Using a Mk3 Tdi lump in my van?

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mikes.bus
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Using a Mk3 Tdi lump in my van?

Post by mikes.bus »

At the moment my T25 has the painfully low 1.6 diesel lump and hopefully one of the jobs to do this winter is to replace that with something with a bit more oomph for next year. We also have a Mk3 Golf Tdi with only 110k on the clock. The mechanicals are good but, the car itself is getting very tired. In light of this, I'm thinking about using the engine in the van but have a couple of queries as I want the transplant to be as simple as possible!


I've been told/read that if I use the tdi lump, as is, there are a lot of electrics to deal with but, it is possible to remove the diesel pump and replace with a mechanical pump (?) which negates the need for all the electrics. Is this correct and if so, could someone please direct me to a thread as I'm struggling to find anything.


Secondly, the existing gearbox. I have the bog standard 4 speed box fitted at the moment. For me personally, speed isn't an issue. I'm quite happy to sit at 55-60 mph on the road, I just want a bit more oomph getting there and I don't want to be having to do 30 mph up hills which is the killer at the moment. Would my exisitng gearbox be ok or, should I look at getting a 5 spreed box?

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Garry2809
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Re: Using a Mk3 Tdi lump in my van?

Post by Garry2809 »

I’ll be following this thread with great interest. I’ve a t3 matkaaja built in Finland. It’s 2.5 tonnes in weight with the 1.6 td engine. The jx I believe. 40 to 45 is my best average. Hills are definitely a no go zone!! Any info for a simplified non ecu tdi swop would be most appreciated!
1986 T3 Matkaaja 1.6jx 5 speed

mikes.bus
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Re: Using a Mk3 Tdi lump in my van?

Post by mikes.bus »

Hopefully it will work out ok. The engine in my Golf is superb and for the age, very low miles. If I can get a simple fit, it makes a lot of sense!

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Garry2809
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Re: Using a Mk3 Tdi lump in my van?

Post by Garry2809 »

I did see a video on YouTube where someone used a cummins 4bt injector pump on one of them. A bit of work involved in it though...
1986 T3 Matkaaja 1.6jx 5 speed

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Garry2809
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Re: Using a Mk3 Tdi lump in my van?

Post by Garry2809 »

https://m.youtube.com/watch?v=6CWiPXq0RAE" onclick="window.open(this.href);return false;
1986 T3 Matkaaja 1.6jx 5 speed

mikes.bus
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Re: Using a Mk3 Tdi lump in my van?

Post by mikes.bus »

Interesting.
Is cummings a Land Rover unit as I'm sure that's what I was told was used as the mechanical pump?

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Garry2809
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Re: Using a Mk3 Tdi lump in my van?

Post by Garry2809 »

Cummins made engines for various trucks etc. Now people are putting them into land rovers!
1986 T3 Matkaaja 1.6jx 5 speed

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mrhutch
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Re: Using a Mk3 Tdi lump in my van?

Post by mrhutch »

Chap,
do some research into the differences between TDi and IDI engines.
The way they perform fuel injection is a paradigm shift, therefore pumps and injectors are massively different..

this is most apparent in the torque produced at rev range..

Think about it, you'll be doing 80 mph in a nice TDi or PD or CR diesel saloon car, in 5th or 6th gear, and the engine will be working at 2K-3K rpm max??

an IDI engine will be running at 4.5-5K rpm to give anywhere similar results..

Then apply this to rpm -> T3 gearboxes

make sense?
1981 Vanagon Westy Burning oil as fuel...  

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mrhutch
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Re: Using a Mk3 Tdi lump in my van?

Post by mrhutch »

there are some mechanical TDi pumps (Renault, land rover 200, 300 tdi's) but IMHO you're entering hybrid territory - do you want to be stuck in France (or further) needing an 'O' ring for a hybrid 1990's Renault traffic pump installed in a VW TDi motor?
1981 Vanagon Westy Burning oil as fuel...  

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volks_womble
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Re: Using a Mk3 Tdi lump in my van?

Post by volks_womble »

Firstly, you need to identify which engine is in your golf - the easiest way is to find the power output. If it is a genuine TDI it will be either 90 (engine codes 1Z or AHU) or 110 bhp (AFN). . The other option in a mk3 golf is that it is an IDI engine, with 74 bhp (AAZ).

The AAZ has very similar characteristics to the JX - which is the turbo version of your current motor. If you were starting from a JX the AAZ is almost a nuts and bolts job. As it is you are starting with the non-turbo motor, so you would still need to source some parts, and you would probably also still want to look at getting a TD gearbox (3H). These are all standard T25 parts though.

If it is a TDI, then the conversion does become more complicated. For me at least, the fuel pump is a non issue, as part of what makes the engines good is the electronically controlled pump. The electrics are not too difficult, and there are people who will take the original TDI loom and make it into a plug and play job for you. Changing to a mechanical pump is something I will leave others to advise on as I don’t think it is worthwhile.

Gearboxes and TDIs is a whole subject in itself. The standard 4-speed box you have will leave you very disappointed. The final drive ratio will mean that the engine will be revving very high to be doing normal road speeds. 4 speed vs 5 speed is a bit immaterial as the range doesn’t really change, you just get an extra gear in between bottom and top. To fix the final drive issue you could attempt to find a late petrol 5 speed box (AAP) but these are rare, expensive and still not ideal. The other option is to get a custom diff put into a 3H TD box, but this is also expensive. You would probably also want to change 5th gear ratio too in order to give yourself a decent cruising speed as the Rev range on the TDI is smaller.

The other option is to use an VAG 012 pattern 5 speed gearbox from a Passat or Audi A4 and turn it upside down. This gives you gear ratios that are really well suited to the engine, and well suited to the van if you get the right code gearbox (ie from an estate/avant I believe). There are however a number of other changes you need to make in order to accommodate the 012 box, as it is a cable shift mechanism. You will also need an adapter in order to make it bolt up upside down, and modify the engine mounts. Have a look at ultimate-engineering as they sell all the bits to do this. Also search here and the brickyard for ‘flipped Audi gearbox’ if you want a read.

I am personally in the early practical stages of a TDI (AFN) conversion on our van. (I am supposed to be pulling the engine from the donor sharan, not typing this...). I have chosen the route of a rebuilt 3H gearbox with modified ratios to match the engine (diff and 5th gear), and a custom wiring loom from to make it as factory looking, using VW parts as possible.

There are a number of other considerations around engine mounting, turbo positioning, intercooling, accelerator pedals, and exhausts to think about too. Don’t let it put you off though as these are all solveable.

HTH
Mark
1989 1.9TDI (AFN) California
1990 2.1MV Syncro Atlantic

mikes.bus
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Re: Using a Mk3 Tdi lump in my van?

Post by mikes.bus »

Mark, cheers for the info - it’s gratefully received!
I have an AHU engine according to the boot sticker so at least the engine looks like it’s useable if I decide to do it. The flipped gearbox sounds interesting and I’ll have a read!

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