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MG TD TF 1500 - supercharger or not

sins a cupel of Years I driving my TD with a Camping trailer. It is a light weight unit from "Dethleff" a well known german camping trailer company.
The max empty weight for the trailer is 400 kg and this allowed to pull the car without a brake system.
Now my question to you: Make it sense to install a Supercharger like the one offered from "Tom Lange" one of the MG-TD Gurus?
I read that the power will degrease from 52HP to around 75HP.
This additional power can sometime. Last year I get in trouble when I go uphill in a Olive Hain at that moment I need additional Power. Fortunately there was some helping hands available. For this rar moments It could be helpful.
My question now, do I need some reinforcement on the Engine or the Gearbox (I have installed a FORD Type 9)
Is there a risk for the factory rank shaft to brake away with the more powerful Engine?
Thank you for your comments.



GK Guenter

GK - I see nobody has answered you yet.

As I remember, your Ford Typ. 9 has nearly the same gear ratios as the stock TD transmission on the first 4 gears, with 5th being a definite overdrive. I must be clear that I have no experience with using a supercharged engine with a Type 9 transmission, but I don't think it would be a problem.

We do expect an almost 50% increase in wheel HP from a supercharged engine, which would help your drive - most of the time on the road you would be able to stay in 5th or shift to 4th. Without the extra power I could see you in 3rd gear, or struggling in 4th.

You ask about the increased power affecting the reliability of your engine - that is a harder question to answer, since every engine is different. I always ask a series of basic questions to determine whether the condition of an engine is good enough to add a supercharger:

1)  When was your engine last rebuilt?
2)  Who does your mechanical work?
3)  What is the running hot oil pressure?
4) What is the running water temperature?
5)  Where do you live, and what sort of driving do you do?
6)  What is your goal?
7)  What other modifications to car and engine have you done, or are you planning?
8)  What model car will it go into?
9) Have you had your distributor rebuilt?
10) Is there a dynamometer shop nearby for sports car experience for final tuning?

As for the engine details, I would say that 65% of our superchargers are oinstalled on engines that are basically stock, with factory rods and crankshafts. Another 35% are modified for greater strength - new forged crankshafts and connecting rods, a Crane or Fanelli camshaft, balanced and similar modifications. It is also helpful to have pistons coated to protect from high combustion chamber heat (Len Fanelli does this).

All that being said, as far as I know there has not been an epidemic of broken rods or cranks with supercharged engines. You are certainly putting a greater strain on your car with a trailer, and I think a supercharger would help. But for now, I would be more afraid of a greatly increased chance of breaking an axle shaft (see mgtrepair.net).

Tom Lange
MGT Repair
t lange

GK Guenter,
75hp would be well under what a Ford T9 should be able to cope with, a 1.6 or 2.0 litre Ford Sierra back in the day would often be towing a reasonable sized caravan.

As the box did not have a drain plug the gear oil often tends to be old or very old (sometimes decades) so worn through use and abuse. The oil has to be syphoned out which again may have put many owners off from changing it.

Some gearboxes have had owners add a drain plug which eases matter quite a bit.

Many owners have found that the gear-changes can be improved further, particularly in cold weather, by using Castrol Syntrans Multivehicle 75W-90 (GL4) rather than the often quoted Comma SX75W-90 GL4 or Ford oil. - (see also attached pdf) - https://www.castrol.com/de_de/germany/home/car-engine-oil-and-fluids/driveline-fluids/manual-transmission-fluids.html#tab_syntrans-multivehicle-75w-90

Improvement to the feel of the gear lever with gear-changes comes with changing the plastic saddle (cup/ rail clip) but the genuine Ford (black) and aftermarket (black) copies soon wear again. Only the (red) heavy duty saddle lasts - how much difference it would make to the longer gear lever on a TD I do not know. - https://www.ebay.co.uk/itm/154337008143







Nigel Atkins

The original cast iron crankshafts fail from a fracture developing over a period of time, stock or modified. That is always something to think about.

As Len pointed out, the extra power and increased load will add higher than normal stress to the axles. Something else to think about.

My concern is you are adding nearly 50% mass to the braking equation with no more stopping power. A disc brake conversion without adding a vacuum booster will likely give you less braking over the stock twin leading shoe drum brakes. You might be wise to look into adding a surge brake master cylinder to the coupling and hydraulic brakes to the trailer axle.

We have two supercharged TDs and one more under construction. We'll never go back to normally aspirated. I put MGB disc brakes on our TD
with the MGB rear end mainly to go with wire wheels and better highway cruising. Because it is capable of much higher speeds, I went to a smaller bore master cylinder for higher braking pressure and stopping power. Sleeving a master cylinder smaller will give it new life and more braking power.
JIM N

Another solution on the brake issue is the installation of an MGB servo. See http://www.ttalk.info/TinkerServo.htm. I have installed one in my TD. I located mine behind the driver's seat, above the differential. Image below.

Bud


Bud Krueger

Glad you added that Bud. A viable option.

Another consideration is electric brakes on the trailer with an inertia switch in the cab.

Both of those are getting a bit involved.

For safety sake, brakes on the trailer would be safest as a rolling trailer has a mind of its own and can spin out the back end of a hard braking car pretty easily. It's better having the trailer pull back rather than push forward "when push comes to shove!"
JIM N

Thank you Folks for all your comments. I read all of them and I try to give you more precise descriptions.
Tom, I’m Günter living some years in North Carolina but since a couple of years I live in Hamburg, Germany.
Some of the comments did not meet my question, therefore here again.
My point was if I have a more powerful engine like I get with a supercharge System. In this case is there any risk on any mechanic element like the original crank shaft. This problem is well known but may be other elements are even not recommended to work with the more powerful Engine.
Even the cluster gear inside the original MG gearbox is such a week element. The axel shafts are another elements.
Do you know any more elements?
• Fortunately, my car was piece by piece refurbished in a Garage in Virginia, USA.
• The rear Axle get a 4.875/1 ratio
• The original gearbox was replaced by a FORD-9 Gearbox.
• The crank shaft is still the old original one.
Somebody experiences with such a situation?
Cheers, Guenter
GK Guenter

Guenter: I repeat what I said above -
----------------------------------------------
As for the engine details, I would say that 65% of our superchargers are installed on engines that are basically stock, with factory rods and crankshafts. Another 35% are modified for greater strength - new forged crankshafts and connecting rods, a Crane or Fanelli camshaft, balanced and similar modifications. It is also helpful to have pistons coated to protect from high combustion chamber heat (Len Fanelli does this).

All that being said, as far as I know there has not been an epidemic of broken rods or cranks with supercharged engines. You are certainly putting a greater strain on your car with a trailer, and I think a supercharger would help. But for now, I would be more afraid of a greatly increased chance of breaking an axle shaft (see mgtrepair.net).
-----------------------------------------
I believe that answers your questions as best as possible. The crankshaft is not a known weak spot, but can break without warning on any MG, stock or supercharged - I have never had one break, but know people who have. Everything inside an engine CAN be improved upon, if you have the money: crank, rods, pistons, cam, head, etc. It would also depend on how you drive - gentle is better, always. And Jim is wise to point out that with more power, your brakes will become the weak spot.

Tom Lange
MGT Repair
t lange

Thank you Tom, understood.
If I can find the Budget I will install a supercharger
Cheers, Guenter
GK Guenter

My TD is dead stock except for a 4.55 final drive. Any tips on preventing a crank breaking? I usually keep the RPMs below 3500 on cruise and on acceleration it might reach 4000 momentarily.
John Quilter (TD8986)

My 2 cents. I had a stock engine,Crank checked out fine. ran it for 3 years. put a Judson SC on the car. drove it to GOF Central in southern MO. back and down. no problem. next spring going to Natters and boom, blew the crank. broke right at the front number one bearing. had less than 6000 miles on the engine at the time of the crank break. Did a lot of research and found that there was no champ-fer on the the first journal that caused the break. Also overheating was a problem. I then put in Crower Rods, modern Venolia pistons and a Moldex crank. pistons made specifically to handle the heat.New rebuilt radiator with much better circulation. I did not put the supercharger back on the car. If your gonna super charge. build the engine to take the extra heat and strain otherwise you takes you chances. It is however more fun than a barrel of monkeys to drive a SC car,especially a TD. JMHO
TRM Maine

The #1 cause of cranks breaking is lugging the engine. Never put a heavy load on it when RPMs are under 3K. They are much happier running at 4-4.5K all day. Cruising at lower RPMs is fine of course.
Steve Simmons

Extra horsepower/torque from supercharging should not increase the odds for your crankshaft to break.* XPAG crank failure is not power related. All I've ever heard about are fractures at the front. Surely the generator, water pump, cam chain and fan aren't to blame for extremely high loads. If it were from excess power, the rear would break where all four cylinders transmit their energy to the trans.

The combination of a cast iron crank (probably with loose metalurgical specs) with only 3 main bearings cut corners in production. The design was acceptable considering back in the old days, 10,000 miles was the expected life poking around 2 lane roads at a modest velocity. The configuration of rotating crank with reciprocating pistons and rods that reciprocate and wobble is a recipe that cannot be truly balanced; the best engineers can hope for is add counterweights on the cranks to minimize vibration. Balancing & blueprinting will further minimize vibration, but not eliminate it entirely. Some engine have counter rotating shafts to play with the harmonics. Some irons are better than others when it comes to "crack tip propagation." If it is not "tough" enough to "arrest the crack" the crack tip will continue to grow, the fracture keeps getting larger until "BOOM," brittle fracture finishes the job. Sharp corners from machining leave stress risers leading to the initiation of fracture; spending a little extra time to radius the corners would improve the situation significantly, but now were back to issue of cutting corners in production. Other inconspicuous factors enter in such as where you live. Ambient temperature- decades of cold starts can be partly responsible. Driving habits! Ignition timing? Detonation? Engine miss! Backfiring! Corrosive oil/stress corrosion (gasoline's sulphur + moisture => sulphuric acid. Google 'Jaguar nickosil cylinders' if you don't believe me).

One of the worst contributors to this high cycle failure can be an overly tightened belt. It pulls up on the nose of the crank so every revolution, every grain of iron at the front of the crank switches from tension to compressive stress and back to tensile stress... that cycle is every single revolution. To approximate out how many cycles your crank has survived, multiply your odometer reading in miles x 5000. Engineers set up tests this way to create cyclic failures in evaluating the life of a shaft or similar component.

*Warning: Don't overtighten the blower belt. Neither the crank nor blower will appreciate it.

Short of pulling the crank, dye checking, magnaflux, balance, smacking it with a hammer to listen to the ring, machining radius adjacent to journals, opting for steel crank... etc. keeping the engine in good tune (including belt adjustment) is probably the best insurance one can hope for to stay out of the "Crankbusters Club."

JIM N

For those in the market for new crankshafts I am a dealer for Marine Crankshaft Inc. They do not sell retail. http://www.marinecrankshaftinc.com/billet-crankshafts.html
" Our crankshafts are manufactured completely in Santa Ana, California, USA from the highest quality E4340 Aircraft quality Cr-Ni-Mo alloy billet steel.

Triple heat treated for extreme strength, toughness & durability.

All crankshafts feature:

• High speed straight line oiling system.
• Dynamic “no holes” balance.
• Through pin lightening holes.
• Ion-plasma nitride for superior journal surface hardness & wear resistance.

We can manufacture crankshafts to almost any custom stroke, journal dimension combination desired"
Photo is typical of their work.
Len Fanelli
Abingdon Performance Ltd.



Len Fanelli

Tom and the other experts have given great advice. I've got one of his blowers in my TF and it goes well with a fast-road cam, bigger valves and 8.5 to 1 compression. I do have forged pistons and rods, and a new crank (not a billet). I had considerable backfiring problems on the track, although the car was fine on the road. Eventually I decided that what I was seeing was leaning out on hard left hand corners, and the tracks I use are largely left turning. I took a very good recommendation to fit an HIF carb, with its central fuel bowl, and this has solved that problem.



D A Provan

This thread was discussed between 22/02/2021 and 04/03/2021

MG TD TF 1500 index

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