427 heat soak solenoid recommend

[Joe L.]

Re: 427 heat soak solenoid recommend

So back to the question, What to do. My cables are in good condition, critically cleaned lugs, inspected and cleaned grounds, etc, using 1050 CCA Optima. (YES fully charged) When I replace the solenoid, the problem goes away for a long time. I have read that inferior spring tension, along with corrosion, loose parts in the solenoid will result in Heat Soak problems. Is there a Heavy Duyty Solenoid that I should be using or will that NAPA replacement work just fine, (which it has not) CONFUSED!!!

Neil----


By the way, if you want to try a "heavy duty" solenoid, use a GM #1114493, aka Delco D-992. This piece was originally used on some 1970's Pontiacs with 455 cid engines. It should fit and work perfectly on your starter. This is about as "heavy duty" as GM solenoids get.

Will it solve your problem? I doubt it. But, at least you will have gone to the "top of the mountain" as far as GM solenoids go.

[Clem Z.]

Re: 427 heat soak solenoid recommend

Ron explained to me that the problem is caused by heat-induced resistance in the purple wire that carries the energizing voltage to the solenoid from the starter switch. By installing the slave solenoid (in a non-high heat area; I used the upper surface of the "triangular" shields below the fender louvers), one ensures FULL CURRENT to the "S" terminal on the solenoid, regardless of temperature.
"if that is the problem just using a remote starter push button between the battery terminal and the purple wire terminal on the solenoid should spin it over" give it a try and don't get burnt. if there is room just jumper between the 2 terminals with a screwdriver

[Joe L.]

Re: 427 heat soak solenoid recommend

Ron explained to me that the problem is caused by heat-induced resistance in the purple wire that carries the energizing voltage to the solenoid from the starter switch. By installing the slave solenoid (in a non-high heat area; I used the upper surface of the "triangular" shields below the fender louvers), one ensures FULL CURRENT to the "S" terminal on the solenoid, regardless of temperature.
"if that is the problem just using a remote starter push button between the battery terminal and the purple wire terminal on the solenoid should spin it over" give it a try and don't get burnt. if there is room just jumper between the 2 terminals with a screwdriver

clem----


The jumping technique you described was always successful for me in getting the starter to operate in hot re-start conditions. However, due to safety issues, I rarely used it. The hot re-start was extremely frustrating. But, it was never frustrating enough that I'd risk creating a variety of safety issues to get the car started.

By the way, this technique will not work for a 1964-82 Corvette small block or a 1968-74 Corvette big block. That's because the solenoid heat shield prevents access to the necessary terminals. It can be done on the small blocks if the rear "tab" of the heat shield is bent away. That's how I did it on my car.

[Neil S.]

Re: 427 heat soak solenoid recommend

Does anyone know to wire in the remote solenoid? Joe?

[Joe L.]

Re: 427 heat soak solenoid recommend

Does anyone know to wire in the remote solenoid? Joe?

Neil----


I previously in this thread described the wiring of the remote (slave) solenoid. However, if you want a complete set of instructions + all of the wring pre-made, I would suggest you obtain one of the remote solenoid kits that are on the market. These contain everything you need.

[Clem Z.]

Re: 427 heat soak solenoid recommend

what puzzle me is if it is a problem caused 100% by the purple wire getting too hot and having high resistance causing a voltage drop why does a new solenoid fix the problem for a while ? if the starter engages BUT does not spin the engine fast enough to start i would guess the high current contacts inside the solenoid are burnt and have high resistance causing a voltage/current drop. i have also found the the solenoid bakelite cap shrinks from heat and the terminals get loose in the the bakelite cap. take your old solenoid apart and see what you find. JMHO

[Joe L.]

Re: 427 heat soak solenoid recommend

what puzzle me is if it is a problem caused 100% by the purple wire getting too hot and having high resistance causing a voltage drop why does a new solenoid fix the problem for a while ? if the starter engages BUT does not spin the engine fast enough to start i would guess the high current contacts inside the solenoid are burnt and have high resistance causing a voltage/current drop. i have also found the the solenoid bakelite cap shrinks from heat and the terminals get loose in the the bakelite cap. take your old solenoid apart and see what you find. JMHO

clem----


I don't think that the problem is actually fixed by a new solenoid (or, new starter). I replaced my solenoid several times with new GM solenoids, including the "high heat" solenoid. I also first rebuilt and then replaced the starter. Each time, it APPEARED that the problem was solved for awhile. However, as I mentioned earlier, there is no real "experimental control" here. That is, was the problem really fixed or was it just that I (or, anyone else dealing with this problem) didn't experience the specific conditions causing the problem for awhile? The hot re-start problem is somewhat intermittent---it usually doesn't occur on every hot re-start.

So, if one replaces the starter and/or solenoid and the problem appears to resolve, does it REALLY mean the underlying problem is resolved OR might one not have had any more problems for awhile even if one had done NOTHING in an attempt to fix it?

The slave solenoid fix I described is the only PERMANENT and 100% effective solution to the problem I have ever found. So, I've got to believe that the problem is related to heat-induced resistance in the purple wire. If it's not, then the slave solenoid addition would have been absolutely useless in correcting the problem and, certainly, it would have cropped up again in the 15 or more years I drove the car after installing the slave solenoid.

One other thing: as you mentioned, GM acknowledged this problem in certain motor home chassis with 454 engines. Their recommended fix for it was the slave solenoid retrofit. If the hot re-start problem had been caused by anything other than the high resistance phenomenon I mentioned, why would they have recommended such a fix? The slave solenoid could ONLY address that kind of a problem. It could not address or "overcome" any deficiency in the solenoid or the starter, heat induced or otherwise. The ONLY thing accomplished by the slave solenoid is ensuring that full current is applied to the solenoid "S" terminal under all operating conditions---absolutely no other benefit could result from a slave solenoid installation.

Also, while GM only ACKNOWLEDGED the problem on the motor home chassis, that only means just that. We all KNOW that the problem occurs on vehicles other than motor homes. This is empirically derived, not theoretically derived or otherwise established by GM acknowledgement. It does not seem possible to me that the problem in the motor home chassis is caused by a completely different underlying condition than the problem in Corvettes and other Chevrolets. So, if GM's recommended fix for the motor home chassis problem is the slave solenoid, why wouldn't that be equally applicable to other vehicles experiencing the problem? Keep in mind that the ONLY thing the slave solenoid accomplishes is as I described above.

[Neil S.]

Re: 427 heat soak solenoid recommend

Here is how the problem started. On a hot day a couple years ago I pulled into a gas station for some fuel. Went to restart and the key had NO effect, No click for about 2-3 seconds then fired up. Shut it off, tried to restart and the same thing happened, a 2-3 second delay in starting. My first thought was the clutch switch. Next time it happened it was hot out again, this time it would not start for about 5 min, NO click No starter movement, just dead silence. This happened quite a few times over the Next month but the 5 min was turning into 15-20. Took the starter out, pulled the solenoid off and noticed that the bakalite was cracked. Started to take it apart and the bakalite fell apart in my hands. Went to Napa, bought one, installed, NO problem for about a year then was at a cruise in, Driving slow in 90 deg heat, shut it off, 1/2 hour later tried to start, NO Click, Nothing. 15 min later, fires up like it should, turns over Fast like it always has. The problem is worse this time, does not take as much heat in the engine compartment, as a matter of fact, I can drive it in 70 deg. weather for 1/2 Hour, going 50mph, pull over, stop, try to restart and same thing happens. Yes with the heat shield on. What has me also confused is when I can start it and only when it is hot there is the 2-3 sec. delay. It seems like no contact in the solenoid, like the spring is taking its time. Is this happening with just our older cars with the old wiring and parts? I cannot believe that this was a common occurance with the new Vettes. Seems like if this were happening back in the day, GM would have been flooded with complaints and warranty claims. I owned a 1966 El Camino 396 with NO problems. Could the wiring harness be getting so tired that it is causing heat resistance problems? Would new wiring be the ticket? As far as I can tell, this is a hit and miss replacing parts problem. Seems to be a weak link here somewhere. Any more input would be greatly appreciated, I know there are a lot of Corvette ownere out there having this same problem and would like it resolved.

[Clem Z.]

Re: 427 heat soak solenoid recommend

Here is how the problem started. On a hot day a couple years ago I pulled into a gas station for some fuel. Went to restart and the key had NO effect, No click for about 2-3 seconds then fired up. Shut it off, tried to restart and the same thing happened, a 2-3 second delay in starting. My first thought was the clutch switch. Next time it happened it was hot out again, this time it would not start for about 5 min, NO click No starter movement, just dead silence. This happened quite a few times over the Next month but the 5 min was turning into 15-20. Took the starter out, pulled the solenoid off and noticed that the bakalite was cracked. Started to take it apart and the bakalite fell apart in my hands. Went to Napa, bought one, installed, NO problem for about a year then was at a cruise in, Driving slow in 90 deg heat, shut it off, 1/2 hour later tried to start, NO Click, Nothing. 15 min later, fires up like it should, turns over Fast like it always has. The problem is worse this time, does not take as much heat in the engine compartment, as a matter of fact, I can drive it in 70 deg. weather for 1/2 Hour, going 50mph, pull over, stop, try to restart and same thing happens. Yes with the heat shield on. What has me also confused is when I can start it and only when it is hot there is the 2-3 sec. delay. It seems like no contact in the solenoid, like the spring is taking its time. Is this happening with just our older cars with the old wiring and parts? I cannot believe that this was a common occurance with the new Vettes. Seems like if this were happening back in the day, GM would have been flooded with complaints and warranty claims. I owned a 1966 El Camino 396 with NO problems. Could the wiring harness be getting so tired that it is causing heat resistance problems? Would new wiring be the ticket? As far as I can tell, this is a hit and miss replacing parts problem. Seems to be a weak link here somewhere. Any more input would be greatly appreciated, I know there are a lot of Corvette ownere out there having this same problem and would like it resolved.

you could try and replace the purple wire with a heavier gauge and see what happens. GM had trouble with hot starts on other cars also as our 69 caddy would not start when used on the road for a great distance. it also would not turn over like a dead battery but what the cure was to use some top engine cleaner to get the carbon build up off of the piston as that was causing them to heat soak and expand in the bore. if you would pump the gas a lot to get some cold fuel into the cylinders and cool down the pistons the engine would turn over and start. this was also a problem with 454 chevy engines

[Glenn B.]

Re: 427 heat soak solenoid recommend

Neil, I am having similar periodic experience with my 67 BB.

I have replaced battery (for other reason), completely rebuilt starter (which I assumed was the issue) - but still have periodic hot start issue (and it doesn't need to be that "hot" - e.g 75 degree day).

Your observation that this situ could not reasonably have been the case when these cars were new makes complete sense to me. This seems to say that the original components (starter, wiring, etc) were designed sufficiently, so a new battery and correctly rebuilt starter should effectively eliminate these as suspects.

I now believe my prime suspect is the wiring harness connectors -specifically the bulkhead connector. It makes a lot of sense that the connection quality will degrade over time - the connectors are almost always a much weaker link (reliability/durability) than the wires they connect.

[Neil S.]

Re: 427 heat soak solenoid recommend

I recieved an Email from a gentleman that has had this problem. He said that if the correct Corvette spring in the solenoid is used, a low tension spring which is discontinued as Joe mentioned, this will allow the solenoid to overcome the spring force and make contact. Also in the email he states that you can take 1-1/4 to 1-1/2 coiles out of a standard car solenoid spring (which I am sure that is what I have now) and accomplish the same thing.This kind of makes sense due to the 2-3 hesitation of my starting problem when hot. But who knows. I will probably try that and see what happens. So many Corvettes with this problem, seems like there should be a trouble shooting guide on this site for common problems like this. I will also be cleaning and inspecting my firewall connection.

[Joe L.]

Re: 427 heat soak solenoid recommend

Neil, I am having similar periodic experience with my 67 BB.

I have replaced battery (for other reason), completely rebuilt starter (which I assumed was the issue) - but still have periodic hot start issue (and it doesn't need to be that "hot" - e.g 75 degree day).

Your observation that this situ could not reasonably have been the case when these cars were new makes complete sense to me. This seems to say that the original components (starter, wiring, etc) were designed sufficiently, so a new battery and correctly rebuilt starter should effectively eliminate these as suspects.

I now believe my prime suspect is the wiring harness connectors -specifically the bulkhead connector. It makes a lot of sense that the connection quality will degrade over time - the connectors are almost always a much weaker link (reliability/durability) than the wires they connect.

Glenn-----


The firewall connector is a possibility. It could be that deficiency here is a "weak link" allowing heat-induced resistance there or otherwise in the purple wire to increase to a point that the wire will no longer carry the current necessary to energize the solenoid. The slave solenoid essentially eliminates the need for the wire to carry significant current. So, that MIGHT explain why the slave solenoid cures the problem if the connector is the root cause of the problem. I'll be very interested to learn what you find with the connector.

One thing, though: my car developed this problem at a VERY early age. I couldn't say that it had it from day-one, but it could be that I never encountered the conditions resulting in the problem for some time after I took delivery of the car. I really don't think that age or natural deterioration was a factor in the genesis of this problem in my case. Plus, on the west coast we don't have a very "corrosive environment" that would cause connector deterioration.

[Joe L.]

Re: 427 heat soak solenoid recommend

I recieved an Email from a gentleman that has had this problem. He said that if the correct Corvette spring in the solenoid is used, a low tension spring which is discontinued as Joe mentioned, this will allow the solenoid to overcome the spring force and make contact. Also in the email he states that you can take 1-1/4 to 1-1/2 coiles out of a standard car solenoid spring (which I am sure that is what I have now) and accomplish the same thing.This kind of makes sense due to the 2-3 hesitation of my starting problem when hot. But who knows. I will probably try that and see what happens. So many Corvettes with this problem, seems like there should be a trouble shooting guide on this site for common problems like this. I will also be cleaning and inspecting my firewall connection.

Neil-----

I don't think the spring will do any good. I tried the "low tension" spring when it was available and it did no good, at all. I also tried a shortened standard spring. No good, either. You can try it though; you don't have too much to lose; the springs are cheap and easily installed.

The firewall connector is another matter (see my response to Glen); I do think that is a POSSIBILITY. I'd be very interested in what you find at the connector.

[Clem Z.]

Re: 427 heat soak solenoid recommend

these corvettes that have this problem still have the batteries under the hood or they in behind the seat? if i remember correctly the ones with the battery behind the seat had the ground run thru the steel frame and if these connection are not clean you will have trouble starting the engine. i do not remember what year they started that. the last new corvette i had back then was a 66 so i am not familiar with the 68 and up. when we mounted the battery in the back of the race cars we used welding cable to make the battery cables because they are pure copper wire.

[Joe L.]

Re: 427 heat soak solenoid recommend

these corvettes that have this problem still have the batteries under the hood or they in behind the seat? if i remember correctly the ones with the battery behind the seat had the ground run thru the steel frame and if these connection are not clean you will have trouble starting the engine. i do not remember what year they started that. the last new corvette i had back then was a 66 so i am not familiar with the 68 and up. when we mounted the battery in the back of the race cars we used welding cable to make the battery cables because they are pure copper wire.

clem-----


The battery behind the seat was first used for the 1968 model year and continued through the 1982 model year.

Cars experiencing the "hot-restart" problem include both C2 and C3, though. It might be a bit more prevalent with C3 but that may be because there are more of them out there.

I have carefully cleaned my negative battery cable-to-frame interface several times.