Block Machining
Turbo Mini Forums

So I'v literally just pulled out the last of the core and gallery plugs and the block is now totally stripped.

What block machining processes should I get done to it before the re-build?

Some people have suggested honing? (not too sure what that is)

Is there anything else that should be done now it's all in bits?

Also should i do anything to the crank or other parts whilst I'm at it?

Cheers

All comes down to personal preference, and the healthyness of your bank balnce, you could just get it honed and new rings on std turbo pistons, or go 1293, lightened/balanced rods etc etc.

Audi s4 b5 - 470bhp & 486ft lbs

On 30th Apr, 2012 Brett said:
yeah stick the bit in and give it a wobble

What engine is it and what are you wanting to do? Your initial post is very vague?

Is the engine a good one that you are just inspecting or is it a POS in need of a rebuild?

If something is worth doing, it's worth doing half of.

Sorry if it was vague!

Its a 1275 metro engine and its going to be rebuild with its standard metro cam, 1275 metro turbo pistons with new rings and a T2 running about 10psi.

Basically whoever has had the engine before looks to have stripped it partially and then sold it - either because they lost interest of its useless.

It looks like a POS. Theres paint everywhere - in all the threads, bores, there's rust and muck in the water jacket and its not a very pretty sight as it stands.

The bores look fine however and are clean with no scores and i can't see anything untoward from my initial inspection.

I just want to know what processes should I get carried out on it prior to the rebuild?

dont bother with the standard metro cam its rubbish in a standard engine

if you keeping it mostly standard fit the MG or kc500

You will need to check the crank and bores for size and the crank thrust faces to see whether anything needs boring/grinding. then obviously fit new thrusts, bearings and piston rings.

on this subject what is the sort of top limit size of the std bore that would still allow for a re-hone and new rings? before you would have to go +20?

one day boost will be mine!

about 5 thou is regarded as the maximum piston to bore clearence.

I built my last engine with that and the ring gaps were right on the limit stated in the haynes manual.

But it did not smoke or use any oil.

is that 5 thou diameter or radial?

one day boost will be mine!

that clearnce,

so thats per side then? so a max diameter difference of piston and bore of 10 thou?

one day boost will be mine!

nope you only measure clearance one side, with no gap the other side,

think of plasigauging a bearing as an example.

and yes skirt to bore, with the skirt measured below the gudgeon pin at the bottom, not on the part of the skirt that wears.

im just trying to find out some things that can be measured prior to buying new rings and then finding that the block should of been bored. so the std bore should ideally measure under 5 thou more than the piston. what sort of amount of material is removed when having the bore re honed?

Edited by wez on 5th Jul, 2011.

one day boost will be mine!

a light hone will remove less than half a thou, BUT you need to hone enough to semove any wear marks, which will depend on how worn the bore is....

the best thing to do is get the pistons measured, and get the bores measured before you do anything,

Also on a fresh rebore I have heard of removing 2 thou or more to get a satisfactory bore finish.

thanks, measuring wont be a problem, i could either do it myself or get it cmm'd at work.
sorry for hijacking your thread carts 60, at least you've got some more info to work with now aswell :)

one day boost will be mine!

Lovely. Well i'm taking the block, crank, pistons and rods down to the rebore place tomorrow morning who said they'll check it all over and ascertain what needs to be done to get it back to working nick.

Fingers crossed the bores are fine, and it can stay as a 1275.

Sorry to be ditsy Wolfie, but i'v always been told the metro cam is quite decent to use?

is the only way to actually measure the lobes against cam specification or is there another way to see which I have.

Im not sure if the engine is MG metro or standard.

See here

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=366575

Andy put the link in at the bottom of the thread to all AC Dodd's pictures

Schrödinger's cat - so which one am I ???