[Bruce Meyer]

Originally Posted by wovenweb

Yes, but it is a dry heat.

Yes it is and I love it! I was visiting Illinois one summer and the temp was 78 degrees with high humidity. I sweated my A$$ off just sitting there. Why do people live there? LOL!

[Lemans64]

Another thing to pay attention to is the distributor. How is the mechanical advance?? Is it stuck in the advanced position? That can make it hard to start when hot. You can check ignition timing to verify that. What is base timing? to eliminate that you can unhook the coil wire and try to crank it to see if it spins any faster, if it doesn't then you have starter issue as most have said.

[gtofreek]

If a GM starter is having issues turning it over, Then something is wrong. This engine doesn't need a mini starter to turn it over hot. Either he has a wiring issue[high resistance], or the starter is bad. A GOOD GM starter will turn his engine over just fine. He just needs to diagnose the REAL problem before blowing money on mini starters. If he has a cable or wiring issue, a mini starter will have problems too.

[Cliff R]

"The problem with factory starters is its really hard to find a good one. They don't make new ones and the rebuilt ones are generally crap."

+2

Over the years I've had next to ZERO good luck with rebuilt factory starters no matter where we sourced them out at.

I agree that a factory starter is PLENTY capable of turning over one of these engines cold or well heat soaked, but even with that said they are a HUGE heat sink and headers can be very hard on them. I use and prefer the mini-starters and have a 20 year old Powermaster on my 455. I think if the battery were up to the task I could literally drive the car to town on it and never allow the engine to start!..........Cliff

[gtofreek]

That's all fine, but he should diagnose the actual problem first, IMO. I come from a background where you figure out what the problem actually is first, then fix that. Instead of the "change every part until you fix it" mentality. All I'm saying is the problem may or may not be the starter. If it's NOT the starter, then he will still have the same problem after spending hundreds of dollars on a new one. If he eliminates power drop across the cables as a problem[not just simply thinking they are new, so they must be good], then it probably is the starter.

[Formulajones]

Originally Posted by Bruce Meyer

Yes it is and I love it! I was visiting Illinois one summer and the temp was 78 degrees with high humidity. I sweated my A$$ off just sitting there. Why do people live there? LOL!

Agreed, from Ohio originally and when I visit I just can't stand that humidity anymore. After getting acclimated to the dry heat, which is easy, I can't see how people tolerate that thick air back east. I'm surprised I even survived

[STEELCITYFIREBIRD]

That's all fine, but he should diagnose the actual problem first, IMO. I come from a background where you figure out what the problem actually is first, then fix that.

[Cliff R]

It's often a difficult problem to diagnose, this difficult hot re-start/starter heat soak thing. It only takes one header tube close enough to the starter to swell up the internals just enough to lock the thing up and make the engine difficult, if not near impossible to turn over after a hot shut-down. I've seen this happen many times as factory starters run pretty close tolerances and a little wear at the bushings moves things even closer together. When this happens one really doesn't know if the starter is just getting weak, or if the heat is making it act that way.

One thing to check for certain is base timing. Some engines do NOT like much initial timing and will "buck" the starter pretty hard when they are well heat soak, which mimics a bad starter, weak battery, bad connections, bad cables, etc Using lower octane than the engine likes will do exactly the same thing. It will crank effortlessly cold, but much slower warmed up and may even "buck" or "kick-back" under certain conditions when things are fully heat soaked.

My own engine is a classic example of this. It will run fine most of the year on 87 octane, but in the hottest summer months when well heat soaked once in a while it will either "run-on" after shut down or crank slow or even "buck" the starter.........Cliff

[red_bumblebee]

Hi all,

Thanks for the replies, I've made a list of everything I'm going to try, starting with better grounds from battery to somewhere else on the head and a better ground for the starter.

If it helps with diagnosing online, when it gets hot it will very slowly turn the starter, making a RR ......................RR......................RR and then sometimes it won't crank anymore at all (that was with the old battery, I haven't tried to crank it for a long time when it's been hot with the new battery yet.)

I used one of those mini battery pack jump starter things once and it seemed to crank more easily, but it still cranked very slowly. It did sound like the battery was dead. I let it cool down and then with the batter jump pack it cranked like a good battery.

Initial idle timing looked to be around 6 degrees or less when I checked the other day.

I'll check the ignition switch as well but the backdrive linkages have been removed and the lockout switch is now with a B&M shifter. The ignition switches a relay which powers the solenoid so I would think that it ok, but I'll check the original solenoid wire as it is 43 years old and has multiple connections in it where its been cut and spliced previously.

[gtofreek]

Originally Posted by red_bumblebee

Hi all,

Thanks for the replies, I've made a list of everything I'm going to try, starting with better grounds from battery to somewhere else on the head and a better ground for the starter.

If it helps with diagnosing online, when it gets hot it will very slowly turn the starter, making a RR ......................RR......................RR and then sometimes it won't crank anymore at all (that was with the old battery, I haven't tried to crank it for a long time when it's been hot with the new battery yet.)

I used one of those mini battery pack jump starter things once and it seemed to crank more easily, but it still cranked very slowly. It did sound like the battery was dead. I let it cool down and then with the batter jump pack it cranked like a good battery.

Initial idle timing looked to be around 6 degrees or less when I checked the other day.

I'll check the ignition switch as well but the backdrive linkages have been removed and the lockout switch is now with a B&M shifter. The ignition switches a relay which powers the solenoid so I would think that it ok, but I'll check the original solenoid wire as it is 43 years old and has multiple connections in it where its been cut and spliced previously.

If the starter is cranking, or trying to crank, the ignition switch is working, so it's not that.
Grounds on the exhaust get worse with heat. That's why I suggested a voltage drop test. That will tell everything. To test the positive cable, you just do the opposite of what I explained for the negative cable. Hook the positive lead from the volt meter to the positive post of the battery, and the negative lead to the other end of the cable at the starter. Disconnect the coil wire, and crank the engine and see if the meter reads anything. A good cable will read no voltage during this test. Any voltage reading over .3 volts and the cable or connection is bad. Connections get worse with heat also, especially when they are not good connections in the first place. They build heat from within as they are being used.

I specialized in auto electrical, especially starting and charging systems, here in the Arizona desert for over 11 years before I started doing engine work. Believe me heat soak is not uncommon around here, but a properly working, stock starting system will still turn over an engine just fine when it's heat soaked. If they wouldn't, GM never would have installed them on these cars in the first place. My 428 had high compression, and headers that wrapped right around the starter. I never had cranking issues with it in the heat of the summer.

[thepontiacman]

You might try a HD Solenoid Spring. Take solenoid loose and replace weak spring with HD spring. It will not collapse when hot.

I had a neighbor with a Grandville with 455 and when it got hot he would have to let it cool off some before it would crank back up. I decided I would do whatever I had to do to prevent this on my car.

Good starter, heavier cables, shield on solenoid and HD solenoid spring, and a higher amp battery. Never fails to start even when super hot with RA manifolds.

I have some springs if you want to try it.

thepontiacman@yahoo.com

[Dr. Drivability]

You've got the right sized ground cable, now do the same for the B+ cable, ZERO gauge on both of mine and it has NEVER had a hot start issue afterwards, even with a chitty Autozone starter.

[Mister Pontiac]

Red, I have an idea that I am certain will solve your hot start problem, and it will cost you almost nothing...

Like everyone else here, I've fought this issue myself. You're in good company. The guys have already given you excellent advice to check voltage drops, proper grounds, bad solenoids, initial timing, etc... All of these things are helpful, and they are also cumulative. Any and all corrections you can make to minimize electrical loss and improve electron movement will help.

However... Your problem will not be completely gone. It will still be there from time to time, although in a smaller capacity. What to do?

25 years ago, my 67 GTO taught me this lesson. I found the ONE solution that absolutely solved my problem. Kill the ignition during the crank cycle. Install a switch in the start circuit to be able to 'open' the power wire while cranking the engine. You simply shut off the switch, hit the key to get the engine turning, THEN flip the switch on. It works absolutely perfect.

Over the years since I first dealt with this problem, I have gone thru almost every wire on the car, repairing/replacing anything suspect. In all of this time and effort, the hot/heat soak start issue still pops up on hot days. But that little ole' switch has been the saving grace. Still works perfect, every time.

Today, I run a 9.2 455 with a 'healthy' cam in the car, and I also have a RobbMc mini starter in it. I have a heavy duty Optima battery, and the heaviest of battery cables. All of the grounds are solid, and the car absolutely cranks like a champ when cold. But once it gets hot, not so much...

You can test this idea out (as someone previously mentioned) by simply pulling the coil wire when hot, and then cranking the engine. You will be amazed at how easy it turns over when the plugs are not firing (none of that RR.... RR.... RR.... you described).

Hope that helps, and let us know how it turns out!

[1966goat]

Gotta say when I had this issue I bought a RobbMc hi torque mini starter and it fixed my problem instantly...

[MyJudge69]

I have been working on Pontiac engines for more than 50 years, both professionally and as a hobby. A great deal of wise information has been discussed.

I find that original equipment starters are adequate for most any Pontiac engine if all the correct parts are used. Many applications such as restorations must maintain originality so aftermarket starters are not an option.

Assuming the electrical system is up to par, I have found 2 common issues that create a hot start problem:

(1) The started brace is frequently missing. The brace attaching to the back stud on the starter motor case MUST be used to prevent a hot start problem. The brace used thru 1969 is a fairly large support with the other end attaching to the motor mount bolt. The 1970 and later engine has additional motor mount bosses and the support looks more like a strap with it's other end connecting to one of those additional motor mount bosses.

(2) A light duty starter was used to replace the original high torque unit. Many are not aware that starters for small cubic inch engines used a lower torque starter that had the same physical dimensions. The field coil inside the HD starter is longer than it's light duty counterpart. It is easy to identify the longer coil from outside the starter. The tab that connects the coil to the solenoid uses a 1/4" by 3/4" spacer and longer screw. The smaller coil on the light duty starter connects directly to the solenoid. The internal armatures are also different but generally not mixed up by starter re-builders.

[GEARDRIVEN]

All if the posters have given great insight.
I recommend the suggestion by Paul in regards to performing battery cable voltage drops.
I have worked in the auto repair field since 1972 and in the GM dealer service departments since 1982.
Testing for voltage drops in the cranking system is a fundamental step and you could imagine what defective battery cable can do to the newer electronic-laden vehicles.
I am in agreement that the wiring in the starting/cranking system should be confirmed good first along with testing of the components therafter.
Also the age is the wiring itself or where repairs have been made need consideration.
I am an old-timer now, but I learned the performance life as an owner of a few....
70 T/A R/AIII 4spd blue/white
'71 T/A 455HO auto white/blue
'74 Formula 350 4spd zzzzzzzz(snore)
'76 T/A 455 4spd white/
Also a 10.0 AMC prepped '71 401 Hornet
S/C (Loved telling the Hemi guys my Mom has a Rambler that I think is pretty fast.......
Good Luck with the starting concern.....a lot of knowledge here for you to use.

[#1965GTO]

Summit has lots of options. There some stock looking starters for $140 but have after market windings and solenoids. Accel used to make a real good one that their yellow powder coated case with excellent internals.
Originally Pontiac used a head bolt with a stud end on it to land the negative side on the motor. The stud end is 3/8" and a perfect ground for the engine. #2 should be plenty to crank any of these engines if the battery hasn't been relocated to the trunk. If the battery is trunk mounted you would need to jump a size or two and always ground the engine directly to battery.
How strong is your alternator???? These jell batteries you mention can go bad too. I've had 3 of them die prematurely.

[sdbob]

In the 60s I bought the tools to install new bushings and rebuild starter drives in starters,simple driver tools. I had same problem as you described,esp when we went out to street race. Embarrassed to just sit there,waiting to cool down so I could start mine.

[thepontiacman]

I have some HD solenoid springs if anyone needs one.

thepontiacman@yahoo.com

[dataway]

Are they the short ones?