What steps to take to check/rebuild short motor

[simonbuk]

Well I attained a short motor assembly, block,crank,rods and pistons. In time I would like to check and build it back up learning as I go.

I stripped the engine down yesterday so I have the bare block, pistons and rods are out and the crank is out. To my relatively untrained eye things look good, no obvious marking on the cylinder walls, no marks on the crank surfaces, pistons look good.

So, I was wondering what steps I should now do things in to ensure each part/parts are useable. Even if I don't get it built up I would like to know that each parts are good to keep as spares.


I was going to get the block checked first. So get the bores measured and checked.


I know that some shell sets aren't available anymore so not sure what happens then. And how do you know what set you need - I assume some measurements have to be take of something - the crank diameter ?


Anyhow, i'm after a step by step guide of things to check so I can learn along the way. I know I could just take it to an engine builder but then I would learn nothing !

[Simon_P]

The manual gives a detailed instructions. Chances are you don't need to measure the bores, engines don't wear like they used to, a quick lick with the the hone is all that they need plus new rings.

Plastigauge is your new friend. If they are in good condition you probably don't need to change the bearing shells, the generic replacements are by now probably aluminium which is inferior and only come in one grade fits all. Very important to note that they are the N/A spec and you will need to drill the missing oil hole.

The most important part is the hours and hours of cleaning.

[simonbuk]

So you would re-use the cam bearings and big end shells if they look ok ? Interesting, I thought they were changed as a matter of course.

Yes, I have been wondering how to clean it up a bit as its a bit unsightly at the moment !! Any tips on what to use ?!

[Simon_P]

There are no cam bearing shells so you don't have much choice.

A very qualified yes. Same engine, same position, in spec, and in good condition - there would be no benefit in changing them.

The manual gives the details.

Cleaning outside wire brush in a drill, inside, petrol to remove oil , then an Eco friendly alkaline cleaner, jet wash, repeat several times then brake cleaner and blow out with compressed air.

[dapinky]

Whilst Simon outlines the 'right' way to clean it all up, I am a great believer in swilling the worst of the gunky oil out by spraying petrol/paraffin/degreaser everywhere, and then hosing it off before putting it into the dishwasher for a nice cleaning cycle......

.... usually when Mrs P is at work

[Simon_P]

As do I, which is another reason for using a food safe, citrus based, industrial cleaner - petrol makes the dishwasher smell.

3 goes on pan wash cycle turning it over every now and then.

[simonbuk]

Can somebody please tell me the bore size of the cylinder and what tolerances are allowed ?

I've tried to look in the manuals but can't seem to get access to them

Also what are the pistons - 80mm ?

[simonbuk]

Just found some Lotus service notes on the web, so think I've got it all.

[Brit-Car-Nut]

All of the manuals are available at http://www.lotusm100.com/manuals

See the bottom of my posts