Audi 80 B4 Overfinow Heater - 1 Zone - '93

Hello,

The reason for this is a timing belt replacement on a 1993 Audi 80 B4.

The open end of the camshaft has a 17mm ring wrench, the holes for pump adjustment align with my finger, and in the window of the clutch bell, I see the "0" without an exact line. So, I am already in the correct range.
"Don't worry, I will get the correct tool for adjusting it when I change it. Not a single screw on the timing belt pulleys has been loosened yet."

But where exactly is the precise OT marking, as I'm used to seeing from the AEL 2.5 5-cylinder engine?

Does adjusting the crankshaft alignment using the dowel pin of the pump adjustment suffice?

Does the pump timing or injection start need to be readjusted after replacing the timing belt?

Is a measurement with a dial gauge necessary, or is it also possible to measure the PWM signal to verify the adjustment range?

Greetings.

Andreas.

Andreas H. wrote:

But where exactly is the precise OT marking, as I'm used to seeing on the AEL 2.5 5-cylinder engine?

Simply adjust it so that the "0" is covered by half of the straight edge in the viewing window.

Andreas H. wrote:

Or is the adjustment of the crankshaft via the dowel pin of the pump alignment sufficient?

How is that supposed to work if the belt is broken/missing?

Andreas H. wrote:

Does the pump timing or injection start need to be adjusted again after replacing the timing belt?

Sure!

Andreas H. wrote:

Is adjustment with a dial indicator necessary, or is it also possible to measure the PWM signal and check the adjustment range?

Ideally, it's best to adjust it using a diagnostic tool, but the method of measuring voltage probably won't be much worse.

Hello wolfi_b,

Quote:

How is that supposed to work if the belt is down?

That would have been the lazy way to do it. Disconnect the pump, assuming that the camshaft (KW) will then be in the correct position (OT - Top Dead Center). Carefully remove the belt and make sure not to rotate the camshaft. Put the new belt on, assuming that the new belt length from the camshaft sprocket to the pump pulley is exactly the same. The injection timing should then be correct. But it's really not a verschandeln or reliable way to do it.

So, it's better to work cleanly after all. Use a torque wrench on the crankshaft bolt, and use a ruler in the camshaft groove to ensure the camshaft is properly aligned with the crankshaft. Then, pre-adjust the pump using a mandrel.

However, the timing setting of the camshaft using the "half-zero" mark on the housing edge seems imprecise compared to the feeler gauge measurements taken at the notch in the camshaft.

Estimate reading errors of +2mm arc length at the "half zero" and estimated swing diameter of 300mm; is this an adjustment error +0.78° KW angle?

The JX 1.6 swirl chamber made of T3 also features precise markings on the flywheel and an arrow-shaped protrusion on the housing.

Let's see if the engine is revving too high and check if there are any other markings on the flywheel, specifically around the "1Z" mark, and also examine the lower part of the housing for any additional protrusions or features.

Regards,


AndreasH.

Hello Andreas,
For manual transmissions, the crankshaft with cylinder 1 must be at Top Dead Center (TDC) when the "0" mark is precisely aligned with the reference edge on the transmission housing. For automatic transmissions, the "0" mark must be centered directly below the reference edge.
(at least that's the case for the Audi 80 B4 with engine code 1Z, manufactured in May 1994).
It's best to get the original repair manual. (https://erwin.audi.com/erwin/showHome.do). The purchase is worthwhile.)
You can initially adjust the injection pump using a measuring gauge (approximately 0.65mm at TDC), but your adapter must have the correct thread for the VP37 (this can be checked with a spare part blind screw). There are different adapters available. A dynamic test/adjustment using VAG-COM is better.

Best regards,
Herbert.
Audi 80 Avant, model 1Z, manual transmission, 298,000 km.

Hello,

Timing belt has been replaced.

I couldn't find a second marking on the flywheel, and there isn't any other opening that would allow a clear view of the flywheel. So, I had to settle for zero.

But the issue with the zero marking for the timing mark on the flywheel becomes clear once you start working on it.

If you have any questions, please feel free to contact us.

Greetings.


Andreas H.