TR6 TR6 Starter problem?

[machinemd]

Time once again to pick the experienced minds.The newly installed, rebuilt starter on my 1974 TR6 after only one months usage is missing and grinding a lot. So I pulled it, inspected and bench tested it, and checked & made misc measurements of the ring gear thru the starter mount hole. The pinion gear is beat up but thankfully the ring gear looks none the worse. The bench test showed the starter working good but I noticed that the pinion gear hits the stop ring on initial firing but immediately backs off from the stop ring .163". So I wired the starter to only energize the solenoid and found it the same. Is this how it's supposed to work or should it remain pressed against the stop ring/collar? I carefully measured the ring gear position to the engine/trans mount plate and did likewise with the starter and the position of the pinion gear. Put the numbers together and even on full throw the pinion & ring gears are only engaging 3/16+". Can this possibly be correct? I further measured that the ring gear was postioned on the flywheel 3/8" from the engine face of the flywheel and it's firmly tack welded there. Is this positioning correct or did a po have some bad work done? I've only owned the car two years and in that time the starter would only occasionally miss. It's like 10x that now with the rebuild. What be the thoughts and advice?
Thanks, Steve

 

[trrdster2000]

Steve, I may be wrong but I don't recall any ring gear having to be welded in place, this sounds like the problem as it's not set back on the flywheel far enough. Wish I had some good news but looks as if you will have to pull the tranny to get the flywheel off and hope you can get the welds smoothed down enough to reuse the flywheel. Wayne

 

[Guest]

[ QUOTE ]
I noticed that the pinion gear hits the stop ring on initial firing but immediately backs off from the stop ring .163". So I wired the starter to only energize the solenoid and found it the same. Is this how it's supposed to work or should it remain pressed against the stop ring/collar?

[/ QUOTE ]

I was under the impression that as long as the solenoid was powered, the pinion would be thrust into the starting mode, ie, engaged in the ring gear. The overpowering of the pinion gear by the fired engine would cast it back into the starter. Hence, if you were to keep the ignition in the start mode, you would cause the pinion gear to stay in the way of the powered ring gear and tear up your starter. The arm on the pinion also activates the starter motor. You may well have a weak battery. With full beam headlights on, can you even get the starter to work? Or, your rebuild on your starter is less than acceptable, may have a defective solenoid.
Check your battery, with less than a ideal volts, the power drops off dramatically.

I use a high torque starter and it works great for me. Now I have to replace the ring gear.


Bill

 

[machinemd]

Wayne,
There are basically 3 1" tack welds...bogus looking at that so I assume done by a dpo. Overkill? Poor fitment? They themselves are not the problem if only the gear were more properly placed. ButI had no great problem with a thoroughly worn out starter with it set up as it is. Just an occasional miss. I was gonna rebuild it over the winter, I rebuilt SAAB/Bosch parts in a previous life, but when I took it apart I found that it needed everything.

Bill,
I guess I could have been clearer. With the solenoid energized it really only pushes the pinion gear to within 1/8"+ of the stop ring. The only reason it initially hit it was the momentum and free play of the fork. It's been 30+ years but I think it's supposed to be pressed up against the stop ring as it spins. Your description is spot on with my memory and all is happening here except I don't think it comes full forward to the stop ring. If it would it would work with the maybe misplaced ring gear just as it always did. Maybe there's an adjustment for the throw of the fork? Battery is fully charged.

Thanks guys....keep em coming.

 

[skikir]

Are you sure your ring gear is where it should be? The early starters in TRs "pulled" the pinion gear to the ring gear and kept it up against the fly wheel flange. The "new" in TR6s "push" the pinion gear out to the ring gear and away from the fly wheel flange. On TR6s sometimes over years the pinion can "tap" the ring gear out of place, away from the fly wheel flange. My old 74 used to do this even with a new ring gear installed. That may be why PO had it welded. Just maybe the welding warped or bent the ring gear and in places it is not engaging.

 

[jayhawk]

I hope your "rebuild" was more than mine-- essentially they turned the armature and put in new brushes. Other than that, they did nothing to improve the ability of the starter to engage the ring gear.

 

[tomshobby]

The solonoid should pull on the arm which then pivots forcing the pinion towards the ring gear. The pinion should be forced against the thrust washer in the nose of the starter housing. It should stay against the washer until the switch is released and then the spring in the solonoid should force it back. If you have the starter out and a vice big enough to hold the starter you can bench test it and verify if this is happening. If it does not there is a problem with one or more of the mentioned components.
If there is enough power to turn the starter there should be plenty for the solonoid.

If the pinion is moving out and staying against the washer and it is then not positioned correctly with the ring gear then you may have the wrong starter or it may need to be shimmed. I very much doubt there is a problem with the ring gear position. To check you might rotate the flywheel and take a few measurements in different locations and check the teeth all the way around.

Here is a stretch, maybe you crossed up the wires on the solonoid and got the ballast resister wire on the wrong terminal and I am not sure if that would even do what you are describing.

 

[martx-5]

I took a look at the starter parts breakdown at the Moss site, and if you say that the starter drive pinion is not going out far enough (it should just fall short of the thrust washer by about .010"), the problem could very well lie in the fork that pushes out the starter drive. If the starter itself cranks, then the plunger that moves out the drive is going in the solenoid enough, as the contacts for the motor itself are closing. The usual place where the fork wears is the two pins on either side of the fork that pushes out the drive. Other wear places on the fork are the pin and hole in the fork where it pivots. A quick disassembly will reveal any excessive wear.

 

[vettedog72]

I think you have the problem isolated. I had a low batt drain so I got a big batt, way over the requirements, and I all ways thought that big batt pushed the ring gear back enough to compromise the mesh of the starter to ring gear. Never had a flat batt though. I had to replaced the ring gear.

 

[machinemd]

To be honest, I don't have a clue if the ring gear is properly situated. But by measuring at 8 points around at the gear it varies no more than .040 so it does sit square. Bottom line tho is it did work 99% perfect with the old worn out starter. The rebuild was purchased not from one of the big three but from one of the more reputable 2nd three. It looked "like new". So far we're talking on it. With a well charged battery, and power only to the solenoid, at full extension it falls short of the stop ring by .163"....more than 1/8". Worn arm @ pivot or pins maybe but I can't tear into it yet until it's determined it's still under warranty or it's voided.

 

[machinemd]

Skikir,
You were on the money! I decided to recheck everything including a talk with my machine shop guru who cleaned up the flywheel over the winter. He said if it wasn't right up against the flange and with good teeth he'd have let me know right away. I popped the carbs off today so I could get a better eye and hand down to the starter area and sure enough a couple light raps proved the ring gear loose. And when I got it out I realized that the ring gear was in backwards...confirmed by Wayne, thanks Wayne. I guess that new starter was strong enough to hammer the ring free when the pinion hit the square edge teeth!
Thanks guys, Steve