The Stovebolt Site Forums The Shop Area Engine Shop Flywheel, from hell.... and starter issue 47 1 ton, ~1960 engine

Okay folks -

Howdy to one and all, hope this note finds you all in fine fettle! Waltzing Matilda, our 1 ton 47 chevy has been doing okay. But, BUT there's a fly in the ointment!

I don't drive her that much, but a while ago, the starter was "growling" - like it had an internal short, or the armature was dragging. Very slow to turn, very high current draw. It would do this a few times, then - no problem. Intermittent as hell! Finally, one day the truck left the Missus stranded at the welding shop. She was *NOT HAPPY* about trying to push start the leviathan... I replaced the starter and everything was fine, for a few weeks - then the same problem! I check voltage drops on everything - hell, there just isn't that much there! I replaced various parts with spares on hand, it would start fine several times... then the growl.

Out of frustration, I took it to our mechanic - he LOVES old iron (though he may rethink this now) Anyway, the flywheel was chewed up and it apparently had the wrong flywheel on the engine. The starter drive only would engage about 1/8". It chewed up the ring gear. So, here we are.

The engine in the truck is a 12 volt 1960 235 (as near as I can tell) The flywheel it is SUPPOSED to have is a 168 tooth FW, with 9 holes in the center hub - 3 sets of two bolt holes and one for a dowel pin. The center hole in the flywheel is 2". The apparent GM part number is 3705410. Does anyone have one of these beasts or knows where I can get one? I am in Northern California, and would appreciate any illumination all y'all can share.

The PO, or the PO PO had apparently installed this later engine, not knowing (or caring) that the starter didn't match the flywheel. The truck wasn't running when we got it, so the PO/POPO may never have even known.

When I replaced the starter, the old one looked okay. The drive teeth were a bit chewed up, but it didn't look that bad. The starter was not that old, so that should have been a tip off....

Any ideas?

TIA,

John

John,
Sounds to me like someone put the wrong replacement bendix on that starter,and now it,s compounded by the 2nd wrong one.
What diameter is the flywheel?
If you have to keep that flywheel to fit that engine,then just change the ring gear!
HEAT,Son,HEAT and it will literally fall off,just let it cool naturally.
I have even flipped the gear over and used the good side when none available.
Whatever You do,just Make Sure You get the correct tooth count for the starter drive to MATCH the flywheel.
regards,
steve sr.

Need a new battery? Checked & cleaned all wiring connections?

What flywheel does it have on it (if it's not the one it's supposed to have)? Post the engine casting codes if you want to be sure it's a truck engine; someone can decipher the code for you.

A new flywheel ring is cheaper than a new flywheel. I have also seen 'new' starters installed to where they did not fully seat up into the bell housing. That would cause some cavities in the flywheel teeth, for sure. But it wouldn't sound like a growl.

Man, I hope you can get it figured out- I'm just bouncing ideas around so you don't leave your wife pushing that big truck anymore. One last one- can you turn the engine over by hand? I don't know, but if it is intermittently growling, there may be a tight spot in the engine.

Brad

The flywheel comes in 2 versions. A 6 volt and a 12 volt. Yep, the trick is to match the flywheel and the starter. A 6 volt starter will work just fine on a 12 volt truck. Turn that ring around on the flywheel and match the correct starter to it. And you will drive away happy. There is a different tooth count and pitch to the ring. The tooth count is easy to find in "search" but here it is.Tooth count, 6 V is 139 teeth and 12 volt is 168 teeth. The starter has the same number of teeth for 6 and 12 Volt, but the pitch is very different. There is a difference in the shaft diameter. A good rebuilder will know what you have.

I'll have to check on the flywheel diameter, but IIRC it takes a 10 or 12 inch clutch. What is needed is a 168 tooth ring gear. The geometry of the existing teeth is wrong and it isn't 168 tooth. I don't recall, at this late hour, what the tooth count is, but it's not a case of being able to simply heating, removing, and flipping the ring gear. As I understand it, the flywheel/ring gear sits too far "back" - for the starter to properly engage, never mind the issue of the teeth count being off. And apparently there is only one bendix for that starter. The kerfluffle apparently had its' genesis in the 6v to 12v conversion. I will measure the flywheel and see if I can get engine casting numbers here tomorrow.... I need to go back and check your post to see if I covered everything.

Yes, I have a 12 v flywheel. Also, the engine doesn't have any tight spots at all. Compression is an even 110-120. Every connection is beyond tight and bright, less that 1/2 a volt drop on both positive and ground circuits - the cables are new, the battery is new.... I was really [censored] that I wasn't able to troubleshoot this. Well, until this little gremlin.

So, is there a different tooth angle or geometry within the 168 tooth, 12V flywheels? Or, if I get a 168 tooth wheel am I all good?

Steve - You're talking about a difference in the starter armature shaft, correct? Offhand would you, or any bolters, know what the different diameters are? My existing 12v starter, bendix damage notwithstanding, should work fine with a 168 tooth ring, correct?

Okay, here's the latest. The casting on the side of the block is 3769716, which denotes, near as I can tell, a 1958 235. The flywheel takes a 10" clutch and is 13 inches, NOT 13 1/4. It has a 139 tooth ring gear. The rub, apparently, is that the crankshaft is an older 6 volt version (pre '55) based on my current, apparently, incorrect flywheel. The difference between 6 and 12 volt, near as I can tell, is the bolt pattern in the hub and the diameter (13 1/4).

The GM part number that I need is 3705410. The casting number on the flywheel itself is 839754-777. If I can find the right ring gear, I'm in....

Any ideas?

I had this company already pulled up, and they have flywheel rings & other things. I do not know if any of them are what you need

I'm still wondering about the "growl" sound- hopefully that is just when the ring gears are in a bind.

Brad

Get a six volt stomp starter and use it with the fly wheel you have. So long as you don't sit on it cranking the engine a long time it will last for ever on 12 volts

Will really spin the engine over also

You can put a 6 Volt flywheel on a 12 Volt engine. The crankshaft is the same diameter at the journal. It is drilled and pined the same. The flywheel was probably used because it fit in the Bell housing. And the bell housing fits the cross member. A 6 Volt stomp starter will work just fine in a 12 Volt truck. As long as it is not run for long periods and over heated. Some one will know, but I think the Armature shaft is bigger in a 6 Volt Starter motor. The mismatch from the mating of gears that don't mesh is what causes the noise. The "Bendix" drive is different for the 6 Volt because the shaft diameter is different. Find a 6 Volt starter and try it. If the flywheel is not too damaged it just might work. And if it won't then you can pull the flywheel off and get a new ring put on it. The starter is 2 bolts and a cable, The flywheel...wel that is a bit more work..He,He.

http://speedprint.com/deves50/flywheel.php

Not alot of other flywheels that would even fit. Probably the problem is you have the wrong starter for the flywheel. I for one like to change the starter rather than the flywheel. Im lazy that way. If you have a 235 with a flywheel, chances are its one of those two. I am no expert. Ask Pre68Dave or HotRodLincoln, but I am not aware of any other flywheels available for the 235 of ANY year. Where they come in, is I am not sure the 250, or whatever newer engine flywheels would fit. If they do, then all bets are off. In any case, its good advice to get the other starter like Steve, Roy, Brad, everyone else says.

As Dave says,,Im no expert either, but the 230,250, 292 flywheels wont fit on a 235 crank/starter/bellhousing.

As far as I know the flywheels from a 216,235, and a 261 will fit. But I am no expert. Pre68Dave will know for sure. There might be an interference issue with some bell housings but as far as I know the crankshaft is drilled and pinned the same. Something to do with that timing and TDC marks on the flywheel. The 230, 250, and 292 are very different animals from the 216, 235, and 261. And for sure, none of the SBC flywheels will fit.

All 1941-62 flywheels use the same mounting pattern.
I have not been following this thread, but in scanning it it sounds like originally it was starting fine with no growling noise. That would not happen it there was a mismatch of 6 and 12 volt parts.
It sounds like both the flywheel and starter are 12 volt in this case.
This may have nothing to do with the growling noise, just the "not fully engaging" problem, but there are two 12 volt starter drives I have seen that look the same except one has a much longer gear. There is a possibility the wrong drive was used.
You need to actuate the lever and see if the drive teeth come back all the way to the end of the shaft and housing.