Starter motor cracked AGAIN.

As the headline indicates, I seem to have an issue with cracking the starter housing, this is the 2'nd time within a couple of months, the first one was my own fault as I didn't shimmed it up properly as I should, but this time Im blanko No:, I know for a fact that it was shimmed up as per manual, but it still cracks, there is a 5mm crack in the first 1/3 of the starter.</SPAN>

Now the 64000$ question why do that keep happening, any suggestions gents before I go ballistic on the car:blast:

 

I had several cracked starters on my 340. I think they were bad rebuild jobs. Frustrating. I managed to not hurt my car.
now I'm having an issue with carb flooding on my 67 wildcat, over and over. Keep cool, take positive action and this too shall pass.

 

Two questions:

(1) What is your initial ignition timing setting?

(2) Are you still using the rear starter bracket? (see http://home.comcast.net/~shinzan/bracket.jpg)

Devon

 

The main reason a starter will break like that is too much initial ignition advance. Advance, if you didn't know, causes the spark to occur while the piston is still on its way back up in the cylinder. Ideal ignition advance is achieved such that the spark event happens, the explosion forms, and starts traveling down the cylinder, while the piston is traveling up the cylinder, and they meet when the piston is more or less at Top Dead Center.

The problem comes from the fact that the starter turns the engine very slowly, compared to normal operating speeds. So what is perfect timing for idle, is too advanced for starting. The explosion strikes the piston when it is still on its way back up, trying to force it back down. All that force is transferred to the crank, which transfers it to the flexplate, which transfers it to the gear on the starter. That's when you start chipping teeth and busting noses off starters.

Solutions? The easiest/best way is to run less initial advance. This can decrease the amount of advance you have at idle, which is bad, but you can add some back by making sure that your vacuum advance is working properly, or by re-curving your distributor so that your mechanical advance comes in sooner. These fixes will let you keep your ideal total advance, but lose some initial advance, which may be breaking starters. Read Larry's timing thread in the FAQ to learn more about all that.

There are also electronic ignition boxes that include a "start retard", which retards your timing way back for easy starting, and then brings it back up to normal for driving. Don't know much about them, other than that they help.

The other more "hack" solution to this problem I have seen is putting the starter on a separate switch from the ignition. That way you can spin the starter and get the engine moving, and then start the ignition once it is at speed, to lessen the chance of breakage. That is treating the symptom though, not the problem.

 

i had same problem turned out to be cracked dist. cap causing misfire on start up

 

Did you rebuild the engine? When the engine starts does it start easily?

 

I put a rebuilt HEI ignition system in my 74 Chevy C20 pickup (with the HUGE 454 in it) many years ago, and that thing ate starters at a horrific pace. Obviously, my timing was off. One backfire from that engine, and the nose cone was hitting the street. Check your initial timing at the distributor and back it off until you're close as possible to stock, and get your manifold vacuum at idle as high as you can.

 

I'm a bit embarrassed to say that Im not sure, but I think that my mate set it @ 12 (is that totaly off?)
2 Yes the bracket is installed.

</SPAN>

Regarding Larry's timing thread, im sorry to say that I can't finde it (yes i did do a search), do you have a link. never minde I found it.

No the motor has not been rebuild.
Normaly the motor starts "fine", well when is has been sitting for a week or so, it is a bit slow, but i thing that is due to the lack of gas in the carb.

In order to "back off" it that just a matter of turning the distributor "counter clockwise"?

BTW; The ignition system on the car is a MSD system and not the stock one(MSD-8552 DISTRIBUTOR - MSD-8202 BLASTER 2)

Gents I know that is a lot of stupid questions, but regarding the timing ect I'm a total "greenhorn"

 

For a stock engine, 12 degrees initial seems a bit high. I don't know what you've got under the hood, but my 67 430 engine has the initial timing at 2.5 degrees. I used to think that wasn't enough timing, but after I got all the other kinks out of my engine, it really does run happiest at that setting, now. I think you can back it down (turn distributor clockwise to retard timing) by at least 4 degrees, but you should check the manual for the stock setting & get it within a few degrees of that neighborhood. Adjust your carb mixture and idle settings to compensate once you've got the timing adjusted so that your idle is smooth & steady without any nozzle drip or backfires.

Distributor rotors spin clockwise, so you turn the distributor counter-clockwise to advance it, clockwise to retard. If you look at the vacuum advance, when it engages the base, it turns it counter-clockwise.

 

Awsome info from all you gent's out there, I just got of the phone with my mate that has done the timing ad acording to him it's set @ apx. 6-7 degrees, so it might be there the "fault" is, the strange thing is now that is has been running with that setting for 2 years without any problem, is it possible that the distributor has moved a bit or?

 

Just one more thing, are you using the correct knurled starter bolts? If not, you need to get them, they narrow the clearance between the starter bolt holes and the starter body, eliminates twist on the starter.

 

I'm using the bolts that the starter was mounted with from the start.

Have no idear if they are knurled starter bolts, is there any way to se that on them ?

 

See the crosshatched pattern just above the bolt threads:



Also, when is the last time you filled up with fresh gasoline, and what is the octane rating you're using?

Devon

 

Hmmm I'm defiantly not using them; better get a hold of them somewhere.

Regarding the octane, Im not sure how to translate it to US standards, but in Denmark it is called 95 Octane, with otcane booster and lead additiv.</SPAN>

 

Then my guess is the fuel is not an issue for you. Maybe someone can suggest a good source for correct starter bolts...

Devon

 

Gent's

Can anyone confirme the these bolt's are the correct lenth and will fit on my car.

http://www.summitracing.com/parts/RNB-45640/

 

Well they do fit.

Now gents, I did a search on this fanatic forum, and there was a few treads that misfiring of the motor also cloud course that problem, IE bad sparkplug cables, in my case i dont think that is an issue as the cables is replaced when i installed the MDS kit, any thought on that ?

To make a summery;
It is most likely that the initial timing is way off and that will course all the problems, is that what it all boils down to gents?</SPAN>ray:

Also I have to replace the starter bolts with the ones that you gents have recommended, just to be on the safe side and to confirm that the starter isn't moving. </SPAN>

Is there anything that i have missed?</SPAN>o No:

Also gents TANKS A LOT for the assistance I cant describe how much its appreciated. </SPAN>:TU:

 

Any problem that is causing a cylinder to fire before it should can break a starter. Over-advanced timing does that, and is pretty common, which is why everyone has asked about it.

Theoretically a short in your plug wires or distributor cap or something could cause the same thing, but it seems pretty unlikely, especially with new (quality?) wires. It wouldn't hurt to carefully inspect the wires for cuts, burns, melts, etc. Some people are super serious about keeping their wires totally separated from eachother to prevent cross firing. In my experience I have not found it strictly necessary, but its still a good idea, if feasible. If your wires are just flopping around, you could add some wire looms and wire separators to reduce the chance of cross-firing.

My money is still on too much initial timing advance though.

 

Cool tanks for your input.
I will address the initial timing advance when I get of the rig (in 3 days) apx.

But as i see it I have a bit of a problem, the new starter is on the way home now, but, when that is installed and Im going to start the car, there is still the risk that it will "kick back" again and break the new starter, how can I avoid that or at least reduce the likelihood for that to happen? </SPAN>
Will it be an idea to turn the distributer a bit clockwise in order to retard the timing? </SPAN>