Engine Rebuild

[silloyd]

I'm currently stripping a 1098 with a view to rebuilding it. This is my first attempt at this, so please be patient.

The engine itself is a bit of an unknown quantity as I've never seen it running, that said it only cost me £50, so I'm happy to see how good/bad it is.

I've got to the point where I'm trying to remove the distributor drive from the crank case. I've removed the bolt that I thought secured the Distributor housing (the bit that the the distributor clamp plate attaches to, part number 10M165 in some catalogues or 12A1136 - item 3 in this diagram) but the thing won't budge and I therefore can't get the dizzy drive shaft out.

Am I missing something? Does it unscrew? Is it removable? Can anyone help please?

[IslipMinor]

Once the distributor clamp plate has been removed, there is a single bolt (1/4" UNF with 7/16" head) that holds the 'Item 3' in place. Once you have removed the bolt, try turning the mounting spigot in either direction to free it off. The single bolt is the only thing 'officially' holding it in place, other than maybe a bit of corrosion or it's just tight!

[silloyd]

Thanks Richard.

The darned thing appears to be locked solid, even with the bolt out. Probably corroded then.

Will have to try Plus Gas and 'persuasion' to see if if will shift.

[bmcecosse]

Just tap it lightly back and forth - copper hammer, or piece of hard wood and steel hammer. It's just a sliding fit with a thin O ring seal part way down.

[silloyd]

Hmmm, tried that but no movement whatsoever and I'm afraid to hit it too hard for fear of breaking the casting. Will see if the Plus Gas will do it its job over a few days - no hurry.

Thanks anyway.

[bmcecosse]

Why do you want it out - are you pulling the camshaft?

[silloyd]

That was the idea.

Like I said, this engine is very much an unknown quantity, so I want to check everything and, if necessary, replace the camshaft bearings.

Doubtless I will have more questions as I go through the process!

[bmcecosse]

Camshaft bearings are very very rarely replaced - only really if an engine has been seized to a halt with no oil and/or no water! But worth looking at them of course - and the cam lobes........

[MarkyB]

As Roy says cam bearings vary rarely wear enough to worry about.
The fist thing of interest is the state of the bores, check for a ridge at the top of the bore that is deep enough to catch your fingernail on.
Next thing is the condition of the big end and main bearing shells and the bearing surfaces themselves.
If all the shells have a nice even grey look they are fine, signs of copper mean they need to be replaced.
The bearing surfaces should be lovely and smooth, no ridges.

Feel free to post pictures of what you find.

[silloyd]

Piccies....

Main bearings:
[frame][/frame]

Big end bearings (1 to 4, left to right):
[frame][/frame]

Pistons and con rods (1 to 4, left to right):
[frame][/frame]

Crank:
[frame][/frame]
[frame][/frame]

Bores (1 to 4 in sequence):
[frame][/frame]
[frame][/frame]
[frame][/frame]
[frame][/frame]

Mains and thrust clearly need replacing and will replace big ends anyway.

Bores look very smooth to me and can't feet any ridges or grooves. I'm also going to replace the piston rings. Do the pistons themselves look OK for re-use?

Crank mains measure around 1.730" and big ends measure 1.602", so from the workshop manual specs I take it that these are both +020"(?)

[izzi]

Hi,

The photo of the crank shaft hybrid reveals a lot of wear, not to sure if that can be remedied.

I would suggest that modification on the rear crank to avoid a oil leak. ( it may solve a few headache's )

Roy.

[bmcecosse]

You can take a chance on the crank - but really it needs a regrind. Don't forget to fit a NEW oil pump. Bores look ok - light hone and fit with new rings of course.

[MarkyB]

I think it would be worth checking that the plate and spring are present in the oil filter.
It has the look of being run on dirty oil.

[bmcecosse]

Indeed it does - or short of oil!

[silloyd]

Thanks gents.

No idea whether it had been run with/without oil or whether the oil filter had been fitted correctly but it did indeed have the standard (not spin on) filter arrangement, so entirely possible it wasn't well looked after. Lots of sludge in the sump.

Forgot to say that I will be installing a new oil pump as a precaution, even thought the one I removed looks OK.

I'm really not fussed on replacing the crank due to cost but there again I'm reluctant to rebuild only for the bearings to fail - will have a think about that one!

Cylinder bores are standard size and look really smooth to me, so why the need to hone? (Please remember I've never done this before )

[bmcecosse]

The 'hone' can just be a glaze-busting exercise - done by hand with a sheet of 80 grit paper. Up and down twisting as you go - to put light 45 degree scratch marks in the surface. The crank needs a regrind.......

[welshrat]

I am also attempting my first rebuild (midget 1275) so watching with interest. I had not realised how expensive it all is, the parts and tools add up. Recently purchased a valve spring tool, piston ring tool and this honing tool which I must say was well worth the money http://www.ebay.co.uk/itm/Car-Engine-Cy ... 20c4a5e6de Then the bearings, gaskets, assembly lube, oil, etc. Any how good luck and keep posting the pics, finding them very helpful.

[daveyl]

I notice those pistons have circlips to retain the gudgen pins. I didn't think these were fitted as standard to the 'Minor' 1098 engine, where there was a preference for the press fit type.

I mention this as the pistons may not be standard and so you will need to take note of the piston serial number to obtain the correct rings.

[bmcecosse]

Circlips are right enough - only much later Mini engines have press fit on the small bore engines.

[MarkyB]

What don't you like about the look of the crank Roy?