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EX engine upgrade


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What to do??

Hi Guys,

My 85 Cabby GTI currently has an EXengine in it. I understand the EX was a non GTI engine so assume someone has swapped the lump out of mine at some point as the engine in mine originally was a DX.
It has been off the road for a few years now and before I put it back on the roadI want to have the engineout and get it reconditioned and possibly have a few mods done to get some more HP at the same time,but I am unsure what is the best route to go down.
I have heard of 16v MK2engine conversions for MK1's. Does that require the whole MK2 engine or can the 16v MK2 head be paired with my EX bottom end? Apologies if that is a silly question but I am quite new to all this! Or should I find a DX from somewhere? I have researched and can't see that there is any difference between the DX and EX only that the DX was part of the GTI engine. As i understand, the stroke and piston sizes etc are all the same between the 2 engines….
The other option is to just get the EX engine reconditioned as it is along with a few mods to get some extra HP.

Any ideas/tips/recommendations very welcome!



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What type of head and fueling is in the car, have they just changed the engine block?

1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 300,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.


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Hi mate.
Yeah it looks like just the block that has been changed.
It's still injection. I think it is k-jet but I'm not sure.


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The cheapest way to do it, is to swap over the whole engine to something else entirely.

Especially if you can find a 16v engine from a mk2 or scirocco that's complete. The easiest way is to buy it with a wiring loom and convert everything over. There are plenty of guides in the FAQs section and the how too's and in the Engine sections.

The other way is to use a 2 litre bottom end as these bolt directly to your head. This give more torque across the range.

As the DX / EX engines are not cross flow heads and cross flow heads tend to be more efficient then a head from a 16v can be picked up and installed although I believe some tweaking is required.
I believe that a mk4 head can also be used but required some re-routing of waterways, so you'd need an engine builder who knows these engines.

The only reason I mention these options is that engine re-builds are expensive. To take your engine apart and refresh all the internals within the block and then do some head work (new seals. guides, springs, lap to valves, 3 seating the valves, port and polish plus skim) will cost around 1500. For the head work alone you'd be looking at around 250.

The full re-build is based on you dropping in the entire engine and then picking the whole thing up again complete.

Your other option for quick, cheap power is to throw away the injection and go either bike carbs or twin carbs.

Lots of options out there!


Cornish Host.
1980 VW Derby
Clive the Cabby
Ujum the Invisible
Mynx the Tintop


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Thanks for the advice! like you say, there sure is plenty of different options out there, just need to decide which route to go down!
A friend of mine runs an engine building/tuning place so i'm hoping to get some cheap labour  :thumbs:


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Anyone know if a KR head woud fit with my EX?



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It won't - the valves will hit the pistons

What's the fuel pump arrangement on your car? If someone started with an EX and put the injection stuff onto it, they'd need to have removed and plugged up the hole where the fuel pump was.

The DX (I'm 99% sure) has bigger valves, but I can't remember if the head was different in any other way. The capacity, bore, stroke and compression ratio were the same though. Not sure about the mounting for the WUR either.


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If its still on fuel injection, all it is they swapped an EX bottom end over and kept/used a gti head. the 1.8 carb bottom end is identical to the gti ev, dx and pb.

carb heads cant be used on injection as they have no injector holes, so it wont be one of those. and the hole at the front for the carb fuel pump, is blocked by the gti WUR mount plate in a kjet GTI or a plain blank in a digifant.

16v head will fit but the compression is dropped far too low (ok for boost though) plus you may have valve clearance issues. plus you need a 16v bottom end so you can swap intermediate shaft, timing belt sprockets and oil pump over from. so in short, fit the complete 16v engine if thats the route you wanna go ;)

16v to a mk1 is well covered, main issue is conversion manifold apart from that it all pretty much drops in, heres my build thread with some tips I used along the way:

Hello my name is John and I'm a dub addict.

My wiring diagrams and other documents have moved here:

VAG Documents & Downloads

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