[DeTomaso] FW: Moment of (sad) truth

Tue Jul 1 15:16:45 EDT 2014

i don't know how to read the graph for air/fuel mixture ratio, but is that on there somewhere?

My basically stock motor had a 780 carb on it when I got it. I had to switch to a 600 to pass smog way back when and the car was more tractable after that with little change in max power so i never changed back.

You are probably losing low and medium speed power due to insufficient air velocity thru the venturis at those engine speeds. 

When I put my other car on the dyno the guy could tell me the air/fuel ratio at different speeds, if the timing was off or the points were bouncing, etc.  Did your dyno guy give you that info?

That car was leaning out at high revs because the fuel pump couldn't keep up with demand and the timing was breaking up.  He had me put in a higher capacity fuel pump and change to electronic ignition with a new coil and wires which solved those problems.  Then he rejetted the carbs (Webers) and all was good.

I would take the car back to the dyno guy with the idea of him changing timing and carb jetting to maximize power.  But first change the spark plugs and fuel filter and check the timing to fix the simple things.

But other guys with 100x my knowledge will probably answer and you can ignore what I write  :-)

Jim Oddie

-----Original Message-----
From: Garth Rodericks via DeTomaso <detomaso at poca.com>
To: npdrs <npdrs at maui.net>; Brent Stewart <bjbstewart at yahoo.com>; DeTomaso Mail List <detomaso at poca.com>
Sent: Tue, Jul 1, 2014 10:12 am
Subject: [DeTomaso] FW: Moment of (sad) truth

   Any idea what your cam specs are?  My stock late 72 351C with an
  Edelbrock F351 intake, Mallory Unilite electronic ignition, and Hall
  Big Bore headers with 90,000 original miles made 250 HP at the rear
  wheels.  Check your tune. And do you have a new harmonic balancer on
  that engine?  An old damper/balancer may have slipped, which means your
  timing may be WAY off. Sounds like something is definitely amiss.
n Tuesday, July 1, 2014 8:06
AM, Robert Stroj <[1]npdrs at maui.net> wrote:
So, finally, my '71 Pantera got through all the import procedures and is now
treet legal in Europe/Germany!
ar is in very good shape, zero rust anywhere, suspension feels very good to
rive (height adjustable koni set), brakes work well (wilwood conversion),
ut there is something not right with the motor.
ngine is a older 351C rebuild using original crankshaft and pistons. Some
ears later it was fitted with CHI 3V heads and intake system, SS valves,
80 Holley and GTS exhaust system.
hen driving the cart was pulling well, but definitely was not feeling as
00-500HP car; this is what I was sort of expecting after talking to person
ho rebuild the engine as well as previous owner...it did not really feel as
00HP car...
 had a chance to put it on the dyno at the friend's garage and got the
ollowing graph (please see the attached image); this are graphs for
djusted power on the flywheel after recalculating looses between engine and
heels.
hat was really interesting is that he had a chance to test 2 other panteras
ecently; one was a client that had rebuilt engine using some "special
arts", bt I am not sure of the actual spec while the other one was black
R4 replica that is currently listed for sale in Germany and was built by
raun Motorsport:
[2]http://suchen.mobile.de/auto-inserat/detomaso-pantera-gruppe-4-m-hist-strass
nzul-neuaufbau-neuried-bei-m%C3%BCnche/159513949.html?lang=de&pageNumber=1&
_lp=1&scopeId=C&sortOption.sortBy=creationTime&sortOption.sortOrder=DESCEND
NG&makeModelVariant1.makeId=7400&makeModelVariant1.searchInFreetext=false&m
keModelVariant2.searchInFreetext=false&makeModelVariant3.searchInFreetext=f
lse&ambitCountry=DE&negativeFeatures=EXPORT
So, finally, my engine did not even reach 250HP, another rebuild pantera
otor did just over 300HP while Braun pantera did very nice 389HP; there is
lso Ford GT40 with racing motor in there; it did 410hp but at much higher
PM.
he most impressive about the Braun car is how smooth the power curve is.
So, now I am wondering where to go from here; could it be that it is as
imple as wrong cam choice?
f going to do a rebuild is there a good configuration someone could suggest
hat would use CHI3V heads and intake, as I already got those?
As well, I had something strange happen twice with the gearbox; it got out
f the 3rd gear by itself; would someone know if this could be due to any
rong linkage adjustment?
Thanks, Robert
References
   1. http://poca.com/mailman/listinfo/detomaso_poca.com
  2. http://suchen.mobile.de/auto-inserat/detomaso-pantera-gruppe-4-m-hist-strass

_______________________________________________
Detomaso Forum Managed by POCA
DeTomaso mailing list
eTomaso at poca.com
ttp://poca.com/mailman/listinfo/detomaso_poca.com

-------------- next part --------------
   i don't know how to read the graph for air/fuel mixture ratio, but is
   that on there somewhere?

   My basically stock motor had a 780 carb on it when I got it. I had to
   switch to a 600 to pass smog way back when and the car was more
   tractable after that with little change in max power so i never changed
   back.

   You are probably losing low and medium speed power due to insufficient
   air velocity thru the venturis at those engine speeds.

   When I put my other car on the dyno the guy could tell me the air/fuel
   ratio at different speeds, if the timing was off or the points were
   bouncing, etc.  Did your dyno guy give you that info?

   That car was leaning out at high revs because the fuel pump couldn't
   keep up with demand and the timing was breaking up.  He had me put in a
   higher capacity fuel pump and change to electronic ignition with a new
   coil and wires which solved those problems.  Then he rejetted the carbs
   (Webers) and all was good.

   I would take the car back to the dyno guy with the idea of him changing
   timing and carb jetting to maximize power.  But first change the spark
   plugs and fuel filter and check the timing to fix the simple things.

   But other guys with 100x my knowledge will probably answer and you can
   ignore what I write  :-)

   Jim Oddie

   -----Original Message-----
   From: Garth Rodericks via DeTomaso <detomaso at poca.com>
   To: npdrs <npdrs at maui.net>; Brent Stewart <bjbstewart at yahoo.com>;
   DeTomaso Mail List <detomaso at poca.com>
   Sent: Tue, Jul 1, 2014 10:12 am
   Subject: [DeTomaso] FW: Moment of (sad) truth
   Any idea what your cam specs are?  My stock late 72 351C with an
   Edelbrock F351 intake, Mallory Unilite electronic ignition, and Hall
   Big Bore headers with 90,000 original miles made 250 HP at the rear
   wheels.  Check your tune. And do you have a new harmonic balancer on
   that engine?  An old damper/balancer may have slipped, which means your
   timing may be WAY off. Sounds like something is definitely amiss.
On Tuesday, July 1, 2014 8:06
 AM, Robert Stroj <[1]npdrs at maui.net> wrote:

So, finally, my '71 Pantera got through all the import procedures and is now
street legal in Europe/Germany!
Car is in very good shape, zero rust anywhere, suspension feels very good to
drive (height adjustable koni set), brakes work well (wilwood conversion),
but there is something not right with the motor.
Engine is a older 351C rebuild using original crankshaft and pistons. Some
years later it was fitted with CHI 3V heads and intake system, SS valves,
780 Holley and GTS exhaust system.
When driving the cart was pulling well, but definitely was not feeling as
400-500HP car; this is what I was sort of expecting after talking to person
who rebuild the engine as well as previous owner...it did not really feel as
300HP car...
I had a chance to put it on the dyno at the friend's garage and got the
following graph (please see the attached image); this are graphs for
adjusted power on the flywheel after recalculating looses between engine and
wheels.
What was really interesting is that he had a chance to test 2 other panteras
recently; one was a client that had rebuilt engine using some "special
parts", bt I am not sure of the actual spec while the other one was black
GR4 replica that is currently listed for sale in Germany and was built by
Braun Motorsport:

[2][1]http://suchen.mobile.de/auto-inserat/detomaso-pantera-gruppe-4-m-hist-stra
ss
enzul-neuaufbau-neuried-bei-m%C3%BCnche/159513949.html?lang=de&pageNumber=1&
__lp=1&scopeId=C&sortOption.sortBy=creationTime&sortOption.sortOrder=DESCEND
ING&makeModelVariant1.makeId=7400&makeModelVariant1.searchInFreetext=false&m
akeModelVariant2.searchInFreetext=false&makeModelVariant3.searchInFreetext=f
alse&ambitCountry=DE&negativeFeatures=EXPORT

So, finally, my engine did not even reach 250HP, another rebuild pantera
motor did just over 300HP while Braun pantera did very nice 389HP; there is
also Ford GT40 with racing motor in there; it did 410hp but at much higher
RPM.
The most impressive about the Braun car is how smooth the power curve is.

So, now I am wondering where to go from here; could it be that it is as
simple as wrong cam choice?
If going to do a rebuild is there a good configuration someone could suggest
that would use CHI3V heads and intake, as I already got those?

As well, I had something strange happen twice with the gearbox; it got out
of the 3rd gear by itself; would someone know if this could be due to any
wrong linkage adjustment?

Thanks, Robert

References

   1. [2]http://poca.com/mailman/listinfo/detomaso_poca.com
   2. [3]http://suchen.mobile.de/auto-inserat/detomaso-pantera-gruppe-4-m-hist-s
trass

_______________________________________________

Detomaso Forum Managed by POCA

DeTomaso mailing list
[4]DeTomaso at poca.com
[5]http://poca.com/mailman/listinfo/detomaso_poca.com

References

   1. http://suchen.mobile.de/auto-inserat/detomaso-pantera-gruppe-4-m-hist-strass
   2. http://poca.com/mailman/listinfo/detomaso_poca.com
   3. http://suchen.mobile.de/auto-inserat/detomaso-pantera-gruppe-4-m-hist-strass
   4. mailto:DeTomaso at poca.com
   5. http://poca.com/mailman/listinfo/detomaso_poca.com