396 Hot Start Issues

[Ken A.]

Re: 396 Hot Start Issues

Hard crank is usually a timing issue, too much initial timing. One fix is to recurve distributor or a high torque starter. On an old TI amp the original circuit board used germanium transistors, which crap out above 230 degrees.The new board use silicon which is good to 300 + degrees. When the old board cools down it'll start right up. That also affects the timing.

[Carl N.]

Re: 396 Hot Start Issues

couple of other little things - make sure valve lash is correct - lots of threads on how to are posted - don't believe this is the issue but can make it hard to "catch" when hot if you have other issuesanother item overlooked is the switch to raise and lower head lights - if contacts are corroded and most are after years and years - clean them - easy to do and might solve your voltage drops

[Joe L.]

Re: 396 Hot Start Issues

Joe,
How, please explain the electrical circuit used for the slave solenoid and how it makes a difference. You may be wiring it differently from what I imagine.

Mike Hanson explained the solenoid workings and I understand it as I have "restored plenty of them. His previous posting on the subject says: "When the solenoid washer contacts both the battery and motor terminals in the solenoid cover, the rest of the entire vehicle electrical system is out of the picture and has nothing to do with slow cranking. Current flows directly through the washer to the field terminal of the motor."

This is understandable to anybody that has tore down a GM starter solenoid. But I can't understand how a slave solenoid is going to increase energy to the starter.....?

PS I have also run into this hot start issues with BB and high torque gear motor starters. And to all reading this, this is a good and interesting thread.

Gene------


The guy that told me about this solution is one of the best automotive electric experts I have ever known in my life, one Ron Oliphant.

Here's how it works: in the revised set-up, the slave solenoid is mounted in a relatively cool location.The purple wire from the ignition switch is then attached to the activating terminal of the slave solenoid. Next, a large gauge wire is connected from battery voltage to the input (i.e. one of the large lugs) of the slave solenoid. Finally, a large gauge wire is connected from the output terminal of the slave solenoid to the "S" terminal of the starter.

In the above configuration, the "purple wire" from the ignition switch does not have to carry much current. Just enough to activate the slave solenoid. The slave solenoid together with the large gauge wires carries the full current necessary to the "S" terminal of the on-starter solenoid regardless of engine heat conditions.

I can tell you this, for sure: I had this hot restart problem on my 1969 small block for YEARS. I tried everything to solve it--- New ignition switch, several new solenoids, several starters (ALL high torque unlike original starter which was standard torque) including a NEW (i.e. not rebuilt) GM starter, new solenoid springs (including the one GM said would solve the hot re-start problem), additional heat insulation for the starter, and more. NONE of these ever permanently and reliably solved the problem and I lived with the threat of (and actually experienced) a no hot restart condition for quite a few years. After I installed the slave solenoid more than 25 years ago, I NEVER AGAIN experienced a hot restart problem. NEVER. Not even in Death Valley in July and August.

As I've mentioned before, the source of the problem had to be what I was told about heat-induced high resistance in the purple wire. If that were not the real source of the problem, then the slave solenoid would have done nothing to resolve it. But, the slave solenoid DID resolve the problem. Completely and permanently.

Many remote solenoids can be used and kits are available which include everything one needs, including installation instructions. A GM solenoid that can be used is GM #1114532.

[Gene M.]

Re: 396 Hot Start Issues

Joe,
As I follow the wiring you suggest it supports the pull in of the solenoid. But I do not see how this would aid the starter motor turning over the engine. The main issue as I understand it is the 396 car's starter had a hard time turning over the engine. The pull in of the solenoid does not seem an issue. The pull in of the solenoid in my experience has not been a issue in most cases. But the starter having a hard time turning over the engine when hot is what most face as the problem. Ford solenoid will only help those that do not get starter engagement of the drive gear due to heat soak solenoid. When the solenoid is engaged the washer face makes contact with the 3/8" copper studs allowing power to reach the starter. Unless this portion of the circuit is enhanced I do not see a benefit to the Ford solenoid. I propose that this Ford solenoid will not help turn over a hard to turn hot soaked engine. High resistance in the starter motor or poor conduction of solenoid washer and copper studs are/is the root of the problem.

So you were fortunate to have a solenoid/purple wire resistance issue and not a hard to turn engine over problem. I see these as two different issues. One is solenoid/resistance and the other is starter/resistance problem. Obviously the former easier to solve vs later.

[Stephen L.]

Re: 396 Hot Start Issues

I agree with Gene Manno. Once the GM starter solenoid is pulled in, the added "Ford" solenoid becomes irrelevant in the main current flow to/thru the starter motor circuit and high resistance due to heat someplace in that circuit is the problem. Things like the GM starter copper washer contacts, poor/corroded battery cables and connections (both positive AND negative), starter mounting condition (paint/corrosion), faulty starter windings, and even the battery.......

[Dan D.]

Re: 396 Hot Start Issues

Gene is correct. All an additional solenoid does is reduce the current in the purple wire. It has nothing to do with engine cranking. If the additional solenoid corrected a cranking problem, it is only because some other issue was corrected in the process.

The OP should measure the battery voltage for us, as we have asked him to do. That will narrow down his problem. A $5 VOM from HF will do this.

-Dan-

[John O.]

Re: 396 Hot Start Issues

Guys,
Thank you for all the great advice. Yesterday we connected a portable sun diagnostic box with a carbon pile to the engine. Upon cold start the voltage was measured at 14.4 volts and stayed in range even after we put load on the electrical system. We then let the engine come up to operating temp...about 200 degrees and let it run for awhile. We did not run it for as long as we have in the past because we wanted to take voltage readings on a hot restart. We shut the engine down waited about 5min and then restarted. One shot of fuel into the carb and it fired back up...voltage was again 14.4. We again put load into the system and it maintained voltage. Our plan is to recheck the timing again today or tomorrow and see where we are.
John and James.

[Duke W.]

Re: 396 Hot Start Issues

Guys,
Our plan is to recheck the timing again today or tomorrow and see where we are.
John and James.

There's more to the spark advance map than initial timing. You should check the entire map, and having a functionally correct VAC (What's the number stamped on the bracket?) that is signaled full time by manifold vacuum is critical to minimizing engine heat at idle and low speed driving. Does the VAC pass the Two-Inch Rule? In order to answer that question you must measure idle vacuum and test the VAC for conformance to spec. The OE cam should pull about 14" @ 900.

Also, measure exhaust manifold temps with an IR gun after driving the car and letting it idle for several minutes. As I said previously if total idle advance is in the correct mid-twenties range the manifolds should be no more than 500F.

The best way to attack a heat related issue is to reduce heat generation at the source.

Duke

[John O.]

Re: 396 Hot Start Issues

Duke,
We can check that and post results. Pardon my lack of knowledge but you are referencing a number on a bracket. Can you tell me what bracket you are referring to?
Thanks!
john.

[James W.]

Re: 396 Hot Start Issues

John,

He is referring to the vacuum advance canister (VAC) number stamped into the bracket that attaches it to the distributor.


James

[Joe L.]

Re: 396 Hot Start Issues

Joe,
As I follow the wiring you suggest it supports the pull in of the solenoid. But I do not see how this would aid the starter motor turning over the engine. The main issue as I understand it is the 396 car's starter had a hard time turning over the engine. The pull in of the solenoid does not seem an issue. The pull in of the solenoid in my experience has not been a issue in most cases. But the starter having a hard time turning over the engine when hot is what most face as the problem. Ford solenoid will only help those that do not get starter engagement of the drive gear due to heat soak solenoid. When the solenoid is engaged the washer face makes contact with the 3/8" copper studs allowing power to reach the starter. Unless this portion of the circuit is enhanced I do not see a benefit to the Ford solenoid. I propose that this Ford solenoid will not help turn over a hard to turn hot soaked engine. High resistance in the starter motor or poor conduction of solenoid washer and copper studs are/is the root of the problem.

So you were fortunate to have a solenoid/purple wire resistance issue and not a hard to turn engine over problem. I see these as two different issues. One is solenoid/resistance and the other is starter/resistance problem. Obviously the former easier to solve vs later.

Gene-------


In every case of a no hot start condition for me, it sounded like the starter was having a hard time turning over the engine. In other words, it sounded like what is commonly experienced with a low or "dead" battery. In fact, replacing the battery was one of my early "solutions" to the problem. It seemed so obvious to me that this had to be the problem. But, it did not permanently or reliably solve the problem, at all. Then came all the other "fixes" I mentioned and more.

Keep in mind that GM once recommended the slave solenoid solution for the motor homes with 454 that experienced exactly the problem I had and what I believe is the problem the original poster experienced.

Also, keep in mind that after I installed the slave solenoid as directed and as described, I NEVER experienced the hot restart problem again and, at the time I installed the slave solenoid I did absolutely nothing else that could have "inadvertently" solved the problem----all I did was install the slave solenoid.

In addition, I have suggested the slave solenoid solution to others who were having this problem over the years and every one that I know used it solved their hot restart problem.

[Joe L.]

Re: 396 Hot Start Issues

A few other things I should have mentioned:


When I successively replaced various components of the starter system I essentially eliminated those components as the source of the problem. Specifically, what are the chances that a component defective in a certain way (i.e. cause of the hot re-start problem) is going to be replaced with a component that suffers from the exact same problem? I replaced virtually all of the components in the system at least once, and several more than once. So, as I see it, none of these components could have been a source of the problem.

I might also add that when the slave solenoid solution was proposed to me, I was highly skeptical. If anyone else had proposed it to me other than Ron Oliphant, I would have dismissed it out-of-hand as a "hair-brained" idea. But, since it came from Ron, I decided to try it. In fact, Ron would have had more self-interest in telling me to bring the car into the shop so they could go through the electrical system. I was "richly rewarded" for following his advice. A problem that had vexed me for years was finally and permanently solved.

I might also stress once again that if the root cause of the problem had not been what Ron described, then the slave solenoid would have NOT solved the problem. In that case, the slave solenoid would have amounted to nothing more than the addition of an unnecessary component in the system---it would not have caused any harm but it would have solved nothing.

[Joe C.]

Re: 396 Hot Start Issues

A few other things I should have mentioned:


When I successively replaced various components of the starter system I essentially eliminated those components as the source of the problem. Specifically, what are the chances that a component defective in a certain way (i.e. cause of the hot re-start problem) is going to be replaced with a component that suffers from the exact same problem? I replaced virtually all of the components in the system at least once, and several more than once. So, as I see it, none of these components could have been a source of the problem.

I might also add that when the slave solenoid solution was proposed to me, I was highly skeptical. If anyone else had proposed it to me other than Ron Oliphant, I would have dismissed it out-of-hand as a "hair-brained" idea. But, since it came from Ron, I decided to try it. In fact, Ron would have had more self-interest in telling me to bring the car into the shop so they could go through the electrical system. I was "richly rewarded" for following his advice. A problem that had vexed me for years was finally and permanently solved.

I might also stress once again that if the root cause of the problem had not been what Ron described, then the slave solenoid would have NOT solved the problem. In that case, the slave solenoid would have amounted to nothing more than the addition of an unnecessary component in the system---it would not have caused any harm but it would have solved nothing.

Not fa nuttin' Joey babe, but it ain't "hair-brained"......it's "hare brained"
Tinkabouddit.

[Duke W.]

Re: 396 Hot Start Issues

When was the last time the starter was overhauled? I could be weak field coils, solenoid coil, armature windings, worn armature bushings and shift lever, and old dried up grease. The battery cable stud also wears due to current arcing, and a new one is included in solenoid rebuild kits, or you can rotate it 180 degrees if its not too eroded.

It's easy to disassemble the starter and do all the electrical and mechanical checks and change any worn parts except the armature bushings. For those I've always taken the frames to a shop that has experience at this task.

Everything you need is in the 1963 Corvette Shop Manual and later COMs.

I've had "rebuilt" starters fail within a couple of years and disassembly showed that they were "rebuilt" with junk parts that were already well worn. Now I do my own, but the last was 15 years ago.

Duke

[Domenic T.]

Re: 396 Hot Start Issues

I will admit that I did not read all the way thru thi thread but I fought this after rebuilding the HIGH torque starter, installing larger cables, you name it. I put the car on the lift after a drive from LA to Garden grove, just over a hour. Changed the starter and got a good start.
Next long drive it had the same problem. I drove my vette 350 CID to work which was farther than LA. I stopped for fuel and car wouldn't start. In desperation and anger, couldn't be late for work, I took the water bucket and poured the water over the starter to cool it. Bingo started right up. So after installing a shield, whited helped, I carried water to cool the starter which worked every time I HAD to use it.
I called my former boss when I worked ( in high school), where I rewound motors and asked him for his views. The only thing I remember him saying was that heat is resistance and that was his explanation to the car starting with a cool starter motor.

Dom