I set my 602 crate at 32* at 4000 rpms as recommended. All of my other built motors were always set around 36*. I have heard that I can gain several Hp just by playing with the timing on these crates. Does anybody have any dyno time with one of these things. I have never had a problem with heat with this motor, so that is not a concern but I also don’t want to affect the reliability of it either.
Don’t know how true,but I heard 32* with pump gas and 36* with race fuel.
Just heard this,don’t know if it’s true.
-JIM-
Check these guy out:
Hendren Racing Engines
1310 U.S. Hwy 221 North
Rutherfordton North Carolina 28139
828-286-0780
www.hendrensracingengines.com
Either call them or ask on line at 4m.net, they normally answer. They seems to be the sources for all Crate motor question & answers.
I’m not sure about your 602 but mine the factory pointer was 4 degrees off at tdc. I was running 36 to 38 after the pointer was reset.
I have no experience with what the optimum timing is on a crate motor but one thing I have learned the hard way is that retarded timing creates MORE heat in the motor, not less. You want the timing to be advanced just this side of detonation. Glowing headers generally indicate either retarded timing or weak valve springs (valves bouncing on the seats)
I appreciate all of the info. I know a lot of it would depend on the jetting, spark plugs, cfm and air-fuel mixture. The spark plugs and valve springs are always brand new or real close. The plugs are the recommended Ac delcos and the valve springs are always the stock Chevy springs recommended by Chevy.
I have heard of people changing valve springs to drop cylinder pressure and setting the timing at 28* and gaining around 20 hp. I have also heard that for every 1* of timing you can pick up 7 +/- hp but you also have to take heat into consideration. I have been around motors most of my life but these kind of things are really interesting and I would love to have the time to spend on a dyno with somebody who is willing to teach somebody that is willing to learn.
[QUOTE=Edm;35068]I appreciate all of the info. I know a lot of it would depend on the jetting, spark plugs, cfm and air-fuel mixture. The spark plugs and valve springs are always brand new or real close. The plugs are the recommended Ac delcos and the valve springs are always the stock Chevy springs recommended by Chevy.
I have heard of people changing valve springs to drop cylinder pressure and setting the timing at 28* and gaining around 20 hp. I have also heard that for every 1* of timing you can pick up 7 +/- hp but you also have to take heat into consideration. I have been around motors most of my life but these kind of things are really interesting and I would love to have the time to spend on a dyno with somebody who is willing to teach somebody that is willing to learn.[/QUOTE]
I’m having a real hard time visualizing how late timing and lower cylinder pressures could result in more power. Lower torque peak, or a wider torque curve maybe, but everything I ever read always seemed to indicate that a mixture that’s on the lean side of stoichiometric and timing advanced just this side of detonation would give the max power output. I always understood that higher cylinder head pressures always meant more power. You can run into some strange stuff when you’re dealing with special circumstances like restictor plate motors and such. I remember running really high advance numbers when we were running the little bitty 350 cfm carbs as well as static compression ratio’s that you’d never get away with in an open motor. I think we were up around 42 degrees ign timing. I do know that peak horsepower doesn’t always equate to quicker lap times. I know I used to run the old weed burner zoomie headers back when we were only allowed under the frame headers and the engine builders absolutely despised those things beacause they really killed high rpm horsepower but I damned sure got around the track quicker because it got into the corners better (no scavenging meant better engine braking) and it came off harder (lower peak torque). It SOUNDED so damned mean with those things that I think the psychological factor might have been good for another 10th or so! Had to wear ear plugs though, it was so loud in the car that I couldn’t SEE at the end of the straights! It was shaking my eyeballs too bad!
Ed,
Call me 407-227-3688