I have a motor that is holding the starter motor in mesh with the ring gear and self destructing.full story is I rebuilt a genuine Delcostartermotor from workshop spares. This operated well for over a year until the solonoid windings open circuited. Achinese sourced replacement starter was fitted and lasted a month before it stayed in mesh and self destructed. Anotherchinese starter was fitted and it has done the same. Upon dismantling I found the solonoid windings burnt out.I have double checked all the wiring and it all checks out fine.I have advised that a geuine Delco starter to be refitted with a higher horsepower rating and will rewire entire starter circuit just to be sure,I have also advised the operator to rest starter if it doesnt start straight away, the reality is this motor starts very easily.Anyone else had similar issues with these imported starters.
skin1235,
Feb 18, 6:52am
whats the cause of staying in mesh, is it welded contacts, or stray feed holding it in, they have wired earth returns, is the earth return in good condition, is the stray feed coming back through that loop
mugenb20b,
Feb 18, 6:55am
Yes, but when I worked for a truck / bus repair outfit, we never had starter problems with Cummins engines at the time (mind you, I was only there for 15 months). We replaced probably a dozen starter motors on Hino trucks and about a third of them failed in less than a year, but not due to staying in mesh.
skin1235,
Feb 18, 6:55am
though if memory still works I used to have Butec starters, great big ugly MF, and give you one hell of a fright after a strip down and new brushes etc cos I'd always wash them clean while working on them - volatile fumes and amps don't go well together, hellova bang
skin1235,
Feb 18, 7:02am
solenoid windings are completely independent to rated hp of starter, all it has to do is pull a slug in that makes the contacts connect - and offer the mesh to the flywheel at the same time, even if it doesn't mesh properly the windings should not be threatened theres something wrong in the system, lousy earth perhaps, starter amps trying to earth back through the solenoid - internal broken earth or not connected properly what condition were the brushes on the destroyed motors
owene,
Feb 18, 7:24am
I don't suppose the motor has been rebuilt just prior to these issues! If so, is there any chance that they have fitted a hypoid starter ring but installed in on the flywheel back-to-front!
skin1235,
Feb 18, 7:29am
I like the way you think - not the starter but further in, especially if it IS the same motor causing the issue
skin1235,
Feb 18, 7:32am
you're thinking starter gear locking and thus motoring the starter consequently over rev and explode they will also generate huge current while doing so which could be why the solenoid wiring cooks - it is wired in parallel to the comm wiring
jan.w1,
Feb 18, 7:36am
Throw it in the rubbish hubby says . They are no good,might get a better one at the wreckers and the right kind.
owene,
Feb 18, 8:19am
Yes, if a hypoid (angled) ring has been fitted the wrong way round, it may well 'pull' the starter pinion into itself instead of forcing the pinion back out. Only a vague guess, it may well be a square starter ring.
granada,
Feb 18, 10:32am
The big ends were done last year, but it didnt get a full overhaul so presume ring gear is original. It has a large battery earth cable direct to insulated starter earth as well as one to the chassis as well as the engine block. Also decent main battery cable to solonoid. All connections are clean and tight.No back feedfrom any other source such as fuel solonoids to activate starter. The two that self destucted were brand new so brushes, etc were all good. There is no adjustment for pinion throw on these starters and it is one of the only things I havnt measured.the only thing they had in common were the fact they were cheap chinese starters.
owene,
Feb 18, 7:43pm
Insulated starter earth! I assume you mean the cable is insulated!
What model engine is it!
skin1235,
Feb 18, 8:29pm
no, insulated earth means completely divorced from body return earth a lot of the larger rigs use it for all their electrics, lights, cab harness etc, they don't use chassis return just another system to check if there is a fail vague memories of someone inadvertently putting an earth wire battery to chassis and played up merry hell with the system - he fitted it so he could fit extra lights and didn't want to run an earth wire back to closest point ( lazy ) coupled with his slack maintainance and dirty battery terminals he would get back surges every so often that would pop all his new lights
skin1235,
Feb 18, 8:32pm
and to confuse even further, some rigs use 'earth return' for the heavier electrics and chassis return for the rest - those ones don't normally give issues as long as the terminals are kept clean and tight
intrade,
Feb 18, 9:00pm
didyou check the ringgear of the flywheel has no damage making the cog from the starter get stuck on to the starter , and that the cog is actuarly the correct size not jaming in to the ringgear stuck every now and then , Distance of travel on cog to size of cog, can be quite mathematic to be sure eoth engeneers tools micrometer caliper and drawings to rule that out
skin1235,
Feb 18, 9:05pm
I'd also be measuring the throw, the 'cheap' starters may actually throw further than the originals, and may need spacing back from the bellhousing
owene,
Feb 18, 10:15pm
Mmm, now that the isolated earth return for starters has been explained, my money would be on an unwanted earth current. What you could do is undo the battery +ve feed into the starter once the engine is running and see if it then disengages. If so then it's certainly an electrical issue and not a dud starter motor issue. Have you got one of those grunty big switches laying around - if so, put it in the starter +ve feed.
bigfatmat1,
Feb 18, 11:14pm
common problem on cummins and cat with delco 42mt the main cause is slow cranking speed causing contacts to weld together. Normally caused by batteries I normally replace the batteries if they are out of warranty and or test faulty when replacing starter motor and for the price diff do not fit anything but genuine delco I am speaking from experiance. You may also have a slave solenoid fault.
bigfatmat1,
Feb 18, 11:14pm
common problem on cummins and cat with delco 39,40,41,42 &50mt the main cause is slow cranking speed causing contacts to weld together. Normally caused by batteries I normally replace the batteries if they are out of warranty and or test faulty when replacing starter motor and for the price diff do not fit anything but genuine delco I am speaking from experiance. You may also have a slave solenoid fault.
bigfatmat1,
Feb 18, 11:18pm
I wouldnt overcomplicate the situation worrying about earths at this stage. It wont make it stay in mesh. Also more common on a 12v cummins as opossed to a 24v
bigfatmat1,
Feb 18, 11:23pm
hahaha cav starters with the endcaps over the solenoid always test with the cap off otherwise the explode and blow the seals out
granada,
Feb 19, 5:07am
Cheers guys for your thoughts and advise, I did forget to mention that it was fitted with two new N200s at the last starter change. Also had a new alternator recently but that was totally unrelated.I think my next plan will be to fit a new Delco starter.Redo all battery cables, battery isolation switch, replace slave solonoid (relay). new ignition switch, and run new wiring for starter activation.I will measure pinionthrowoutdistancewhile it is off.Cost is not important but I really do need to educate them on the cheap chinese starter motorsAny more imput is appreciated
bigfatmat1,
Feb 19, 5:19am
is this a foden!
mrfxit,
Feb 19, 5:20am
*Just watching*
Any hoot. yep agreed. Back to basics because of the hassles & cost. Did that on a smaller job (Surf) that had a lot of random starting issues & in the end simply rebuilt the whole starter /battery cable system. Replaced all the cables + Crimp & solder EVERY joint
skin1235,
Feb 19, 5:22am
I'm picking the brother - ERF, lol
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