Blocked cracked by starter, any way to fix?

ruger1

Member
I installed a new 12v conversion on my TO30 yesterday and when i went to start it i heard a strange noise from the starter and decided to take it off and have a look. The picture shows what i found. The starter caused the block to crack near the lower mounting hole and there is now a hairline crack near the upper mounting hole also. Is there a way to fix this? does anyone know what caused this?

This is a brand new starter that was installed a few weeks ago. A few of the teeth are broken off of the starter gear. I had to buy a new starter because the same thing happened to my old one except that the whole nose cone and teeth were broken off of that one.
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That is what we call in the industry a "Bad Thing"!
Drill and tap from the side to install a bolt to reinforce across the crack then grind out and weld up the crack.
A shame that happened. Wrong starter? or is the flywheel bent, out of round?? Odd failure to my thinking!
 
I'm thinking the timing is off for it to kick back like that way off. Yeah you can weld cast iron i use a stainless steel welding rod with good results. I would think you can take it and have it done with no worries.
 
Based on your explanation:

The LOWER crack is what caused the upper crack. OR to put it another way: had the lower crack not existed then the upper crack would have never happened. NOT visa-versa either.

SO does the "brand new starter" fit the round recess just fine or was it a very tite fit????? Is there an obstruction inside of the transmission housing that is causing the nose cone to bind????

Cracking the block like that is rather odd. Usualy if there is any binding when trying to fit a starter then the mounting ears of a starter will break off before any part of the block will crack break.

Did the engine backfire real hard when this happened???? U made no mention of a backfire.

ALSO. In the pic the bolt is still in the UPPER hole. Therefore are we to assume that the upper hole is not cracked both sides of the hole like the lower hole is cracked both sides.
 
Over the years i've seen a number of starter bendix gears that split or broke completely in half. Never saw one where a tooth or teeth just broke off. Sounde like the gear is just weak production. It happens.
 
In my ignorance, I would tend to suspect you need to remove the engine to inspect clearances. Especially when mounting the starter. What is the clearance between the starter drive and the flywhhel when engaged? Then I might be sorely tempted to mount studs to hold the starter in place. As this is also a cast iron block you might need to find an oven and a welder who knows what they ae doing. The fun part is not the heating of the block to weld it properly, the cooling is what is more critical.
Now if not possible to get this done for under $250, the $500 block below becomes a good deal.
But you still get to mount your starter and check clearances. Unless you like repeat performances. . .
 
There was no binding when installing the starter either time. The upper hole is not cracked on both sides like the lower hole, i actually only noticed the crack with the flash from the camera. The engine did not backfire when this happened. I had the engine running a few hours before this happened and it ran fine. I was going to let it run for a while since the tractor had been sitting for a while when this happened.
 
(quoted from post at 15:29:03 11/12/12) In my ignorance, I would tend to suspect you need to remove the engine to inspect clearances. Especially when mounting the starter. What is the clearance between the starter drive and the flywhhel when engaged? Then I might be sorely tempted to mount studs to hold the starter in place. As this is also a cast iron block you might need to find an oven and a welder who knows what they ae doing. The fun part is not the heating of the block to weld it properly, the cooling is what is more critical.
Now if not possible to get this done for under $250, the $500 block below becomes a good deal.
But you still get to mount your starter and check clearances. Unless you like repeat performances. . .

I dont have any idea what the clearances are, i just installed the starter and drove it. The odd thing is that i have started the tractor a bunch of times and it always started and ran fine and then all of sudden this happens.
Im not sure what i am going to do at this point. Iim not too sure i want to mess around with splitting the tractor and installing a different block. I dont think i have anyone in my area that can weld this up the correct way. I may just decide to part the tractor out at this point.
 
(quoted from post at 14:35:33 11/12/12) That is what we call in the industry a "Bad Thing"!
Drill and tap from the side to install a bolt to reinforce across the crack then grind out and weld up the crack.
A shame that happened. Wrong starter? or is the flywheel bent, out of round?? Odd failure to my thinking!

The first time the starter gear and nose cone blew up it was the original starter from what i could tell. This new starter was the correct one. Im thinking it must be the flywheel but would a bent flywheel allow the tractor to start just fine say 50 times and then have this happen?
 
If you have fitted a new or different starter, this could be the problem. On the original starter there was a lip all the way around the face where it sits in the hole for the starter in the block. If this lip is wrong dimensions, it would cause your problem, compare it with the original starter.
With the starter not mounting correctly, it will not mate up with the block properly and will be mounted at an angle instead of square-on to the Block. The lip was to provide support for the starter and take the load off the bolts.It would also be the cause of damage to the teeth on the Ring Gear...John(UK)[email protected]
 
(quoted from post at 16:05:18 11/12/12) If you have fitted a new or different starter, this could be the problem. On the original starter there was a lip all the way around the face where it sits in the hole for the starter in the block. If this lip is wrong dimensions, it would cause your problem, compare it with the original starter.
With the starter not mounting correctly, it will not mate up with the block properly and will be mounted at an angle instead of square-on to the Block. The lip was to provide support for the starter and take the load off the bolts.It would also be the cause of damage to the teeth on the Ring Gear...John(UK)[email protected]
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Count the number of teeth on the Starter pinion, you may have two different types here.
What is the number stamped into the starter body, this may also help us to know just what you have....John(UK)[email protected]
 
Measure diameter of starter lip. It mite b significantly less than OEM by .020" or more. Also note the groove around the end of starter shaft in new starter. There should have been somekind of a tite fitting snap ring in the groove????? In some cases such a snap ring acts as a shock absorber to keep the bendix from pounding the nose cone.

Based on the pic the ring gear on flywheel looks ok but my computer resolution is not the best in the world. Inspect ring gear all the way around it. U will find more wear at 2 points 180 degrees apart because that is 2 points where the engine stops each time it is turned off. Mite find a broken or really bad ring gear tooth at 1/2 way points around the ring gear.

To gerry rig/repair LOWER Crack;
Cut a strip of 3/16 steel about 3/4" wide and about 2 to 3" long. Bend it around outer diameter of engine block spanning the crack like a bridge. Drill 2wo holes and bolt it to the block. Do NOT use self tapping bolts. Use a grade 5 BRAND NAME bolt. If bolts have NO markings on head of bolt they are junk bolts and will most likely break.
 
Both starters have 9 teeth on the gear. The new starter does not have anything stamped on the body. I checked the flywheel teeth more closely. There was an area on the flywheel where there was significantly more wear on a few teeth. A few inches away from that areathere was a tooth that was broken in half. I will measure the starter diameter later on.

In regards to the fix, i understand what you are saying in regards to the bridge. After closer inspection there is a hairline crack above the the upper hole also. What if i hade a plate made up the fit into the cutout area where the starter mounts?. This plate would have the starter hole and mounting bolts cutout but would also have the two bolts in that area that are used to bolt the block and tranny together also cutout. That way these two aditional bolts would help support the entire area. The only issue would be the plate thickness would affect how far the starter goes into the block. Would this be possible with a thin enough plate?
 
Is it possible that a broken piece of the old starter is still in there and a tooth on the flywheel picked it up and that is what broke the drive on the new starter?

Bob
 
quote
"A few inches away from that areathere was a tooth that was broken in half. "

Top half or broken length wise???? Probably doesn't matter. Most likely cause of the problem. But it surprises me that while starting it several times there was no indication of noise, binding or other conspicuous evidence of a problem.

Assuming flywheel has a removeable ring gear it definately needs a new one. Probably not too expensive to do. I'm guessing about $75. A local automotive machine shop ought to be able to do it while u wait. Of course that's assuming the ring gear IS removeable And u'll have to split the tractor to do it. Splitting tractor is not real difficult.
 
(quoted from post at 18:04:08 11/12/12) Is it possible that a broken piece of the old starter is still in there and a tooth on the flywheel picked it up and that is what broke the drive on the new starter?

Bob
No, there were pieces in there but i removed them after it broke the first time.
 
(quoted from post at 20:18:42 11/12/12) quote
"A few inches away from that areathere was a tooth that was broken in half. "

Top half or broken length wise???? Probably doesn't matter. Most likely cause of the problem. But it surprises me that while starting it several times there was no indication of noise, binding or other conspicuous evidence of a problem.

Assuming flywheel has a removeable ring gear it definately needs a new one. Probably not too expensive to do. I'm guessing about $75. A local automotive machine shop ought to be able to do it while u wait. Of course that's assuming the ring gear IS removeable And u'll have to split the tractor to do it. Splitting tractor is not real difficult.

The tooth was broken lengthwise. There was no indication of binding at all when i started it several times earlier that day. I could hear it binding when it finally broke. I hit the starter twice and knew something was wrong, thats when it broke. Im a long way from nashville, i live in western new york. Looks like i will be splitting the tractor and replacing the ring gear or whole flywheel.

What do you think about having a small plate fabricated to go on the face of the block under the starter. I plan on doing your bridge idea for support also. There is no one near me that can weld cast iron.
 
The plate idea mite work. But look at the teethe on the starter for a wear pattern. Measure from end of gear to wear pattern. That will be the max amount of thickness for the plate. I'm guessing 1/8 inch max allowable. Also note that crankshaft moves fore and aft probably 1/32" MAYBE as much as 1/8" if heavily worn so have to allow for that. If no wear pattern on gear then blue the gear and spsin by hand to get such a wear pattern. Make sure crank is pushed all the way back toward rear of tractor when measuring or getting wear pattern.

The problem with the plate is getting it precision indexed so that the starter is not out of alignment.

I think the bridge type reenforcement should be enuf and probably easier. Note that cast iron is tricky to drill and tap. Usualy requires a different angle ground on the drill bit. Google it for the proper angle. I don't recal the angle rite now. When tapping take small cuts. 1/4 turn of tap at a time. DO NOT FORCE TAP. If it breakes off u gotta a real big problem because taps are harder than the front seat of hell and cannot be drilled out.
 
Need to measure (mite have to use a micrometer) the pilot shoulder on the starter motor. Compare it to an OEM pilot shoulder diameter.
 
(quoted from post at 23:02:01 11/12/12) The plate idea mite work. But look at the teethe on the starter for a wear pattern. Measure from end of gear to wear pattern. That will be the max amount of thickness for the plate. I'm guessing 1/8 inch max allowable. Also note that crankshaft moves fore and aft probably 1/32" MAYBE as much as 1/8" if heavily worn so have to allow for that. If no wear pattern on gear then blue the gear and spsin by hand to get such a wear pattern. Make sure crank is pushed all the way back toward rear of tractor when measuring or getting wear pattern.

The problem with the plate is getting it precision indexed so that the starter is not out of alignment.

I think the bridge type reenforcement should be enuf and probably easier. Note that cast iron is tricky to drill and tap. Usualy requires a different angle ground on the drill bit. Google it for the proper angle. I don't recal the angle rite now. When tapping take small cuts. 1/4 turn of tap at a time. DO NOT FORCE TAP. If it breakes off u gotta a real big problem because taps are harder than the front seat of hell and cannot be drilled out.

What size bolt will be sufficient for the bridge and how deep? What should i do about the lower hole that is split, should i try and close it up or should i leave it alone? Im not sure that the lower bolt will secure the starter if left as is.
 
i"ve welded lots of cast-(john deere had the best)u cant do this proper and make it last without splitting the tractor.crack has to be ground out and welded fom both sides.
 
I was thinking a bridge along the outer perimeter of the block. Z120 is 9/16" thick. Just barely enuf for a 1/4-20 bolt. Maybe have to use a #12 screw.

12152.jpg
 
I don't know about the upper crack because there is no pic of where it ends. Since that part of the block did not fall off i assume it ends at a non critical place to cause oil or coolant leak. It mite be bridged the same way as the lower crack. Bridging the lower crack as shown in my pic above should be enuf. Maybe drill a small hole at the end of the UPPER crack to keep it from creeping is usual procedure for cracks in anything.
 
Quite frankly, the more i learn about these Continental blocks the more they appear to be a real flimsy P.O.S. I have a recenetly acquired bare Z120 block up on the bench now for any case studies that may come along.

I have one Z120 that has performed flawlessly for over 18 years and probably 1500 hours. Another Z120 that appears to be very low useage and nearly no ridge in the liners. Cylinder webs cracked top and bottom as well as two very flimsy head stud bosses between #2 and #4 cylinders, just over the starter motor that are broken. Now we have a starter hanging up and breaking the block.
 
I know I haven"t see it all but I have never seen that failure before. From the way the cracking occured it looks like the flywheel locked up and the reaction from the starter broke the casting. I wonder if it had a small crack there all ready? Is the drive pinion on the starter correct? is there something in the bell housing that might cause the flywheel to jam?
 
(quoted from post at 02:16:29 11/13/12) I know I haven"t see it all but I have never seen that failure before. From the way the cracking occured it looks like the flywheel locked up and the reaction from the starter broke the casting. I wonder if it had a small crack there all ready? Is the drive pinion on the starter correct? is there something in the bell housing that might cause the flywheel to jam?

It could have cracked from the first time the starter cone blew up inside the housing. I removed the chunks that were loose inside the first time. I figure after all the new parts i have put into the tractor i might as well fix it. The tractor runs great and the hydraulics are strong. I found a local guy that can weld cast, im going to talk to him and see if he can weld it up. I have to split it to replace the ring gear so might as well try and fix it right.

Thanks everyone for the help so far, will update when fixed.
 
I bought mine in 1996 and it was converted to 12v before i bought and has the original starter. The starter does produce more torque with 12 v than with 6v but I have had no problems with the starter. You jus dont want to run it it for long periods of time because it has twice the current running through the winding than if it ran on 6V. so the I^2R (read heat input) is twice as high.
 

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