Replacing 1.5 with 1.8 - anything else to change

The engine in my 1.5 GX is getting very tired. I was thinking of rebuilding it, but I don't want to be without the car for the duration of the work as it is my everyday transportation. I also rather fancied the idea of a little more power to make motorway cruising and traveling up hills a little bit more comfortable. So I thought maybe if I could find a decent 1.8 carbed engine from a later golf/scirocco, that I might replace it with that instead, which will always give me the option of rebuilding my 1.5 at leisure in case I ever wanted to replace it for the sake of originality (probably not likely once I'd got a bit more power underfoot!).

However, although I know those engines will drop in without any modifications, is there anything else I would need to change? If the engine comes with the correct manifolds, etc, will the current exhaust system match up to it? What if I didn't replace the gearbox, but put this engine onto the gearbox I have already? Would those gear ratios be totally inappropriate for the new engine? Anything else that I would need to consider before embarking on this?

Chris

couple questions to start with, does the car have electronic ignition (3 pin plug on dizzy) and what carb is it running?

at the basic level yes you can swap the lump over and all the old bits fit, the exhaust manifold will bolt right on. the inlet may or may not? basically the 1.8 will have the 2e2 carb with a coolant channel from the head into the inlet, I have a feeling the 1.5 will not have this so you'll have to go with the 1.8 carb. this will mean a bit of wiring as the 2e2 has a few extra bits, nothing too difficult though. if it has a weber on it though you're laughing just needs an ignition live to the heater on the front (if fitted!) and you're away.

swap the old gearbox over, I would put a new 210mm 1.8 8v carb/gti clutch on and keep the 1.8 flywheel though. the old box is probably similar ratio wise to the 1.8 one anyway

Kepping my eye on this!

As i was discussing this option with a few mates earlier.

So, all you would need is lump, with manifold, both inlet and exhaust, new carb, and a different gearbox, starter motor, alternator etc.

Would mounts need changing?

Richy_Rich said

Kepping my eye on this!

As i was discussing this option with a few mates earlier.

So, all you would need is lump, with manifold, both inlet and exhaust, new carb, and a different gearbox, starter motor, alternator etc.

Would mounts need changing?

Hi,

starter motor, alternator and engine mounts will be the same on 1500 and 1800, I think.

Robin

the early alternator is a bit different, it has a 3 pin spade connector, late uses 2 ring terminals. id go with the later type as easier to get, but you'll need the alternator wire as well.  mounts all the same, box same, starter same, exhaust same etc

if it was me i would fit full gti exhaust and use the proper 6 bolt flange manifold and downpipe that really peps up the carby lump

Cheers guys!

What cars came with the 1.8 8v carb?

can a k-jet lump be used as a bare lump?

Sorry for the Hi-jack

later mk1 cab and scirocco, mk2 golf. all the 1.8 bottom ends are the same gti or carb, heads differ carb to gti and kjet have different injector inserts to digi but those can be swapped. some kjet have extra pipe on the back for air shrouded injectors, just cap off if not needed.

carb heads have a coolant channel for the inlet which is required for the 2e2 carb, so bear that in mind when fitting a gti head. on some heads you can drill the coolant channel, or you could fit a weber carb which doesn't require the coolant channel

Brilliant thanks! 

Im planning on going down the bike carb route, so ill keep a eye out for a carb lump. 

Thanks!