Starter & Flexplate Stuff

[Rich72C10]

I been having starter problems. 1st it was my nosey neighbor telling me my starter didn't sound right (he is a diehard chevy guy). So I got a ACDelco Gold (3361822) from RockAuto Feb 2021.

Then late last year this starter actually sound like it was flying apart and couldn't turn the motor over. So I just assumed I needed a replacement, which RockAuto was happy to send me a replacement.

Then less than 50 starts later the replacement started to make the same sound/not being able to get the engine started. This time when I dropped the starter down, I put it back up with outside shims. I torqued the starter bolts to 35 foot pounds and then installed the proper rear GM starter bracket. This lasted even less time before it started to make a little grinding sound. At this point I decide I am an idiot and I am just going to take it to a dedicated Starter shop (that is highly recommended).

So starter shop summary (which swears I shouldn't need shims):

1. Tried to file down the deck (for no shims), did not help at all.
2. Ended up with 4 shims, problem fixed.
3. Teeth on flexplate are banged up a little bit but he feels the starter will clear that up and it will likely sound even better.
4. The flexplate isn't 100% true, has a bit of a wobble but he has seen a lot worse that don't cause a problem.

I swear there was too much distance between the tooth and valley of the flexplate. Like double the space of a paperclip and that is with no shims. I'll be pulling the dust cover this weekend because I want to seen how the teeth line up and the shaft to the top of the plate!

Now I have a question: for a 72 C10 350 with a TH350 Auto Transmission and the starter has an Offset bolt (diagonal) pattern - what is the stock flexplate?

I think it is (and suppose to be) a 168 tooth flexplate. But the shop thinks (says looked up) for a 72 C10 it suppose to have a 153 tooth flexplate.

[Rich72C10]

I forgot to add, I can now see what my neighbor was trying to tell me. It does sound soooo much better. It is like a low frequency / hollow sound now (can't really explain it).

[Accelo]

This is a classic issue with GM starters.
Most, if not all, the rebuilds come with nose cones that are generic (China). Easy to tell if yours is a generic replacement, look to see if it’s missing the GM part number on the nose. Most replacements have zero markings. I have changed out countless flex plates for this reason.

Best and most permeate fix is to identify the correct starter part number and replace it with the factory specified one. If I am forced to replace not rebuild, I always switch out the nose before installing the starter.
Another check/inspection is to install the starter without the solenoid attached. Then operate the arm to engage the gear to the flex plate. Sometimes you will be able to see the error and can file or shim the starter to get a better engagement. This works best with the transmission out but isn't necessary. If the flex plate is damaged you will need to change it as it will never work like it should. Also to be sure to install the arm that goes on the outboard side of the starter. It goes between the starter and the block. This is almost always missing. This is almost never an issue on a manual as the starter nose is different.

Remove the large cable from the starter and battery and use a jumper wire to the terminal with the small wires to extend the starter gear. You want .035 clearance between the starter tooth and flywheel. A paperclip makes a good checking device . Unfold it until you get enough to hold onto.

Best of luck.

[Rich72C10]

Yep, I bought & installed the brace (the truck came to me without one). The shop guy even commented on the truck's starter actually having one (and how it makes it a pain to remove/install the starter).

I am 99% the nose didn't have any stampings on it. Assuming this is a problem, it is a shame because I made it a point to get a ACDelco Gold Starter but I suppose that doesn't really mean anything these days.

I'm on the fence about the flexplate and the main reason why I took it to a shop. Though the guy say the flexplate should be okay but should isn't any guarantee.

Which brings up, what do you know about the flexplate teeth: 168 or 153?

[HO455]

The angle starter pattern is meant for the 168 tooth flywheel. I installed the 153 flywheel on my truck's 350 not knowing there were differences. Dhooo! I ended up drilling my block so I could use a 153 starter.
This link should help.

https://www.chevytalk.org/fusionbb/s...hp?tid/171683/

[Rich72C10]

Thanks guys and for the chart add too @Accelo! I hate how the forums make images (that have text) almost unusable.

Interesting there is overlap for either a 153 or 168 Flexplate - which makes James (the shop guy) not completely wrong. I also looked in my Chevy maintenance and overhaul manuals but it does say anything about 153/168 Flexplates.

[Rich72C10]

Anyone have a recommendation on a flexplate? I searched all the ones on Rockauto, two manufacturers, ATP and PIONEER. List below from $19 bucks to $84. Summit has these too, which of the reviews the PIONEER 871001 "SFI" has the highest ratings. The lower ones, often I read their bolts holes don't line up or they are bent.

All cross with #471598 168 Teeth/14in (Auto, v8, Internal Balance/2 piece Seal, 70~85)

1. ATP Z111 {#340296, 471598} Without Weight $19.63
2. PIONEER FRA100 w/o Weight {340296, 361950, 471597, 471598} $$21.79
3. ATP Z460 {#340296, 471598} Without Weight; Heavy Duty $$40.79
4. PIONEER FRA100HD Heavy Duty; w/o Weight {340296, 361950, 471597, 471598} $$41.79
5. PIONEER 871001 {#361950, 471597, 471598} Racing Flexplate; SFI Certified; w/o Weight $84.79
   
6. @Summit (and local O'Rileys) B&M Flexplate Part #20230 $132.95

Seems to me the PIONEER 871001 is the one to go with, even if you don't need a "racing SFI" flexplate. Also, I could care less about paying the $84.79, I'd pay double that to know I am getting a good part, heck the lower prices one makes me feel like you get what you pay for (cheap = crap)

Edit: I can get the B&M Flexplate #20230 local to me for $1 more at O'Rileys (in Stock too). Which B&M seems to be part of Holly but don't know if that means it is made here in the States, Mexico or China. On the Summit site, it is highly reviewed.

[Accelo]

I just purchased a flex-plate from Napa for an LSX motor and paid $95 with tax. Good news if it doesn't fit you can exchanged it quickly. Before installing confirm it bolts it up to the converter.
I have taken the tour at Holey. Watched them make the BM blower cases in a big CNC milling machine. My bet is almost all flex-plates are made outside of the US.

[Rich72C10]

Update!

My brother fessed up that he had to put on a different flex plate on because mine ended up being MIA after the engine build. They found it a few months ago when moving a desk in the shop, it had fell behind it.

I been at my brother's in East Texas and we swapped the POS flex plate and put in my original one on. We also got our hands on a older starter and had a local Starter/Generator place rebuild it. Now she starts up like dream - image that?

So nice to be able to put the truck on stands and have all this room in my brother's shop too!

Idiot Tip: Don't pinch your wires behind the distributor - things will not go well at all with +12v short to ground. I really dodged a bullets on this one!

[72SB]

Here is a cross reference chart for standard starter to gear reduction type. When I put in my higher compression 355 motor the stock starter faded quickly. Bought the gear reduction version from Rock Auto. Spins the motor nicely.

They come in 153 or 168 tooth and with or without R terminal applications.

[kwmech]

Staggered starter bolt pattern takes the 168 tooth (14'')----- and the 153 tooth (13'') starter will bolt up in the straight across pattern

[MySons68C20]

I will never be as smart as KW.....with respect!!

[Lost in the 60's]

Originally Posted by Rich72C10

Update!

My brother fessed up that he had to put on a different flex plate on because mine ended up being MIA after the engine build. They found it a few months ago when moving a desk in the shop, it had fell behind it.

I been at my brother's in East Texas and we swapped the POS flex plate and put in my original one on. We also got our hands on a older starter and had a local Starter/Generator place rebuild it. Now she starts up like dream - image that?

So nice to be able to put the truck on stands and have all this room in my brother's shop too!

Idiot Tip: Don't pinch your wires behind the distributor - things will not go well at all with +12v short to ground. I really dodged a bullets on this one!

Glad you got your issue resolved. Starter problems like this can be a major PITA. Your brother did match the correct starter to the 168 flex plate, but he probably bought one of those junk chinese flex plates and that was the issue. If it had a wobble, it may well have been out of round too, which is common with that crap. Your original is most likely still a GM part and runs true and getting an original starter rebuilt by a reputable local shop was icing on the cake.

I wouldn't know anything about pinched wires...

[Rich72C10]

The flex plate we put back on had orange overspray paint, so it is 100% what came with the truck in '72. We stacked the two plates up and the teeth seemed to match up. We didn't do much more than that, as I didn't really care - I just wanted my original flex plate back on!

Yes, that old starter was a nice, basically free, starter. The guy that let us use his transmission jack gave us two old starters to choose from. I picked the one that looked "older". When I brought him back his jack stand and the unused starter to him I laid out $40 on his shop desk with a "thank you" note (he was out - so he had no option to refuse the $$$).

The best thing, my neighbor across the street (big Chevy fan) is finally happy with the way my truck sounds when I am starting her. So I am glad to have him off my back about it LOL

As for the wires, I really thought things were F'ed up bad. I was able to drive her for about 3 miles until the pitch made a short. It was at night and the truck just shut off, 100% dead and no lights. Luckily my brother has a 18 foot trailer with a winch. All we did was loosen all the transmission bolts, brother wiggled it under the truck and I pulled the wire out - which was the +12v for the stop solenoid. Other than fixing some wires, all was good and drove home the two days later back to Austin!

[Rich72C10]

A very interesting thing now that I have the proper flex plate and starter that is from the 70s during starting. When I now go to start the truck and it has been sitting for days, if not weeks, I give the gas pedal a pump or two and she fires up lickety split! I hardly have even turned her over and she started. And this is with the colder weather, even when it was in the 20s she started right up.

Before the flex plate / starter swap, she was mildly harder to start after sitting. I had always thought the fuel had gone away in the carb. I'd do my pump or two, turn her over. Stop, perhaps give another pump and then she would start up.

So not only does the truck sound so much better when starting, the time until the engine is running has greatly improved! Just shows you, having proper bits on your truck is important. I feel like I have had some kind of a upgrade LOL!