Starter Barely Engages with Flywheel

[skhorleb]

Hi Don,

I have gradually experienced more trouble with the starter engaging on my A4's flywheel (serial # 191095). Most recently the starter catches on the flywheel for a just second and then the pinion jumps off and just spins. I took the starter out and (based on the wear patterns) the starter gear has been engaging only about 1/8 of an inch with the flywheel teeth. I found metal shavings around the area of the starter gear and flywheel. In other words, this is grinding away at the very back end of the flywheel as well as the front of the starter gear itself.

I am suspicious that the previous boat owner installed a starter is not really made for this engine...I know many starters look just like the Delco and seem compatible but are not...for whatever reason. The label on the starter shows it to be made by a company called ARCO in Pensacola Florida. It says the company is in Pensacola Florida. The model is Marine SAE J1171. New starters are not cheap. Before I spend any money on this, I thought I had better check with you.

1.) How far should the starter gear engage with the flywheel teeth--the entire 1/2" width of the flywheel tooth?
2.) Are there any repairs I can do on this starter so that it works correctly?
2.) What is the model number of the Delco starter that goes with this later model A4?
3.) Assuming it would be difficult to find the original Delco model locally, are there any other starters that are readily availably at auto parts stores that can be substituted without compromising quality?

As always, thanks Don!

[Don Moyer]

Steve,

I'm hoping that ARCO might be a remanufacturing firm and if so, you might find a Delco number on the main housing. Even if you do find a Delco number, in many cases viable main housings have been mixed and matched with renegade nose cones which simply will not work reliably on all Atomic 4s. If you find no Delco number on the main housing, I have no idea how to help you.

I'm attaching a pdf file of a Q & A we prepared some time ago on the subject of starter compatibility which may help you, but please be ready for a very confusing explanation.

There is one other thing you should check. Sometimes the starter ring on the flywheel moves forward a bit on the main part of the flywheel (being a separate part that has been pressed onto the flywheel). The best way to check if this has happened is to remove the starter and look at the back of the flywheel through the opening in the flywheel housing. The back side of the starter ring should be flush with the back side of the flywheel. If the starter ring has displaced forward even 1/4" or so, it would explain your symptoms.

Don

[skhorleb]

Starter Barely Engages with Flywheel

Don,

As always, thank you for the quick response and including the starter compatibility Q&A.

Yes, I thought the starter was a rebuilt item too. No numbers in the starter that were similar to the known Delco models like 1107-678, 1107-320, or 1108-422. The only number on the starter is 160....that's it. The starter ring does not appear to have slid toward the front of the flywheel. In case I am missing something, I attached a photo. Please let me know if I overlooked a detail, how a starter ring would be reseated, and special tools required.

Since I can count on the compatibility and quality of your supplies, I ordered one of your Delco rebuilt starters last night.

I have two remaining questions for you:
1.) How far should the starter gear normally engage with the flywheel teeth--the entire 1/2" width of the flywheel tooth?
2.) Without the starter model match on the housing, can I ship my existing starter to you to cover the core charge?

As always, thanks for your help.

[Don Moyer]

1.) How far should the starter gear normally engage with the flywheel teeth--the entire 1/2" width of the flywheel tooth?

If half of the tooth engages the ring gear it should be enough for the starter to function. By the way, the condition of the teeth on your starter ring gear appears to be quite normal, so your starter malfunction must be fairly recent.

2.) Without the starter model match on the housing, can I ship my existing starter to you to cover the core charge?

Sorry. We need a reusable core to credit your core charge.


Don

[skhorleb]

Normal tooth wear

Thanks for the feedback Don.

Yes, the problem just developed within the past few months. I have not run the engine much lately as I am amidst some significant engine work. (My large number of questions lately reflects this.) Who knows...by the time I am done I may have a candidate for your pin ups.

You mentioned the tooth wear looked normal. This is great news! 'Glad I included the picture. This made me hopeful that this starter may not be a "basket case", so I tore the starter apart and found there was no lubrication on the starter shaft. I greased it up, will reinstall it and see if the starter gear interlocks across at least half of the flywheel. Maybe I can salvage my old starter after all.

[Don Moyer]

Good for you! I'm reluctant to believe that the PO installed a starter that never worked.

Don

[skhorleb]

New starter works

Don,

Yes, you are correct. My existing starter did work for the first two years I owned the boat. Not sure how long the PO had it installed. The lube job I did on the old starter did nothing to improve the situation. Even a new GM solenoid did not make any difference. I think the starter gear shaft was about 1/8-1/4" shorter. Hence once the teeth wore down a bit over time it would no catch on the flywheel.

However, good news. Santa delivered my MMI rebuilt starter today! Installed it immediately and it works just fine now. I think the only thing I can do with the old starter is to replace the starter gear (if such things can be found at local auto parts stores and keep it as a spare...for emergency use only. Thanks again for your help resolving this!

[dfoulds]

Hi Guys:
I am having exactly the same problem as Steve. The starter is not fully engaging the fly wheel and is just spinning. It has sheered of about 1/8th of an inch off the teeth at the back of the fly wheel. My flywheel looks similar to the one in the photo Steve posted maybe a little worse and the ring is not detached at all.
I have a number of questions.
1) Is the flywheel reversible:

2) How far in should the starter gear engage the flywheel? By Steve's account the new started resolved the problem so I am guessing a lot more then 1/8 of an inch.

3) I am wondering if I will need a new starter and flywheel as the ware on my flywheel is slightly worse then Steve's. I would post a photo but I don't know how.

4)Most important what caused this to happen. The engine is a rebuild from MM and has fewer than 250 hours on it. It still has the MM paint on the teeth.

[skhorleb]

Gentle persuasion and patience

dfoulds,

The A4 starter ring is pressed on to the flywheel. In the final analysis, my starter ring had gradually shifted alignment on the flywheel after many years of the starter gear engaging against the starter ring teeth.

Although the flywheel had not shifted away from the drive shaft or become deformed, the pressed ring gradually moved out of reach of the worn starter pinion teeth. In my case, the ring was offset from the hub by over 1/8". I guess the starter pinion exerts quite a bit of lateral force against the starter ring. Hence, the starter no longer engaged with the starter ring and would just spin freely.

Here is the resolution that worked for me. The saved me the expense of a machine shop properly pressing the starter ring back onto the flywheel or replacing the entire flywheel. I have experienced no recurring problem since I did this a couple years ago.

1.) Unbolt and remove the flywheel housing.
2.) Unbolt and remove the flywheel/starter ring.
3.) Lay the flywheel/pressed ring on a hard flat surface such as a concrete floor. If my memory serves me correctly, the back side of the flywheel should be facing up.
4.) Under the starter ring I placed 4 small 2x4 blocks evenly spaced around the perimeter of the starter ring. Use soft wood to avoid any damage to the starter ring. Make sure that the 2x4 blocks are positioned outside the perimeter of the flywheel but supporting only the starter ring. This elevates the flywheel hub and starter ring off the floor.
5.) Using a 5 pound hammer, I lightly tapped on flywheel adjacent to where the 2x4 blocks were positioned. Be gentle so not to crack or deform the flywheel or the starter ring.
6.) I went around and round the perimeter of the flywheel to slowly but evenly re-seat the flywheel ring. I used a micrometer to measure the amount of movement as I went and ensure the movement remained balanced. I stopped once I reached 1/8" + movement. No heat or lubrication was applied. This step took less than a half hour.

Voila! Gentle persuasion and patience paid off. The starter ring was adequately reseated on the flywheel. Nothing scrapes and no flywheel wobble. No trouble with starter engagement since. No more rebuilt starters.

Unfortunately I do not have any before and after pictures to share with you. I hope this helps.

BTW, if my problem does reoccur, I may add a few spot welds the next time as a preventative measure.

Maybe Don or someone else has a more elegant way to resolve your situation other than replacing your flywheel.

[lat 64]

flipping the ring gear

I have never done this to an A-4,(I don't even know if you can or should) but I've done it to lots of old chrysler products.
We would tap the ring gear off with a brass drift and hamer, then put the ring by itself in an oven and heat it up about pizza-baking temperature. The ring would expand with the heat and then it would usually just drop back on the seat of the cool flywheel. A little tapping while it cooled to make sure it got seated was prudent.
The danger in this method is that you get all excited about not burning your fingers, and you put the ring gear back on the same way it was to start with.
...Don't ask.

[Mo]

Did that too Russ, once upon a time with an old Jeep. It works!

[jpian0923]

This is not a one piece unit?
The teeth are on a separate ring pressed onto the flywheel?
I did not know that. Cool stuff.

In dfoulds case he just has to remove the toothed ring from the flywheel, flip it around so that the good portion of the teeth are facing the starter?

By the way, this thread started 5 years ago. It's good to see the person that started this thread is still around and posted his solution, finally.

[lat 64]

Careful, iron can be chipped.

Did that too Russ, once upon a time with an old Jeep. It works!

There's a little fog lifting now about this; I seem to remember that if we were not going to save the ring gear, we would cut it with an abrasive wheel or heat it with a torch so we would not risk chipping the edge of the iron flywheel as it was knocked off.

So much time—so little memory

[rrranch]

All the ring gears I've ever replaced, except one I did at home, I use a torch with a big rosebud tip to heat the ring gear then just dropped it on. Seriously I must have done a hundred of them and everyone else I worked with did them the same way. I never heard of a torch hurting them. I cranked the oven up as hot as it would go at home and it barely worked. It does work good putting transmission gears back on the shafts though. I just got done rebuilding the ZF in my F350. In the kitchen! My wife loves me.

[lat 64]

Yea, the oven method does take time.
Good to know about the torch. Our shop was mostly machine work and the ring gear stuff was mostly done by the mechanics themselves.

Are you gonna buy the wife a new oven?