Santa Claus was good to N11018 this year and delivered a new (actually a low-time) B&C Specialties BC320-1 starter that was picked up from a fellow pilot who ran it on his RV-4 for 42 hours. As all airplane maintenance/upgrade tasks go, nothing is ever simple and installing this starter was no different. I was expecting a quick bolt-on project that would be done in an hour or so, but when attempting to mate the starter to the block there was a 2″ shaft blocking the way. AH CRAP!
Not knowing what to do, I hit the interweb to see if Lorena Bobbitt might have some advice for removing this thing. That search was fruitless, so I began searching for all the other folks that have come unto this same predicament with their Continental starter installations. Apparently not many have, or if so, they’re keeping it a secret.
After following more links than Mr. T has around his neck, I eventually stumbled onto this page which had a link to this information which included a non-link to this write-up at SkyTec for modifying a Continental C-85 from a pull starter to a push-button starter AND IT INCLUDED PICTURES. HOT DIGGETY! I don’t have a C-85, but the details were close enough to be applied to an O-200. Although I’ve never bought a SkyTec product, I sincerely thank the person at SkyTec that took the time to document AND PHOTOGRAPH the installation of one of their starters that is similar to the BC320-1 I was attempting to install. That saved me some serious grief. Thank you.
I began by soaking one end of a shop towel in WD40 to “catch” metal particles then tucked it inside the engine.
Then made a cardboard cutout that roughly matched the profile around which I would be cutting.
Using some modeling clay that I purchased from the nearby craft store, I packed it into all the places that I couldn’t protect with the cardboard. Not all clay is the same so make sure you read the label before purchasing. I didn’t wanna be chiseling this stuff outta my engine so I got the Bob Dole kind that never hardens. I recommend you do the same.
You’ll need a die grinder to cut the shaft and if you’re like me and the people at SkyTec, the shaft will need to be cut twice in order cut off as much as possible. If your die grinder has a long neck, then you might be able to accomplish this task with one cut. Lorena would be proud.
The amount of shaft you remove is critical. According to the B&C specifications, when the starter solenoid is activated, the drive gear will extend 2.46″ into the engine housing so this means you need to make sure the remaining stub of the shaft is at least 2.47″ from the starter mounting surface on the engine.
Use a straight edge placed across the mounting surface (dashed yellow line) and a caliper to measure the depth into the engine where it meets the shaft. Mine came out to 2.44″ which meant I had to get back in there and file off some more. When finished, the clearance was 2.49″ so I was safe to proceed.
When the job was done, the total amount of shaft cut out was the two solid pieces totaling 1.884″ plus the 0.05″ I had to file down in the previous paragraph which equals 1.949″. When factoring in an additional two “thicknesses” of the die grinder wheel (for the two cuts I made), I think it’s safe to say that 2″ of shaft was cut off.
I’ll spare the details of how to install and wire the starter because if you’ve made it this far, you’ve proven your competence for completing the job. Here’s a before and after shot so you can see what my installed BC320-1 starter looks like.
This is the 1st “blog” I’ve ever commented on and only because of your BOB DOLE comment. That had everyone in the shop laughing. I’m still laughing about it.
Did the same as you but,,, used a XPR 4000 Dremel with the flex shaft. Removed a small collar on the hand grip to gain more depth. Also, started off with a slightly used Fiber cut-off wheel and after max depth from that wheel, the switch was made to a NEW fiber cut-off wheel. Was able to cut it off easily although a slight angle was required (tilting the hand grip). It was easily trimmed/polished to a nice finish with the edge of the fiber cut-off wheel. It cut a full 2.00″ off and it was finished to the small radius that can be seen the transitions the shaft to the journal. Enjoyed the funny comments as well. :)
Local shop used a dremel tool just like this to cut the starter shaft and after about 100 hrs had to rebuild his engine due to the fine metal particles that you can’t catch using this technique. Did this myself as an A&P. Go the extra mile and pull the engine and removed the back accessory case and cover the entire engine where you can scavenge all metal particles and rinse with mineral spirits. That is what the B&C company recommends. They do not recommend using a dremel tool since it has particles that are no magnetic in their blades. A stitch in time saves nine. Do it right the first time.
I can say with certainty that I secured the area as thoroughly as I could and then cleaned the holy heck out of the area with mineral spirits before reassembling because I was concerned about particles I may have missed. I’ve since flown almost 300 hours since this modification. Nothing in the oil filters nor annual inspections have given any concern that the engine has sustained any damage from this, though I do understand your concern.