Spinning Starter Motor

[Lukas]

Hi all,

6.9 #1 has a long-term issue where the start motor will sometimes spin but not crank the engine. "Remedy" at present is to simply retry starting, at which point it will either crank correctly or the above will happen again. Happens at most 3 times in a row. I can't figure out any trends - happens sometimes when hot, sometimes when cold (both weather and engine).

Questions:

1. Assume this will eventually get worse and cause a failure to proceed?
2. Believe this is due to some mechanism that extends the starter's cog into the engine, and not extending it the full distance every time - is it fixable by pulling the starter apart and replacing a spring or such?

Thanks

Lukas

 

[Tony66_au]

Usually it is a prime symptom of your starter failing.

The cog is literally thrown forward by centrifugal force when the starter spins, it may benefit from a cleanup and light lube but id be refurbishing or replacing the starter.

 

[Tony66_au]

BTW my SE suffered the same issues, I refurbished the starter myself as I had new brushes and solenoid handy and I also did bearings and washed the grunge out in the parts wash.

Starter worked fine on the bench and I cycled it 20 or 30 times as well as using a lump of pine to load the starter up with the application of the pine to the spinning cog to assure it was all hunky dory, reinstalled the unit cleaning contacts as I went and placed a nice new battery (Calcium plate ofcourse).

Went to start the car and it was perfect the first and 2nd times and then played up again lol

Its better, but not fixed.

 

[Helmet]

Sounds like you need a new drive gear Tony

 

[Tony66_au]

Sounds like you need a new drive gear Tony

Cleaned up ok but it had wear, I have a newy (Starter) in its box but im not fitting it till im ready to do the SE incase it is needed elsewhere.

Im told there is also a reduction starter available aftermarket that might be worth a look, those old girls pull a fair whack of current through some elderly cable.

I got the new unit thru a mate who is a Bosch agent in a related field, should pick his brains on parts and prices because the new unit was far cheaper than I thought it would be.

 

[Oversize]

Lukas, I'm having the same trouble with #5298 and it seems to me the pinion isn't being thrown out far enough to make contact with the ring gear. I've heard of ring gears being replaced on 6.9s before, but I'm not sure why. My old ZB Fairlane had a worn ring gear and it'd make a horrid grinding noise on the odd occasion. Not what either of us seem to be experiencing.... When it was removed, half the teeth on the gear had been ground away by the starter pinion! Then again mine will spin, then clunk and seem to turn the motor slightly. Next shot it'll turn the engine without a problem. Hopefully my ring gear wasn't worn completely away by the PO and there's almost nothing left (hence no grinding noise). But if that was the case, I wouldn't think she'd turn over at all.... Or turn then stop, with a corresponding scream from the starter as it hits a spot with no teeth.
So I'd pull the starter, get it checked and thoroughly check the WHOLE ring gear while it's out.... That means turning the engine one full rev with a socket on the front of the crank. Unfortunately they don't seem to wear evenly, so one section might appear fine and the other's completely gone. Probably due to compression and the positions where the engine stops after shut-down.

 

[Tony66_au]

Just throw a new unit in guys, Starters are too important to muck about with.

 

[Lukas]

Thanks for the tips all.

Based on the above, can anyone advise off the top of their heads:

• Approx cost of a replacement - eBay suggests $200 to $500
• If 350 and 450 starters are compatible (I'd think not).

I'm still tempted to pull it apart at least - will check the ring gear as suggested.

This car also came with an alleged spare starter as the problem existed at sale time, so if I pull the current one I can also compare vital stats to see if it is indeed a valid replacement.

Lukas

 

[Tony66_au]

I paid $235 for mine plus $15 freight, Bosch unit.

 

[Styria]

There is a difference between the Starter Motor for the 450 and the 6.9. I admit to not knowing what difference there is, but I'd head for my trusty Auto Electrician. Routine items like brushes should be no problem, but once you get a bit further in, parts can become expensive. Regards Styria

N.B. I recently had a unit refurbished at a cost of $280.00 and I was impressed with his comments that "I can now understand why these units are so long lasting" ! I was impressed, as he also thought that they were at least ten years ahead of their time.

 

[kunbarrie]

sounds like a slipping clutch in the bendix drive,

 

[SEL_69L]

It could very well just be a weak or broken
Bendix spring.

 

[Tony66_au]

The issues with DIY starter repair is the initial diagnosis and chances are that if one item is kaput then the others wont be far behind.

So you either reco the whole thing or be prepared to do the job 2 or 3 times, Even my crude loading method with the pine on the starter gear has its limits especially on the larger starters.

There should also be some machining done when you replace brushes so they seat properly with minimal arc and if you go too far with the brass then you create other issues.

Its fun to muck about with, but better to go pro or new IMO.

 

[Oversize]

Welcome Kunbarrie and thanks for your input!!! Sounds like you're quite knowledgeable, so care to start another thread about you or your vehicle/s?

 

[Lukas]

Okeydokey,

So, after the initial attempt to remove the starter failed due to clearance issues (not a lot of room in there), I got the thing out just last weekend. This leads to 2 more questions:

1) What size socket / widget do I need to fit the big nut on the front of the engine? This is so I can turn the engine by hand, to inspect the ring gear. Have already removed radiator fan. Aside: seems you can turn the engine via the holes on the edge of the disc with the timing marks - presumably a bad idea?

2) Costs for a starter rebuild? Styria said he had one done for $280, MBSpares said closer to $500 given that some bits are approaching unobtainium and the 6.9 connection.

Thanks

Lukas