[DeTomaso] Pantera fall down go boom :<(

[Asa Jay Laughton]

Wow, that's quite the story.  It also helps fill in the gaps from Dan's 
email to me earlier.  I still have an original Crane steel gear in my 
engine in the Mach I.  However, I've not thrashed it on the track as you 
did.  I also don't use a high pressure oil pump, though it might be a 
high volume (I can't recall).  My pressure is good between 65 and 75 psi.

I'm interested to hear what is said about the composite gear.
Asa Jay

Asa Jay Laughton, MSgt, USAFR, Retired
&  Shelley Marie
Spokane, WA
******************************
http://www.racingagainstautism.com
http://www.teampanteraracing.com
http://facebook.com/racingagainstautism


On 6/19/2011 4:09 PM, MikeLDrew at aol.com wrote:
> Hi guys,
>
> Those of you who were at the POCA Fun Rally last weekend perhaps noted that
> every single Pantera that drove to the event, safely drove home at the end
> of the weekend, save one.
>
> Unfortunately, that one was mine. :<(
>
> I've been loving my new 408 stroker Cleveland, which has utterly
> transformed the car.   I had a wonderful drive up and over the Sierras, tempering my
> enthusiam a bit in deference to the handful of Panteras that were running
> with me (also a reflection of a recent run-in with Johnny Law that I managed to
> escape from for about $300, but my next ticket will result in points on my
> license).
>
> At the track event, the first thing I did was to bleed my brakes, as my
> pedal was soft and squishy.   I got a bit of trapped air out, which improved
> things, but they are far from where they should be.   I think this is a result
> of some uncharacteristically horrible engineering that took place when my
> friend who restored the car years ago, fabricated new brake lines.   For
> reasons unknown, he deliberately placed a big loop in each line, which is
> seemingly guaranteed to trap air and result in a spongy pedal--exactly what I have
> had all these years.   I think I am going to trash all the hard lines and
> start over.
>
> But anyway.   Once the brakes felt up to the task (although far from
> perfect), I started driving on the track Thursday afternoon, and the car was much,
> MUCH faster than two years ago.   I'm still very handicapped by my
> super-crusty tires (my intent was to burn them off at this event and then replace
> them when I got home) which kept cornering velocities laughably low, but also
> provided lots of opportunity for sideways antics at relatively low speeds.
>
> Two years ago, I would enter the front straight in 3rd gear, upshift to 4th
> at about 5500 rpm, and just be nudging 110 mph when I felt it was prudent
> to lift for the first of the three S-curves leading to the hairpin at the
> end.   This year, with all the extra power, I was topping 130 mph.
>
> Whee!
>
> The thing is, I would reach the 6000 rpm rev limiter well before the
> turn-in point.   My choices were to either upshft to 5th gear for just a moment,
> then back down to 4th, or to just coast for a bit.   Since nobody was paying
> me for this and there were no trophies on the line, I elected to do the
> latter.   My car has an MSD system with the 'soft touch' rev limiter; the bumpf
> that comes with the MSD box indicates that there is no harm in just riding
> the limiter, as it randomly cuts spark from various cylinders to keep the RPM
> at a predetermined maximum point.   So often times, I'd keep my foot to the
> mat and just ride the limiter for 100-200 feet or more, then lift off and
> turn in.
>
> At the end of the first day, the car was running just a little bit weird.
> I was having trouble with the idle speed, and in fact the next morning I
> had to turn the idle up quite a bit.
>
> I then went out for a second day of more fun and games on the track, and
> the motor seemed 'off' ever so slightly.   I was driving with a raised
> eyebrow, and then I came down the front straight and noted that it was well down on
> power; with my foot to the mat it was 20 mph off at the turn-in point.   I
> determined that I would pull in at the end of the lap for a look-see.
>
> Didn't happen. :<(
>
> When I got to the steep uphill, the engine started stuttering, and I had my
> foot on the floor trying to keep it going to at least the top so I could
> pull off.   But just before the top, it went POP and quit, leaving me stranded
> on the side of the track, and causing a yellow flag in that area for the
> rest of the session.
>
> I figured the distributor shear pin had sheared.   There were no other
> indications, I had fuel, no clanking noises from the engine, so it was pretty
> apparently an ignition issue.
>
> They threw the checkered flag and I coasted down the hill to a safe spot
> and abandoned the car until lunchtime.   Rich Boschert was kind enough to tow
> it in to the paddock on his flatbed trailer, and then any number of
> volunteers stepped in to help sort it out.
>
> Steve Liebenow offered up some shear pins, and I figured I'd be rolling a
> short time later.   But then the distributor cam out.   Bad news.
> Distributor gear totally mangled. :<(
>
> Then we started thinking about getting a replacement gear from Summit, just
> down the road.   But Chuck Melton took a look-see down into the engine, and
> what he saw was far from good--the drive gear on the end of the camshaft
> was destroyed as well.
>
> Trailer time. :<(
>
> Fortunately for me, Rich has to drive within a mile of my house on his way
> home.   He was kind enough to trailer my Pantera back to the hotel, and then
> back home Sunday afternoon, and allow me to follow behind at the wheel of
> his lovely green Pantera, so all things considered, this went about as well
> as could be expected under the circumstances.   Sunday morning we had an
> uneventful drive home, and since we had two other truck/trailers and another
> Pantera in convoy with us, it was easy to unload the car and push it into the
> garage, where it now sits, sad and forlorn.
>
> Here's some photos of the gear on the distributor.   All of the teeth were
> filed razor-sharp, creating much slop in the timing (the cause for my idle
> problems no doubt).   But then, a number of teeth simply sheared off
> completely, which caused the car to stop dead.
>
> http://www.poca.com/index.php/gallery/?g2_itemId=32311
>
> When you click on each photo, it opens up in a normal-sized view, but you
> can select the max size, which shows really excellent detail; you can clearly
> see where the teeth were literally sheared off.
>
> I've since been in touch with Dan Jones, John Christian and others,
> attempting to determine the cause of the problem.   I was using a steel hydraulic
> roller cam core, and a Crane steel gear advertised to work well with such
> things.   However, I did have a couple of things going against me:
>
> 1)   Excessive oil pressure.   I purposely re-used the oil pump from my
> previous engine because it delivered 50 psi there (verified with a mechanical
> gauge) and I did not want high volume or high pressure, both of which are bad
> for Clevelands.   However, my new engine (perhaps due to tighter
> tolorences) sees the oil pressure gauge pegged.   Probably 80 psi at operating RPM.
> The literature that comes with the cam gear says that it will live with a
> steel cam, EXCEPT if excessive pressure or volume oil pump is used.   They say
> that rapid wear will then result--which I got.   So, since oil pumps are
> cheap, I'm going to start over from scratch with a new Melling M-84A.   (The
> Summit website is incorrect and doesn't list this for the 351C, only showing
> it as applicable for the 351M and 400M.   But in fact this is a 351C pump,
> as shown on Melling's website.)
>
> 2)   Driving on the rev limiter.   Although MSD says this about their
> system:
>
> There are two ways to limit your rpms. The rough way simply cuts off
> ignition spark, which can cause backfiring, extreme engine roughness, and possible
> engine damage. The gentle way is with these MSD Soft Touch rev controllers.
> They use sophisticated computer circuitry to drop spark one cylinder at a
> time, until your engine is at or below its maximum rpm. Those cylinders are
> then fired on the next cycle, to prevent them from loading up with fuel. The
> result is smooth rev limiting action without all the rough stuff.
>
> The truth appears to be that even this 'gentle' process is rather hard on
> the system, perhaps aggravated by the fact that I'm running a gear drive
> instead of a timing chain.   It didn't occur to me that running on the limiter
> for a few seconds at a time would stress the system, but in hindsight (and
> after consultations with Dan, who hadn't heard of such a thing but
> subsequently did research and found other stories of people suffering similar damage to
> mine after running on the rev limiter, regardless of whether they were
> using a timing chain, gears or whatever) I'm sure that my driving habits on the
> track created this problem.   I'm going to address this by fitting a higher
> RPM pill in the MSD (the motor is built to go to 6500 all day long but I was
> being 'conservative' and had a 6000 rpm chip in the MSD) and by avoiding
> touching the rev limit, if at all possible, and certainly avoid deliberately
> doing so and just keeping it on the limit.
>
> I think the gears were perfect when I drove over the hill to Reno, and I
> just busted them all to hell at the track.
>
> Tomorrow I'm ordering a new cam, same as the old one (did I mention how
> wonderfully this engine ran?).   Dan also turned me on to a new distributor
> gear.   Tri-Tec Motorsports now makes a carbon-reinforced polymer distributor
> gear for the 351C/460.
>
> http://www.tritecmotorsports.com/Carbon_Ultra-Poly
> -Ford_Distributor_Gears.htm
>
> I am going to phone them and see what they have to say.   I don't want to
> run a bronze gear, because of all the maintenance hassles, but a steel gear
> might not be as good a bet as one of these glorified plastic ones.   At this
> point I think I've got nothing to lose by trying.
>
> The motor will come out of the car early next month (no time before then),
> by which point I should have my new components in hand.   With the help of
> friends more knowledgable than I am (which is most of them, when it comes to
> engines anyway!), I hope to have it repaired and ready to go in a day, then
> installed another day later.
>
> I will have to pull the oil pan and clean all the metal shavings out (and
> also from the front of the engine), and the oil pump pickup is likely filled
> with debris.   It goes without saying that the oil filter will be changed as
> well.   While we'll take a look at the bearings while we're in the
> neighborhood, I'm fairly confident that the rest of the motor was unaffected by this
> little glitch.
>
> We'll see!?
>
> Once it's up and running, I'll pull the distributor every few thousand
> miles to inspect for any signs of untoward wear or failure.   I'm hoping this is
> a one-time situation to be quickly and relatively painlessly resolved.
>
> Fingers crossed!
>
> Mike
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