AAZ conversion - a few questions.

[garyd]

Ok, I now have an AAZ engine (95 Passat, supposedly) and have compared it with my JX and all the advice I have found here and at Brickyard. A couple of questions remain so is anyone able to help with the following, please?

1) The recommendation seems to be to use the JX exhaust manifold and either turbo. I didn't get an AAZ turbo so will go with the JX one. It would be nice to use the JX inlet manifold too but it appears that this does not properly align with the ports in the head - have I got that right? Simon Baxter's notes suggest that opening the manifold ports to match leaves the walls too thin - therefore I should go with the AAZ inlet manifold.

With this set up I would 'loose' both the EGR (exhaust gas recirculation) from the AAZ and the air dump valve from the JX. Are either of these critical or will it work properly without both? I presume that the dump valve prevents over pressure in the manifold when you suddenly reduce the fueling (foot off the pedal)?

2) I picked up somewhere a recommendation to swap the JX throttle lever onto the AAZ injection pump in order to get the right amount of travel - ie to match it to the throttle pedal. Can anyone please confirm that they have done this and it works OK?

3) Is the timing belt tensioner/ adjuster on the AAZ a service replacement item? Does it need to be changed with the belt?

4) Which crankshaft spigot bearing should be used - AAZ or JX? Or are they the same?

5) My manual suggests that there should be tinplate heatshields above and below the exhaust manifold plus a pipe to deliver cool air onto the turbo. My JX has none of these. Are they considered critical?

6) I understand the the air filter has to be re-located into the void behind the n/s/r lamp unit. It looks like I will need an elbow to join the existing incoming pipe into the side of the filter housing. Any suggestions on a source for this, please?

thanks for any help
Gary

[vantheman]

I have experienced the same problems albeit with a Seat Ibiza doner
engine.

I used the AAZ turbo but with the JX manifold. You can relieve the
ports slightly at the corners to help gas flow without compromising wall thickness.

Lose the EGR and air dump valve.

Change the throttle lever over to the original JX one. You will need to attach the cable to a point much closer to the spindle to get enough travel. I also eliminated the original spring as this was too strong and replaced it with a simple expansion one. This set up still gave me too little throttle travel and in the end I had to increase the lever length of the crank under the throttle pedal

Always change the tensioner at the same time as the cam belt


Use the JX spigot bearing

I reused the JX heat shield plates (another reason for using the JX manifold) but have no knowledge of a system for blowing air onto the turbo.

Using the JX exhaust manifold means that that the Air filter can still be used in its original position .

I modified the pipe from the cam cover to the Oil Separator to raise the separator so it just fouled the engine cover to avoid oil surge to the Turbo when cornering hard.

Best of luck with your conversion

Vantheman

1.9 TD Panel Van /camper conversion

[HarryMann]

Gary , the modified inlet manifold for the AAZ is here as well as the dipstick - vital!


http://wiki.80-90.co.uk/index.php/Alter ... ine_1.9tdi

If you block the BOV (I used a a wine bottle cork), then ensure the wastegate is operational (see Turbo section on rebuilding and testing)

Heat shields do help, the turbo compressor is very close the the red-hot exhaust manifold, and generally VW decided they were needed though many run without them if it's a hassle (see linkl above, am making stainless ones now, so more info on its way). Andy McClements says they are not a lot of dosh OEM, but need 2 ior 3 depending on year?

Importnat you consider the Oil separator, good advice above, extend the outlet higher, or use a seperator bottle.. Biggest danger is picking up oil and running on it - oil level, and maybe breathing issues... won't last long if it does, so on right hand climbing turns lift off abit until you know the limits

Oil level critical and dipstick calibration so read the link above. Don't have to do the inlet manifold mod straight away, can run without of course.

Just think 'cool' inlet air right through system...

2 critical things - Oil temperature /oil pressure (surge), see Simon Baxters recommendation of correct JX pump pickup... as low as poss in sump.

Careful tightening sequence on ally sump, use torque wrench and use JX set-screws not AAZs, don't tigten bellhousing through bolts till sump set-screws all nipped up !!!

More later but def. good advice from VanTheMan

[garyd]

Thanks for the detailed responses guys. May I seek some further clarification, please?

Both of you make comments which suggest that the dump valve is not critical and can be removed - am I reading that right?

Van's comment 'Using the JX exhaust manifold means that that the Air filter can still be used in its original position' . I presume this only applies if you also use the JX inlet manifold or a long loop of hose around the back of the filter/head to connect turbo to inlet?

I guess that repositioning the cam cover breather to the highest side (rather than the top of the upright engine) would also reduce the chances of it being affected by oil surge?

Whats the position with these stainless heat shields then HarryMann? How soon & how much? Are you familiar with the blower system to cool the turbo - is it a syncro thing?

Your reference to Simon B - are there more than one JX oil pick pipe designs?

thanks again
Gary

[HarryMann]

Gary,

Glad you've found an engine, but sorry I am too busy to get over to help at the mo'

Both of you make comments which suggest that the dump valve is not critical and can be removed - am I reading that right?

It's set to about 12psi and is a safety valve if the wastegate sticks or malfunctions - no need to touch it unless overboosting. Otherwise, above 12psi it obviously would limit the boost. Std wastegate setting of JX turbo about 7.5psi, think AAZ runs more like 9-10psi but am not sure of that. Can bleed easily to give 12~15psi, but fuel setting really needs upping - suggest you stick to std. for initial period - see how she goes.

Van's comment 'Using the JX exhaust manifold means that that the Air filter can still be used in its original position' . I presume this only applies if you also use the JX inlet manifold or a long loop of hose around the back of the filter/head to connect turbo to inlet?

Yes, the JX inlet manifold allows the JX short hose to the turbo (suitably encased in an aluminium concertina pipe for insulation) - it runs very close to exhaust manifold, even if heat-shields are fitted still a good idea.

I guess that repositioning the cam cover breather to the highest side (rather than the top of the upright engine) would also reduce the chances of it being affected by oil surge?

Not sure if it cab be re-positioned, wonder why they put it that way a round unless for clearnace space considerations then - maybe it connects up to the block breather hose better like that. Ideally, a separator bottle could be used, but if you can turn it a round 180 deg. then hey ho, let us know

Whats the position with these stainless heat shields then HarryMann? How soon & how much? Are you familiar with the blower system to cool the turbo - is it a syncro thing?

The position is I'm making another set for someone else at the mo, as well as a host of other things, so making you a set wouldn't be before Coney Farm but maybe a week after at the earliest...

Your reference to Simon B - are there more than one JX oil pick pipe designs?

Apparently, I forget what he called the pump from GSF (they do more than one) but was of Mexican origin ? The post is still in the Alt Engines somewhere, will have a look tonight... he fitted the sump and found by looking thro' the drain hole that it was very close to the bottom, considered better...

Another consideration is whether to re- fit the 'windage' tray (and combined sump gasket) - most seem to say not...

Turbo cooling fan and pipework - def found on Syncros, dunno about 2WDs, think its relayed to come on with the auxiliary electric water pump, with same relay, pretty sure this is after turnibng off, to keep centre turbo bearing cool during spin-down and thereafter so heat-soak doesn't carbonise oil within turbo. I should think most have long since packed up or been thrown away, fan behind l/h taillight with relay box, pipe and wedge shaped nozzle aimed at turbo's central bearing housing.

[syncroandy]

TD exhaust manifold shields:

Upper shield 068 253 283 13.76
Lower shield 068 253 283 13.76

From chassis no. F24-H-000001, a third shield that goes over the other two:

068 253 283 C 21.98

The shields fix to the manifold using four M8 studs. They are just bits of pressed steel, which you could make up if you had something suitable lying about. I have a template I can email on request.

The convoluted insulating shield that goes over the turbo-inlet manifold pressure hose is 068 145 627, and really silly price for what it is. I used an old piece of heatshield material from an A2 car, which proects one of main looms running across the bulkhead just above the manifold.

I believe the turbo cooling fan is Syncro-specific.

[HarryMann]

That's all good extra info from Andy..

Just the one thing, is making some up, as they're not all flat sheet, have curves in 2 planes (not just straight folds) and are really press-work. I've compromised a bit with mine, and think I've got a reasonable result, which sits fairly close and gives just about enough access to the manifold bolts. If they're not too dear then buying some would save a good few hours work unless you have the kit to do sheet-metal work or want to wait a goodly while.

[Simon Baxter]

The oil pump is a Shadek Item, looks slightly different to OEM but the actual pick up is mounted lower in the sump, so less chance of oil surge.

Separate oil breather tank is good idea, as noted it cures the chance of it running on it's own oil doing right handers.

Windage tray doesn't really fit with the oil pump design of the JX without removing most of it, then removing the useful effect you gain from fitting it, then the sump mounts lower so the gearbox to engine mounting bolts don't fit, so just leave it off.

JX inlet manifold has different shape ports to TDI/AAZ/SDI etc.. if you "Match port" a JX inlet then they end up thin as f**k, not worth risking IMHO.

BOV (Blow Off Valve) was no fitted to AAZ, no real need for it.

JX airbox will have to be relocated behind the left hand rear light with the AAZ inlet manifold, no big deal.

Spigot shaft bearing - Use JX item.

Only Syncro 1.6TD models have turbo coolers, not 2WD. Won't fit in the OE place if relocating the airbox behind back light.

Use 1.6TD alternator and belts if you have a rev counter as it seems that the AAZ style set up messes with the speed readings as the alternator turns at different speeds, not asomething I have come accross myself as the ones I have left the AAZ set up have had no rev counter, the ones that have had revcounters have had 1.6TD belts! just flukey that I think!

Get it in, get it running, shake it down before you start messing with the pump, turbo etc..

[HarryMann]

Thanks Simon, Shadek, must train ny brain

JX inlet manifold has different shape ports to TDI/AAZ/SDI etc.. if you "Match port" a JX inlet then they end up thin as f**k, not worth risking IMHO.

Unless you do this with loads and loads of JB weld (and yet to be tested in anger) !

[Simon Baxter]

It's thin isn't it!
I would prefer mine with a tad more meat and not full of glue, but thats me.
I suppose it could be welded, shaped and then skimmed but it's a lot of messing when the AAZ inlet fits and works with much less work and more reliably (in my eyes)

[HarryMann]

Yes, thin, No. 3 very thin!

Think it will hold up though, almost 2 packs of JB weld, wants to run away from the job.

[garyd]

Thanks again for all the good info. When I have reached what seems to be the generally agreed consensus on all the details I have thought of, I shall post it up for further comment or things I have missed.

On the question of the turbo running on oil - there seems to be two possible causes that I have been advised of. At one end I have been told that it is a failure to drain the turbo bearing lubricant due to the hose being connected into the AAZ block port rather than the JX sump port. I can see that the couple of extra inches of fall could make a significant difference. This would require the turbo oil seal to be passing oil though, wouldn't it?

The above responses, however, are concentrating on a build-up of oil in the cam-case being sucked through the breather into the inlet manifold - a much more direct route. Given the cant of the T25 installation, a right hand turn would throw oil into the left side of the cam-case where the breather is located. This effect is heightened by the left side also being the low side of engine now. I wonder whether a new hole can be cut in the cam-case on the high/right side to raise the breather up a bit. Until the engine is fitted in I wont know how much space there is for this.

Any thoughts?
Gary

[HarryMann]

I can see that the couple of extra inches of fall could make a significant difference. This would require the turbo oil seal to be passing oil though, wouldn't it?

2" would make a significant difference. The general turbo installation guidelines for aftermarket trubos is that the return feed should be above the oil level. It's not just that the oil can't get out under additional roll to port + cornering 'G' forces, being belwo the oil level it is effectively being pushed back up a bit perhaps... regardless, if the oil level in the turbos main bearing housing fills up? The seals are designed to work in an environment where the housing is being fully drained, not a flooded one.

There would be room on a Doka for sure to move the vent to the top-side.

I certainly don't know which is the culprit, or if its both even.

But the fact that on nominally upright installs, FWD VWs with E-W installs, I've heard that they can still do this, and separator bottles have been used, make sme think that aspect is certianly not to be ruled out. They may not do it when new, which would suggest it alos a function of blowby and oil burn, the oil building up somewhere in the nlet tract to accrn/declrn or cornering tips it into the turbo inlet.

[Simon Baxter]

http://cgi.ebay.co.uk/STAINLESS-Oil-Cat ... dZViewItem

[HarryMann]

OoOoOoOoOh Nice!

Price