Easy "fix" for starter kick-back

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MopaR&D

MopaR&D

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A few months ago I installed one of those carb heat shield plates to help reduce fuel percolation (hard starting when hot, rough idling etc.) and it worked great. However it raised a new problem, that being some nasty starter kick-back when trying to start the engine warm. For my engine combo my cam is pretty small (Lunati Voodoo 256/262* dur. in a 360 with 10.5:1 compression) and makes a lot of cylinder pressure at low RPM. Backing the timing down made no difference unless I went way down to like 4* BTDC or less which totally threw off the rest of my timing and made it run rather crappy; other than the starter kick-back it runs great with 10* initial and 32-33* total (minus vacuum of course) with no pinging on mid-grade pump gas. I thought about why that happens and figured if there was a way to crank the engine first without spark to get it spinning in the right direction and THEN turn on the ignition it would take away the possibility for the rotating assembly to kick back the other way when I go to start the car. I am running a Mallory HyFire-6A box so I simply wired a toggle switch into the circuit going to the 'ignition-on' signal to the box. When I go to start the car warm I leave the switch off and crank it over for a second, then flip the switch and VOILA! fires right up with no fuss. Seems to be an easy way to get past starter kick-back without having to resort to very low initial advance or a starting-timing-retard function in your ignition system.
 
MOPEkidD-3 said:
other than the starter kick-back it runs great with 10* initial .
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I think you have other problems. No engine should kick back at only 10 initial

Check the balancer with a piston stop to be sure your marks are even accurate

There has been some posts on the www indicating timing light problems with MSD, if that's what you are using, so your timing might not be where you think it is.

Otherwise, not enough battery, something wrong with the flywheel, bad starter, etc
 
67Dart273 said:
I think you have other problems. No engine should kick back at only 10 initial

Check the balancer with a piston stop to be sure your marks are even accurate

There has been some posts on the www indicating timing light problems with MSD, if that's what you are using, so your timing might not be where you think it is.

Otherwise, not enough battery, something wrong with the flywheel, bad starter, etc
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I assembled the engine myself with a new Summit SFI damper barely 3 years ago and the timing marks were spot-on. I am using a multi-spark box but it's made by Mallory not MSD, I am aware of issues with those and the dial-back timing lights and mine is a regular one; I don't need a dial-back light as the damper has timing marks all the way up to 60* BTDC. I also know the parts you mentioned are all good I am using a mini-starter which cranks super fast; I do need a new battery but this was happening even when I had a full charge. It would kick back before the engine even had a chance to turn over once, literally almost instantly after I would turn the key to crank the engine.

I even Sea-Foam'd the engine (twice) to remove carbon which I thought was causing hot spots and preignition but that made no difference. Something I do notice now when I crank the engine hot with no spark it "sputters" a bit like the fuel-air mixture is igniting itself solely from compression and heat... My combo is a little "unusual" I have a 360 bored .060" over with KB flat-tops and factory iron Magnum heads (with factory 1.6:1 rockers), true static compression was verified during assembly at 10.42:1 and like I said the cam is very small for the cubes/compression this engine makes MONSTER torque on the bottom end and runs perfect aside from the starter kick-back I had before I did this ignition mod.
 
crackedback said:
Starter cables and grounds.
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Could you elaborate a bit? I will check when I get the chance but I am currently in Dubai and won't be back in Denver until the 30th lol... If my starter seems to work perfectly fine how would the cables and grounds cause this problem?
 
When my 493", aluminum headed 12.8 to 1 motor gets hot, it just stalls the starter on the first try, but usually spins it on the second try. Sometimes. it's to easier to start if I spin the motor with the starter and then flip the toggle switch for the ignition to light. I wired in a cut out switch to the ignition box using a relay.

I heard guys with roots style superchargers do the same thing, but in their case to avoid blowing the blower off the top of the motor. Could be. I never had a blower on my car.
 
jbc426 said:
When my 493", aluminum headed 12.8 to 1 motor gets hot, it just stalls the starter on the first try, but usually spins it on the second try. Sometimes. it's to easier to start if I spin the motor with the starter and then flip the toggle switch for the ignition to light. I wired in a cut out switch to the ignition box using a relay.

I heard guys with roots style superchargers do the same thing, but in their case to avoid blowing the blower off the top of the motor. Could be. I never had a blower on my car.
Click to expand...

My problem is (was?) exactly what you describe it would stall out the starter first try then fire up the next try; it spins the engine over plenty fast. I got really freaked out a couple times it was so bad I heard the starter teeth grind that was my "F that SH**" moment lol...
 
You did`nt say but have you tried giving it a couple 1/4 throttle shots of gas when hot?
Mine will do the same when hot and that`s all mine needs, Still have to fine tune my timing.
 
MOPEkidD-3 said:
I assembled the engine myself with a new Summit SFI damper barely 3 years ago and the timing marks were spot-on. I am using a multi-spark box but it's made by Mallory not MSD, I am aware of issues with those and the dial-back timing lights and mine is a regular one; I don't need a dial-back light as the damper has timing marks all the way up to 60* BTDC. I also know the parts you mentioned are all good I am using a mini-starter which cranks super fast; I do need a new battery but this was happening even when I had a full charge. It would kick back before the engine even had a chance to turn over once, literally almost instantly after I would turn the key to crank the engine.

I even Sea-Foam'd the engine (twice) to remove carbon which I thought was causing hot spots and preignition but that made no difference. Something I do notice now when I crank the engine hot with no spark it "sputters" a bit like the fuel-air mixture is igniting itself solely from compression and heat... My combo is a little "unusual" I have a 360 bored .060" over with KB flat-tops and factory iron Magnum heads (with factory 1.6:1 rockers), true static compression was verified during assembly at 10.42:1 and like I said the cam is very small for the cubes/compression this engine makes MONSTER torque on the bottom end and runs perfect aside from the starter kick-back I had before I did this ignition mod.
Click to expand...

I'd find out for sure about this if I were you.
It may not be just from compression or heat but from a wild out of time spark from the box.
I would explain a lot wouldn't it?
Maybe see if there is any spark at all out of the coil with your switch turned off.

It's a long shot, but who knows.
 
Racers have been doing the toggle switch thing for decades. Spin the motor over then light the fire. tmm
 
toolmanmike said:
Racers have been doing the toggle switch thing for decades. Spin the motor over then light the fire. tmm
Click to expand...

Yeah found that out just now with a little web-surfing, felt pretty good to figure it out on my own though LOL #-o

I'll look into the other things mentioned when I get back home...
 
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