Just noted in a discussion was going on via the Yahoo group.
Here is one minor difference between the syncro and 2wd engine - the dipstick.
Apparently the lower mark sits higher in a syncro to ensure there is enough oil for severe angles when off-roading:
Great info Scott
Makes you wonder. Is this attention to detail from VW, or is it a bandaid fix for a motor not intended for off road
The syncro is definitely a hybrid vehicle as it was designed originally as a 2wd and the 4wd system added by another vehicle builder so its understandable that you get these little yet fairly well engineered changes.
I like the extra seals and cooling system changes which I am sure were designed to keep the engine alive in the more extreme conditions it will get during off-roading.
This is required because they don’t have a normal sump.
Was looking at distributors, I have part number 025 905 205 M on my (MV) engine. But I see there was a part 025 905 205 AC listed for the same years (86-91).
Would anyone know where you can see what was different between the two? (are they interchangeable?)
And I know the answer may be obvious, but is the distributor off a 1.9L (025 905 205 D) any use on a 2.1? (I’m not sure if they have a hall sender?)
1.9 distributor will not work on a 2.1. The 2.1 has the advance controlled by the ECU. The 1.9 has the advance built into the distributor but still has a Hall sensor.
Do you have a 1.9 distributor?
Thanks Phil, no I have a 2.1 MV, am chasing spares, when I looked up the number on the distributor I was offered, I saw it’s for a 1.9.
Are you still after a syncro distributor? I have a lot of parts for sale.
I had a 2WD and Syncro motor side by side and took a few notes on differences.
So not an in-depth list, but certainly a lot of changes that are easy to pick.
The changes are primarily to compensate for the engine sitting 60mm lower in a Syncro relative to the body.
Rear engine support (Moustache bar), bar same shape/profile, brackets on the ends are 60mm taller.
Tinware above muffler (what expansion bottle sits on) is 60mm taller to compensate for engine being lowered.
dip stick, as noted above, lower mark is 8mm higher.
Thermostat housing is different to accommodate different coolant pipe routing above engine, essentially turned 90 degrees (due to Syncro fuel tank). The pipe/hose from water pump to thermostat housing is the same. The Syncro also has a different temperature sender (for ECU)
Coolant pipes above flywheel on Syncro (not there on 2WD)
Air flow meter to throttle body bellows is 60mm taller in a Syncro.
Rubber air hose/pipe from idle control valve to intake bellow is longer.
EFI fuel supply (feed line from pump) is routed to the left of engine in a Syncro.
Coolant hose (RH head to pipes over flywheel) different to 2WD.
All bleed hoses (to ring main in engine bay) are longer.
Oil fill pipe bent up higher on Syncro.
Oil dip stick tube, as above, bent up further.
The pulley seal is also different for off road use.
The exhaust, as best I can tell Syncro and 2WD systems are the same with the exception of pipe at the front of the engine (under flywheel). This pipe goes from No 1/3 cylinders to the junction on the LHS of the motor. This pipe is slightly closer to the engine case, and also has two kinks either side of the flywheel to clear the bars running under the engine on a Syncro.
the pipes from No 2/4 Cylinders to the junction on the left, and from the junction to the catalytic converter/muffler all look the same. (I think the Syncro had a different tail pipe out of the muffler originally)
I am sure there is more, but these are the obvious ones. Some are not really significant, but others like exhaust, engine mount etc are critical to swap engines over.
Anyway, hope this helps.
Thats an extensive list - some of which I had forgotten about - particularly the oil dip stick and filler tube - both need to accommodate the lower set engine.
You could still use a 2wd engine and swap into a syncro yet you would need a syncro engine to be able to swap over the essential items.
I am surprised the 2wd and syncro have a different Temp 2 sensor - is this due to the thermostat housing design and a screw in instead of press-in/ clip system or does the syncro need a different signal to its ECU?
Great write up though!
Yes, quite a list and am sure there are more that I have missed.
No idea why the temp sender was changed, but yes, it’s due to the socket in the thermostat housing, and yes both temp senders have a different connector.
From memory the manual does not differentiate the output of each, so am guessing from the ECU’s perspective they are the same.
You could easily get away with not changing much of that, eg the tinware over the muffler would be easy to extend and re-attach to the body and keep the 2WD filler etc. Not a big deal and would make changing the water pump and oil pressure switch easier!
Just on the changes, I never realised just how different a diesel was. The starter motor sits on top of the bell housing. So this part of the housing is unique (in addition to different crown wheel and pinion).
I am guessing this means the fuel tank must also be different?
Yes, the diesel tank is different again.
All diesels - 2wd and 4wd have the different bellhousing. But 2wd doesnt matter as the tank is up the front…as you know but still - I agree - there are so many variants in a T3 - possibly another reason why they turned them into a Japanese style van in the T4 design - much more consistent…
The T3 was the end of an era for VW, but there are still many variations in the T4, T5 with different wheel bases, van, kombi, caravelle, dual/single cab, different engine and gear boxes, syncro and 4 motion etc. I think the variations were still there.
The T3 had all those too - just the body become like all modern vans with front mounted front wheel drive set-up. VW still had the syncro in a T4 which later became the 4 motion but no where near the complexity of the T3 variations.