[Vwdiesel] 1980 vw diesel timing belt broken when trying to start

[Libbybapa at wmconnect.com]

Loren's answers were all correct, but sometimes it is helpful to have another 
wording, so here goes.

In a message dated 6/22/06 5:27:55 PM US Mountain Standard Time, 
tolbert192 at hotmail.com writes:


> Not clear on a couple of areas;
> 
> Since cylinder #1 is the one near the gears, (closest to the fender on the 
> passenger side) besides the TDC mark on the flywheel,
> should the offset of the camshaft be pointing down when at TDC?
> 

There are eight cam lobes that are offset and they will all be facing in 
different directions.  The timing mark is a cutout through the center of the end 
of the cam.  It is not offset.

When the flywheel mark "0" is in line with the pointer, the *slot* in the 
rear of the cam should be parallel with the valve cover sealing surface of the 
head.  The two lobes of the #1 cylinder should be up and away from the center of 
the cam like rabbit ears.

> Since the engine rotates clockwise when standing behind the timing mark 
> opening
> on the transaxle, then to start rotating the engine to get to TDC, the bolt 
> on the crankshaft sprocket must be turned counter-clockwise, which opens the 
> door to loosen the crankshaft sprocket bolt. How does one overcome this 
> problem?
> 

The engine rotates clockwise while looking at the crank bolt.  Hand rotating 
of the crank by use of a wrench on that bolt will *tighten* it when you are 
turning the crank in the direction that it normally rotates.

> I also read that to rotate the engine, can cause damage to the camshaft, 
> bend valves, damage pistons.
> 
> The above implies that to reduce the amount of damage, the camshaft assembly 
> should be removed, but I can find no documentation to that effect.
> 

I would personally remove the cam by loosening the bearing caps.  Then the 
crank can easily be placed at TDC.  Then the cam can be laid in place with the 
lobes pointing in the right directions.  The pump can be turned by hand until 
the mark on the pulley lines up with the mark on the bracket and pinned.  

****Loosening the cam bolt should NOT be done by holding the cam by the 
timing slot.  The pulley should be held by a pulley holder or some other adequate 
contraption and the bolt loosened and tightened thusly.  Holding the cam while 
tightening or especially loosening the bolt will often (and I mean quite 
often) break half of the back of the cam off.****

The mating surface of the cam and cam sprocket should be completely clean and 
dry, free of any oil residue(brake cleaner works well).

The cam bolt should then be snugly installed, but allowing the cam sprocket 
to rotate on the cam itself.  The bar should be installed in the slot.  The 
belt can now go on with pump, cam and crank all lined up.  All slack should be in 
the tensioner area with the belt taut between the crank, pump and cam 
sprockets and the marks still lined up.  At that point the cam bolt should be snugged 
down tight (20 ft lbs) with the bar in the cam slot.  Then the bar should be 
removed and the cam sprocket held otherwise.  The bolt should be tightened to 
33 then whacked sharply with a hammer, then tightened to 45, then whacked 
sharply and checked for torque to 45.  If it moves when checking then whap it 
again and check it again, etc.

I realise that the above torque spec is above and beyond the factory 
recommended, but lots of vw diesel community experience has shown that even from the 
factory some cams slipped time and so 33 is well known to not always be 
adequate.

Andrew