TDI Swap on 020 Gearbox in MK1 RABBIT

[chi1337]

TDI SWAP THREAD

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Looked around a lot, the opinion of people is that the 020 gearbox cannot handle all that torque.

For reference, the AAZ & 1.6TD uses the 020 gearbox, and produces 111 lbf⋅ft of torque. 1.6TD is nearly the same: 112 lbf⋅ft

The ALH/AHU generates 154 lbf ft if I look at this Malone chart:

https://www.cascadegerman.com/wp-content/uploads/2015/06/Malone-stage-I.png

However, the AAZ produces 150 lbf ft +- too, if it's tuned to 90 horses:
https://www.thesamba.com/vw/gallery/pix/1559156.jpg
So nearly exactly the same as the ALH, however the torque is produced at higher rpm and for a longer time.

I was thinking, while running the electronic TDI, I can reduce fueling in the 2000-3000 rpm range, so that torque bulge /spike there doesn't happen [VAGEDCSuite supports this]. Yeah kind of defeats the purpose of a TDI, but more fuel efficiency & more modern platform

[RabbitJockey]

most people dont know what theyre talking about. An 020 can handle a slightly modified tdi just fine as long as you use a good clutch.

the thing is that spending the money on a good clutch is money that may be better spent on an 02a or 02j. It's up to you since it's your car. 020 will work, 02a/j is better no doubt. I bought a spare 020 and used the 020 with my swap it's easier and cheaper. worst case i have to swap in another 020 that paid $100 for.

[chi1337]

hi, thanks , yeah I suspected as much since a tuned AAZ will make more torque than a stock AHU. Just the RPM range is different.

I'm going to buy a 2nd hand Golf GTD gearbox (020, 3.941 final drive, only 30 bucks lol), then I can mount up everything, starter, etc etc, and test it at home on the engine stand, so it works perfect. I'll use a new 210mm pressureplate & flywheel.

Then swap out the old engine & gearbox out in 1 go. Will salvage the old 020 for spare =)

Shopping list:
- Wiring loom ($75 for electronic throttle, n75, injection pump connector, cranskahft connector, injection sensor connector, map sensor connector)
- $20 for 1.5mm2 wiring
- Gearbox $20
- Engine $100
- Alternator, starter, battery: $50
- 210mm flywheel & plate $66
- Timing belt stuff $35
- Other stuff $50

+- 500$ total (Im in Europe so price in euro)

[RabbitJockey]

thats a good deal to have a running tdi. I'd want a taller final drive but i know sometimes its best to use what you have. Make sure your flywheel has the correct timing marks, sometimes aftermarket and gas flywheels dont have the correct tdc mark for a diesel.

[chi1337]

Thanks, will do. Want to do some checkups (for the engine running without oil, since this is the biggest risk as I see); turbo shaft seems fine.

1. Can I remove 1 camshaft cap, so I can inspect the cam scoring? I read somewhere, long time ago, that this would lead to unbalanced pressure on the camshaft, and possibly snap the camshaft

2. Any tests people suggest me to do while engine is on engine stand ? I'll do the compression test through the glowplug holes

3. What kind of seals should I replace; I’ll do the: rear main seal, front main seal, valve cover, new oil pan (steel + alu) with new RTV gasket, oil filter housing gasket. Don’t want the engine leaking oil

4. Other stuff I need to do? Ofcourse will do timingbelt, waterpump (I got one with alu impeller)

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Long story
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I recently bought an ALH engine in “unknown” condition. The engine turns over and gives heavy resistance (although not as much as my 1.6D) in the compression stroke, so that’s good.  I have looked around and made a plan to test it;

1. Remove glowplugs & boroscope internals (make sure no scoring on walls, crosshatching is there)

2. Do compression test, using impact on the crank
- I heard some people say it’s bad, but I’ll remove 3 out of 4 glowplugs), the crankshaft bolt can go to 200nm and my impact 150nm max

- Compression test is done while engine is on engine stand, so cold. Should give slightly lower results (as per my experience on the 1.6D), but:
-- Even when cold, the compression result should be above wear limit
-- Difference between cylinders should be 50psi or lower

3. Leakdown test (if compression test is bad)

4. Check cam caps

5. Remove oil from engine, check for shavings

6. Flip over engine, replace oilpan

[RabbitJockey]

1. Yeah, you can remove them individually no big deal

2. I don't think an impact will work for a compression test, but I guess it's worth a shot. I would pull the head, but that's up to you. it will allow you to really inspect the condition of the valves, bores, and rods. also, it would allow you to make a perfect TDC mark on your flywheel.

3&4 sounds like you have the right idea.

[chi1337]

Nice, I did some more digging. The top end looks really nice: https://imgur.com/a/T6S5QeN even after 200k miles.
The 2 outer caps were stuck and I didn't want to losen them up (probably under tension, dont want to snap things), but the middle 3 looks super nice.

Next up compression test

[ORCoaster]

I pull all the injectors out and do the compression test on one cylinder at a time.  Spins better that way.  I also have the diesel set that makes the perfect fit in the injector bore with all the proper spacers and keeps the volume the same, like an injector was in there.