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803 rebuild progress

Posted: Tue Oct 09, 2012 6:19 pm
by JOWETTJAVELIN
Today I had some good news in the form of the block, new crank and sump being returned to me after some work had been done on them. The sump and block had been submerged in a tank to degrease and clean them, and the bores had been honed and deglazed. Thanks to a club member, a secondhand crank was obtained which needed attention to the journals as they were a touch rusty, but this has polished up nicely and came back with the measurements:

Mains: 040
Big ends: 040
Thrust: STD

The cost for the polishing, honing and cleaning? £20.

I'll upload some photos soon but now the rebuild can progress in earnest and eventually I can start enjoying the car instead of it being laid up.

P.S. A few of you said the con-rod which was knocking may have been distorted. Will a used one from another engine do, or buy a new one or leave alone? My man in the trade has said it will most likely be fine.

Re: 803 rebuild progress

Posted: Tue Oct 09, 2012 7:50 pm
by les
First find out if the rod IS distorted. If it is ---you know what to do!

Re: 803 rebuild progress

Posted: Tue Oct 09, 2012 8:08 pm
by bmcecosse
I doubt you can buy a new rod for an 803!! Check the knocking rod carefully before reusing. I would scrap it and use another one if available. CERTAINLY use new bolts in the rods!

Re: 803 rebuild progress

Posted: Tue Oct 09, 2012 10:34 pm
by mike.perry
Plenty of conrods available for the side valve engine
I notice in a catalogue that it lists for A Series engines, rod connecting 1 & 3 cylinders and rod connecting 2 & 4 cylinders. The Workshop Manual lists two conrods as well. I was not aware that there was a difference

Re: 803 rebuild progress

Posted: Tue Oct 09, 2012 10:57 pm
by les
I think you'll find it's because of the cylinder spacing.

Re: 803 rebuild progress

Posted: Wed Oct 10, 2012 6:39 am
by Declan_Burns
There is an interesting article written by Rolf Corbat on the Swiss Moggy website about crankshaft and main bearing failure on the 803 cc engine. It's in German but the photos and pressue tables are easily interpreted.
http://www.morrisminor.ch/pdf/oelfilterbeitrag.pdf
Basically what Rolf is saying is that the original filters had a hole for the oil passage of 1.5mm whereas the modern filters vary from 2.5 to 3.5 mm depending on the supplier. This causes a pressure drop which leads to premature failure. The table shows the measured pressures with the original compared with two modern filters and it is clear that the main problem occurs below 2900rpm. He recommends inserting a small orifice with the 1.5mm hole to fix the problem as shown in the photos.
These orifices are made and sold by Rolf Corbat. I have no idea of the price. His contact details are shown below and Rolf has an brilliant reputation here.
There is also an excellent article on engine rebuilding with brilliant photos on that website
http://www.morrisminor.ch/pdf/Motorrevision.pdf

If anybody wants to contact Rolf:
Rolf & Erika Corbat
Tel/Fax: +41(0)56 241 22 54
E-Mail: rolf.corbat@swissonline.ch

Regards
Declan

Re: 803 rebuild progress

Posted: Wed Oct 10, 2012 10:31 am
by bmcecosse
The 803 filter is a by-pass filter - it doesn't filter ALL the oil. Just a miserable dribble that then returns to sump. so yes - in that sense there is a constant bleed of oil away from the bearings. The main problem mis the pathetic oil pump with 'vanes' instead of the later 'gear' formation. And of course the tiny big ends of the 803 crank! Conrods for a 948 will NOT fit.

Re: 803 rebuild progress

Posted: Wed Oct 10, 2012 6:26 pm
by JOWETTJAVELIN
As per your advice I am fitting a 1098 pump (making sure it is primed this time! :roll: ). Even on another worn out 803 this 1098 pump gave excellent pressure readings. My engine which has been the cause of so much trouble was fitted with the Burman rotary-vane pump, which, as you note, made little or no pressure at idle, even when the bearings were in good condition. Some 803s have a Hobourn-Eaton oil pump of an improved design, but as I have not driven a car thus equipped I am unable to report on its performance.

Re: 803 rebuild progress

Posted: Wed Oct 10, 2012 6:31 pm
by JOWETTJAVELIN
In any case Declan I thought oil was full pressure to all bearings? It is a by-pass filter and not full-flow (where does the rest of the oil go?) after all. Thanks for the link - certainly food for thought. Of course the increased pressure made by the later pump will force more oil through at a faster rate, going quite some way to ameliorate the problem (I hope).

Re: 803 rebuild progress

Posted: Sat Oct 13, 2012 11:44 am
by David53
Great pictures on that site of the engine rebuild. But a bright orange A Series?? Sure looks strange :-)

Re: 803 rebuild progress

Posted: Sun Oct 14, 2012 8:28 pm
by stevey
interesting point about the filter hole size. Going to start rebuilding my 803 soon, so a 1098 pump it is, any ideas about adapting the new filters?

Re: 803 rebuild progress

Posted: Sun Oct 14, 2012 8:38 pm
by JOWETTJAVELIN
I doubt it is worth the bother fitting a later filter. Keep it standard, fit a magnet to the sump plug and change the oil regularly.

Re: 803 rebuild progress

Posted: Sun Oct 14, 2012 9:55 pm
by bmcecosse
I don't know how you COULD fit a later filter to an 803 block..........

Re: 803 rebuild progress

Posted: Mon Oct 15, 2012 3:25 pm
by JOWETTJAVELIN
Thinking about it now, me neither... the filter hole is machined into the block and then there is the issue of the by-pass.

Re: 803 rebuild progress

Posted: Mon Oct 15, 2012 4:30 pm
by stevey
No, i wouldnt dream of fitting a later 1098 filter, i meant the new 803 filters you get now as per the article on the other website, about keeping the oil pressure up.

Re: 803 rebuild progress

Posted: Mon Oct 15, 2012 5:05 pm
by bmcecosse
Note - in picture #15 of the orange engine build - the oil thrower is on wrong way round........ And a crankshaft damper on an 803.......well......does no harm of course - but hardly an engine that's going to get revved enough to justify it!

Re: 803 rebuild progress

Posted: Mon Oct 15, 2012 6:09 pm
by JOWETTJAVELIN
Oh, I don't know - that step up from 3rd to top is quite a gap! :lol: :wink:

Re: 803 rebuild progress

Posted: Tue Oct 16, 2012 12:10 am
by irmscher
:lol: :lol:

Re: 803 rebuild progress

Posted: Tue Oct 16, 2012 12:27 am
by bmcecosse
I you are wise - you will use a 948 box, reto-fitted with the 803 gearlever of course......

Re: 803 rebuild progress

Posted: Wed Oct 17, 2012 11:33 pm
by JOWETTJAVELIN
ESM surprisingly had a NOS 803 con rod in stock. :D I am just waiting for rings now - crank is in place and mains are done - though I do wonder about those loose thrust washers.