From: Angela Barla (barlowf@earthlink.net)
Date: Mon Feb 07 2005 - 18:53:33 PST
Have you checked your valve clearance and/or even pulled the valve cover to
see if the pushrods are bent?
Lee
----- Original Message -----
From: "Mil-Veh Co." <milveh@sbcglobal.net>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Monday, February 07, 2005 6:21 PM
Subject: Re: [MV] More test results ... re M151 mystery miss
> RE: No fire on #2 cylinder. Stock M151.
>
> Summary: Looking for a miss on #2 cyl., but despite
> best efforts that miss continues.
>
> Lastest effort: Made a new set of intake gaskets in
> case it was a manifold air leak. (short version - it
> didn't help!!!)
>
> (long version) I applied a sensible amount of permatex
> blue gasket maker to the gaskets and let them skin up
> while I inspected the manifold and the intake ports on
> the head.
>
> They were all fine, #2 had black carbon on the top of
> the intake valve built up, but seemed consistent with
> an older engine.
>
> No obstruction and no leaks. Least none that I could
> determine by visual inspection or by applying ether to
> number 2 intake area during a prior test run.
>
> Checked all vacuum lines again (like 10-12 times now),
> all intact and no visible signs of any leakage.
>
> Removed the spark plugs again (at least 10 times now)
> they all seemed to be burning fine, except for number
> 2..black sooty looking, but electrode clear of carbon
> buildup.
>
> Replaced intake manifold and tightened everything and
> used gasket sealer on all brass fittings.
> Re-inspected everything...looked darn good. A careful
> r/r was done to everything.
>
> Attempted to start engine, but engine bucked as if
> timing too advanced. Got a little backfire through
> the carburettor, this has been typical since problem
> started. Hard starting since miss on #2. So I used
> some ether and it started up, but ran rough. To me, it
> starts like its out of time, I say this because it
> resists or drags on the starter, which to me indicates
> overly advanced timing...but it will run and seem to
> have about 60% power on test drives, won't get any
> better by moving dist. around, only gets worse.
>
> Vacuum gauge said it was within time.
>
> Removed plug wire from #2 engine continued to run as
> before...rough. Visible spark to #2, but still not
> igniting fuel in cyl. Note: I had swoped plugs again
> with number 1 to see if the plug was somehow fouled.
> Didn't matter, problem stayed on #2.
>
> Swoped #3 lead with #2... no difference at all. #2
> still not firing!
>
> This is a NOS electronic dist. and its 3rd one I've
> had in there since this problem arose. The miss
> problem has stayed despite changing distributors,
> changing to NOS set of HT wires, and all plugs checked
> at least 10 times!
>
> Re-re-re-checked clearance on distributor magnet to
> cam lobe, right on. This all brand new stuff now,
> everything looks right!
>
> I swear the engine acts like it is out of time, will
> barely start, but then #1 reaches TDC and the timing
> mark lines up on crank pully???
>
> What the *%#%$#@&* is going on here!
>
> Next opportunity I'm going to replace the ground cable
> on the battery just to be safe, but it looks ok.
> Maybe somehow, someway there is corrosion somewhere on
> the negative cable, but I sure didn't see it. Maybe
> there is a short on the negative pole of the battery?
> But, it looks good.
>
> I'm basing my plug wiring order with number 1 HT lead
> being the at top/front left if you were facing towards
> the radiator from the rear of the Mutt.
>
> I replaced HT wires based on TM firing order.
>
> I tried to remember back to when it all started and it
> seemed I was having a low battery problem due to a bad
> alternator. Mutt was running great till then. When
> batteries were charged back up it ran fine for a day
> or so, but as batteries discharged it definately had
> an effect on the running.
>
> Since then I R/R'd the alternator, running the 8 ga.
> pos. lead direct to the pos. on the battery, charged
> both batteries back to full and it continued to run
> rough.
>
> Just FYI as a reminder: Compression test was done
> earlier after pulling all the plugs, each cyl. was
> about 101-105 lbs dry.
>
> Thanks for indulging me on this, despite not having
> found the cause, your suggestions have helped keep up
> my moral. I know I will find the miss eventually, but
> I have to admit this is an odd one and its been real
> frustrating. This should be an easy, no brainer,
> right? Uh-un, no way... stay tuned for more.
>
>
>
>
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