The Hercs use thrust washers on the cam and aux shafts (grrrr!) that need
periodic adjustment and replacement. Because they are driven by helical
gears, they can move back and forth if this clearance/adjustment is not
maintained. It will also destroy the water pump seals which could be
(remotely) the source of your knock. My 30kw genset has this problem on its
JDXL (long) engine 339 cid
This engine may last longer than a GMC cckw engine, but as far as ease of
working on in a tight place and the above mentioned 'feature' make me glad I
decided to do WW2 GM's....
Steve AKA Dr Deuce
----- Original Message -----
From: Howard Wright <dvsww2@micron.net>
To: Military Vehicles Mailing List <mil-veh@mil-veh.org>
Sent: Tuesday, November 14, 2000 5:44 PM
Subject: Re: [MV] Hercules JXD engine "knock"
> Myself, I'd check the oil for gasoline in the oil, or oil period first,
then
> try to diagnose the problem. JXD Hercs are not easy to find from my
> experience as a lot of them were robbed for civy trucks and equipment. I
> thought I had a corner on a Herc out of a Diamond T truck and the guy that
> had it had a forklift with a Herc and would not part with it. I finally
> found a Stude 6x6 with a trashed frame and body for mine. Thanks Howard
> ----- Original Message -----
> From: <CYCLOPSRAM@aol.com>
> To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
> Sent: Tuesday, November 14, 2000 2:40 PM
> Subject: Re: [MV] Hercules JXD engine "knock"
>
>
> > Knock at idle. Knock at decelleration, Knock at accelleration?? All
> have
> > different causes... Mechanical fuel pumps are known to knock at
idle...
> A
> > tight or frozen valve lifter is known to knock... A loose piston pin is
> > known to knock.. A loose main bearing is known to knock and a loose rod
> > bearing is known to knock.. A loose bolt on the clutch flywheel pressure
> > plate is known to knock... Get out you stethoscope doc and find where
> the
> > noise is coming from... Ya starts by removing one plug wire at a time
> and
> > seeing (hearing) if a particular cylinder is at fault... For whom or
> what
> > would you be evaluating a vehicle??? Typically only vehicle experts
> would
> > try to evaluate a vehicle.. as in give a value... If you are checking
it
> > out for possible purchase yourself, go get an expert to evaluate it for
> > you... RAM MVPA #217
> >
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> >
>
>
>
> ===Mil-Veh is a member-supported mailing list===
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This archive was generated by hypermail 2b29 : Sun Dec 03 2000 - 20:29:52 PST