Welcome to our resource for MG Car Information.



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 Midget and Sprite Technical - Carbon thrust replacement

Lawrence Slater's design for a roller clutch release which I copied , and variants are now being fitted, or have been fitted, to Several Sprites and midgets, is limited in its application.
The design only allows it to be used on 1275 / 1098 engines.
The design will not suit a Frogeye where the spigots that enter the yoke are much closer to the bearing working face.
I am playing with an idea for a Frogeye but will it be too weak.
The picture shows the body in unwelded condition. The idea is once the spigots have been TIG welded on and the internal bore cleaned of excess weld a Lawrence type backplate will be welded on to locate the stock roller bearing.
Imput welcome.

Alan Anstead

A reminder of my adaptation of Lawrences idea.

Alan Anstead

Is this an engine or gearbox related issue? I'm assuming that you have a smooth-case on your frogeye? I have a rib-case mated to a 1098 with a 948 flywheel/clutch & and a 1275 clutch fork / carbon release bearing. This all works for me. Would substituting the clutch fork for a 1275 variant improve matters?
Simon Wood

The issue is the frequent failures of carbon thrusts experienced by some folk.
Lawrence Slater came up with a roller bearing that when mated to a homemade backplate was suitable for 1275 / 1098 engines. I tarted up Lawrences design and have made some for some Kent Masc members.
The concept is not adaptable for the Frogeye so I am trying to come up with something different.
My Frog is still on a carbon thrust. It has a T9 box with homemade bellhousing and apart frpm the driven plate is stock 948 clutch.
I am just experimenting.

Alan Anstead

What is the objection to the various commercially available roller bearing replacements?
Jeremy Cogman

Sorry Alan,
I didn't make myself very clear. Yes I was aware of Lawrence's roller bearing mods. The question that I was posing was as to whether transplanting a 1275 clutch fork into a frogeye would enable Lawrence's design to be utilised?
Simon Wood

The Morris Minor roller bearing is interchangeable, but too heavy for a Sprite/Midget.

Just my two penn'orth.

Happy with carbon.
Nick and Cherry Scoop

I only know of two available roller thrusts.
Peter May supplies one for 1275's and a chap in Aus supplies for, I believe, all engine sizes.
I haven't heard a bad word about any. It is just fun to make your own!
(and sometimes cheaper).

I am trying to make something that would be a straight swap into a 948 yoke.

If I knew the spec of the bearing used by the chap in Aus I would probably replicate his set up. Anyone know its specification?


Alan Anstead

I dont understand why this is only an issue on frog eyes with the 1275... wouldnt the midget also suffer with a 1275

the website the other day called mammba ? We were all talking about I cant seem to find it know ... had several differant options for your clutch dilima... it was dealing with front mgb shocks for the midget

Prop and the Blackhole Midget

This is about 948cc engined cars. The issue is trying to make a roller thrust race that utilizes a 948cc clutch and yoke.

There are various options for 1275 engined cars. I have made a roller thrust race for a 1275 / 1098. Infact I have now made several.
I have two currently sitting on my workbench.

Mamba Motorsport was the fitment of MGB shockers to any Spridget.
I dont have a clutch dilemma!


Alan Anstead

Ah ... i understand now

actually aAan... RE check out the mamba website its NOT just suspension

they have a huge section on aftermarket clutch componetants... they even have there own carbon rubbing blocks for the a series set up and roller bearing conversions. Plus concenritic slaves

Prop and the Blackhole Midget

And mamba even makes an adapter to convert the A+ into an inline engine with a regular A series flywheel

Prop and the Blackhole Midget

This thread was discussed on 31/03/2016

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.