Date: Mon, 26 Sep 2011 20:40:49 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Timing belt replacement and valve timing in VW gas and Diesel
engines
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hi..
you always need to loosen the cam sprocket from the cam ,
any time you replace the timing belt.
It 'can not' come out exactly right......
if you do not release the sprocket from the cam.
( and do not use the cam lock to hold the cam and sprocket while you torque
the cam sprocket bolt as a final step in the whole process ! ) To remove
the cam bolt I either impact it off, or use the procedure for holding the
cam sprocket further below.
So don't even pay attention to that few degrees off thing at the flywheel.
Keep that at TDC while you get the belt into place with cam sprocket ,
tensioner, IP sprocket.
here's a little trick ..
rather than slide t-belt over the edge of the sprockets..,,do this....
with cam sprocket in your hand..
put belt in place ..then put cam sprocket 'into' the belt, and onto the end
of the cam.
My IP pin is just a tad loose ..which allows me to tweak the IP sprocket
about 1/3rd of a tooth to the right ..
which is 'just right' ..
to get belt in place without crankshaft moving.
sometimes it takes a few tries.
with cam sprocket bolt mostly tightened ( but sprocket still free to move on
cam ) .tension up the belt ( cam is locked still of course )..
as you tension the belt...make sure flywheel marks do not move or change.
Once you get there..
tighten cam sprocket more - medium firmly, so sprocket is locked to cam for
now.
The remove all locks..
Turn engine through two complete turns ....check that it all lines up again.
the for final cam bolt tightening ...
rotate engine so you can put a bar through cam sprocket to hold it against
the head, while you do final tightening on the cam sprocket bolt. Don't try
to use the cam lock to hold the cam from turning while you tighten that bolt
( ! ).
then set the Injection Timing.
Do it this way, and it'll be exactly right.
Scott
www.turbovans.com
----- Original Message -----
From: "Poppie Jagersand" <poppie.jagersand@YAHOO.CA>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, September 26, 2011 7:39 PM
Subject: Re: Timing belt replacement and valve timing in VW gas and Diesel
engines
Finally got to put some time into the TD injection pump seal replacement.
With job, family, inlaws etc the bus isn't receiving the time and attention
it used to... I prepared the engine a month ago by removing all the
ancillary parts in the way (my home made air intake for the 1.9TD, the
timing cover, various hoses etc). Today I finally found my dial gauge so
felt I could continue the job. Thanks to Mark, Bryan, Scott and others who
have provided advice along the way.
So on to timing belt removal, p 13.16 and 17 in my VW 1.9TD engine manual.
Got engine aligned at TDC mark on flywheel. Oddly neither the bar on the
crankshaft, not the injection pump locking pin would go in at this position.
Had to turn the 5-6mm more clockwise to get the crank and pump locked up.
More on that later.
Took off tensioner and timing belt.
Took off injection pump drive pulley.
Tried Bryan's tip of pulling out the injection pump shaft seal using screws
into the seal, however didn't succeed before it turned dark today. I tried
to pre-drill holes in the seal metal flange using a regular handheld drill,
but the drill bit would wander despite I had tapped an indentation in the
seal with a drift. Remember I'm doing this with the injection pump in the
van, so I have to drill through the license plate access lid. Not so easy
with a regular drill. Tomorrow after work I'll see if I can locate some
drill bits for my dremel. That should be easier to hold.
Another "tool" that might work to pull the seal if it existed would be a
very small diametre inside pulley puller, that is something with outward
pointing jaws that would grip the inside flange of the seal.
Note on the apparent misalignment of the engine between the flywheel TDC
mark and the valve and injection pump lock positions:
6mm off on the flywheel diametre of 210mm is 6/(210*pi) = 0.009 or 0.9% of a
revolution, 3.3degrees.
I counted 22 teeth on the crank pulley. If I were to move the belt 1 tooth
forward to would mean a 16 degree change. That is way too much.
By leaving it as is, if the flywheel mark is indeed correct I would be
running with injection pump reference and valve timing is 3.5 degrees
retarded compared to flywheel (and presumably cylinders).
So I wonder if anyone else have seen this difference on a VW factory
assembled engine? (This is a 1.9TD AAZ engine with the std Vanagon Diesel
flywheel bolted on. I haven't note/thought about it before as I recall, but
I haven't worked much on the Diesels in the past decade.
I can of course change the valve timing by adjusting the valve pulley. I
didn't loosen it now assuming I would get the belt on with Mark Drillock's
"counter rotating injection pulley" technique, but could do the valve timing
separately afterwards.
Injection pump lock pin and flywheel TDC would remain misaligned though if
I'm not mistaken. That shouldn't affect timing since it is done w.r.t. the
TDC mark, but If I change the valve timing belt changes would be difficult
since I couldn't get the injection pump and valves locked up in the same
position anymore.
It is still odd that valve lock and the injection pump lock lined up
perfectly, but not TDC mark. So the two locks are consistent against the one
TDC mark.
3.5 degrees off is I believe not a huge deal in terms of timing. Maybe
affects starting a bit, but when running the pump varies timing with RPM 20
or more degrees anyway through the advance mechanism. The 1.9TD pump also
has a load dependent timing circuit that I haven't even hooked up in my
vanagon install.
So I'm inclined to leave it as is unless people have good reasons to do
otherwise.
Martin (and '82 Westy 1.9TD "Poppie")
----- Original Message -----
From: mark drillock <mdrillock@cox.net>
To: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Cc: vanagon@GERRY.VANAGON.COM
Sent: Monday, August 22, 2011 4:30:24 PM
Subject: Re: Timing belt replacement and valve timing in VW gas and Diesel
engines
Having the cam gear loose on the shaft does simplify the belt installation
since then there are only 2 fixed gears to get the teeth count positioned
exactly on. Also the gear will move out slightly on the taper and give more
slack to the belt while you fully position it. I still avoid doing it that
way since disturbing the cam gear just to make the belt go on easier is not
worth it to me. However it can be quite a struggle to get the 1.9 belt on
all 3 fixed gears exactly right. There is a trick to it, involving
preloading the injection pump gear in reverse direction slightly, with the
locking pin still in place.
Mark
Poppie Jagersand wrote:
> When replacing the timing belt in a Diesel, the VW instructions say to
> (first to lock everything up) then *loosen the camshaft nut* (Then put new
> timing belt, tension, tighten camshaft nut etc). This camshaft nut
> re-setting seems to be for precisely setting the camshaft angle at TDC.
> (or is there another reason?)
>
> If I remember right (and I may be wrong - it is a long time since), for
> the similar 70's and 80's 4cyl gas engines instructions were basically
> lock up cam, replace timing timing belt. No camshaft nut loosening and
> re-setting of cam timing.
>
> Any reason a Diesel would be more sensitive to (very small variations in)
> cam timing? Anyone skipping the camshaft nut part?
>
> Martin (and '82 Westy "Poppie")
>
>