Pick the cam: Monster torque at low RPM
#1496962
09/06/13 10:14 AM
09/06/13 10:14 AM
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Joined: Jan 2003
Posts: 28,067 Irving, TX
feets
OP
Senior Management
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OP
Senior Management
Joined: Jan 2003
Posts: 28,067
Irving, TX
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I'm thinking about swapping cams in the Imperial. Quickie rundown:
5300 lbs dry 255/70-15 tires (29" tall) 3.23 gears 440 engine Edelbrock heads iron manifolds (maybe switch to HP pieces) wonderful 1972 low compression (8:1 if I'm lucky) a518 transmission (.69 OD) port fuel injection
The intent is to build a highway cruiser.
In stock form, the engine is sufficient at best. The car will cruise nicely but it's burdened a bit by the 1960s cam laziness.
I will not pull the engine so I'm stuck with the low compression.
So, what kind of cam does this thing need?
I was eyeing the Hughes HEH1019BL but doubt I have the cylinder pressure to make it work well.
Intake Valve Lift 1.5 .461" Exhaust Valve Lift 1.5 .489"
Intake Duration at .050" 210° Exhaust Duration at .050" 219°
Lobe Separation Angle 112º
Intake Opening at .050" -4° BTC Exhaust Opening at .050" 44.5° BBC Intake Closing at .050" 34° ABC Exhaust Closing at .050" -5.5° ATC
Min. Suggested Cylinder PSI 150 Sweet Spot RPM IDLE - 4600
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
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Re: Pick the cam: Monster torque at low RPM
[Re: feets]
#1496963
09/06/13 11:51 AM
09/06/13 11:51 AM
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Joined: Jan 2005
Posts: 12,419 Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
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Advance it 4 degrees. I would run some 1.6 rockers to get even more lift without significant increase in duration.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Pick the cam: Monster torque at low RPM
[Re: HotRodDave]
#1496976
09/07/13 01:10 PM
09/07/13 01:10 PM
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Joined: Sep 2006
Posts: 1,139 West Tennessee
rbstroker
super stock
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super stock
Joined: Sep 2006
Posts: 1,139
West Tennessee
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Like HotRodDave said. just advance your stock cam 4*. That will increase your dynamic compression ratio, by closing the intake valve sooner, increasing lower RPM power with little loss of top end. Your stock cam should be about 268* intake valve duration seat to seat. Exactly what you want.
This is the land of the free
because of the brave
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Re: Pick the cam: Monster torque at low RPM
[Re: goldmember]
#1496977
09/07/13 01:23 PM
09/07/13 01:23 PM
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Joined: Oct 2003
Posts: 3,698 NE Oklahoma
Von
master
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master
Joined: Oct 2003
Posts: 3,698
NE Oklahoma
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Quote:
NO reason to put a larger exhaust lobe on anything for LOW RPM torque.
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Re: Pick the cam: Monster torque at low RPM
[Re: rbstroker]
#1496978
09/07/13 03:27 PM
09/07/13 03:27 PM
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Joined: Jan 2005
Posts: 12,419 Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
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I was not thinking the stock cam but the one he posted specs for That is about as good as it's gonna get. The other cams listed give up lift and increase duration, bad things for low RPM The short duration is gonna help it make gobs of TQ at a 1500 cruise and the high lift is gonna give it some air flow for passing gear revs. As for the gearing, if my Dakota that weighs nearly as much as the imp can handle 3.55s a 31 inch tire and .69 OD with a 239 V6 than surely a 440 in a slightly more aerodynamic car and shorter tires will be fine with a 3.23 and OD
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Pick the cam: Monster torque at low RPM
[Re: HotRodDave]
#1496979
09/07/13 03:51 PM
09/07/13 03:51 PM
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Joined: Feb 2003
Posts: 8,671
Andrewh
master
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master
Joined: Feb 2003
Posts: 8,671
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Quote:
in a slightly more aerodynamic car and shorter tires will be fine with a 3.23 and OD
lol. I bet it has more front end surface area than your dakota.
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Re: Pick the cam: Monster torque at low RPM
[Re: feets]
#1496981
09/09/13 10:12 AM
09/09/13 10:12 AM
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Joined: Jan 2006
Posts: 8,162 USA
360view
Moparts resident spammer
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Moparts resident spammer
Joined: Jan 2006
Posts: 8,162
USA
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since you have and use machine tools, what about trying to machine a tapered flat onto the inner piston of your present hydraulic lifters? If it does not work, you will be changing to new hyd lifters with the new cam anyway..... http://www.freepatentsonline.com/5623898.htmlsample quote SUMMARY OF THE INVENTION The variable duration hydraulic valve lifter described herein is designed to provide favorable characteristics over the entire speed range. At low and intermediate speeds a closely controlled oil leak in the pressure chamber is permitted to prevent pumping up to a wholly solid condition. This is accomplished with uniquely configured grooves in the outer surface of the plunger of the valve lifter. These grooves extend the entire length of the upper portion from its top edge to its bottom edge and also on the bottom portion from its top edge to its bottom edge. Each of these grooves has a greater width at their bottom end than their width at their top end. The width of the grooves at their top end is in the range of 0.0042-0.0612 inches. The width of the grooves at their bottom end is in the range of 0.0150-0.0625 inches. The configuration of these grooves is referred to as a pyramid type cut. Also the depth of the grooves may increase from their top edge to their bottom edge. The depth at the top edge of the grooves is in the range of 0.0075-0.0150 inches. The depth of the grooves at their bottom edge is in the range of 0.0080-0.0180 inches. Control tests have been conducted on a 1991 Ford pickup truck that was tuned-up to factory specifications. Then it was sent to a California smog station for testing. Once the smog testing was completed, it went to a wheel dyno for horsepower and torque testing. Thus provided with an accurate starting point established, the Ford pickup had the novel variable duration hydraulic valve lifters installed. No modification to the vehicle's engine of any kind was required nor was any retuning of the vehicle necessary following installation of the novel valve lifters. The Ford pickup was tested again at the smog station and on the wheel dyno. The testing revealed that the novel valve lifters made the following improvements: 91% reduction in hydrocarbons at idle, 37.5% reduction in hydrocarbons at 2500 rpm, elimination of deadly carbon dioxide at idle or at 2500 rpm, increased air flow through the engine, and 7.9% increase in horsepower and torque from the engine. The engine's warm-up time was also cut in half. An additional benefit was that there was an increase in gas mileage from 18.6 mpg. to 20.7 mpg. The use of variable width grooves and/or variable depth grooves in the external surface of the plunger of the variable duration hydraulic valve lifters allows them to be effectively used with multiweight engine oils. In prior art variable duration valve lifters such as the Rhodes lifters, the external grooves in the plungers had a constant width and depth. It was therefore difficult for the oil in their respective reservoirs to enter the bottom ends of their respective grooves and also insure that there would be a continuous flow of motor oil up the length of the grooves. As a result, spurts of oil would be ejected from the top ends of the grooves instead of a controlled continuous flow and the valve lifters would operate inefficiently at low and mid-range rpm. This produces a lose of horsepower and torque, incomplete combustion causing increased emissions and a decrease in gas mileage. The use of variable width grooves and/or variable depth grooves in the external surface of the plunger of the variable duration hydraulic valve lifter also decreases the recovery cycle time considerably for the oil to leave the respective reservoir areas at the bottom of the respective upper portion and lower portion of the plunger, pass along their respective external grooves and return to their respective reservoir areas. The recovery time can be reduced by as much as 50 percent or more.
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