Yawn Dart??? 1968 Hurst hemi proTouring clone

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mderoy340 said:
Do you street drive or is this track only car?
What do you have your timing at? Initial and total mechanical.
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I will street drive it in the future after I restore it over the winter but for now its a track only car. Initial is 16 but I can't get my total until I get a better timing light. Yes I know I can tape the balancer just haven't done it yet.
 
Dubs Chops said:
I will street drive it in the future after I restore it over the winter but for now its a track only car. Initial is 16 but I can't get my total until I get a better timing light. Yes I know I can tape the balancer just haven't done it yet.
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Your car is porpoising leaving the line, watch the video in slow motion. Rear tire loaded and unloaded several times. Make sure the rear shocks are long enough with the rear suspension hanging. I run Comp Eng 3 ways in 50/50 setting, Fronts are 90/10. Some folks will say you need big money shocks to fix the launch, but the CE works on my car running 11.7
You need more timing and need to fix that before messing with the carb. I run 25* initial 34* total in my 340 with the XS274S solid cam. Modified OEM distributor welded slots with one medium/light spring. Fix that and go back to stock jetting.
I launch at 2k foot brake and use 33 nozzles. I use a white cam in #2 cam and throttle hole on the primaries to delay the pump shot start. Launching at 3k you have use some of the pump shot before leaving the line. The rear is fine with pink cam #1 hole.
here's a good read for carb tuning
Carb Tunning
 
mderoy340 said:
Your car is porpoising leaving the line, watch the video in slow motion. Rear tire loaded and unloaded several times. Make sure the rear shocks are long enough with the rear suspension hanging. I run Comp Eng 3 ways in 50/50 setting, Fronts are 90/10. Some folks will say you need big money shocks to fix the launch, but the CE works on my car running 11.7
You need more timing and need to fix that before messing with the carb. I run 25* initial 34* total in my 340 with the XS274S solid cam. Modified OEM distributor welded slots with one medium/light spring. Fix that and go back to stock jetting.
I launch at 2k foot brake and use 33 nozzles. I use a white cam in #2 cam and throttle hole on the primaries to delay the pump shot start. Launching at 3k you have use some of the pump shot before leaving the line. The rear is fine with pink cam #1 hole.
here's a good read for carb tuning
Carb Tunning
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I was wondering about the pumps, I'm floorboarding it so I am using all the pump before the hit. I had read it wouldnt matter saint the cart was wide open. I'm not sure what stock jetting is, I think like 71/80 was what came in the carb. Yes I do think more initial timing will help. Wouldnt more initial power help keep the suspension loaded until i shifted to 2nd? I'll give the link a read also. Thanks for the info. I do have adjustable shocks on all four corners I'll take a look and report back with how they are set.
 
Dubs Chops said:
I was wondering about the pumps, I'm floorboarding it so I am using all the pump before the hit. I had read it wouldnt matter saint the cart was wide open. I'm not sure what stock jetting is, I think like 71/80 was what came in the carb. Yes I do think more initial timing will help. Wouldnt more initial power help keep the suspension loaded until i shifted to 2nd? I'll give the link a read also. Thanks for the info. I do have adjustable shocks on all four corners I'll take a look and report back with how they are set.
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I'm not a trans brake driver so maybe some else can comment. I think the rear shocks may be to short. Have someone video the rear suspension and put a white stripe on the rear tire so you can really see what is happening.
74/80 should be stock jetting
Brawler BR-67213 750 CFM Brawler Street Carburetor Mechanical Secondary
 
After doing a little studying over the weekend I believe whats going on here is it is Dead Hooking the tire. I may need to up my PSI a few and perhaps soften the rear shocks some. We shall see.
 
Dubs Chops said:
After doing a little studying over the weekend I believe whats going on here is it is Dead Hooking the tire. I may need to up my PSI a few and perhaps soften the rear shocks some. We shall see.
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After watching the video it looks like a bog, probably going lean? I agree with Mderoy that it probably wants more initial timing and then you can start tuning the accelerator pump circuit with pump cams and nozzles.

Do you have a wideband and AFR guage?
 
Walker434 said:
After watching the video it looks like a bog, probably going lean? I agree with Mderoy that it probably wants more initial timing and then you can start tuning the accelerator pump circuit with pump cams and nozzles.

Do you have a wideband and AFR guage?
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No I don't, However with the trans brake and the pedal on the floor I have no accelerator pump action on the hit. they have already done their thing during the stage.
 
Dubs Chops said:
No I don't, However with the trans brake and the pedal on the floor I have no accelerator pump action on the hit. they have already done their thing during the stage.
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That makes sense. Wasn't thinking about the trans brake. I'm a foot brake guy.
 
You have a junk torque converter in it, super simple. Put a good one in there, watch your 60ft and et drop significantly
 
Because your able to stall to 3k, but it 60 fts like a slug, that's what's bogging the motor.
 
I think the converter is your whole issue, I don't know how many other ways to say it.
 
replicaracer43 said:
I think the converter is your whole issue, I don't know how many other ways to say it.
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Sorry i'm probably not being clear. I was asking if a converter can lock up when going bad causing the bog? I always thought a bad converter would slip instead of lock up.
 
Call someone like ultimate converter, and have a unit built for YOUR cars specs, and you will be amazed by the difference
 
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