Morris Minor Owners Club

I am rebuilding two 803 BRITMO engines and here is a small update.

This one was still on standard bearings and bores when it was taken off the road in around 1965-70? and came to me part dismantled with my '53...looking at the pistons I cant think why?



So I used my small boring machine that I normally use on bike engines and started at 10 thou, then 20 thou. Its a first for me doing a car engine rebore but very satisfying. I did it in the back yard as the weather was so nice today the machine clamps on the face of the cylinder thro one bore with a special clamp.

I will use a local engine shop for the crank grind.


I was amazed that despite the areas where the broken bits of top rings had 'worried' the cylinders (being held captive and wiggling around in the ring grooves) the bores cleaned up perfectly at +020"



Taupe

Well I’ve not seen a machine like that before, very satisfying doing your own rebores, looks great taupe.

That photo of the rebore in the garden belongs in the post “ Can you really fix them on the side of the roadway?”
Does that machine have a magnetic base? How do you align/indicate the bar to the bore?

59Elva wrote: ↑Mon Sep 21, 2026 11:38 pm That photo of the rebore in the garden belongs in the post “ Can you really fix them on the side of the roadway?”
Does that machine have a magnetic base? How do you align/indicate the bar to the bore?

There is an expanding clamp that goes in an adjacent bore and also hooks on the bottom of the cylinder.. the machine then clamps firmly to the cylinder face.

Alignment is done by three precision pins (cats paws) which are expanded equally when the small knurled top knob on the boring bar is tightened which gives precise centering. There are six sets of matched pins to suit different bore diameters. The bar can be wound up or down so the centering can be done at any position in the bore so you can choose the least worn area. The machine is then firmly clamped as above and the pins are drawn back and the cutter tool is inserted.

Taupe