Higher compression ratio

Hi, i have a 1.8 jh engine in my mk1 cabby. Its now totally stripped and this engine has a compression ratio of 8.5 to 1.
This is because of the pistons. i would like to have a compression nearer to 10 to 1.
I have thaught of skimming the head down but after some calculations it results i would have to skim about 2.3mm off the original head wich is going about 1.5mm over the limit according to the haynes manual.

Anyone any ideas? What pistons could i fit??
I have a spare 1.6 RE engine sitting in my garage.
This was supposed to be a cheap performance upgrade.


Thanks guys

Who suggested increasing the compression ratio of a JH engine would be a cheap performance upgrade? Just sounds like a lot of flapping around to me.

Buying new pistons is never going to be cheap, but maybe DX ones would fit. How about an entire DX engine instead of a JH? They are plentiful. Or, an even better one, if you're serious about extra performance.

skim would have been cheap.
Where does it state i was buying new pistons?
Maybes dont help me
flap flap


Thanks for ur quick reply

Secondhand pistons don't come up for sale that often! Whole engines do though - and would be a better approach. Do you definitely want to persevere with raising the compression ratio of your existing engine, or would you consider other options to improve perforamnce? I am all for innovation, but there's reasons why people do certain things, to make a Mk1 Golf go faster. One of the reasons is that a lot of information is readily available 'out there' so its easy to find solid answers to problems, because no doubt someone has been in a similar situation.
 
I hope someone can help you. DX pistons are certainly nominally the same diameter, but they have a different top profile and may need to be matched to an overbore on the block. For sure, you'll be wanting to put new rings in if you do find secondhand pistons, and a bunch of other new compoents, which would surely send the cost over a reasonable secondhand engine.

ill just skim the head to its limit nd stick the thing back together, im putting new rings on. Its a jh engine running on the carb and manifolds of the 1.6 as that was the original engine. i took it apart cause it was burning oil trough stem seals.
just dont like the fact of the low compression but hey. Can´t have everything

anyone got any idea if my 1.6 RE pistons would work????

give me a couple hours and i will do some etka part number searching.

but i think proper 1.8 gti dx/ev/pb pistons will swap right in though, its a case of are the crank and rods also going to need changing, i doubt it but you never know.

are these engines available in your country? if so i would just fit the whole block rather than mess about swapping the pistons

Skim the head and deck the block

ok so the only difference is the pistons

026 105 101 E - crank shaft, DX, JH
026 198 401 A/B - con rod, DX, JH
026 198 151 A - piston ring set, DX, JH
026 103 265 KX - cylinder head with valves and camshaft, DX, JH

026 107 065 R - piston, DX
026 107 065 Q - piston, JH

trouble is if you go for pistons you'll need to get new rings and hone the block, if you're happy with that then sorted. otherwise see if you can just get the whole block and swap it

Thanks rubjonny, youve allways got the right answers!
Ive taken my head to the shop today to get skimmed.
There gonna skim it to the max, im puting new rings on the original pistons and ill put it back together.
 ill definitly keep my eyes out for a dx block nd that might be a little project for the future.
I love golfs, there so simple o work on.

Thanks guys!!!