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Hot Start

Guest Deke

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Have recently reassembled "63 Rivi. Runs good except for extremely hard start problem when engine is at operating temp. Timing is OK, new starter, no fuel flow problems. Even added solonoid on top of fender well in attempt to reduce any heat resistance in wiring to starter. New batt. cranks engine very slow only when engine is hot. Just when you think this batt wont turn engine one more time it fires off and purrs just fine. Any thoughts to this problem will surely be welcome.


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Guest Straight eight

Sometimes a slow turning of the starter when hot occurs, the field coils in the starter are defective. Your rebuilt starter could have been rebuilt without the field coils being checked hot.

You may wish to remove the starter and bake it in the oven to duplicate engine heat, and the check the field coils.

Lots of luck, I had this problem and the solution came from GM Proving Grounds.

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When starter was rebuilt stator and rotor were replaced. This shop workes only on starters and alts, seemed competent and entirely reliable. I will revisite them, however. Thanks for your input. Baking the starter is certainly an original idea. How hot should I set the oven? I'm going to try it before I return to the repair shop. They had to send to Texas for the stator(I'm in Fl.).I bought ths car in pieces, literally. The engine had obviously been rebuilt(it was one of the pieces),but sounds good,tight,smooth. Can you think of anything that would cause hard start,bearings overtightened,high compression? I'm just a back yard mechanic grasping at straws. Thanks

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Make sure your battery cables are correct. Went through this exact same problem only to find out the positive cable was replaced with a cable that was too long, giving way too much resistance. Only found that out after a new battery and starter.

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Original battery cable went from battery to starter. I rewired so now battery cable runs from starter to solonoid mounted next to horn relay on fenderwell then from solonoid to battery. Is this too long? Seems distance is the same except cable is now in two parts.

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Many middle 1960s Chevy "hot rods" seemed to have this problem. Sure some parts didn't get "cross-bred" while things were apart?

Seriously, though . . . GM typically didn't use "in line" solenoids in any of their starter circuits. There were a few specialized TSBs for motor homes, though, but not many and only for particular ones.

There are also some stamped sheet metal heat shields which were used on Chevys, with some similar ones available from the aftermarket. They would be specific to the rh-mounted starter, though. Some were bigger than others, but they all were usually on 454/big block applications for many years. The attached to and shielded the solenoid on the starter.

Is your starter the "long housing" or "HD" starter? There were only two lengths of AC-Delco starters . . . the "normal" and the "longer" one for HD applications. Your starter rebuilder can probably tell at sight, as you might also be able to do, once you know what you're looking at.

As battery cable length is increased, so must the "gauge" of the conductor. The cables used on longer runs (think Corvettes with the battery behind the driver's seat, older SuperStock hot rods with the battery in the trunk area) are bigger (larger gauge, smaller number gauge) as a result.

I never did really undestand this seeming quirk of some GM vehicles . . . slow start when hot . . . as other brands of vehicles with equally long, or longer, battery cable runs never seemed to have issues. Or why it seemed to be more frequent on only some Chevy models, even small blocks.

Unless there's a particular reason you feel you need a solenoid in the circuit, I'd run the cable direct to the starter, but also make sure the cable gauge is at least as big as the OEM cable's conductor's size. You might need to get into a battery cable catalog to find one. With the Ford-style remote starter solenoid, they were sometimes succeptible to issues on the contact disc inside of the unit. "Tapping" on it would sometimes get it to a new spot and then it'd work better.

Before you go "messing up" the oven, you might investigate other methods of heating the starter. As you heat things up, the uncured items in the various wire insulations, paint, lubricant, etc will further cure out, which might leave some unfavorable "things" inside of the oven. Sure, they might cook out with an empty oven turned up higher, but also be aware that you'll need some good oven mits to handle the starter with as you desire to test it "hot".

OR, you could get it good and hot on the engine, let it heat soak for a little while, then remove it from the engine "hot" and do your testing that way.

Might also be a battery quality issue, combined with a wiring quality and gauge issue.

An alternative would be to get a ThermoTec Battery heat shield, which would be an enclosive heat shield for the complete starter.

Be glad you've (obviously) got an ignition points-style distributor! If it was an electronic system, when battery voltage gets below a certain level, the control unit will not fire the plugs as the engine turns over. With points, if the battery has enough juice to transfer electricity to spark a spark plug, it'll start as it turns over verrryyyyy slowly.

Just some thoughts,


Edited by NTX5467 (see edit history)
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What kind of parts do you suspect might have "jumped the fence" during this assembly process? This never even entered my mind, just assumed my pick up load of Buick was all Buick. Actually, it was two pick ups of Buick and a shell on a flatbed.

You were right, I got the inline solonoid idea from my motorhome, it really didn't have much effect anyway. I'll go back to original wiring with larger guage. Starter has the long housing, do these starters necessarily need more juice when hot than a "normal" one?

The battery is new 750 CCA. Need more?

Your comment about the points is also news. At the time I just happened to have one of those electronic point replacement kits in my back pocket. So the ignition points style disttributor sort of fell in the tool box. Do you think returning to points will make a substantial difference. That's the only "modern" change I made. Distrubutor and coil remain the same.

Thanks for your input

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Thanks for the update and other information.

The "long" starter usually takes no more juice to work than the shorter one, at least in normal situations. Until you look, you generally don't know what's under there.

One thing I just thought of . . . at least in the world of Chevrolet, the end housing determines how deeply the starter drive gear meshes with the flywheel gear teeth. There is a desired depth of engagement for these two sets of gear teeth. This is where the famous starter shims come into play, for whatever reason, to get the "depth" relationship more correct. It might be a long shot, but might the starter gear being engaging too deep into the flywheel gear, causing additional drag? But that, as with heavier viscosity oil, or whatever other "contributing factors" might be causing the hot restart issue, really should not be that signficant in normal situations--period. None really affect hot restart cranking speed performance anyway, or not significantly, if they really do. Even if the "build tolerances" stacked up, they really shouldn't matter.

It all might just end up being a heat issue with the starter. Not sure why the starter would be getting that much heat in it, compared to other Buicks we've known about or lived with over the years. In this orientation, what is the operating temperature when you shut the engine off? How well is the fan clutch operating? Do things change if you happen to nose it into the wind when you stop it outside?

So far, the focus has been on the starter. What about the carburetor and fuel system? You've noted that it has "gas", but might the carburetor be succeptible to "fuel percolation" from a heat riser valve that's stuck closed (or mostly so)? A fuel line that's too close to a heat generating source? Resulting in a somewhat flooded situation, which the starting engine must get cleared out before the spark plugs will reliably fire? Does the carb have the correct base gasket under it? What throttle setting are you using during this hot soak restart?

A 750CCA battery should be plenty, especially compared to what the vehicles came with new, back then. I presume the battery has been fully-charged when the hot restart situation has been operative, rather than having sat for a while, or otherwise partially discharged?

A few years ago, I had two cars I was going to get "resuscitated". I went to the local WalMart and purchased two identical batteries, about 700CCA top post models. I knew that one car would need one sooner than the other one. When the shop had the first car, I took them one of the new batteries. A few days later, they called and said it would start the car once, but not twice. No extended crank time issues, either. They'd charge it, as it just appeared to be a low battery, but got the same result each time. So I approved them getting "something" from a trusted auto supply, which fixed that problem. Previously, I'd put a WalMart battery on my Camaro, due to the pricing compared to OEM, and it lasted a good two years before it started acting a little weak. In the mean time, my finances had improved so I put a new Delco in it and that was the end of that problem. Be that as it may . . .

Basically, until the source of "the heat" is found, there are lots of theories which can be discussed and not really solve anything. As long as the electricals are in order and OEM specs, then figuring out where the heat source is would be the next thing, which can also relate to the possibility of there being some fuel percolation issues with the carburetor.

For general pricniples, you might take the starter back to the shop and get them to re-check it, possibly in a heated condition. Perhaps there's something in there that's deteriorated or something?

Please keep us posted on your progress.

The reason I mentioned the voltage requirements for electronic ignition "boxes" vs ignition points is that I've seen that happen, after reading about it in the Chrysler Direct Connection Race Manual years ago. For higher performance applications, they recommended the "Orange box" ignition controller, but also mentioned that it needed a minimum of about 12 volts to fire the plugs off, which is more than the stock control box needs. One night, at a large cruise, there was a '70 'Cuda there that would spin over just fine, but not start. Perplexed, a set of jumper cables was hooked up to another car. The 'Cuda fired instantly--Orange Box strikes again!

If you've already got an electronic system on the car and it fires things off at the suspected lower voltage, I doubt that returning to ignition points would improve anything (as to how quickly it would fire the plugs and start). As long as the battery voltage isn't dropping too much, then the electronic system is probably helping things with solid sparks from the plugs. But if the plugs are fuel-soaked, they'll have to be somewhat dried-off to fire, which the electronic system can help do, too.

Take care,


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