Starter questions

[Daveo91Burb]

1. Did squares ever use a bracket that bolts to the front of the starter on one end and the side of the block on the other? My '76 corvette has one, looks like this, but I don't think squares used them? At least not the later ones? Other GMs? Why did some need it and not others?

2. How long should the bolts be? Should the serrated part of the bolt stick out past the starter's mounting flange and into the block? Or should it only be threads sticking out?

3. Is the "R" terminal needed for any electronic ignitions? Correct if I'm wrong but I think it was a holdover from points-type ignitions? I don't think it's used on my '76 HEI, and I know it wasn't used on the '91.

4. How hard is it to replace the drive gear?

5. I've got clearance between the pinion tooth and flex plate tooth that allows a 14 ga solid copper wire, but not a 12 ga. Sound OK?

The reason for these questions is I'm using a much older OEM delco. I think it's '72 vintage. Everything bolts up and I know it works (I've actually started the engine with it when I test ran it) but there are some subtle differences between it and the one I had on originally. And there's a little bit of damage to the solenoid, there's a hole in the plastic where the "R" terminal is supposed to be. Considering a new solenoid for the '72 OR reusing the '91, but if I do that it will definitely need a new drive gear. Ever since I bought the burb four years ago there was bad gear clash when cranking. I tried shimming it multiple times to no avail. A few months before I pulled the motor I usually had to turn the engine a few degrees to get it past a bad spot to start it. Right before I pulled the motor I couldn't start it at all - good timing! When I got the engine out I checked out the FP - toast with multiple teeth gone. Trying to do everything right this time to avoid these problems.

You must be registered for see images attach

You must be registered for see images attach

 

[hatzie]

1 The 27MT & 28MT starters on the 6.xL AMG GM diesel used a brace from the block to the starter. GM usually used the brace on the high torque gasoline starter motors as well. The pictured starter is a high torque unit ID by the spacer connecting the solenoid to the copper strap going into the motor.
2 Starter bolts are specific to the starter and they have to fit properly. The knurling is to provide a snug fit in the starter nose casting to locate the starter. I don't believe the knurling is supposed to extend past the nose casting. GM used at least two different lengths and even one short and one long bolt was used on some starters.
3 The R terminal is to bypass the ballast resistor or resistance wire to feed the points and coil a full 12v when the starter is spinning. It has no function on HEI engines.
4 You have to disassemble the starter. Not too bad if you take your time... The earlier service manuals have detailed procedures.
5 Pinion gear clearance on a direct drive Delco starter like your picture is supposed to be between 0.020" and 0.030". 12AWG solid copper wire is way too loose at 0.0808" and 14AWG is 0.0641" (still too loose). I've heard and read suggestions of using a paperclip as a gauge. I'd mic one with a caliper or micrometer before I trusted it to be the right diameter for a gauge. It's worth noting that some of the newer gear reduction starters call for 0.140" to 0.060" clearance... That direct drive unit in your pictures ain't one of those.

http://www.chevyhardcore.com/news/chevy-starter-fitment-is-not-a-one-size-fits-all-situation/

 

[HotRodPC]

Whew, @hatzie I knew about 2/3 of it, but you saved me all of it.

I'll add to #3, as rule of thumb to help remember the posts on the solenoid, R is for RUN (Voltage cut down) and S is for START (As in Cranking and getting full voltage) IIRC, the actual labels mean Resistor and Stator, yes Stator not Starter.

And yes, it is for Points style ignition only and not even used in HEI or other aftermarket ignition systems requiring 12V.

 

[hatzie]

Whew, @hatzie I knew about 2/3 of it, but you saved me all of it.

I'll add to #3, as rule of thumb to help remember the posts on the solenoid, R is for RUN (Voltage cut down) and S is for START (As in Cranking and getting full voltage) IIRC, the actual labels mean Resistor and Stator, yes Stator not Starter.

And yes, it is for Points style ignition only and not even used in HEI or other aftermarket ignition systems requiring 12V.

Some actual thought was put into the connections on these older starters too...

I believe R is a #10 stud and S is a #8. So... As long as the ring terminal on the crank wire is original or the correct diameter replacement you can't hook the crank wire to the wrong stud.

 

[Snoots]

1. Yes
2. No
3. No
4. PITA
5. No

Overall, unless you truly want to keep it 'original' you'd be better off to go to one of the newer 'mini' starters (gear reduction).

 

[highdesertrange]

if you want the best starter get one for a 1969 Chevelle SS 396 4 speed. they have a cast iron nose cone. they take the medium length bolts, get the correct AC Delco bolts. if you want a gear reduction starter get a brand new AC Delco. I have not had good luck with the aftermarket ones. last but not least use that front bracket, it is a must. highdesertranger

 

[Snoots]

use that front bracket, it is a must

X2

 

[bucket]

The serrated portion is supposed to go into the block too. The threads don't start until further down in the block.

 

[Daveo91Burb]

@hatzie and everyone else: thanks! Lots of good info. I ordered the front brace. $7 shipped from a Corvette parts supplier (Corvette Central). Still not sure why I can only find them in Corvette catalogs though. Also working on shimming. I think it's going to take a thin half shim on the outboard bolt only to get it a little closer. Glad to hear it's a high torque model. Only thing concerning is that hole in the end cover of the solenoid (where the "R" terminal should be). I was going to swap the plastic (or bakelite?) cover between that one and the other one I have, but they're different enough in design that I don't think it will work. Also thought about swapping the entire solenoid assembly, but the piston that operates the bendix is bigger on the vintage one so that won't work either. IF I decide to get a new solenoid, how would I ensure I get the right one for that starter?

1. Yes

Overall, unless you truly want to keep it 'original' you'd be better off to go to one of the newer 'mini' starters (gear reduction).

I have no logical argument about that, I think the gear reduction starters are great. But I've got two of the old style, one of them a high torque, and I think I'll be able to get it working well. Plus, if they're shimmed right, I like the sound of the old Delco direct drives. Totally senseless argument, but I just like the retro sound for my retro vehicles. I've got an OEM on my Vette, too. But neither is real high compression and I don't have headers on them either.

if you want the best starter get one for a 1969 Chevelle SS 396 4 speed. they have a cast iron nose cone. they take the medium length bolts, get the correct AC Delco bolts. if you want a gear reduction starter get a brand new AC Delco. I have not had good luck with the aftermarket ones. last but not least use that front bracket, it is a must. highdesertranger

I think the vintage one that I have is cast iron nose as well, might be the same starter or pretty close. Do you know how to order the Delco bolts? I think I need 4" long ones. I looked on Amazon tonight and didn't have much luck.

The serrated portion is supposed to go into the block too. The threads don't start until further down in the block.

Thanks for the clarification. That's what I thought too. I tested it out tonight with the starter off. The bolts screw into the block far enough to almost completely cover the knurling. Based on that, 4" should work well if I use the vintage starter.

 

[highdesertrange]

here is a link to them on Amazon,

https://www.amazon.com/ACDelco-15544950-Original-Equipment-Starter/dp/B0013FDEEU

these are the long bolts. the bracket is in the ad too. down where it says bought together.

ARP also sells the bolts.

highdesertranger

 

[Snoots]

Cool.
Whatever turns your crank.

 

[Daveo91Burb]

here is a link to them on Amazon,

https://www.amazon.com/ACDelco-15544950-Original-Equipment-Starter/dp/B0013FDEEU

these are the long bolts. the bracket is in the ad too. down where it says bought together.

ARP also sells the bolts.

highdesertranger

Cool thanks, just ordered.

 

[Daveo91Burb]

The starter brace came yesterday, pretty pleased original GM, came in sealed “genuine GM” bag and from a Chevy dealership. (Wasn’t sure based on Amazon listing). Fits up nice and can even use original heat shield with just a minor mod of bending or removing a tab.

You must be registered for see images attach

You must be registered for see images attach

 

[Snoots]

Looks good! How's the alignment?

 

[Daveo91Burb]

Looks good! How's the alignment?

It's good. I put in one half 0.02 shim on the outboard bolt and I think that brought it in just right. You guys prolly knew this, but I figured out I can put 12v to the trigger terminal, but nothing to the main motor terminal, and it will pop the bendix out so I can check clearance. A regular size paperclip just barely fits, the bigger size doesn't fit. And found out the other check is to slide a 1/8" drill bit between the armature shaft (with bendix not engaged) and the flexplate - it just barely fits too. So I think I'm good.

I'm into this '72 vintage starter now for good or bad. I'm doing pretty much doing a full rebuild - new drive gear ass'y (bendix) and new brushes. More parts on order...... I'm sure it would have been smarter to get a reman from a shop or especially smarter to a get a good gear redux, but I have the two starters on my bench side by side and it's interesting to see how much better made the '72 one is compared to the '91.