----- Original Message -----
From: tonygull <tonygull@ozemail.com.au>
To: Military Vehicles Mailing List <mil-veh@mil-veh.org>
Sent: Monday, June 25, 2001 5:31 PM
Subject: [MV] CCKW road test, some more questions, Hercules engines
> took the CCKW with 12V conversion for its road test today,
> and it did prove to be a test.
>
> Firstly the truck starts well now, at least for the last 2 days
> a dozen times, no real trouble.
>
> There still seems to be a fuel problem, needs choke to rev,
> and tends to stall, backfires under load...maybe lean??
>
You could also have a break/split or leak in the line from the tank to the
pump
> well anyway, we went down a local track, so i could have
> my mate drive it about while i listened and looked for
> noises and binding etc....its is dirt, with a large cul-desac
> and bush, but very steep...the road is about as steep as a regular
> road is allowed to be, a 1st or maybe 2nd gear road in a standard
> car. On the way back, the GMC started to splutter, backfire and then died.
>
> No fuel was evident at throttle pump, tank was 10-20% full, so
> we surmised that more fuel would be good...to the servo, 20 litres
> in a jerry can, she starts and we get home,Does the fueltank pickup
> have problems at steep inclinations and low fuel tank?
Should not have a problem with a say 1/2 tank
> Power is low and backfire is evident.
> Fuel is leaking out the carbie, so this would also probably
> make it more lean.
>
> I will soon put on a Stromberg that is on another GMC, I believe it has
> adjustable mixture needle.
If the carb was on a Cheby, it will be too lean
>
> My gear changes are atrocious, but i did seem to need to engage low range
> to negotiate the steep hill...which brings me to TM9-801, page 19,which
> states "maximum grade in High range 3.5*(3 1/2).....Low range 65*
> * GVM 19500. Is this a misprint?..What does the figure shown
> for High range represent?. Do they mean 31.5 gradient?
>
> I would have thought the truck should easily
> pull a grade like that( estimate 35%) in 1st, with no load?
>
Not sure, they may mean 5th in High if the figure is that low
> Also, whilst stalled on the steep hill, we noticed oil trickling out
> from what appeared to be the rear main oil seal, it stopped when parked
> on a level..lost about 1/2 litre, engine was probably 1-2 litres overfull
> how hard is it to change the rear main oil seal?
> would i need to? or can an overfull crankcase flow a little out?
>
Run it low on oil. Instead of 10 qts, use 8
> Can it be done with the engine still in, by using a little jigger tool
> to sneak it in like on Chevys or Jags.
>
You will probably never stop this leak. Get use to it.
> I presume the seal has hardend due to lack of use, over the years.
>
> 12V certainly seems the go, spins the starter really well.
You should also run the wire that runs the truck (not the starter) back to
the battery
With the 6v starter, you get quite a voltage drop thru the battery cable.
>
> Does anyone on the list have a dumper GMC?
>
> I am curious also about Hercules engines, I looked them up om Net search
> engines, but could find little, to my surprise.
>
> What i understood is they are large 6 cyl petrol engines, developed from
> stationary engines. Are they side valve?...a GM product?
L-heads made by Hercules, not GM. They supposedly lasted longer in the
Studebakers
because they used harder metal for the block. I have a JXLD on a 30kw
generator. I
personally would sell the truck I I had one of them in it! With the
exception of the 11.5"
clutch on the cckw, the GM designs in WW2 have it all over any of the
L-heads that I have worked
on. All of the bolts on a GM engine are dead ended or go into oil. NONE go
into the water jacket!
> If some knowlegable lister would point to a website etc, that would be
good
>
> with regard to the electric fuel pump, one lister did point out
> the problem of overpressure on the needle/seat causing flooding.
I have electrics on one Cheby and my cckw with no problem. They also start
better as they tend to boil off/evaporate all the gasoline when shut down or
sitting for a few days.
>
> I think i remember reading a article describing an adjustable fuel
pressure
> regulator, i think it had a screw type fitting, and went down to 2 PSI
> Does anyone know of these?
Have heard of them, but I have not seen one in many years. My GPW has a hard
time holding
back the gas at the needle valve with the mech pump.
>
> Maybe i should just mount up a set of injectors into the underside of the
> manifold, add extractors, injector computer,HP pump, electric fan,
> electronic dizzie, cell phone and be done with it.
>
One trick you can do with a carb, is to warm the engine up with the air
cleaner off.
Manually hold the throttle wide open and just before you think it will come
unglued, put
your hand over the carb and choke the S* out of it. This will create such
suction on the carb
as to pull thru any small pieces of dirt that may be clogging various jets.
WARNING: When you do this,
take your hand off with the throttle still wide open in enough time to let
the engine recover (run) or
else it will be flooded and tough to get going again. This technique has
helped more than once in the field.
> regards tony
>
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This archive was generated by hypermail 2b29 : Thu Jul 05 2001 - 00:40:38 PDT