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Re: torque engine build
[Re: rbstroker]
#1069640
09/20/11 02:15 PM
09/20/11 02:15 PM
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Joined: Feb 2003
Posts: 1,665
Milwaukee, WI
Prince_Valiant
top fuel
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top fuel
Joined: Feb 2003
Posts: 1,665
Milwaukee, WI
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Honestly, spec a cam ~ 228 @ .050 duration with a wider lsa of 112-114. This will give you peak torque in the ~-2500-3000rpm range, probably on the order of 550-ish ft-lbs.
1979 Dodge Lil' Red Express - 360 rwhp, 13.2 @ 103mph
1968 Coronet: 318, 2.76, 15.2 @ 92mph! (SOLD)
1976 Valiant: 360, 3.90, 12.90 @ 106 (SOLD)
1989 Shelby CSX #500/500
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Re: torque engine build
[Re: rbstroker]
#1069641
09/20/11 06:39 PM
09/20/11 06:39 PM
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Joined: Jan 2007
Posts: 7,664
IN
ahy
master
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master
Joined: Jan 2007
Posts: 7,664
IN
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Quote:
The math for the compression ratio turned out to be exactly 9.9:1. Everything was exactly cc'd.
I do have a mild pinging issue if I roll into the gas a bit too hard in high gear at lower RPM. I use pump premium without ethanol. I also have the proper amounts of sta-bil and Marvel Mystery Oil in the tank. I believe that the MMO helps lubricate the valves without leaded gas.
This morning, I decided to replace my early 60's timing light, that I bought new about 1963, with a digital type so I can get some exact numbers. I am able to set my idle at 800 RPM. My initial was 8.4* and stayed that way through 1000RPM. At 1500 it went to 18.2* and maxxed out at 25* at 2000RPM. With the vacuum advance hooked up, I read 9.1* at 800RPM and I had 10# vacuum. At 1000RPM I had 20.5* and 15# vacuum. At 1500 the total was 38.3* and 18# vacuum.
Per suggestions, I set the initial at 18* at 950RPM. I watched as the mechanical advance maxxed out at 1880RPM. I read a total of 34.9* at 2000 RPM without any vacuum advance.
If the streets dry up a bit, I'll try this initial setting and then try with the vacuum advance hooked up.
Thanks again, I will keep you posted.
If you can slow the mechanical advance so it is all in around 3000 RPM instead of 2000 you may reduce the pinging problem and smooth out operation below 2000 RPM. Marvel Mystery oil is a great lubricant but it does drop the octane a bit.
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Re: torque engine build
[Re: rbstroker]
#1069643
09/21/11 01:34 PM
09/21/11 01:34 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
I wonder what simply changing the intake centerline from the recomended 106* to about 111* would do.
I'd definitely swap the intake to an eddie RPM...
you'd want to go the other way-- move from 106 to say 102, to get the intake closing point earlier.
for a cam, I'd probably drop to a Lunati voodoo 60303 (IIRC, 268 adv, 226@.050 and about .5" lift), should still work reasonably well with your compression.
or maybe even a 60302 (~262 adv ~220.050, ~.475" lift)
add long tube headers, even 1 3/4" cheapies...should be an easy 20 lb-ft of torque throughout the rev range.
the wider LSA of the lunati cams (IIRC both are 112 degrees) will reduce overlap and smooth out the idle at the cost of peak midrange torque (torque curve will be flatter, but with a slightly lower peak)....the wider LSA also helps carry torque higher up in the rev range, offsetting the duration loss to help with upper RPM HP production
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: torque engine build
[Re: ahy]
#1069644
10/03/11 12:23 PM
10/03/11 12:23 PM
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Joined: Sep 2006
Posts: 1,139
West Tennessee
rbstroker
OP
super stock
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OP
super stock
Joined: Sep 2006
Posts: 1,139
West Tennessee
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Quote:
The extra cubes will lower the RPM range with that cam and boost peak torque. All in the direction you want to go.
The only thing I wonder about is pinging/detonation. I believe you posted you have 10:1 with iron heads. Is the 10:1 calculated with everything cc'd or based on the piston manufactures estimate? Piston manufacturers estimate high just like MOPAR did. If it is true 10:1 your current cam's higher duration may be keeping detonation at bay. Less duration may cause a problem but may not. The wider LSA actually helps prevent detonation (per comp's guidance) so it may be a wash.
Bottom line, I think the cam is a good fit. The 6 pack is also... its dual plane for good response at light loads running on a single 2 bbl. May be a little trickey to set up but good for what you want to do, a great runner and lots of fun.
It sounded like your current distributor was advancing too fast as well. I would get it checked out and adjusted. About 15 degrees initial advance and 19 mechanical advance (34 total mechanical) all in by 2800-3000 RPM should about right. This is a gentle advance curve for a heavy car and high pump gas compression ratio. An additional 15-20 degrees vacuum advance can be added on top for cruising.
I received and installed a set of distributor springs and an advance limiter from 4 seconds flat this past weekend. Per advice given here, I set up my old tach drive distributor (no vacuum advance can) with the heaviest of the springs and a 20* mechanical limit. Installed everything with about 15* initial and a total of about 34* at full advance (over 3000rpm). No other changes. Drastically decreased the "surging" and I can now let out the clutch at a stoplight without having to bring the revs way up. Pinging seems to be minimized if not gone completely. A lot more driveable all in all. I think that I'll do a bit more tweeking and once satisfied, re-install the six pack. I find that the folks on this site are pretty darn knowledgeable and willing to help.
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