Went to the dyno this morning....

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72Duster440

72Duster440

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And pulled less power than I was expecting. It was sure blowing the carbon out of the motor though on the first couple pulls.

Here's the specs that I know on the motor, I haven't done anything to it since I got it.

1967 HP 440 BLOCK, RODS AND CRANK
FORGED TRW FLAT TOP PISTONS
572 CRANE CAM
915 CLOSED CHAMBER HEADS, PORTED, POLISHED AND FLOWED
2.14 INTAKE AND 1.81 EXHAUST VALVES WITH DOUBLE SPRINGS
MOPAR PERFORMANCE SINGLE PLANE INTAKE
HOLLEY 780 VACUUM SECONDARY CARB
2” PRIMARY LONG TUBE HEADERS WITH HOOKER MUFFLERS
MSD 6A IGNITION BOX


IMG.jpg



One thing we did notice on the last pull, above ~5500rpm the fuel pressure dropped to 1-2psi, but even at idle I can't get it above 5psi regardless of where the regulator is set. I also noticed that the fuel filter after the pump barely has any fuel in it.

Would this be a puel pump on the way out?
 
Your horsepower certainly seems low. The first thing that comes to my mind is who did the head work and how much do they actually flow? An amateur port and polish job could actually decrease the amount that they'll flow. Also, the M1 intake may be a little ambitious with those heads, especially if they happen to have a poor port job.

Just my $.02
 
What's the static compression ? Have you done a cylinder leakdown test on the motor ? The carb. calibrations and timing may be poor. How much octane are you running ? (pump gas ?
 
I honestly don't know, my wife got me this car as our wedding present and the guy she bought it from wasn't the guy who built it. The only motor info I have is the stuff listed about, which was in the for sale ad. The car is setup for the track, so I would have assumed it would put more to the ground. It's got a TCI Streetfighter trans, 3500 stall TCI converter, narrowed 8 3/4 with 3.91 gears, 30 spline alloys, 489 case with an auburn and 13.5" wide slicks. ANd the shift light comes on at 7k, but the power stops at 6k lol

That tells me it should have more power, unless its just really over built.
 
Mr Hemi said:
What's the static compression ? Have you done a cylinder leakdown test on the motor ? The carb. calibrations and timing may be poor. How much octane are you running ? (pump gas ?
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I don't know the CR on the motor, I just had the carb rebuild and 'tuned' from a carb shop. It runs 93 pump gas. From some of the receipts I have, the motor was built about 10-11 years ago, and has had about 3-4k miles put on it since then.

They want $120 an hour at the dyno shop to tune and said it should be under two hours, I think at the end of the season I'll take it up there and see what they can do.
 
I agree with blackhand about the heads. The hp numbers seem a little low. I think I would be more concerned with the low torque #. A duel plane intake and smaller cam would probably wake it up a lot.
 

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I can't see the sheet on this PC. Was this a chassis dyno or engine dyno? What did it pull for tq and hp and at what rpm? Did they have a wide band on it?
 
moper said:
I can't see the sheet on this PC. Was this a chassis dyno or engine dyno? What did it pull for tq and hp and at what rpm? Did they have a wide band on it?
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Chassis dyno, it pulled 322hp @ 5080 and 345 ft/lbs @ 4750.


I just ordered a new Holley fuel pump for it, I figured that was a good starting point as well.
 
I punched in your info into "cam-quest" and the dyno numbers you posted look similar after drivetrain % loss.

The 440 in my Scamp prolly has about the same horsepower yours does, maybe a lil' less than yours, and its quickly getting to rebuild time. Motor runs great, just seems like not enough horsepower anymore. Maybe in another year or so I'll be able to put together some Max Wedge fun with light weight pistons and some 11:1 compression action.

Bad Shrimp

P.S.
When I bought the car the previous owner said the heads were worked over and flowed etc.............I dont think he was lying, but I assumed he may have been telling a big fish story. Only way to know for sure is by pulling the heads, if I do that I know I wont be putting them back on lol.
 
Purple Haze said:
If it were me I would start with the fuel problem.
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I would pinch the rubber fuel line before the filter while running and then let it go to see if the gas just trickles into the filter or a nice steady steam flows in, I had a simile problem. Fuel pump going out . Nice Wife ! wedding gift:angel13:
 
wheres the a/f ratio chart? do a cranking compression check and see what kind of numbers you get.
 
How about stock lines? Were they upgraded? Some say it isnt nessary and some say it is. Look for obstruction and clogged lines filters. It could have a stock pump on it which may not be enough. If the power stops at 6k why go to 7k? I wouldnt be waiting for the shift light to come up.. Unless your going through the traps.
 
When I pinch the fuel line and let go nothing changes. From what I can tell it appears to be the original. Summit is shipping me out a new one along with a new carb feed line today.

Im pretty happy with the feel of the car, I will probably just leave everything as is once the fuel issue.is fixed.

There was no air fuel, they usually only monitor it when they are dyno tuning, plus I don't have an O2 bung installed.
 
72ScampTramp said:
How about stock lines? Were they upgraded? Some say it isnt nessary and some say it is. Look for obstruction and clogged lines filters. It could have a stock pump on it which may not be enough. If the power stops at 6k why go to 7k? I wouldnt be waiting for the shift light to come up.. Unless your going through the traps.
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The fuel lines from the tank are all 1/2" then out of the pump they are 3/8". There is a Holley adjustable regulator on it with two lines running to the carb. The filter is brand new.

I usually don't rev it past 5500, now that I know where the power drops, I definitely have no need to go much higher than that. I'll get a new chip for the light so it comes on sooner.
 
Get some time slips, a dyno is a tuning tool. As long as you feel the motor is healthy to do so.
 
72ScampTramp said:
whats the pressure before the regulator?
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I haven't measured that, I'll see if I can swap the gauge to before the regulator. That was another thought that I had was the regulator was stuck.

edit:

I put the gauge before the regualtor, it never moved off of 5 3/4 psi. Still a pound low, but better than whats coming out of the regulator. The new pump I ordered has a maximum pressure of 6.5-8 psi. Should I still run a regulator with it or is that a safe enough pressure to stick with?

I ordered this one...
http://www.summitracing.com/parts/HLY-12-440-11/
 
The outlets on that pump are 1/4 inch? Also yes I would set that regulator at 7psi and start. You will know if you need to go up or down. Not sure thats enought pressure or volume to fuel a build like that.

You could remove the regulator and see if its better? It probably wont be by much but will let you know if you are on the right track.
 
Damn, good catch, it was the only one they sell for a 440, I didn't notice the 1/4" size. That might give me a little issue, I may have to return it and get one with bigger fittings from somewhere else.

Currently I can't get 7 out of the regulator, I'll have to wait till the new pump shows up to try that.
 
Electric pump, regulator set at 7 psi and (minimum) 3/8" line from the tank to the regulator. Use a 1/2 pick up in the tank or better yet add a sump with 1/2 " NPT bungs.

Need to KNOW the compression ratio and the cam specs to KNOW where you're at in producing (or not) the power.

915 heads don't do much if the pistons are .080 in the hole. Cam duration and CL both ground and installed are critical. If the cam is 270 at .050 for example, it's going to have a hard time making torque with low compression.

It the very minimum I'd pull the heads, have them flowed, evaluate the deck height, get the numbers from the cam and go from there.

A basic, flat top 440 with even mild heads and cam should go 400-425 HP on the dyno and have so much torque it'd be hard to keep on the rollers.

If you took it to the Jake I'm thinking you did, RIGHT THERE is a GREAT source to waking her up!

Yes, a HIGH-FIVE to the bride...Way cool wedding gift!
 
What is ignition timing settings at idle and at 2500 rpm. If too low will not have the power. Should be about 34 to 37 at 2500 rpm. The MSD dist should give a lot of adjustment.
 
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