J2 Stater motor

[Mike Adams]

I have just started to sort out my J2 electric start. I appear to have a shrunk on steel starter ring and a bronze starter dog. The dog is quite worn and the previous owner said it would not engage. The starter is mounted on what appears to be a fabricated bracket with straps although it has the facility for flange mounting and is slightly fouling the timing gear case. Should I change the dog to a steel one or could I machine the end and move it along a bit? I have a new CAV45 starter with the same dog but in steel which I could mount in its place with some suitably machined spacer rings. This is a more modern starter so spares might be easier. Also I appear to have some stainless steel core plugs that are leaking. Any thoughts on these appreciated. Pics below.

[Bee]

I wonder if you could just take the pinion off and turn it round?

[philjw]

36 minutes ago, Bee said:

I wonder if you could just take the pinion off and turn it round?

That looks like a good idea at first sight but I would wonder what has caused the damage in the first place.  Is the pinion fouling on the ring gear whilst the flywheel is turning?  I would have said the noise would make this obvious if it is the case.

[Mike Adams]

It is not posssible to turn the pinion around as shown below and if available they seem to be a couple of hundred quid.

[Batavia]

3 hours ago, philjw said:

That looks like a good idea at first sight but I would wonder what has caused the damage in the first place.  Is the pinion fouling on the ring gear whilst the flywheel is turning?  I would have said the noise would make this obvious if it is the case.

These bronze ones are designed to be sacrificial.  With the Bosch starter motors on 2 of my  Bolinder 1052 engines, I have one with steel and one with bronze - and both types are still avaiable, so presumably a matter of choice - and of how much you value the teeth on the flywheel!

Chris G

[philjw]

I see. £200 is a high price for a disposable item.  I suppose they must be good for quite a few starts.

 

[BEngo]

You can't just machine it off and move it along on the shaft because the bit that stops you turning it around has to be in the right place IIRC. You could shorten the teeth and move the whole starter along, but each tooth will need its engagement chamfer machined in the right position and on the right side. That could easily cost as much as a new pinion unless you can DIY.

What I think has happened is that the current drive gear was the right number of teeth but the wrong rotation so the engagement chamfer has been destroyed. It is also possible that the starter was installled at the wrong distance from the face of the ring gear. The gap should be 9/64 in and needs to be checked as the starter motor can move, especially on a fabricated cradle.

 you might  PM Sir Nibble of this parish and ask his advice on getting a new drive gear. They are easily changed.

Failing that there is a company near Preston who will courier collect and sort out your starter then return it all for a sensible price. I think the last BS 5 I had done by them was about the same price as you quote for a pinion. Twas a couple of years ago though.

N

 

[Mike Adams]

I think the problem is with the design of the fabricated holder for the starter motor. On closer examination it is bolted to the crankcase with two through  bolts, fairly close together with nuts inside the crankcase. I am not sure if this is the normal method but it seems unsatifactory to me and I can see that the bracket has twisted slightly and hence ruining the alignment. I think I need to modify the bracket so that it is capable of resisting the torque of the motor. One idea might be to make a plate to fit on the crankcase cover bolts or possibly to the mounting foot. Any pictures of other conversions would be helpful! I have removed the dog from the starter. There is one on ebay for £170 + Vat but I don't think that would solve the real problem. The inner splines seem to be handed so I don't think is the wrong rotation.

Thanks

Mike

[dave moore]

We have a J3 and experienced similar issues, the brass pinion spinning against the flywheel teeth before engaging, resulted in damaged teeth. The issue was within the starter motor itself, it should have been applying modest force initially to engage the pinion before delivering full cranking power. Kelvin guru Dick Goble arranged for the repair.....I refitted it with new pinion and have had no further issues since. This was a  good few years ago now......hope it may be helpful. Happy to provide details for Dick if needed.

Dave

[BEngo]

2 hours ago, Mike Adams said:

I think the problem is with the design of the fabricated holder for the starter motor. On closer examination it is bolted to the crankcase with two through  bolts, fairly close together with nuts inside the crankcase. I am not sure if this is the normal method but it seems unsatifactory to me and I can see that the bracket has twisted slightly and hence ruining the alignment. I think I need to modify the bracket so that it is capable of resisting the torque of the motor. One idea might be to make a plate to fit on the crankcase cover bolts or possibly to the mounting foot. Any pictures of other conversions would be helpful! I have removed the dog from the starter. There is one on ebay for £170 + Vat but I don't think that would solve the real problem. The inner splines seem to be handed so I don't think is the wrong rotation.

Thanks

Mike

The original item is a cast 'U' shape with a flat  base at the bottom of the 'U' which is held to the crankcase by two substantial  (I think 9/16)  bolts into BSF tapped holes.  There are no nuts on the inside.  The motor is held to the cradle by two 'U' bolts, like a 5in diameter exhaust clamp!

It seems like someone has in the past stripped the crankcase holes, or has fitted the fabrication with nuts and bolts small enough to pass through the original holes into the crankcase.  That inevitably leaves a clearance round the bolts and the whole thing will fret and wobble.  If you refit the fabrication using bolts tapped into the crankcase  then WW or UNC threads would be better than BSF.  If you want to re-use bolts then I would make some tight-fitting top-hat bushes  for the holes and the bolts as well as using locknuts.   The original cradles are about- Dick Goble may know where to lay hands on one.

It is essential to get the centreline of the starter parallel with the centre line of the engine both horizontally and vertically and the right distance off the engine so that the pinion is properly aligned.  Not too bad if the access is good and is easier if you remove the magneto and impulse drive.  I made my own fabrication and shimmed it out from the engine whilst the engine was installed,  so it's deffo doable.

 

N

[Mike Adams]

If it normal to only have the two bolts I will try that first. I can see the remains of the thread in the crankcase holes so I will try drilling and tapping oversize. I will also machine the end of the pinion and mill the ends of the teeth and give it a go. Looking at the end of the pinion it probably needs moving out a bit so a shim between the bracket and crankcase.

Thanks

[BEngo]

4 hours ago, Mike Adams said:

If it normal to only have the two bolts I will try that first. I can see the remains of the thread in the crankcase holes so I will try drilling and tapping oversize. I will also machine the end of the pinion and mill the ends of the teeth and give it a go. Looking at the end of the pinion it probably needs moving out a bit so a shim between the bracket and crankcase.

Thanks

Looking again at the picture in your post I am not at all sure the  chamfer is on the correct side. The pinion rotates clockwise looking from ahead of it and I would expect the chamfer to be on the leading edge rather than the trailing as shown. I can't actually check mine as it is miles away but worth a double checl before cytting I would say.

As far as brackets go, the original cradle has the two mounting bolts  between the two motor mounting faces. Not sure how your device is arranged but there is quite some thrust as the pinion comes out .

N

 

 

 

 

[Mike Adams]

I will also check tomorrow. I thought it was on the leading edge of the flywheel (driven gear) and on the trailing edge of the pinion(driver). When the two chamfers hit it accelerates the pinion forward to engage. The bracket, although fabricated looks similar to the one you describe which was probably cast. I need to find out the chamfer angle which might be more tricky!

[Gardner]

I have experienced the same problem with the starter fitted to a Gardner but same motor.  Essentially you must get the motor checked out first but also I have discovered that the starter battery must be in tip top condition in order to provide maximum power to the motor. Once engaged a less that perfect battery will turn the engine over and even start it, but full power is definitely  needed to propel the armature forward sufficiently to engage. I wouldn't entertain fitting a steel pinion or you risk damaging the ring gear. Whilst the bronze pinion are expensive and difficult to source, they are far cheaper that replacing ring gear. Hope this is of some use.

 

[Mike Adams]

I have now been given 2 pinions , one is the wrong hand, but niether has the lead in to match the starter ring. I have to conclude that the starter ring was not really right for the starter.When I dismantled the starter I found the cause. Someone in the past had filed of the trip on the soleniod so instead of being two stage it just wacked in at once. So I am going to try the CA45 starter, which is of a smaller diameter by 1/2 inch with some packing pieces. I have retapped the mounting bolts to M14 so I could be in buisness, or at least onto the next problem.

[Sir Nibble]

Solenoid, depending on which of two types is not expensive.

[Mike Adams]

Good news - I have ditched the old starter and fitted a CA45 using some additional sleeves and an additional bracket. Steel pinion on Steel starter ring it and works a treat! Wizzes round even on full diesel compression. Yet to try the thermostart and start the engine. Thanks for advice.