Skytec starter installation in Continental C 85 C75 O200
On factory pull-start engines (C85-12 thru O-300-C), certification eligibility is by modification per:
1)STC SE10076SC(engine modification),
and
2) STC SA10077SC (airframe modification to replace pull-start mechanism with push-to-start button)
Download a Letter of Authorization to use the STC's.
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Converting an old pull-type starter to the KCST2 is very easy
STEP 1: Order a KCST2 (not a C12ST2 or a C12ST2/S - just order a KCST2)
STEP 2: Prepare for installation: cut off the pinion shaft
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Step 1 - Out With Old
Gather Tools (NOT these tools)
OK - These tools are more like what you will need
Remove old starter - Weigh it (ours was 16 lbs)
Here's what you'll see - A shaft (your victim) Step 2 - Prepare to Cut
Prepare the area Clean out all oil around shaft
Make a cardboard cutting shield using the enclosed template
Pack some clay Enclose all gaps
Get ready to cut with 1-1/4" fibrous Dremel bit Step 3 - Cut The Shaft FLUSH
Problem: Our Dremel tool's neck interfered with the shaft...
...we couldn't get a square cut so we cut shaft twice...
...First cut only half of shaft Then go back and get all of it
This will make clearance for neck of Dremel tool Step 4 - Clean & Install
Your shaft should be cut FLUSH - that's within 1/16" of the case
Flush area with long stream of clean fluid (we used WD-40)
Remove shield & clay Wipe clean
Mount new starter Torque per instructions >Step 5 - Wire & Sign
Follow instructions in box (KCST2) to wire the new starter
You'll use these terminals to wire power & new switch
Send in your 337's Have A&P sign logbooks
Not nearly as fun as flying the thing when you're done, though.
STEP 3 : Familiarize yourself with the STC # SE10076SC and other paperwork. INSTALLATION NOTES
Installation details are covered thoroughly by the installation paperwork included with the KCST2 starter.
However, two notes that are easily overlooked:
1) CUT FLUSH - You need to cut the OE starter pinion shaft off FLUSH. How flush? FLUSH. Can you leave any of it hanging out? Hmmm...maybe up to a sixteenth of an inch at MOST (0.0625"). Better yet, cut it FLUSH without damaging or marking up the crankcase halves.
2) BOLTS - You need to reuse the OE Continental bolts to secure the top of the starter. Our STC was predicated on a default scenario wherein the customer is replacing an OE pull-type starter. If your engine did not have an OE pull-type starter installed (you have been hand-propping), you will need to find/buy/borrow or steal the OE pull-type starter mounting bolts. They are odd ducks. 5/16"-18 thread (coarse) and a freakishly uncommon length with a drilled head. The Continental P/N for these bolts is 538999 which our customers believe is an MS20074-5-33 bolt. |
One user report: your experience may vary
I finished installing the Sky-Tec starter yesterday following their instruction sheet which generally speaking is adequate. However I
can add some worthwhile items. The cardstock template is a good start but I made a second one after fitting the first one and
finding that it can be tailored to fit a bit closer into the crankcase cavity.
Be very generous with the use of the modeling clay. I started with a 1 lb. brick and used 2/3rd's of it. The more you use to block off the area, the less cleanup of grinding dust will be required. I used a Dremel flexible shaft machine which has a small diameter handpiece so getting into the space was easy. I used a reinforced cut-off wheel. I cut very close to the face of shaft large diameter. Do not attempt to cut into the shaft from underneath it as you will cut thru the template and into gear teeth. All cutting should be done from above. I cut thru 95% of the diameter and simply broke off the remainder.
Upon fitting the starter I tried to determine how close the starter came to the remaining shaft. By putting a small piece of modeling clay on the stub shaft I determined that there is about 3/8" at least clearance. What this tells me is that trying to keep the shaft stub very short is not critical. A 1/4" stub would suffice and make it much easier to accommodate the cut-off wheel.
The Sky-Tec really whirls the engine !!
Cheers John