Date:         Mon, 20 Aug 2001 08:44:54 -0400
Reply-To:     Jay L Snyder <Jay.L.Snyder@USA.DUPONT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Jay L Snyder <Jay.L.Snyder@USA.DUPONT.COM>
Subject:      Re: do we have a vacuum leak?
Content-Type: text/plain; charset=us-ascii

---------------------- Forwarded by Jay L Snyder/AE/DuPont on 08/20/2001
08:46 AM ---------------------------


Jay L Snyder
08/20/2001 08:43 AM

To:   "Scott G. Terry" <sgterry@ENGINEERING.UCSB.EDU>
cc:
Subject:  Re: do we have a vacuum leak?  (Document link not converted)

I am getting 15" at idle.  I adjusted my valves over the weekend as per
Boston Bob's procedure.  Excellent so far.  Quiet valves and more power.
Also, cold starts are much improved.  I backed off the adjusters to 0 lash,
and just tightened ~1/4 turn.  I think most of the fuel pressure problems
are vacuum related.  I would suggest replacing the FPR if it is still the
original piece (10 to 20 years old).  I teed the vacuum guage in at the
distributor/FPR line.  Is this where everyone is measuring it?
                                                        Jay '85 Westy



"Scott G. Terry" <sgterry@ENGINEERING.UCSB.EDU> on 08/17/2001 10:18:09 PM

Please respond to "Scott G. Terry" <sgterry@ENGINEERING.UCSB.EDU>

To:   vanagon@GERRY.VANAGON.COM
cc:    (bcc: Jay L Snyder/AE/DuPont)
Subject:  do we have a vacuum leak?




Hi Michael,
Thanks for responding to my post.  I'll be interested to read your results.
Please carbon-copy me when you post them to the list.  I subscribe in
digest-mode and don't always have time to keep up with the traffic.
Pearl is fluctuating rapidly between 7-9" vacuum at idle so I think by
anybody's standard I do have a leak.  Lucky me!
I think I can hear a leak but I can't get the engine to race when I hose
suspect areas with carb cleaner (not the safest approach, use cat.
converter safe brand, etc. etc.).  Maybe a worn valve train... maybe I'm
just hearing induction noise...
this is where experience (which I lack) would really help.
So is 10-12 " indicative of a healthy vacuum or a leaky vacuum?  I believe
the question remains unanswered.  My conclusion from my test was manifold
vacuum should be 15".  Yet no one has stepped up to the plate and said
they're getting 15" in their wasserboxer.  Matthew Pollard is getting
awesome gas mileage in his 1.9L(?) and I think I remember that he brought
his fuel pressure into spec with a new FPR, so this would imply his engine
has good manifold vacuum.  So, Matthew, how about borrowing a vacuum gauge
from UI and measuring your manifold vacuum at idle (and maybe 2000 rpm
while you're at it)?  We would make you second author if we publish the
findings in the Journal of Vanagon Vacuum (J. Van. Vac.).  First author if
you also do some NMR on the head gasket adhesive and solve the riddle of
the water leak.
Scott Terry
'85 Westy "Pearl"
Santa Barbara, CA
>While attempting to evacuate my AC system, I noticed the MV as 10" to 12"
>Hg just as you state.  Do you think I have a leak somewhere -- I hadn't
>thought that it might should be 15".
>
>Thanks,
>Michael Townsend
>90 Carat
>Durham NC
>
>PS.  Finally got my R-134a charged this morning -- looking forward to a
>cool drive home!