Leon Speed

First time I´ve run into s problem I can´t immediately fix since starting my top-end and timing belt refresh.

I´ve put a new timing belt on, together with a new pump, new oil pump gear, recoated sprockets, refreshed tensioner, new pulleys, new bushings.

Issue 1: the timing belt seems to be tracking towards the front instead of in the middle. I know this is common, but I am a bit worried about tracking on the tensioner pulley. The belt runs right on the edge of the pulley. The pulley is 30 mm wide, the belt 26 mm. So the belt offset by 2 mm. I can't see why the belt is not running in the middle of the pulley. There's no rubbing on the inside of the tensioner arm, but I am worried that there is more rubbing on the front crank gear guide plate than necessary. See pics attached.

Issue 2: there is less tension on the belt at TDC on cylinder 1 than at TDC on cylinder 6. When I set the belt tension in the upper window of the Kempf tool at TDC on cylinder 1 and rotate the crank a few times, the tension at TDC on cylinder 6 is outside the window. Sometimes by half a window length, sometimes by a whole window length. Why is that??

PorKen

1.) 2-3 mm from the front of the gear is 'standard'. (more info)

2.) The difference in valve spring pressure between #1 and #6 applies different levels of tension to the belt.*

#1 is used for the WSM spec.


Measured with the 32V'r, you may find up to a 2° difference between #1, and #6.


*The measurement is actually the inverse of what you are seeing.
There is more valve spring pressure at #1 so the belt is stretched more (higher actual tension) between the crank, oil pump, 5-8 and 1-4 gears.
Extra belt at the tensioner pulley created by the stretched belt on the pulled side means less tension is observed on the slack side.
Because the stock tensioner system cannot expand to compensate for extra belt.

Leon Speed

Allright!! So no issues then!

Thanks for the post, 'good' to see even in the WSM the belt is tracking to the front. It is weird to see though.

Regarding the tension, I understand! In your bump stick manual it says 1-4 tries to move ccw and 5-8 cw. That stretches the belt between the cams and causes slack between cam 1-4 and the crank.

Btw your stuff rules..! The 32Vr and Bump stick are pure works of genius.

Bilal928S4

Whose recoated gears are you using? Price?

Calgary Ole

Mine runs about the same location. Have hit many thousand RPM without worry.

Bill Ball

It looks like you haven't yet installed the dampner, crank pulleys and crank bolt. It may settle a bit further back after it is assembled and run a bit. There may be a slight bias to the belt. There even was a bulletin in the late 80s that the belt should be installed so you can read the lettering from the front of the motor. I was dumbstruck when I saw that bulletin. My lord, if that were important why not put a direction of rotation arrow on the stupid thing? I ran 60K miles with one of my belts "backwards" according to this and I could see no issue with it at all.

Leon Speed

Colin (Lizard) coated them for me.

Good to know, thanks.

Why was that Bill? Was it because of tracking or because it was easier to read

Bill Ball

Here, read it for yourself. We can only guess. I've never seen the lime green insert either, even with belts acquired from Porsche.

Leon Speed

Right, that only leaves to guess. But, naturally, we follow suit and install the belt with letters to the front