1.5 to 1.8

Hi,

Im looking at putting a 1.8 8v carb engine into my mk1 which currently has a 1.5 carb engine fitted. What items will I need to change e.g. drive shafts, radiator etc…

Thanks.

I'd like to know the same thing actually just out of curiosity as I may consider it one day…..

are you wanting the gearbox too or will you re-use the old one? what carb is on the 1.8 lump 2e2 or weber? mk1 or mk2 engine?

I will want to change the gearbox because I only have a 4 speed at the moment. Not sure what carb will be on the 1.8 as I dont have the engine yet. I want the engine to be froma mk1, so i'm guessing I need a 1.8 8v out of a cabby?

well the 1.8 cabby/rocco engines are the same as the equivalent age mk2 engine really, just some slight differences on the coolant hoses.  knowing the age and car it came from will help with the box identification too.

basically box will either have 90mm flanges like your old one so straight swap with the shafts you have now, or 100mm flanges which means late cab/rocco 100mm shafts are needed or you'll need to find a late 020 box to swap the 90mm flanges from (your old ones wont fit later boxes)

Great thanks for the info. So sounds like a fairly straight swap then. What about the rad and exhaust? Can i use whats on my car now?

exhaust swaps over, though if i were you id hunt out a gti 6 bolt flange 4-2-1 manifold and downpipe it'll free up some hp plus it aint a rubbish design! probably need a tintop gti system to match it, id imagine the 1.5 is smaller bore?

for the rad see how you go, if it runs a bit hotter than you would like go for the 1.8 rad its a bit bigger. need the hoses and rad fan shroud to match it

I take it wiring wise it will be much the same? Also is there a particular engine code I should be looking for?

that depends on the carb, if you get a weber its simple just need to plug the inlet heater in same as it was before and an ignition live for the carb heater there should be a wire for that too.

other thing i just thought of is your car points or electronic ignition? if points you'll either need to swap the dizzy over or add the electronic ignition wirign and run an ignition live for the coil from fusebox

My cars on points. Thank you for your help.

righto just swap the dizzy over for an easy life, saves you wirign. dont throw the 1.8 one away, in case you get fed up of the points system later on

Does anyone know if the ancillaries off my 1.5 JB engine will fit onto a 1.8 8v carb EX  engine, e.g.

Starter
Alternator
Fuel pump
Ignition coil

Thanks

yarp will all bolt up

though with the coil it depends on what ignition system you want to run, the DX will be electronic ignition and the 1.5 is probably points.

so the old points coil wouldn't be any good on the DX dizzy, you would want a mk1/2 electronic ignition coil plus all the ignition amp and wiring from it, plus may need to run a fresh ignition live to the coil.

rubjonny said

though with the coil it depends on what ignition system you want to run, the DX will be electronic ignition and the 1.5 is probably points.

so the old points coil wouldn't be any good on the DX dizzy, you would want a mk1/2 electronic ignition coil plus all the ignition amp and wiring from it, plus may need to run a fresh ignition live to the coil.

Thanks for your help, although I'm looking for a 1.8 EX carb engine not the DX gti engine so not sure whether the dizzy is a straight swap or not

the DX dizzy has a better ignition curve on it so you'll want to use it if you have one

Thanks for your help and advice