Date: Sat, 11 Mar 2000 10:27:14 -0500
Reply-To: Martin Jagersand <vwjag@HAMMER.CS.JHU.EDU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Martin Jagersand <vwjag@HAMMER.CS.JHU.EDU>
Subject: Re: timing question
In-Reply-To: <a9.2c0e97f.25fb1bfd@aol.com> (Travelbike@aol.com)
I agree that the description in Bentley is confusing. The problem is that
they tell you what do to, but do not motivate why or explain how the
procedure relates to the function of the pump.
In addition to Dana's excellent clarification let me add:
Look at the injection pump drawing on my page (link below,
click on injection pump).
Find the cam plate in the drawing. The "bumps" on it is what drives
the plunger in and out.
The purpose of the first several steps is just to make sure that
you move the cam rollers to a point between the bumps and then
you "pre load", ie make sure that the dial gauge is in contact with the
plunger. All this is so that you start your measurement from the 0-lift
reference point.
The last step; the movement back to TDC is what measures the lift. (and should
be done precisely by sighting TDC from straight above)
Cheers,
Martin
--
Westy 1.9l Turbo Diesel
Quantum 1.6l Turbo Diesel
New and used parts for sale, gas and Diesel:
http://www.cs.yale.edu/~jag/vw/forsale.html
Martin Jagersand email: vwjag@hammer.cs.jhu.edu
Computer Science Department
Johns Hopkins University
Slow down and visit the VW diesel Westy page:
WWW: http://www.cs.rochester.edu/u/jag/vw
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From: Travelbike@aol.com
Just got a timing gage and have read the Bentley Mannual a few times. Just a
few questions on the procedure.
Step 1 - Turn crankshaft till the TDC mark on flywheel aligns to pointer at
the bell housing hole with all valves closed.
STILL OK to this point.
Step 2 - Remove timing check plug. Screw in tool till gage till it indicates
2.5mm
Still OK
Step 3 - Using wrench on Crank bolt. Turn crankshaft counter clockwise
normal direction till gage stops moving.
Question - As you turn the crankshaft, should the reading on the gage
increase from 2.5mm going up ? My assumption is yes since the injection pump
is moving back in preparation for the plunge to TDC.
Step 4 - Readjust the dial indicator so you can zero it with a 1mm preload
Question - this is where I get a bit confused. At this point, do you just
turn the dial face so that the arrow points to Zero on the dial face ?
Step 5 - Turn crankshaft till TDC in normal direction.
Dial should read to about timing limits in the mannual (.90-1mm for 84 NA).
In short, is the procedure done so that we can check that the plunger travel
from step 3 to step 5 (TDC) is about 1mm max for an 84 diesel NA ?
Sorry for this stupid sounding question. Thanks to all for any help
