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 - Shorrock blower problem

Heard intermittant clunking noise under hood, mainly when coming off the throttle, suspected inside Shorrock blower, removed forward drive housing, found excessive wear in drive slots on blower end of drive shaft flange.

Question: Is this due to normal wear? Where can I get a replacement driveshaft? Blower is a Shorrock model C75b.

Please advise.

Paul C. Goehrig
Paul C. Goehrig

Paul,

Try this link to see if they can help with parts:

http://www.bcsc.co.uk/abc.htm

Good Luck,

Jim

Jim Goreham

Paul,

What you are experiencing is quite normal for a Shorrock blower. There are a few ways to fix this problem.

1. Replace all the worn parts with new components, VERY costly and you are unlikely to find a new drive shaft anywhere!

2. You can replace the drive pins in the blower flange with some of a larger diameter(they will require a step to fit into the original holes) and then also enlarge the slots the the driveshaft flange.
This has worked very well for me through the years as the new pins have more area to carry the load and will wear much slower than the originals. It is also the least expensive way to go.

3. Recently I built a Shorrock for a T type from parts and discovered that I lacked a drive shaft. So I set about making a new one from scratch. I was unwilling to reproduce the original flawed design, So I designed a new one utilizing a "drive biscuit" from a modern Eaton supercharger. the end result was a driveshaft and blower flange that is absolutely silent and will never wear out.


Good luck,


Ben Travato

I have had a similar problem on my blown TD as well, which resulted in more expensive noises.

Unfortunately, the clattering looseness on the driving "pegs" at the blower end of the driving shaft, resulted in small, but significant lateral movement at the pulley end. This culminated in the pulley coming loose on the shaft, with consequent damage to the shaft and the keyway. This was repaired by building up the shaft, cutting a new keyway, and bushing the pulley.

Regretably, I did not follow through completely, so certain was I that I had caught the trouble, and so, when I started the motor for the first time after the unit was re-installed, I was unpleasantly surprised to find there was still a great amount of rattling and wobbling of the drive belts. Upon inspection, I discovered that the vibration of the blower pulley and the oscillation of the belts had been transmitted to the crankshaft's pulley, the retaining bolt had fallen out, and the crankshaft had been damaged in a likewise manner by the wobbling of the pulley.

Out with the whole engine, off with the sump, and out with the crankshaft!!

My set up uses an idler pulley to try to reduce the driving belt's thrashing to a level where they won't get caught in the fan. I use the original type of pulleys with 2 1/2" belts. I believe there are pulleys with smaller width belts available. Do either of you use them, and, if so, how do they compare?

Since completing the job, I now find I have another problem which is causing me a headache. When cruising at about 55 mph and about 2800 rpm, the engine will suddenly start to run roughly, and then dies. Releasing the accelerator pedal for a few seconds rectifies matters. I am told by people who have followed me they see flames in the exahust tail pipe. As I get some banging and popping going downhill with my foot off the pedal, I am not surprised. I am running a 11/2" S.U. with a 0.10" jet. I forget what the needle is. The car goes like s--t off a shiney shovel however, but lots of soot is noticeable in the tailpipe.

I am under the impression that the carb. bowl is flooding at certain rpm, possibly being caused by small vibrations preventing the Gross jet to be fully closed by the float and this is causing a huge increase in raw petrol being induced into the cylinders, and, not being fully burnt, is discharged into the exhaust where it is ignited by the hot metal. I am told at night time the effect is quite dramatic, and has a disquieting effect on the peasants whom I am passing at the time. On one or two occassions, I have been shouted at.

It is something I could do without, and any helpful suggestions will be gratefully received

Geoff Love
Geoff Love

Geoff,

You should be running a "RA" or "RH" needle with that 0.100" jet. Shorrocks vibrate at speed like "a hound dog trying to pass a peach pit" - painfull to watch!
However there is a lot of mass trashing around in there. I've run into a similar problem on a buddys Shorrock equipped TD. We solved the problem by using the float bowl mounting hardware off a MGA, which have rubber mounted bowls. You will need the following Moss numbers:
1)370-080 Banjo bolt, 1)370-030 Washer, 2)370-020 Gromet, these parts will set you back around $12.

It is a good idea to saftey wire the float bowl banjo bolt and cover bolt on any Shorrock equipped car, as these have been known to migrate loose and fall off! Another speed trick with supercharged SU's is to replace the standard float with a smaller float from a 948cc Sprite, (Moss# 378-050 $18) This will effectively increase the available fuel to the carb as the area of the float is smaller, displacing less fuel in the bowl. Remember a stock MG has two bowls, where as the Shorrock has only one.
On the Pre-war MG's fitted with blowers, they had a giant float bowl the size of a beer mug!

Hope this works for you, Ciao

Ben.


Ben Travato

Thanks for the comments, Ben.

I had already tried the smaller float trick, but that didn't seem to work. I have not had an air filter fitted to the carb. because of lack of space near the hooter,but I am going to move the horn and fit one soon. I am also going to make up a small pair of brackets which will be bolted to the firewall, to which I can attach a couple of springs going to the carb. Hopefully these mods may have some beneficial effect in dampening down the vibrations.

Have you tried any of this?

Geoff Love.
Geoff Love

Wow guys, I must lead a charmed life. I bolted on the shorrock, rebuilt the carb, fired it up and have had no problems since except finding the correct range of plugs to use, which incidently are bosch platinum. I did put in a grose jet in the carb, but otherwise standard. One problem I did come across was keeping the nose piece filled with too little oil. The instructions I got with the shorrock said to fill it only until oil spilled out the front drain, but I found this to be too little. Works like a charm.
Cheers, Rob
Rob Silverman

This thread was discussed between 04/05/2001 and 26/05/2001

MG TD TF 1500 index

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