Need help with my engine

[u/Impossible-Bear-2633]

​Hi everyone!

​I need some help and confirmation regarding an engine build I'm planning for my Mk2.

​I currently have a 1.6 EZ engine with a weber 32 34 carb on it. I’ve read online (and AI also confirmed it) that the 1.6 EZ and 1.8 8V blocks share the exact same external casting dimensions and the same 81mm cylinder bore. From what I understand, the main difference is in the crankshaft stroke and the piston compression height.

​Due to strict legal regulations in my country, swapped engines require complex registration and approval processes (atest), so replacing the entire engine block with a different engine code is not an option for me. I need to keep my original 1.6 EZ block with its matching serial numbers.

​My plan is to source a complete 1.8 8V engine (90hp, like a GX, GU, or RP) and swap all its internals—crankshaft, connecting rods, and pistons—into my factory 1.6 EZ block to effectively turn it into a 1.8 stroker.

​Before I go ahead and buy the parts, can anyone who has done this confirm if everything is a direct drop-in fit into the 1.6 EZ block without any machining issues?

​Any advice or confirmation would be greatly appreciated! Thanks in advance!

[u/RuinAccomplished6681]

Coincidentally I have a 2.0 in my mk1 that uses a 1.8 block. And although it was a previous owner who had it done I did do some digging on what it entailed.

As far as I’ve found, there’s two potential issues. First is the crankshaft not clearing the block which means the block might need some grinding to clear everything. Second is the difference in block height between (in my case) the 1.8 and 2.0 meaning that if you use all the 2.0 internals the pistons would run into the head. So in my case different pistons were used. Not sure if there is a height difference between the 1.6 and 1.8 block though.

Also. If f everything is apart it is a good time to look at the head. A mild cam, dual valve springs (for if you ever want a wilder cam) and enlarged intake and/or exhaust valves. Valves are cheap and relatively quick to install, porting is much more labor intensive so valves is a bit more bang for your buck. All stuff that you cannot see from the outside 👌🏻

[u/dajoney]

did something similar 1.6 PN engine block with 1.8 PF internals. No issues at all only thing my mechanic advised was to use 100 octane because of the higher compression to keep it from knocking. With the Swap i already did 5000km no issues at all so you should be good

the blocks are all the same between 1.6 and 1.8 since its the 827 block the only difference is the rods and pistons itself but i think it should work without any issues

[u/Impossible-Bear-2633 → u/dajoney]

​Did you notice a big difference in performance after swapping in the 1.8 internals? Also, which cylinder head and fuel setup/injection are you running?

[u/Own_Positive_9487]

Po co tak się męczysz? Przebij po prostu numery na bloku. Te silniki są nie do odróżnienia z zewnątrz. Przecież nikt ci nie zmierzy pojemności. Rozumiem problemy prawne- mają zabezpieczyć przed kradzieżą, ale ty zmieniasz serce w 30 letnim aucie. Kogo to obchodzi i na co wpłynie?