Lowdown on Hi Torque Starters

[Alec Merchant]

Having suffered a jammed starter a few times in the last few months - always, inconveniently, in a petrol station after top up - I took the gearbox cover off to get at the Hi Torque starter a previous owner had fitted to my TR3 to see what the problem was.

 

The good news was the car still has it's original shrunk on starter ring with 91 teeth with forward facing chamfers, matched to 9 tooth starter pinion that also has chamfered, not square cut teeth. The bad news is that, while the starter pinion appears to be unharmed there is damage to the tip of the leading edge of every tooth on the starter ring. If you run your finger along the top edge of the starter ring teeth, from the back coming forward, there is a distinct burr or rough edge to the damaged leading edge tip. There are also fine metal filings in the film of oil on the casing below the flywheel. Otherwise all the starter ring teeth are present and in good condition apart from the damaged tips.

 

Pondering why there is damage to the starter ring I am considering three possibilities -

 

1. The nuts holding the Hi Torque starter in place did not need much effort to turn them, barely more than finger tight, though there was no indication the starter itself was loose or out of line. The starter casing design includes a step in the casing so that the starter casing sits inside the engine casing flange it fastens to.

 

2. A TR enthusiast locally who has high torque starters fitted to his competition TR3s suggests that it is not just the number of teeth but whether the teeth are fine or course in profile that is an issue?

 

3. My own best guess is that this is simply a case of damage caused by impact forces being transmitted by a high speed, high energy starter hammering into a fifty year old starter ring? If this is the case, then I am considering trying to obtain a more gentle and leisurely lazy Lucas starter of original pattern - ie the 'outward throw 'bomb' type starter that used to be considered adequate for the job.

 

Has anyone else any similar experience to share? The starter mechanism itself moves freely enough and is not seized. Is there an issue about fine teeth v course teeth, even though the number of teeth on the starter pinion seems to be the correct specification?

 

Alec Merchant,

 

Isle of Man.

[TomMull]

Having suffered a jammed starter a few times in the last few months - always, inconveniently, in a petrol station after top up - I took the gearbox cover off to get at the Hi Torque starter a previous owner had fitted to my TR3 to see what the problem was.

 

The good news was the car still has it's original shrunk on starter ring with 91 teeth with forward facing chamfers, matched to 9 tooth starter pinion that also has chamfered, not square cut teeth. The bad news is that, while the starter pinion appears to be unharmed there is damage to the tip of the leading edge of every tooth on the starter ring. If you run your finger along the top edge of the starter ring teeth, from the back coming forward, there is a distinct burr or rough edge to the damaged leading edge tip. There are also fine metal filings in the film of oil on the casing below the flywheel. Otherwise all the starter ring teeth are present and in good condition apart from the damaged tips.

 

Pondering why there is damage to the starter ring I am considering three possibilities -

 

1. The nuts holding the Hi Torque starter in place did not need much effort to turn them, barely more than finger tight, though there was no indication the starter itself was loose or out of line. The starter casing design includes a step in the casing so that the starter casing sits inside the engine casing flange it fastens to.

 

2. A TR enthusiast locally who has high torque starters fitted to his competition TR3s suggests that it is not just the number of teeth but whether the teeth are fine or course in profile that is an issue?

 

3. My own best guess is that this is simply a case of damage caused by impact forces being transmitted by a high speed, high energy starter hammering into a fifty year old starter ring? If this is the case, then I am considering trying to obtain a more gentle and leisurely lazy Lucas starter of original pattern - ie the 'outward throw 'bomb' type starter that used to be considered adequate for the job.

 

Has anyone else any similar experience to share? The starter mechanism itself moves freely enough and is not seized. Is there an issue about fine teeth v course teeth, even though the number of teeth on the starter pinion seems to be the correct specification?

 

Alec Merchant,

 

Isle of Man.

 

Alec, I am not a fan of the high torque starters and have no experience with them for that reason. However, for what it's worth, here's my experience with starters and ring gears. I've had issues in the past with occasional starter lockup with the original TR3 starter. It became standard starting procedure to pop it into fourth gear and push it backwards to clear the jam. It turned out to be caused by low voltage (bad battery connections). Damage to the ring gear was minimal and confined to a small area. If yours is damaged all around it would seem reasonable to suspect misalignment, very loose bolts or mismatched gears.

I like the old Lucas alternative. I find that the original Lucas starter (and decent voltage) is all that's needed, and the ring gear is relatively (compared to modern cars) easy to replace.

Tom Mulligan

[Alec Merchant]

Alec, I am not a fan of the high torque starters and have no experience with them for that reason. However, for what it's worth, here's my experience with starters and ring gears. I've had issues in the past with occasional starter lockup with the original TR3 starter. It became standard starting procedure to pop it into fourth gear and push it backwards to clear the jam. It turned out to be caused by low voltage (bad battery connections). Damage to the ring gear was minimal and confined to a small area. If yours is damaged all around it would seem reasonable to suspect misalignment, very loose bolts or mismatched gears.

I like the old Lucas alternative. I find that the original Lucas starter (and decent voltage) is all that's needed, and the ring gear is relatively (compared to modern cars) easy to replace.

Tom Mulligan

 

[Alec Merchant]

Alec, I am not a fan of the high torque starters and have no experience with them for that reason. However, for what it's worth, here's my experience with starters and ring gears. I've had issues in the past with occasional starter lockup with the original TR3 starter. It became standard starting procedure to pop it into fourth gear and push it backwards to clear the jam. It turned out to be caused by low voltage (bad battery connections). Damage to the ring gear was minimal and confined to a small area. If yours is damaged all around it would seem reasonable to suspect misalignment, very loose bolts or mismatched gears.

I like the old Lucas alternative. I find that the original Lucas starter (and decent voltage) is all that's needed, and the ring gear is relatively (compared to modern cars) easy to replace.

Tom Mulligan

 

[Alec Merchant]

Hi Tom,

 

Thanks for your response and info. Since posting my query I have identified a snag which might complicate and increase the cost of refitting an original bomb type starter. Scale drawings show it would need 10 + inches of clearance between the flange that the starter is bolted to and the exhaust down pipes. With this car a previous owner has fitted a replacement stainless steel exhaust system with down pipes that do not angle far forward enough to provide that clearance. I would guess the Hi Torque starter was fitted at the same time, as much as anything to provide more space for the upgraded exhaust. The first time the starter jammed I tried putting the car in gear and rocking it, first in reverse and then in second gear as someone on the scene advised at the time, with no success in freeing the starter. What did work was getting enough pedestrians to give me a push for a rolling start in second gear and letting the clutch out. That got the car going and freed the starter in the process on a couple of occasions. Most recently however the starter had remained jammed, even after a rolling start which is why I took the starter off to see what was going on. I thought the starter mechanism might have seized but that appears not to be the case. Voltage drop doesn't seem to be a problem either, the battery is in good condition, holds a charge and the connections are all good - the solenoid is working also.

 

Maybe there was some debris in the pinion mechanism which has now cleared as a consequence of being removed and examined? The only way to test that theory is to put the starter back on the car and try again. I was reluctant to do so without checking for other members wisdom first because I don't want to cause further damage to the starter ring. I was hoping to get on the road quite quickly and not end up having replace the starter ring - I would have thought old or replacement flywheels and starter rings are not all that easy to find?

 

Cheers,

 

Alec.

[roy53]

My problem was much the same re not turning the engine, and as i said before this was solved by placing a spacer to one side of the starter there by moving the rear of the body closer to the engine and the cog further from the flywheel as i beleave mine was hitting the flywheel.

ROY

[Alec Merchant]

Hi Roy,

 

Thanks for that, and for your patience. You can see that I am plodding my way through this one step at a time, trying to get my head round various complexities I am picking up via the Forum and other sources. I have found an instructive set of postings about HT starters on the TR4 Forum. I have had the starter ring inspected by a local motor engineer who specialises in classic cars. He has pronounced the starter ring to be in good condition despite some wear/damage the the tips of the teeth and that, as the starter was working before, it is an alignment problem caused by the securing nuts working loose. I did find the securing nuts 'barely more than finger tight'. On close inspection the locking washer for the lower bolt is quite flattened and no longer resilient and possibly allowing the body of the starter to move out of parallel and strike the starter ring teeth on a more declining angle if the top bolt remained tighter than the bottom bolt. This would have reduced the advantage of the bevels on both the starter ring and the starter pinion maybe?

 

So the next job is to put the starter back once I have procured a replacement sprung locking washer and made sure everything is tight.

 

I will try your suggestion, but given that the starter is located by top and bottom bolts, I wasn't quite sure how you arranged your packing washer to achieve the effect of bringing the body of the starter closer to the engine block? Probably in my state of frustrated confusion I am missing something? The sun is shining today and a just want to get on the road.

 

Does anyone know what the reasonable service life of HT starters might be? I have read on one forum posting that they start to give trouble after five years? In which case the one on my car might be past it's best and I should be shopping for a replacement?

 

Alec.

[roy53]

Alec

they can be rebuilt so no need for a replacement.My spacer was nothing more than a spacer/washer between the engine face and the starter

half way down between the 2 bolts so that when it was tightend up it forced the starter of line a fraction.not a propper job but it worked for me and like many tempory things it'still there

[Alec Merchant]

Hi Roy,

 

Thanks for that and the encouragement,

 

Alec.

[Trevor S]

Alec, I do not have personal experience...yet, but am having problems with a rebuilt TR2 where an original lucas starter is not disengaging when the engine is running. Having been unable to make progress I was thinking about a Hi torque replacement and discussed this with TRGB. I was advised that in their experience problems only arise when you have two chamfered surfaces trying to mesh together, ie the ring gear should be chamfered on the starter motor side, or the starter motor pinion is chamfered on the flywheel side, but not both. Your first post reads to me as those you have two chamfered surfaces trying to mesh together.

As I say this is second hand information so I cannot personally state if this is the source of your problem but it may be an aspect worth researching further.

[Alec Merchant]

Hi Trevor,

 

Thanks for that. Yet another bit of an increasingly confusing picture.. I did e-mail the Register Technical Team - they have given some insights, but have not yet been able to give me full chapter and verse. They did recommend the Forum as a way of establishing just what the collective wisdom is, but the picture I am getting is a very fragmented one as various individuals have installed varying combinations of starter rings, pinions with and without bevels or chamfers - there is no consistency of experience to build on. I am also not clear just how many different manufacturers of Hi Torque starters are out there and to what extent their products differ?

 

What I did find yesterday when putting the starter back on the car was that the lower bolt, with the retaining nut tightened to the end of it's thread, was still just slack enough to rotate. In other words the part threaded bolt is just too long. I note from old Moss catalogues that different length retaining bolts were available depending on flange thickness of different gear boxes. This might also be true of starter motor casings?

 

The simple solution I have adopted is to put in a packing washer under the bolt head. I ran out of time and light at that point, but just as soon as I have tightened everything up and put the air filters and choke linkage back I am going to press the button and see if it works.

 

Regards,

 

Alec.

[Kiwifrog]

 

 

What I did find yesterday when putting the starter back on the car was that the lower bolt, with the retaining nut tightened to the end of it's thread, was still just slack enough to rotate. In other words the part threaded bolt is just too long. I note from old Moss catalogues that different length retaining bolts were available depending on flange thickness of different gear boxes. This might also be true of starter motor casings?

 

Regards,

 

Alec.

 

 

Easy fix, 5 minutes with a hacksaw and the bolt is the right length

 

Alan

[TR 2100]

Easy fix, 5 minutes with a hacksaw and the bolt is the right length

Alan

 

 

I think Alec means that the non-threaded shank of the bolt is too long.

As Alec says, a spacer would solve the problem (as long as it doesn't

lead to another problem) or just cut a slightly longer thread on the bolt.

 

AlanR