mk2 16v head on mk1 bottom end

is i possible to fit a mk2 16v head on to a mk1 8v gti bottom end? and what else would need changing, Or is it better to re-bore the 8v to a 2l

I don't know if it physically fits, or if the oil and coolant channels all line up, but I do know that the 16V has oil sprays which spray onto the bottom of the piston to help cooling. Given the price and availability of secondhand 16V engines, it would make sense to seek one of these out.

i'm sure it's been done before, though i believe compression is different. don't know why swapping heads would be easier than the whole block though.

As far as I know you can't do it…otherwise people would be using teh 8V 2.)L bottom ends on the valvers all day long.

Its not worth reboring anything, 2.0l 8V bottoms ends are around.

the yanks use 2.0 8v bellies with 16v heads to run turbo's.

It has been done.

Remember Max Power (back in the day, say mid 90's) and there was a guy that had done a 1.8 8v and put a 16v head on it out of a MK2 Golf.

I cant remember the details, but it was made out to be reletively straight forward  :roll: but then again probably not.

I would save the hassle and just transplant the whole 1.8/2.0 16v out of a donor VW…

8v and 16v use the same head gasket, the compression is the same.

There are only two problems with fitting a 16v head on a 8v block. some say you must others say its not that important, and that is the oil squirters and crank case ventilation.

1.8 8v cod-rods and crankshafts are the same as 1.8 16v but the 16v block has the oil squirters, people rev 8vs to 16v revs with out squirters or drillings in con rod to little end with no problems so that really depends on you personal prefference depends how much work u wanna do if its lots might as well get 16v bottom end.

The crank case ventilation is a must tho, the problem is 8v vent out the rocker cover and 16v out the side (front when in car) of the block. If you dont  do something about the ventilation youll blow all the oil seals in the engine and even worse have a mega crank case explosion (i have seen one on a v8 blow the inlet manifold off the heads), an easy remidy would be to drill a nice sized hole in the rocker cover and fit one of them little air filters or a pipe in to the air box.

regards
Rich

Cheers Rich, didn't realise that    Sounds like the oil breather mod would be simple enough, would be more worried about the squirters…but don't remember my 9A having any…

Richie_T said

8v and 16v use the same head gasket, the compression is the same.

Rich

without sounding surly, are you sure. same headgasket doesn't mean same compression. head design and pistons play a part in that to.

ive seen a 20v head on a 16v block they had to block some of the oil ways off it looked stupid cos the head overhung the block cosiderabily (bad spelling moment   )

The 16V pistons definitely have 2 inlet-valve-shaped recesses into them. Surely if you put a 16V head onto an 8V block you'd need the same recess in the piston? Or does the 8V piston clear the valve?

If any thing the compression will be lower on it as the 16v piston is flat on the top (with 2 little cuts to clear the inlet valves) and the 8v pistons have a small dish in them and the have the same compression with the right head on dont they? if you want to check how close they get bolt the head on the block put a small bit of blue tack on the valve of piston time it up turn it over by hand. If it jams then they hit if it dont the clear but how much by? well take the head back of and see if the blue tack has been squashed if so get a set of verniers out and measure it. using a g60 head gasket will help a tiny amount as they are nice thick steel ones.

Regards
Rich

The Mk2 16v head will go on a 1.8 8v block but the compression ratio will be low.  Ideal for supercharged applications.  However, I'd use a late model Mk2 bottom end as the lubrication system is far better.

Oil squirters under the pistons are not a nececity and it'll produce better oil pressure without them.  Use late model con rods though as these have lubrication channels in them (you need to re-drill the brank to suit though).

Can I venture to suggest just dumping a whole Mk2 16v engine in the bay, stops all the messing around and you know it's all going to work.

Mk2 16v head won't go on a 1.6 Mk1 8v at all (well it might but there would be no squish bands) but you could fit an Oetinger (sp?) 16-S french market head with uprated pistons, 16-S sump and a bottom end harmonic balance - again, it's an involved conversion and my money would still be on a whole GTI 16V head and block together.

You can build a 2.0 16v out of a KR 1800 16v and an Audi block - but, unless you are a skilled engine builder - I'd go for a 2.0 16v out of a Mk3 GTI with better cams (the standard cams and map is asthematic).

You'll need a conversion exhaust manifold to fit a 16v in a Mk1 - ashley sell them.  You'll also need either a Scirocco american market GTX 16v inlet manifold or (my preference) twin carbs/throttle boddies.