Tdi into T25

[Vento James]

Firstly I'm new to this forum, so hello my name is James

I currently own a '97 Vento Tdi GL, it has a good engine which is very economical (you can probably see where this is going)



I've been interested in campers vans for over a year, since meeting a friend who is an enthusiast.

Having accepted that a split screen and bay are out of my budget, I have taken to the thought of a T25.

I have been considering purchasing a T25 1.6Td and swapping in the Tdi (AHU) engine and all other parts required from the Vento on a budget.

I've been searching this and other forums on the topic a lot but haven't been able to find anything definite on the subject. I have read the wiki, searched 'tdi' across the forum and tried the 'read this first' link but it doesn't work.

Many posters views have been that it's fairly complicated and therefore expensive so use a MTdi or 1.9D conversion. I can understand these options and they are a good choice but that's not the answer I'm looking for.

As I see it (through searching and not factually), the main issue and most expense will be for the gearbox. I presume that I need to use the 1.6Td box and bell housing, however the gearing is inadequate and the Tdi will munch through it soon enough.

My questions are:

Will it simply be a case of using the Tdi internals inside the 1.6Td casing or is there much more to it? If I supplied the two gearboxes to a specialist to create a hybrid box, could the costs be kept down and would it be strong enough.

Another question is about the angle of the engine, does tilting the Tdi at a greater angle than originally fitted cause any oil starvation problems? If so, what can be a solution.

Any information regarding these questions and also more infomation would be greatly appreciated, I know that this type of subject comes up all of the time but I have searched with no form of enlightenment.

Regards James.

[Aidan]

Decide on your tyres long term size then start with what you've got. But ideally you're going to want to put a long fifth gear on a petrol 5 speed 2.1 4.57fd box or put a longer third and fourth on a 4 speed again find a 4.57 box to start with, hybrid clutch with standard diesel input shaft. If you've got a 4.83/6 ratio box and it's a good one then use that and accept the lower top speed compromise.
Finding a good 5 speed to rebuild isn't easy ime
There's no reason not to fit the engine you've got and run it electronically but you've either got to mount it at vento angle and sort the bellhousing and the engine lid or you run it at t25 angle and sort the turbo angle and oil feed and inlet pipework, basically that is

[Vento James]

Thank for that information Aidan, very informative indeed.

So I guess that the standard T25 box is able to handle the extra torque/power and it's just a case of economical gear ratios.

I would prefer to keep the engine at its designed angle, so some kind of bell housing adapter needs to be fabricated.

This gives me more to think about

James.

[moonshine]

James, the tdi engine mounted as the Td is fine, I've heard people have "runaway" where the engine runs off on its own oil, but its never happened to mine, and there are precautions (oil catch tanks).

If you do this conversion properly (which may mean sometimes stretching that budget) you'll have a satisfactory outcome.
I drove my already tdi'd bus back from Germany in 2005, and although it ran almost completely without incident, it was decided that it had the potential to be a time bomb, so it was taken out an redone.

You must be good with electrics, (or be able to do them to a good standard), as so much relies on electrics even on first generation tdi's.
You really need to afford a taller 5th gear,a half decent long legged petrol box for rebuild and the cost of such a build. ^Aidans the man to do that part. Even then you're probably looking at 90mph top end, and thats a bit buzzy as the tdi vibrates through the td engine rubbers quite a bit.
You'll probably feel like you've married the bloody thing, laying awake at night thinking of new places/options for the intercooler to go...how to make it quiet.....wondering why its not like driving the Vento it came out of etc.....

budget and tdi don't really go together. Maybe 1Y is the answer if you're counting pennies.

Still its good when done, and since redoing mine, asides from stupidly trying biodiesel in it, there's been no incidents to report whatsoever.That includes 2500 miles round France in it, and being my daily driver.

[HarryMann]

I would prefer to keep the engine at its designed angle, so some kind of bell housing adapter needs to be fabricated.

Don't forget the engine lid height implications.. unless its a Doka or Sika you're wanting

[Vento James]

Again great reply, much appreciated

I'll look into mounting it as originally positioned in the T25 then; it does seem like an easier option. I was just a little bit worried about oil starvation.

I'm fairly confident with electrics, it'll take some time to get my head around but do-able with a couple of manuals and a soldering iron.

The main expense seems to still be the gearbox. I've taken a couple of gearboxes apart in college but I'm not sure how difficult transferring gears and the like would be. Probably best left to the professionals though and that's when the budget goes! As you mentioned, another option is to keep it simple with a 1.9Td for my entry into the camper game. I just love the tdi economy, especially as it'd be a daily driver.

Thanks, James.

[HarryMann]

Some more things:

The upright can perhaps be a better overall installation, but with the proviso above as well as the time and cost of getting/making the right parts.

If you decide to cant it JX fashion at 50 degrees you'll need the JX turbo sump, engine carrier bars (2WD) and (suggest new) rubber mounts and still have to think about the turbo and exhaust positioning relative to the l/h engine mount. The final exhaust pipe and silencer can be done in stainless throughout fairly easily, at some cost, or a JX one modified cheaply.

Everything needs thinking thorugh from the options on air-cleaner and intercooler. Air/air with fan or water/air with pump (and maybe fan).

The canted arrangement does not like an engine that breathes heavily or has a turbo with bad seals or bearngs... if these are OK then a normal oil level is OK with the JX sump. An oil cooler up front doesn't go amiss, as it adds some capacity above the usual 4.5 litres but a good intercooler arrangement is probably the main thing to get right... efficient cooling but above all robust pipework.

I think they give at least 5mpg more than a 1.9 TD .

[Vento James]

Cheers for the continued information HarryMann,

I guess the turbo could be repositioned with an adapter off of the manifold, as some exhaust system would probably have to be fabricated any way. Still do-able with a budget, it seems like mounting at 1.6TD angle is the easiest option now.

I've been reading through a post that mentioned about Porsche gearboxes. Anybody know if they are a fairly direct fit (if cable operated)?

Regards, James.

[HarryMann]

I really would stick with the 4-speed T25 box, or the 5-speed with a full rebuild specifically for Tdi use. If you want to pursue a Porsche box option, you might run it past a few on here. Simon Baxter or Mike Ghia on Brickyard could probably give you an idea of cost/complexity .

[futbus]

Alot of Tdi`s have a different engine mount bolt pattern to the JX so your`ll have to make at least the nearside one. We are developing a setup at the moment as we are fitting a 150 pd setup for a customer.