alloy block

[A1quattro]

we are hopeing to to repair my alloy block with extra thick custom made alloy sleeves ,then get the sleeves nikasil plated due to the fact it had been overbored . as we rally a quattro under current rally rules we can go down to 1999cc and run a 34mm restictor , therefore we should still get 300bhp [saving 25kg ]and if all goes well be able to use the alloy block. but the new bore size will be 76.70mm rather than the standard 81mm . a poss problem we just thought of is will the bore size be to small to match the chamber /valves in the head.

[twoqu]

Bit exotic for us mere mortals!
Out of interest is the block one of the batch originally fitted to some WR's or is it a KW one from a Sport?
Salvaging it sounds very expensive, especially with the repair as outlined above. Whats the thinking behind that rather than a traditional ductile iron liner solution which seems to be used on other alloy I5 I have seen?
I guess you have discounted the 2L shorter stroke I5. Rumour has it that the crank is cast rather than forged and you would still have the weight penalty. Having said that, with some careful choice of accesories, it would be possible to shave a few Kg off here and there. I weighed the stock alloy sump recently and was shocked at how heavy it was.

[AndyP]

Looking at how close the valve are to the edge of the combustion chamber, I think you might be sturggleing to reduce the bore by that much. JP would be the best person to ask.

[A1quattro]

hi

we may use a steel liner instead of nikal plating but due to the bores [currently with liners removed] ,only being 2mm apart hence the reason for inserting a bigfat alloy sleeve/ liner and building a smaller 1996cc engine [ other than that the block would prob be scrap] . the block came from the late gary midwinter , i beleave it is a ex works block

[twoqu]

Here are some pics I saved, not sure where from.
Just thought that for its intended use, durability and ease of replacement would override the desirability factor.

[A1quattro]

twoqu how much does the sump weigh? i bought a 2ltr iron block complete bottom end [from a passat] but these run same dia piston as aby. They have different stroke crank and rods . as i realy want to use the alloy block the only way [unless anyone on here knows diferent] i can bring it back to life is by going smaller bore [if its poss] it may well be the first alloy block 15 or even iron block to be reduced in bore size , i know im mad but to me this is a wrc engine and if all goes to plan the car will be getting very close to 1100kg

[A1quattro]

that looks like a picture of james buffkins engine , i have spoke to him on here before . his was built by a porsche race engine building firm in texas

[twoqu]

Seem to remember it was over 5kg!
Well thats the problem. No point in investing a large amount of money to have an end product that is unable to be used. If you can find a 4V per cylinder VAG engine with the same bore spacing that uses such a narrow bore then it might be achievable.
So the other option is to adjust capacity by reduction in stroke. Whether that is desirable in terms of power delivery is open to debate. From what I remember Audi did reduce stroke to 85mm on some rally applications with a marginal decrease in the bore size to allow for the mutiplication factors at the time.
You would have to get your calculator out and number crunch to see if the 2L engine can get a rebore and still be under the capacity limit. Lots of theories about longer rods being desirable depending on choice of piston height etc.
Another issue being whether you want to have off the shelf availability of components.
Have you had any quotes for the work and the associated components (pistons etc)?

[twoqu]

Well I thought it was a 10V from the size of the bowls and the 79 written on one of the pistons!
Having just checked the Sport used 79.3mm which was 8.0:1! Certaintly looks different to the Bufkin pics.
Of course part of the problem is most of us (if lucky) have only ever seen the outside of such ratities nevermind the insides.
So at least we know a bore of 79.3mm can accomodate the valves.

[terrybullwon]

This may sound mental. But why dont you just buy a new Alloy block?

[Pirvu Eugen]

After the pictures...the first thought is... the old Renault engines and skoda also..had removable liners....
Wy you dont use the same thing?
An shoulder at the botom with an thin copper ring...and removable liners?
Just a thought!

[twoqu]

This may sound mental. But why dont you just buy a new Alloy block?

I had read they were available from Audi Tradition but couldn't find it!
Wouldn't solve much if he wants to further reduce the bore size. He would have to liner a new one so more expense on top!

[twoqu]

For comparsion here is a pic of Bufkin's engine which is according to him a KW with Sport pistons 8.0:1:

[A1quattro]

thanks again for your input ,dont think you can still buy the alloy blocks but if you can and the price was in my budget i will buy one [any one got the part number] i wouldnt reduce the bore size on a new block . the only reason to do it with my current block is because its been overbored and there is hardly any meat between the closest part of the cylinders . also after rallying with a 2226 aby for the last 6 years running a 34mm restrictor which the msa originaly said was fine ,now in the last year they have decided that anything [ with turbo ] over 2ltr has to run a 32mm restrictor loosing me 40 bhp therfore it made sense to me to build the block to a narrow bore giving it a new lease of life. the works cars as far as i know still ran 86.4 stoke/144 rods the sport had 79.3 bore for 2133cc but now im thinking a bore of 76.7 is prob to small sport 79.3 - my 76.7 = 2.6 total which is 1.3 smaller at each side of bore. i can get the pistons from je any size but i need to make sure the valves e.c.t are ok . as ive said before i realy wany to use this block if poss and if it can be made reliable [ i know iron block bullet proof] the escort boys rallying spend £15,000 on the millington alloy cosworth blocks , 25kg is a massive saving i can lift the alloy bare block over my head ,the iron block 50kg bare i can lift it to knee height at the most. plus i feel it will finish my car off, current spec 01e dogbox front and rear plated lsd with 4.4final drive 330mm brakes all round , A1 kevlar and carbon body kit incl roof plus loads more

[twoqu]

What I don't really understand is why you are saying the block has been overbored. Surely it would have originally been linered and its the liner that wears out rather than the block. If it is a motorsport block then the liner would have ben removed and a new one installed. So the block is sized for the liner.
Unless of course somebody has already attempted to salvage it by over enthausiastically maching the liner out!
Does the block resemble the pics posted allowing for the fact that there are no liners installed? Clearly that type of liner also uses the flange to reinforce the deck. Would be interested in seing some pics to be honest.