spark retard and starters
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,028
Likes: 0
From: San Antonio Texas
spark retard and starters
i have always had hot start problems with my 79. after running engine to operating temperature, if engine shutoff for less than about 30 minutes, the starter "bogs" badly on restarts (like the battery is almost dead or starter is bad). after 30-45 minute shutoff it starts normally. have always been told its a "bad wiring" problem. just recently installed an MSD ignition (not for this reason). however, the unit (digital 6) has a spark retard function. retards spark 20 degrees during engine cranking. with this feature enabled the starter now cranks the engine normally even when hot. when i disable the spark retard feature, hot start problems return. Question: why does retarding the spark 20 degrees during cranking allow the starter to crank the engine so much easier when hot???? the difference is really dramatic.
Burning Brakes
Joined: Aug 2004
Posts: 971
Likes: 7
From: roanoke va
when the timing is retarted it lights the fire in the clys. later in the compression stroke. think about it eng. turns 360 degres if you light the fire at 8 degres before top dead center you have not completed the full 360 degres. if you retard the timing 20 degres you will be fireing the cly. at 12 degreas after top dead center. so with the timing retarted you are not asking the engine to fire against it's self.
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
Classic starter heat soak problem on vettes. You can wrap it with a thermo block shield, or relocate the solenoid via Ford kit. Retarding the timing fires the plugs later in the cycle, resulting in less cylinder pressure - so it's eaiser to crank.
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,028
Likes: 0
From: San Antonio Texas
i had already (previously) put a starter relay in. is that the same as what you're suggesting. it helped a little. i've put on a metal heat shield and the "wrap around" stuff. they didn't seem to have any effect at all.
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,028
Likes: 0
From: San Antonio Texas
battery's new and fully charged, charging system working fine. battery terminals clean, freshly brushed and shiny bright. when you say "all grounds" what specifically are you referring to. also, how can i test for voltage drop when cranking with a voltmeter.
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Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,028
Likes: 0
From: San Antonio Texas
i'll have to check it. i've adjusted it through trial and error. there is a lot of initial timing but the engine was rebuilt and cammed up. i adjusted it to just below the point of detonation on hard acceleration. in 0-60 trials that also gives me the best performance. also, much less than this causes the engine to "bog down" in hard acceleration (rich bog??)
Drifting
Joined: Sep 2000
Posts: 1,616
Likes: 2
From: Round Rock, Texas, USA Texas
If you put a cut off switch to the distributor -- you can turn the motor over with no spark -- once the motor is turning flip the switch -- she will fire right up..... also makes a resonable poor man no-start alarm
I found a switch like this on my '77 not long after purchasing it --- I don't need it for starting --- but a least I flipped it while sittingin traffic at a light ---
I found a switch like this on my '77 not long after purchasing it --- I don't need it for starting --- but a least I flipped it while sittingin traffic at a light ---
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
Originally Posted by greyghost79
battery's new and fully charged, charging system working fine. battery terminals clean, freshly brushed and shiny bright. when you say "all grounds" what specifically are you referring to. also, how can i test for voltage drop when cranking with a voltmeter.
Good luck
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
Probably wouldn't hurt. I guess the small design keeps the starter cooler. I would go over the electrical first. C-3's are old cars & these electrical problems are common. Keep us advised on what you find.
Le Mans Master
Joined: Mar 2004
Posts: 7,502
Likes: 1,509
From: Little Rock AR
I saw your other thread on the starter issue. Ignore the Ford solenoid thing if the car is cranking but only slowly. The Ford relay thing is only for when the starter will not even begin to crank. If you can use a screwdriver to start the car, you can do the Ford relay trick.
If the MSD retard thing is getting the car to start, you need to check the curve on your distributor. Too much initial will cause difficult cranking. You could back off on the initial and make it up with manifold vacuum to the vacuum advance can. Takes a little work but maybe you can tune it out.
-Mark.
If the MSD retard thing is getting the car to start, you need to check the curve on your distributor. Too much initial will cause difficult cranking. You could back off on the initial and make it up with manifold vacuum to the vacuum advance can. Takes a little work but maybe you can tune it out.
-Mark.
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
I discovered this years ago. I ran lots of initial advance and the motor had trouble turning over hot. Nothing whatever to do with heat soak in this case. Anyway I discoverd that our distributors advance system never returned to zero, you had extra advance while cranking. I tried mallory and accel distributors and found both suffered from erratic advance curves and not returning to zero.
Checking with a very knowledgable builder and he told me he has a seperate switch for the ignition . He gets the motor spinning then hits the ignition switch. End of problem.
That is mickey mouse so I went to a fixed distributor, no advance whatever in it, went to the msd timing master with 20 degree retart and a proper electronic advance curve.
After checking I found the advance curve was consistent, returned to Zero all the time and never had a problem with starter kick back when trying to start the car again.
I have over 30 years of working with performance distributors, making my own, modifing many Mallory and they all suck.
Go electronic and get some consistency.
Checking with a very knowledgable builder and he told me he has a seperate switch for the ignition . He gets the motor spinning then hits the ignition switch. End of problem.
That is mickey mouse so I went to a fixed distributor, no advance whatever in it, went to the msd timing master with 20 degree retart and a proper electronic advance curve.
After checking I found the advance curve was consistent, returned to Zero all the time and never had a problem with starter kick back when trying to start the car again.
I have over 30 years of working with performance distributors, making my own, modifing many Mallory and they all suck.
Go electronic and get some consistency.
Le Mans Master
Joined: Mar 2004
Posts: 7,502
Likes: 1,509
From: Little Rock AR
One of the things I do when recurving an old points style distributor is to reduce the amount of centrifugal advance. Typicaly I would remove the rubber bushing and braze one end of the slot in the autocam plate a little bit to do this. The trick here is to braze it closed on the end where it would rest when at idle. You close it up on that end and it will slightly preload the advance mechanisim so the centrifugal advance springs will be pulling the plate back to zero at idle rather than allowing the plate to dither around at idle and not return to zero. Select springs that allow the advance to begin a few hundred RPM above idle and keep going stiffer in single spring steps from there if it is pinging.
Or you could just buy the MSD box.
-Mark.
Or you could just buy the MSD box.
-Mark.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Same Old Story
Hot and cold starters should crank the same. Yes, timing can be a problem when hot. But the often overlooked problem is that the alternator is not correctly charging the battery. Your saftey valve for a restart is the voltage of the battery as nothing begins to operate until the engine is running. If your into looking for a new starter, use the late model 350 starter. A small powerful OEM unit and perfect replacement for the large case 350 starter. It will also fit the BB engines. Good batteries will recover by themselves but the more cranking amps the better off your cranking system will be.
