom, I have just realised that your question relates to Bob's photo of his racing car. I must be having a fuzzy brain day or it's the pollution here in China where I am staying.
I will email him and maybe he can explain.
Ian
Ian Buckley

Ian, you must have been poking the wrong direction on the holes (grin)...there is definitely connection between the block and the head other than at the rear.
Gene Gillam

No, the barrier is within the block. Water from the pump travels along the "log" and then through the back gasket hole almost exclusively. Yes plenty of holes between block and head (16 of them) but the space they come from around the bores is not supplied by the flow from the water pump! Looking at the top block face, poke the wire down the rear hole as far as you like. You won't be able to see the wire around the bores through any of the other 16 holes. Similarly, poke the wire down any of the 16 foremost holes. You wont be able to see it through the rear hole. The "barrier" is deep inside the block. In other words the 16 smaller holes, which are obviously connected to each other, are not connected to the large rear hole until the water gets to the head. This is too late if the rear hole is blocked by the inverted gasket.

Another way to explain. If you got a long wire and thread it down the rear, large hole, it will eventually reach the water pump but will at no time be in the water jacket around the bores. Conversely, if you thread it down any of the other 16 holes it will be in the water jacket around the bores but it will not get to the water pump. The only exception is if you managed to get the wire through the tiny (about 3/16") hole behind the core plug in the "log".

BOB SCHAPEL (a friend of Ian. Sorry, I have no idea why my comments come up with Ian's)
Ian Buckley

Bob, Ian probably sent you a link to this website. The login info is contained in the link itself, hence you are "Ian". Log out then back in with your own login.
efh Haskell

Bob (Ian?), look at the last two photos on the link Bud gave you. It's obvious that water can go to the head, from the water pump, if the gasket is in backwards. Not as much, but there is flow.

Gene
Gene Gillam

The channel leads only to the back of the head. With the head gasket on upsidedown, the only flow is through the one tiny hole in the channel behind the core plug (ot two tiny holes in some cases). The flow would be miniscule. That also assumes the small hole isn't plugged wit rust & crud.
JRN JIM

What a good website Bud! But Gene, it backs up exactly what I have been saying if you look and read it carefully. Jim you are correct. Thanks efh Haskell, I will set up my login. BOB SCHAPEL
Ian Buckley

I discovered what might have been providing a minimum amount of cooling. The smiths after market cabin heater was incorrectly hooked up to the back of the head by the previous owner. That would have provided a small amount of flow. I estimate about 1/3 the flow of the normal flow from the back of the head.The water pump really would have had no where else to push the water too. I think its cooling ability to cool was overcome by the first long high speed , higher rpm run on the highway.
K. McKenzie

Ken, the only difference between the back of the head hook up and tapping off the bypass valve at the front for cabin heat is 7 degrees C. Regards, Tom
tm peterson

The one circuit we ignore- with the head blocked, the pump probably pushes water out behind itself through those two thin gaps around #1 cylinder.

My feeling is those slivers normally do nothing, as the block is at virtually the same pressure as the pump discharge. If the head is blocked off with the gasket, then a bit of coolant can slip past the front cylinder into the block, then quickly exit up the head and out the thermostat housing, IF there is a bypass circuit or IF stat is open. A heater circuit, correct or incorrect, would add to THIS circulation, but it doesn't provide any possible circuit other than this.

Kieth, you mention one hose attached to the rear head plate, but you didn't mention the other hose. I assume it runs up to the suction side of the pump. If it is hooked to the thermostat housing, your heater will have ZERO circulation since both of those hoses will be at the pump discharge pressure.
JRN JIM

What am I missing here?

From the back of the block to the side -

Gene Gillam

and from the back of the block to the head through the smaller holes which are all interconnected in the head.

Gene Gillam

Gene,
Those strings do not connect to the channel on the side of the block. That channel feeds virtually all the coolant to the water passage on the block deck directly above the core hole with the two wires. That water passage exit is behind #4 cylinder and between the studs. That round core hole in the rear does not connect to that passage. Most every bit of coolant runs up that passage into the rear of the head, as long as there's a matching hole in the head gasket.
JRN JIM

Jim,
Here is a photo ( old one ) of the heater hose pick-up from the rad return pipe to the pump.
Well, Muriatic acid worked great, reducing the amount of honing I had to do . 95% of all scratches out of the cylinder just 3 tiny shallow ones left.
Good used 4 ring split piston and good used big end bearing. The al now measure out to proper clearances. Put the sump on tonight. Head goes on tomorrow with some luck I will fire her back !
The builder apologized and agreed to refund a portion of the original rebuild cost. I will bill him when I'm done.
We will see
Cheers, Keith
K. McKenzie

Keith,
That was quick work, but I wouldn't be too anxious on submitting your final bill to the mechanic. It sounds like you're sticking in what I call the "Hepolite cloned piston" (split piston?) where your new ones are the "Mowog cloned" style which appear to be more robust. I'm curious as to the weight difference. You don't have another split piston + 4 rings to compare with your galled one + 3 rings, do you? What's the exact bore (STD, +.020".....). Maybe someone has one sitting around they could weigh for you for comparison. Please pay close attention to vibration, and maybe compared it at idle and at speed with another TD! The cast iron cranks don't appreciate shake, rattle & roll.
I wish you good luck!!!
JIM
JRN JIM

Photo

K. McKenzie

I went to the foreign auto supply many years ago to buy a piston for my buddies alfa romeo. The clerk said "if you love your car, you'll buy all four pistons" I said love has nothing to do with it and put in the one piston. The piston had been scored buy overheating due to the block being filled with leak sealer which had jelled and looked like cottage cheese.
I do believe it's a good idea to have all the piston-rod assemblies the same weight and it's easy to do.
P.S. the stopleak didn't work.!

chuck
cj schmit

Well she's on the road again and humming along.
I will run this season on the split piston then replace it with a new aerolite ( mowog clone ) over the winter.
Do you think it will be alright till then Jim? It seems to run smooth and no leaks from the modern front seal or the Moss rear seal.
Thanks for everyones help !
Cheers, Keith
K. McKenzie

If it seems to run smooth, it could last forever. The "hepolite" with the split skirt and all the curvy notches have seemed flimsy, from my experience, whereas the "Mowog" looks solid and possibly heavier. I assume you did not install the bottom oil ring, as they're not normally supplied anymore. My concern was there may be a significant difference in mass that could give it a nagging vibration.
JRN JIM

This thread was discussed between 25/05/2014 and 10/06/2014

MG TD TF 1500 index

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