Bore 80mm to 85mm

[VectorSix]

Help for a rookie if you please:
Looks like the Standard 85mm engine has more parts available for much less money than the 80mm. Would it be within tolerances to bore the 80mm to an 85mm or am I talking crazy? Is the crankshaft the same? What else would be affected? Thanks.

 

[Richard L]

Look at the 7th post prior to yours and that should answer your question. It is titled "confused TEA20)".

 

[Klaus]

Hello vector.

I have a 80mm aswell as yours. Well if your engine is 100% shot I might see your point. But why not just keep your 80mm running? IMO that is the original Standard MOTOR Company engine.
Sentimental? Maybe
If not, I would just get one of those Korean Things.
Klaus

 

[VectorSix]

They mfg the engine in both the 80 and 85mm. It is not completely shot, there is some ticking but otherwise runs fine. I inspected a couple of the bearing journals and they are well out of stnd tolerance, It will be .020 come rebuild time. I am just gathering info at this point. I actually did find a source for a complete rebuild on the 80mm for much less than I thought. I was seeing it around $550. I was thinking that if it is just as easy to increase to 85mm I may as well and get a few more ponies out of her.

 

[Klaus]

yes yes I know a few fore ponies are tempting. But 80mm. ROCK!.

Klaus

 

[John (UK)]

You can bore the Block of an 80mm to accept 85mm Liners almost everything else is the same, there are one or two differences but nothing major. Parts for 80mm and 85mm are available.Crankshaft is the same, normally the Heads would be different but they will operate successfully with the original type used on the 80mm....John