MG Midget engine rebuild

[Chris152]

I'm not sure if this should be in Projects, of even if UKW is the best place at all, but I know some of you are knowledgable about such things, so thought I'd try here.

A couple of years ago we removed this from a Midget in poor condition, but the engine seemed fine. But, as it was bought as a learning project, we took just about everything apart. Lots of distractions along the way have slowed the process but we're ready to start the rebuild. I've been tasked with the engine, so here goes.

We'll be using this as our general guide
https://mossmotoring.com/restoring-british-engine/
and MG sources for specifics. We're going for hardened exhaust seat inserts but keeping most of it standard (maybe a little head skim), and the cylinders are very good.

First question: How should we clean the block before reassembly? I've looked at various videos etc, but wonder specifically about washing. Brush out passages and chase threads, then soak in parts cleaner for a day or two, then soapy water followed by air/ heat and WD40 in the cylinders - does that seem to be a reasonable way? Or should we be paying someone to do that bit?

Plenty more questions to come as we go...

Thanks for any thoughts, Chris.

 

[deema]

Waiting with anticipation for the next update. Brilliant

 

[Terry - Somerset]

I suspect the key issue is not the obviously visible surfaces, but oil ways, and cooling system to ensure all crud easily displaced by the cleaning process is removed. A high pressure air line would no doubt be useful.

 

[Spectric]

How should we clean the block before reassembly?

A chemical dip is easiest but you can lightly sandblast providing you have a bare block and throughly wash it afterwards. To do a through job you could remove and replace all the core plugs as it is much easier on the bench.

Being Iron you should have no issues with the block face but get the bores checked and if ok then a light hone before using new rings.

 

[johnnyb]

Sizer and a scrubbing brush with a long and intensive (pref hot) pressure wash, blasting all ways especially if it's been machined at all.

 

[Cozzer]

Ah...
I had a '74 Midget once, in an ugly "Tundra" colour. Didn't like it at all until I went to one of the Nationals at Donnington, and saw how comparatively rare a colour it was, so decided I liked it after all.
Not having a garage, the engine and gearbox sat on a cradle in our kitchen for a while : I'd had the cylinder head skimmed by Sheffield's Beckett & Garner, and they'd seen to the bores and crankshaft as well...it was going to be an over-sized shell bearing job if memory serves me.
Anyway I'd decided to use some recommended cleaner for the lump - apply, scrub, re-apply, leave, rinse....
Worked very well, until I noticed that it had managed to change our vinyl (?) floor tiles into sponges....

It won't surprise you that Mrs.C was singularly unimpressed....

 

[Amplidyne]

Know more about Minis than Midgets. Change the oil pump, and the timing chain and sprockets for sure.

 

[Cabinetman]

I may be wrong as it’s many years ago but I think the gold colour of the block shows it is a reconditioned engine? Which might be good as it will have done a lot less miles than the car says.