803cc Engine Some Questions

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Athena
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803cc Engine Some Questions

Post by Athena »

Hi Folks
I'm busy getting the 1955 back on the road. It has an 803cc engine and that will suffice for now as it will only be doing a few local trips most weeks. It's been part restored but it is mainly as built.

The chasis code is shown on the V5 but not the engine number.

Chasis is FBE1/343800, so I know it's a Minor 2dr mid green. This is also on the bulkhead plate.
The engine number is also on the bulkhead plate 193623, but the brassplate on the engine is worn so cannot be deciphered.
As I can't read the plate on the engine there is a very remote chance this is a replacement engines. I think not.
I am making an assumption that the engine is the original one, as the numbers on the plate match.

I need to order a set of core plugs as one popped off during our first engine test. And a car choke spring.

What do people think about the original oil bath filter? I had a very similar one on my 1953 Mayflower side valve, it was adequate. I would be open to changing it for a frying pan style if there was any tangible benefit. I would not want a modern looking filter. I've not looked in detail but I assume it's a H1 carb, but I may be wrong.

I've added a few photos from before I started work which might illustrate what I'm rambling on about.

Thanks All. Trevor
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oliver90owner
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Re: 803cc Engine Some Questions

Post by oliver90owner »

Just a rambling reply from me - I’m not an expert on these engines.

The valve cover does not appear, to me, to be original. The engine appears to be ventilated via the valve chest cover, so any other is a bit of an excess and a waste of space.

Oil bath air filters are generally regarded as less efficient than paper elements (but likely are more than adequate for all these old engines), mainly due to the smaller particle sizes that are retained by paper elements. All my old engines were fitted with oil bath type air cleaners - and I have no intention of changing any!

I would dump the in-line fuel filter. Unnecessary and a possible nuisance.

The fuel pump cap could do with a bit of attention.

Apart from that, I’ll leave it to others to comment further.

BTW, I expect the oil bath air cleaner would likely be a saleable item - to those that like to keep their minors original.
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svenedin
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Re: 803cc Engine Some Questions

Post by svenedin »

Agree with Oliver's comments.

The fuel pump looks like it has not had any attention for a long time. Its might be great inside despite shabby outside but I rather doubt it. At the very least a clean up of the contact breakers would be advised and remove and clean the built in filter. The fuel in that inline filter (agree it is best got rid of) looks a horrible colour. Is the fuel ancient? I would be inclined to drain and at least rinse the fuel tank if not remove it and clean out properly.

The routing of the metal vacuum advance is very odd going behind the engine. It is normally in front but if it works best not to disturb it. Often the diaphragm in the "flying saucer" perishes or goes hard so it may not function.

The rocker cover look incorrect. The breather pipe is open to atmosphere and it should be connected to the oil cleaner with a rubber pipe.

Caveat, I am not really very familiar with the 803cc engine.

Stephen
1969 1098cc Convertible “Xavier” which I have owned since 1989.

Stephen
serowman
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Re: 803cc Engine Some Questions

Post by serowman »

That is not an oil bath air cleaner,they are just an oil lubticated gauze filter/silencer
Oil bath cleaners have resevior of oil in that catches debris in air as it flows past.
ManyMinors
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Re: 803cc Engine Some Questions

Post by ManyMinors »

svenedin wrote: Wed Sep 09, 2026 5:17 pm

The routing of the metal vacuum advance is very odd going behind the engine. It is normally in front.

Stephen
The vacuum pipe is normally at the front of A Minor 1000 engine.
On a Series 11 with the 803cc engine it is routed around the back just as the photo shows :wink:.
myoldjalopy
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Re: 803cc Engine Some Questions

Post by myoldjalopy »

To answer the original question - no, there will be no tangible benefit in changing that air filter (which, as stated by 'serowman', is not an oil bath type).
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geoberni
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Re: 803cc Engine Some Questions

Post by geoberni »

That's not an Oil Bath Filter, the Oil Bath was casserole pot shape to actually have the 'bath'.
What you have was actually listed in the Parts Book as a 'Silencer', although it's basically a wire filter; it was only used on Home Market SII AFAIK.


That rocker cover, with a straight pipe, is correct for the 803, you're just missing the pipe.
I also suspect that is the original engine, although your mention of a Brass Plate is a bit suspicious. I thought they were always a grey alloy.
Basil the 1955 series II

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philthehill
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Re: 803cc Engine Some Questions

Post by philthehill »

I believe that the brass plate (round) was fitted to factory reconditioned units.

Athena
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Re: 803cc Engine Some Questions

Post by Athena »

Thanks for all your comments. Today I managed to deep clean the brass plate and the engine number matches that on the bulkhead.
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geoberni
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Re: 803cc Engine Some Questions

Post by geoberni »

Athena wrote: Thu Sep 10, 2026 9:08 pm Thanks for all your comments. Today I managed to deep clean the brass plate and the engine number matches that on the bulkhead.
I'm not convinced by that looking very DIY.
Not only is it a strange shape, there's no prefix to it.
Here's an 803 plate from the internet.
I think someone may have changed the engine but altered the serial to march it's predecessor.
803 serial.JPG
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Basil the 1955 series II

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philthehill
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Re: 803cc Engine Some Questions

Post by philthehill »

I suspect that the engine has been reconditioned which has resulted in the original factory engine number plate being lost. The plate shown above is not a factory item and most likely was fitted by the engine reconditioning company with them just copying the engine number specified on the bulkhead plate.

Athena
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Re: 803cc Engine Some Questions

Post by Athena »

I agree the brass plate looks unusual whn compared to the other photo.
Does that mean it is more likely to be a local garage recon or the factory recon?
What era is that likely to have been in?
Just curiousity,
Thanks
philthehill
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Re: 803cc Engine Some Questions

Post by philthehill »

It could have been fitted by any number of engine reconditioning companies or a garage that possessed a boring bar as way back garages did their own cylinder boring.
As regards era - how long is a piece of string!
I would suggest the late 1950s - early 1960s as later a worn out 803cc engine would be replaced with the much better 948cc engine.

Edward1949
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Re: 803cc Engine Some Questions

Post by Edward1949 »

If you are recommissioning an 803cc engine it's worth searching "Declan Burns Oil Filter Restrictor" which is designed to correct a serious deficiency in modern 803 replacement filters.
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Re: 803cc Engine Some Questions

Post by taupe »

I'm currently working on two early 803 engines (late 53 and early 54) ...both of which are BRITMO cast blocks rather than BMC or MOWOG and were originally painted blue grey colour.

Here is a pic of one of the original engine plates which is not reverse stamped like later engines.


Engine Number 2.jpg
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Taupe
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