Deck height and compression ratio numbers....

Leave it - the deck is good and so is the CR.

Cleanliness is vital and why doing this in a muddy field would be so difficult.

 

Easier if it's somebody else's.
And these were all stock 1600 like for like, no measuring of anything other than checking the pistons didn't protrude past the barrels. Nobody really knew what they were doing, that was half the fun...and the beer was the other half.

 

Thanks, gents. that is a relief. Your help has been invaluable.

 

Excuse my ignorance, but would you mind explaining the deck height problem as I may be going down the same route as you @Fronkjunior

 

Hi, it is worth getting to know about deck height and compression ratio. It took me a while! There is a good book about rebuilding your VW engine by Tom Wilson which is informative, as well as YouTube videos, and the help from this forum is fantastic too.

My biggest learns were to understand that all the measurements in the CR formula need to be accurate as small variances in input can have a big influence on the results. Everything was weighed and measured the same way. Mating surfaces were cleaned, and each barrel tightened down the same amount (not too much though, the casting can crack). A solid edge with no flex to measure the deck height with, and a decent measuring device. To measure the cc of the head I hired a kit from Cool Air for £5 something. Well worth it.

Measure, measure, then measure again!

 

Deck height isn't a problem, it's just something that needs to be measured, especially when you are building a non standard engine, like converting an 1800 to 1911cc for instance. Deck height is the amount the piston is below (or above) the top of the cylinder at TDC.

 

That makes sense. Presumably, this is unlikely to be an issue if I stick with stock 1800 barrels and pistons.

 

You cannot buy stock, as in VW, barrels and pistons, and it's just as likely to be a issue, or not, regardless of the size of new barrels.
These will fit: https://www.heritagepartscentre.com...iston-kit-type-4-1800cc-dish-top-93x66mm.html and so will these: https://www.heritagepartscentre.com...911cc-96mm-x-66mm-for-1700-1800cc-type-4.html
The 1800 pistons are dished and would probably result in a very low compression ratio, the 1911 are flat top and will increase the CR if the deck height is the same.
Don't fit head gaskets whatever B&Ps you decide to fit and you will need to measure the deck height.

 

Looking online, there seems to be a bit of a shortage of shims to be able to set the deck height (unless I'm looking in the wrong place for them).

 

Until you get the parts and do some measuring you wont know what size shims you need, if you need any at all. And TLB has a selection of shims, I just can't remember who has them.

 

I've got them for Type 4 flywheel end float, not deck height.

 

I remember now you've told me.