Author Topic: Question about starting the motor  (Read 918 times)

Offline cudabob496

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Question about starting the motor
« on: July 23, 2016 - 08:42:12 PM »
Lately, when I fire it up, there seems to be a bigger boom or bang, on the right side of the engine,
that really jolts the car. Then, it idles ok, and runs good. But may be getting more difficult to start also. Anyone
know what might be up?
« Last Edit: July 23, 2016 - 09:33:00 PM by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000




Offline cudabob496

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Re: Question about starting the motor
« Reply #1 on: July 24, 2016 - 01:28:15 AM »
maybe I need to back of a little on the timing. will try that.
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline HP_Cuda

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Re: Question about starting the motor
« Reply #2 on: July 24, 2016 - 12:46:10 PM »

Timing and put AFR on there
1970 Cuda Clone 440 4 speed - sublime green
1970 Cuda 383 4 speed - yellow - SOLD

Offline cudabob496

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Re: Question about starting the motor
« Reply #3 on: July 24, 2016 - 04:51:27 PM »
ya, got AFR.
I think what is going on is I crank the engine frist, then cut in the ignition system by flipping a swith
to the MSD box.  Same benefit as timing retard at startup. Might be loading up the cylinders with more gas than normal, thus the bigger boom
when things ignite.
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Chryco Psycho

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Re: Question about starting the motor
« Reply #4 on: July 24, 2016 - 08:31:09 PM »
My question would be did you or what did you change when the situation changed ?

Challenger - You`ll wish You Hadn`t

Offline cudabob496

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Re: Question about starting the motor
« Reply #5 on: July 25, 2016 - 02:31:28 AM »
My question would be did you or what did you change when the situation changed ?

Only diff is its been hotter outside lately. going to try to flip the ignition switch
within a second of hitting the start button. IF no change, will need to take
a closer look at carb, or timing.  May need to check other electrical stuff as well.

If I have holes in throttle plates, do I need to have the gas pedal slightly depressed
when starting?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline cudabob496

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Re: Question about starting the motor
« Reply #6 on: July 25, 2016 - 03:09:23 AM »
dang, just remembered, I did make a change. Two weeks ago closed idle adjust screw a quarter turn to increase idle
from 1100 to 1400. Will go back to 1100 and see if starting easier.
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline HP_Cuda

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Re: Question about starting the motor
« Reply #7 on: July 25, 2016 - 11:48:15 AM »

I know a few guys who write down all their changes so they can go back and see what's up.

 :bigsmile:
1970 Cuda Clone 440 4 speed - sublime green
1970 Cuda 383 4 speed - yellow - SOLD

Offline CUDA JAS

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Re: Question about starting the motor
« Reply #8 on: July 25, 2016 - 12:18:34 PM »
dang, just remembered, I did make a change. Two weeks ago closed idle adjust screw a quarter turn to increase idle
from 1100 to 1400. Will go back to 1100 and see if starting easier.

why are  you idling the engine so high???

Jason
74 'cuda 360/727



Gearhead: car nut, automotive enthusiast, one who loves hot rods, muscle cars, hot trucks, burnin' rubber and neck snapping performance. 

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Offline cudabob496

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Re: Question about starting the motor
« Reply #9 on: July 25, 2016 - 12:58:03 PM »
why are  you idling the engine so high???

Jason

With my cam, engine just seems to like it. Should have mentioned that is in neutral. In gear, around 1100. Also the higher
rpm idle gives better performance of the alternator (for my electric fan) and water pump. Also, when I stab the throttle
at a stop light, car is more responsive with the idle high. When driving, only at idle maybe 1% of the time, so no
biggee.
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000