MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey 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 Midget and Sprite Technical - 1098 cam end float (too much)

While building a fresh engine for my 1098 Sprite, I have discovered that I have too much cam end float(about 20thou). The spec says between 3 to 7 thou.
There are no cam shims listed on the Moss exploded drawing only shims for the crank, which won’t fit the cam, so how do I go about reducing the end float to get it within limits? The cam plate is not new, it is from my previous engine but there are no signs of wear.
Bernie.
b higginson

Bernie, is that 20 thou end float before or after you've fitted the timing chain and sprockets.

I've just rebuilt my 1275 and was horrified at the 20 thou end float on the cam until I did some homework and checked it again after I had fitted the timing gear. The end float was greatly reduced and it just took a bit of torquing to bring it to spec.

I can't remember if I found the answer in the workshop manual, Haynes or by googling.

Colin
C Mee

IIRC isn't there a shoulder on the cam sprocket whose depth controls the end float, it fits into the cam thrust plate so the thrust plate is sandwiched between the cam and cam sprocket when done up.
David Billington

The cam plate holds the cam in the block. The end float is measured between the back of the cam wheel and the cam plate. I checked mine with a dial gauge without the chain fitted and the cam nut torqued to 88nm .
I have now fitted the duplex chain, so I will check it again as suggested by Colin.
Bernie.
b higginson

Is the camshaft sprocket new?
Dave O'Neill 2

I had a similar issue when I rebuilt my B engine, I had to put the sprocket in the lathe and take a few thou off the face, I was careful just taking off what was needed but if you go a bit too far you could pack it with shims.
R.A Davis

The chain shouldn't change anything
As per Dave, Is the sprocket new.--?
I've struck quite a few new ones that needed a swipe off the inside where they butt up to the end of the camshaft--not a big job but annoying when you use all new parts and it's out of spec. And it's not always too much clearance , sometimes it can be a bind up situation where the rubbing pad part of the sprocket needs 'adjusting' in the lathe. I like to go for minimum spec. like .002"-.003"

willy
William Revit

After watching a video on YouTube by Thomas Classic and Modern, on the subject, it looks like I need to get the cam wheel in a lathe and take off the required amount to bring the endfloat within limits. Trouble is, I Don’t have a lathe, but I think I know a man who does.
b higginson

Bernie
Be careful when removing material from the cam-wheel that you don't remove too much so as to compromise alignment with the crankshaft gearwheel.
However if you were considering adding shims are you sure that you want to remove material.
I have had occasion where there was no radius on the camwheel centre hole and it was held off the camshaft by a large radius on the camshaft.
Alan
Alan Anstead

Yes, it’s certainly worth fitting the sprocket to the camshaft without the retaining plate and checking that it seats properly, without a gap.
Dave O'Neill 2

This thread was discussed between 20/12/2025 and 21/12/2025

MG Midget and Sprite Technical index

This thread is from the archives. Join the live MG Midget and Sprite Technical BBS now