Date: Thu, 4 May 2000 12:41:56 -0400
Reply-To: Bob Donalds <bostneng@FCL-US.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Bob Donalds <bostneng@FCL-US.NET>
Organization: Boston Engine Exchange
Subject: Re: Lifter/Valve question
Content-Type: text/plain; charset=us-ascii
>
> Bulley wrote:
> >
> > Bob-
> >
> > As always, I value your guidance.
> >
> > My 1982 Westfalia 2.0 liter with 96mm jugs/CW crank is due for what I
> > consider a "normal" service, but I thought I'd check my experience with
> > yours.
> >
> > I have found that 5-7k after an air-cooled rebuild, it is helpful/necessary
> > to re-torque the lower head bolts, re-adjust the valves (even if hyd), and
> > snug up the exhaust manifold nuts. I'm planning on doing this service on
> > Saturday a.m. (since there is no VW mechanic here).
> > My questions:
> > 1. Have you found the need for head re-torque/valve adjust/exhaust
> > re-torque to be true? Am I just carrying mental baggage from my days
> > building type 1s? (we used to re-torque lower head bolts at 5k, then every
> >
> >
> > Thanks,
> >
> > G. Matthew Bulley
> >
> Matt
> glad your back on the list I have missed your input and wit
> re-torqueing heads bolts is a time honored tradition with the air cooled
> engines.
> As you may know I rebuild single port engines for use in zambonis (ice
> rink resurfacing machines.) Air cooled enignes in this application live
> a very hard life that was measured in months not years until I made some
> simple changes. these poor little abused engines had all the symtoms of
> the its street counter part but in a tenth of the time pulled head studs
> burnt valves cracked heads. When I lowered the compression ratio to 7
> from 1 from 7.75 to 1 the life of these engines increased to the point
> that I was putting my self out of the zamboni engine business. I now
> offer a 2 year warrenty on all my air cooled industrial engines. I keep
> in touch with the techs that maintain these these engines. As a part of
> tuning they retorque the lower heads nuts before they adjust the valves.
> They report to me that some engines don't loose there torque. One of
> these engines is local and I have stopped in and measured the oil temps
> after it makes ice. this engine runs at 185 oil temp and its propane
> fueled but thats another story. The point In am trying to make by
> telling you this story is that when the engine is within a reasonable
> oil-head temp range it makes better power, lives longer and it heads
> nuts are not as likley to loose there torque. I do use the fuelie bug
> blocks on the propane engines they are made of the same stuff the air
> cooled vanagon blocks are made of. The bottom line is if the head nuts
> loose there torque the engine is getting to hot.
>
> Gene Berg was right! he said to me more than once what do I have to
> gain by telling you to run lower compression ratios. he gained my trust
> and loyalty.
>
> . When you adjust type 2 valves how many turns do you give? (I'm a one
> > turn guy, but I know some say 'no clearance' some say '2 turns', or 5/8s
> > turn, etc.)
> >
> Just preloading valves a turn or two would be a mistake some hydraulic
> lifters cant take much of a preload ever I dont know why. This has
> become a huge problem for the air cooled vans and I have seen it in the
> watercooled also. Burnt valves in a very short time is not uncommon even
> with the good seats and valves. The valves must touch the seats to
> disapate the heat or they fail.
> To prevent burnt valves I now tell my customers that they need to do a
> compression test before and after the engine has had the the lifters
> preloaded and they preload the lifters at there own risk! I have backed
> off my customers preloaded valve adjustment with gains of 20 pounds
> across the board when they just preloaded and did no testing. There has
> been no report of lifters failng because of valve adjuster
> lash(clearance) my own van has run this way for 2 years. Its not clear
> why this is happening but I have personaly backed off the adjusters for
> the editor of the vanagon manual and cured his low vacuum,poor
> performance and low compression readings in his own air cooled vanagon.
>
> 3. How frequently should I adjust my hydraulic valves (ever?).
> >
> It may take more than once to get the valves there they need to be or at
> least as close you can get to preload. A compression test needs to be
> apart of any valve adjustment. once the the valves are set and checked
> for full closing your done with adjusting.
>
> My man at Bentley says
> (Bentley gets its info from VW and passes it along without
> passing jugdement they have told me they do not feel free to modify
> that's been handed to them without a tech bulletin to back it up even
> when I have proven to them that there is a better way. I did ask them to
> include my web page address in the next vanagon book but they declined
> go figure.
>
> I am looking for fuelie bug blocks if anybody has one or more to sell
>
> hope this helps I must get back to work assemble yet another 2.1 long
> block
> Bob Donalds
> http://www.bostonengine.com
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