BRITMO 803 Rebuild

[taupe]

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?

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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.

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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"

Britmo Engine (10).jpg (933.21 KiB) Viewed 3682 times

Taupe

[les]

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

[59Elva]

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?

[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?

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

[taupe]

I love Ebay!

Set of original +20 pistons NOS £76 ....Just like my standard originals with a chrome top ring

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Water pump bearings pair £6.98

Water pump seal £5.55

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All including postage

From what I had read I expected series 2 water pumps to be expensive to repair but apparently not!

I also numbered my conrods today to save confusion later!

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Taupe

[taupe]

Ive been working on the BRITMO cylinder head today. I numbered (using a Dremel engraver) and then removed the valves and inspected the rockers etc. A new rockershaft has been ordered as it shows typical wear.

The exhaust valves are in fair condition but the seats were rather pocketed in the head. The inlet valves were found to have well rounded seats but less wear in the head so I ordered four replacement inlet valves from ebay.

I decided to have a go at doing the refacing of the seats myself as I'm trying to do this rebuild on the cheap...So I purchased a cutter set on ebay.....it was under £30 and after I had machined up a brass rod for the pilot I was able to cut the three seat angles most satisfactorily.

I can also use the cutter on my motorbike engines!

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I will post some pics of the head later....here you go:-

Here is the brass rod/tube fitted to the pilot to suit the valve stem dia.

BRITMO Valve seats (3).jpg (58.46 KiB) Viewed 745 times

and this is the cut seats ready for valve lapping with fine grinding paste

Seats (1).jpg (58.05 KiB) Viewed 745 times

Taupe