T25: Cost/Benefit of 1.9 AAZ or 1.9 TDI engine replacement

[davesm]

Hi All,

I am sure this has no doubt been done to death but I'm hoping someone can explain in noddy's terms the cost/benefits of replacing a 1.6 JX TD engine in a VW LHD T25 'G' plate Westfalia California (which I am in the process of buying) with either a 1.9 TD AAZ or 1.6 TDI AHU engine.

I will be keeping the van for the long haul and it will be an on-going project i.e. not much up front cash to get things sorted but I will have things done properly. I also have no technical/mechancial ability to do things myself other than basic stuff.Asking and reading around it appears that the TDI engine is the one to go for in terms of performance, economy, the downside being that the gearbox has to be altered and the quote I've had for that off a reputable chap is ~£1800. There is someone I know who will sort the electronics side of things so that won't be a major cost. I have an option of buying a donor car for not a huge amount of pennies either.

Replacing the original engine with an AAZ engine am I right in thinking that the gearbox does not have to be altered thus saving me a substantial amount of cash? Therefore the cost of doing this replacement is a lot less.

So my question is:

Will installing the TDI engine with the associated extra cost but with improved performance (by which I meand cruise happily at 65-70 on the motorway and climb hills without being asthmatic), economy and hopefully relability give me a profound benefit over installing the 1.9 TD AAZ with less installation cost? Basically, will I notice a material difference when driving the van?

Apologies if I am rehashing an old debate but I want to be clear in my mind about things before I commit to one or the other.

Many thanks.

[scimdiesel]

Costs.... Thats to open ended question. £4k to £4

If your JX motor is sick the AAZ is a good replacement. If its not, the difference may not be worth the sweat. Finding a good AAZ is not easy anymore. If your JX is in good condition your not going to gain much. The shorter stroke of the JX might make it more revy than the AAZ?????

AAZ's suffer with the timing pully falling a apart which leads to death. They are all old! Its an easy install but still lots of messing about. Also they really need an expensive Brickwerks oil cooler or the oil gets super hot. Also you need to be sure you get one with a good injector pump. Some don't give extra fueling to utilise the turbo. You have to make a hump in the engine cover to clear the Injection pump. The turbo needs clocking to allow the oil to escape the turbo. Most of the work is nut and bolt stuff.

1Z/AHU TDI these are the early 90 bhp ones, easy install. Engine mount to make on the near side. Mechanically fairly straight forward install. There's an ECU, loom, etc which could be troublesome if your not that way inclined, You can get a loom modded to fit your van. Intercooler/ charge cooler needed, 30% more torque than the AAZ. To make use of the torque an re-geared box is nice and is the icing on the cake but not as essential as people suggest. It is best to use the TDI clutch and change the output shaft in the box

I've used AAZ with 5 speed petrol box code ABN, AHU tdi with same box and clutch, and then upgraded the box which was the original plan before i got the TDI bug.

A good AAZ is dependable and simple but when your driving you need to keep the revs up if you want some performance and I always felt I was pushing it quite hard. Probably like a 1.6 TD. The TDI with the same box was a very easy drive and was just as happy to be reving as the AAZ. Just because of the extra torque it felt like it could use an extra gear more. The JX clutch did not slip as suggested it might do. The AAZ has the potential to go faster than TDI due to its higher rev limit but its unlikely to get there anyway. The TDI with the improved final drive is lovely to drive. A roads and monster hills the engine never feels stressed. It just feels easy. Its no Grand tourer still.

There is the AFN 1.9 tdi 110 bhp, this has a variable vain turbo. More power, more torque. There's a bit more work / finding the correct parts to get the turbo draining well. I can't comment on there performance I've never been in one. I suggest there cruising speed is much like the 90 bhp engines. since this is down to gearing,

Your desire to cruise at 75-80 maybe optimistic, people on here claim amazing cruise speeds. I have to much mechanical sympathy and I like my MPG to much, I define cruising as a comfortable speed where everything quiet and peaceful, not a maximum maintainable speed. If your a little mutton jeff and don't feel the pain then your fine. Don't forget its almost 2 tons and shaped like a brick its no recipe for motorway cruising.


My AAZ did 35-38 mpg and I would follow the trucks on the motorway (sat naff 56). My balls would wither from time to time as some lorries would out pull me on the hills. Peski Scania 480's and 520's

now..I get 37- 42 mpg normally 39 from my AHU tdi, poptop loaded up but I cruise at a very relaxed Satnaf 60mph which i do up and down most hills, I generally don't abuse it. It will go fly along, but I can't hear the conversation in the rear then, and the MPG would drop off.

[keith]

In short a 1.9 tdi ahu or afn is a completely different animal to a 1.6jx or a 1.9 aaz.

I personally think you need to factor a grand for a rebuilt and longer gearbox to get the relaxed cruise at 65 to 70.

Weve just done a two week tour of mid, west and south wales and the van storms anything you can throw at it.
The previous jx was ok......but agricultural in comparison.

[davesm]

Hi, thanks for the in depth reply and following on from what you have said and from speaking to other people I am convinced that the 1.9 TDI is the way forward. The issue is the gearbox so the options are the original box reconditioned and altered or perhaps go down the flipped gear box or 2.1 petrol gear box. I won't be doing the work myself as I am truly hopeless with a spanner! We live in rural mid-Wales so having a bit of power for the hills is a prerequisite and I don't want to cruise on the motorway at 75-80, more like 65-70!

Keith, whereabouts were you in mid Wales? We are Aberystwyth way.

[Twodogs]

Hi,
I had a 1.9 TDi put in my Westy Hitop by Tim Shettle in Bristol.
It is great, it was expensive @ £4K, but for that I got 110 bhp & 5 gears as Tim used the gearbox out of the donor vehicle.

I spent a large part of last year driving through Europe and averaged 40 mpg over 19000 miles.

Good luck with it.