1.8 GTI from mk2 into a 1.5 mk1

Hi all!

I'm new to this forum and relatively new to Golf MK1.
I've searched for a thread that answers my questions, but after endless hours of reading I'm just more confused.

I got a -81 Golf GLS 1.5 in good condition with 85000km that I've slammed and detailed a little.
I also got hold of a GTI 8v with 5-speed box from a MK2 Golf.

You've probably figured out what's up, but anyways……

As I've read this is a pretty straight swap, but is there any differences between the MK1 GTI and the MK2 GTI engines that I should be aware of?
I'm gonna run this with a Weber 32/36 setup. I don't won't the hassle with fuel tank and fuel lines as well as a clean engine bay.

Here's a list of things I'm curious about:

1: Does the gearbox fit the original linkage without mods? Or do I have to go for the original 4-speed box?
2: Can I fit the 1.5 dizzy to the 1.8 GTI? The 1.8 dizzy have a three-pin connector which is different from the 1.5. Or do I have to run with the original ignition from the 1.8? (ignition module?)
3: Can I fit a OEM mechanical fuel pump or do I have to go with a low pressure electric pump with a FPR? If any, which OEM pump fits the 1.8?
4: Should I fit a 4-2-1 exhaust manifold from MK1 GTI?
5: I want the original tacho and warning lights to work. The tacho works with the original coil (and dizzy)? The watertemp and oilpress use the same sensors on both engines?

That's all for now, but I'm sure there will be more questions.

Hope someone can help me on my way and that I've posted in the right forum.


And you'll have to excuse if there's bad writing. I'm from Norway and english isn't exactly my mother tongue or writing. cf_emoticons__BangHead:

the Mk2 box will be missing the 3 studs for the rear engine mount.
your clocks should still work.
the mk2 exhaust manifold will need to be changed for a mk1 GTi and use the mk1 exhaust.
inlets are different too but if your running carbs this wont matter.

Thank's for the reply.

So I can't use the mk2 box without mods?
Can I fit the 1.5 flywheel and clutch to the GTI and use the 4-speed box or maybe the clutch is the same?
190mm on the 1.5? And 190 or 210mm on the GTI?

I'm thinking of buying a MK1 GTI 4-2-1 exhaust manifold so that one is sorted.

Okey, this is what I got so far:


Original 1.5 4-speed box with clutch and flywheel
Original 1.5 dizzy
Original 1.5 motor mounts
Original 1.5 block mounted fuel pump
1.8 carb inlet manifold with Weber 32/34 DMTL
Aftermarket 4-2-1 exhaust manifold suited for MK1 GTI

Along with a Techtonics 272¤ cam and proper 2 1/4" exhaust system I hope this can be a driveable and fun car.

Any thoughts?

1. yes, you'll need the upper mount though plus most of the linkages from mk1 5 speed
2. yes
3. yes, the old fuel pump will swap right over
4. ideally yes, the old 1.5 system will still fit tho
5. yes

keep the mk2 210mm flywheel, replace the clutch with sachs 1.8 8v unit. check the gearbox code first to be sure its a 8v and not a 16v (if 16v then buy 16v clutch kit)

with the mount issue pointed out above, if the studs are missing the box will still have the holes you need, so either use short bolts or remove the studs from the old 4 speed box:
020Mount

Thanks alot!
That was very helpful, rubjonny.

Then I'll have to search the web for MK1 5spd linkage and a Sachs clutch kit.

The puzzle is coming together. Anything else I should think of? Parts that needs to be swapped or anything?

for the clutch kit try ECP sometimes have good deals on or if not:
AVS Car Parts - [The VW - Audi - Seat - Skoda Parts Specialist]

cant think of much else really, bits that need swappign over will become obvious as you go thru the swap, things like flanges, oil pressure switches etc change over if they differ

Thanks!

What about the driveshafts, will they fit the MK2 box even though the joint diameter is different?
They are both 22 teeth with M20 threads but MK1 joints are 94mm and the MK2 is 100mm according to bestpartstore.co.uk.

ah yes, you'll either need to change the shafts for post-84 cabrio/scirocco 100mm ones or fit later 020 90mm flanges:
Flange Types
020 Flange

Ah, okey.
I think I'll start out with the original 4spd box with a new clutch.
If it breaks it's a lesson learned the hard way.

It's still a 020 so I guess it depends on wether the clutch can stand out 120hp or not.

just use the mk2 210mm flywheel and a 1.8 8v sachs clutch, be fine then

AVS Car Parts - [The VW - Audi - Seat - Skoda Parts Specialist]

Sorry for being really slow here, but what youre saying is that my original gearbox with. 190mm clutch will pair up with the 210mm clutch and flywheel? No problem with bellhousing or shaft splines?

no, I'm saying use the mk2 210mm flywheel, and buy a 1.8 8v clutch kit, which are also 210mm

all the 1.5 clutch & flywheel parts -> bin

Hehe, bin it is, sir.
Thanks alot for your help.

Btw, are the VW 210mm clutches made with many different splines?

yarp, theres the 8v one and the 16v one. the 8v clutch kits fits most 020 gearboxes both your 1.5 and the mk2 gti one, the 16v one obviously fits the mk2 16v box plus the 2.0 8v mk3 gti gearbox.

best bet to check the code on the mk2 gti box just in case, it might not be the original. but the 4 speed boxes are all 8v spline so it'll be fine with the 8v clutch for sure

Sweet. I'll order the. 210mm Sachs clutch kit for MK1/MK2 GTI and guess I'll be fine with that.

Another question popped up here.

Do I have to replace the throttle cable or will the original 1.5 cable fit the 32/34 carb?

the cable should be fine, you may want to replace it anyway if its the original its probably past its best