Date: Tue, 28 Aug 2001 15:08:25 -0700
Reply-To: "Scott G. Terry" <sgterry@ENGINEERING.UCSB.EDU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "Scott G. Terry" <sgterry@ENGINEERING.UCSB.EDU>
Subject: Re: valve lash adjustment
In-Reply-To: <E15bo3U-00021C-00@mail.engr.ucsb.edu>
Content-Type: text/plain; charset="us-ascii"
Jay et al.,
Your original post describing your success with the Boston Bob valve lash
adjustment inspired me to give it a try.
I'm not sure if I understood the approach and did it right, but here's what
I did (I'm new to wrenching Vanagons and not a very experienced mechanic in
general):
Saturday I set the valve lash clearance to 0.005" cold. You all would
laugh at how long it took me to do this! The funniest part was me trying
to turn the crankshaft pulley by hand to get to top dead center (tdc). I
expected this to be difficult but found it to be impossible. Figured I
would reduce the compression by pulling the spark plugs. As I pulled the
third plug I suddenly remembered I had parked the van in 1st gear. Duh.
As you can imagine, it was quite a bit easier to turn the engine with the
tranny in neutral. After popping off the distributor cap, I used the rotor
position and the tdc notch in the crankshaft pulley to locate tdc for the
#1 cylinder, set the rocker clearances for #1, then turned the pulley 180
degrees (clockwise) to get #4 tdc, set #4 clearances, and repeated for #3
and #2 cylinders. I think I read the Boston Bob procedure called for an
initial 0.006" clearance but the closest feeler gauge I had was 0.005.
Drove the van on a short errand in town on Sunday. A fair amount of lifter
noise but not really alarming. It was my understanding that the lifters
would expel any trapped air and "pump up" after a some driving which could
take up to a week.
This morning I decided to drive the van to work to give the lifters more
exercise. Now that I was on the highway I realized that she was way low on
power! I exited the highway and returned home. What have I done to my
van, I thought... I decided to perform the second part of the Boston Bob
adjustment immediately. I couldn't imagine driving the engine like that
anymore. This round of valve adjustments went way faster. I found that
some of the lifters had pumped up as evidenced by the absence of any
clearance at tdc. I went through and adjusted each valve to zero clearance
plus a quarter turn tightening of the adjusting screw, slapped the valve
covers back on, and fired her up. She purred. Idled rock steady at 950
rpm and no lifter noise. Drove to work with full power. I'm going to
measure the manifold vacuum at idle and see if there has been any
improvement.
As I adjusted the valves for each cylinder a second time I could feel a
difference in the lifter action as I made the final 1/4 turn of each adj.
screw. Some of the lifters felt very firm, others felt spongy. What does
this mean?
Scott
'85 Westy "Pearl"
Santa Barbara, CA
>From: Jay L Snyder <Jay.L.Snyder@USA.DUPONT.COM>
>Subject: Valve Adjustment
>Excellent results so far with the zero-lash valve adjustment. I want to go
>to about 1/4 turn to see if I can quiet the valves completely. I get some
>initial noise, but no clacking as before and they quickly pump up and are
>quiet from then on, even when hot coming off the interstate. Much better
>low end grunt and cold starts. I would like to pull the valve covers and
>check to see if any of the adjustments has changed since I last adjusted
>them (any lifters pump up further?). Anyone have a good solution to
>marking the 180 degree spot opposite the TDC notch? I have a scratch mark
>drawn, but I am not sure it is accurate. There isn't much room there with
>the triple pulley. Maybe I could put masking tape on it and mark off in
>inches? It would be nice to have a total advance mark too, to check the
>total distributor advance. And maybe a 5 degrees BTDC mark.....
> Jay ('85 Westy)