Saving Cont engine weight

[Dan R.]

I'm sure you know about Bob and saving weight and especially with the LSA. Besides building the 4 seat Bearhawk, I'm building a JMR Special and using a Cont- C-85-12F and trying to get it as light as possible for this small airframe, and the same as a lot of you building the Bearhawk LSA. Just finished majoring the C-85 and made block off plates for the starter and Generator from aluminum. Also should get a couple more HP by not turning the large starter gear and the Generator, besides saving a lot of weight.
The small Cont engines use a heavy brass elbow fitting that screws into the block on the right, front side for the crankcase vent. Being brass, its very heavy, and has a weight of 5.1 oz for a small fitting. You can save a lot of that weight by going to an aluminum fitting from Aircraft Spruce. You can also save a little weigh by buying 6061 aluminum tubing the same size as the steel intake tubes that go out from the intake spider to the heads.
Dan R.

[Cherokeedriver]

Hi Dan, please post some pics when you, would like to see. Does anyone have a list of mods which can be made to a C-85 to add lightness and power? What do you anticipate the final weight of your engine to be? What weight savings will your mods result in? Thanks.

[Dan R.]

Bob used a -8 accessory housing on the rear of his engine to save a couple pounds over the -12 housing. The -8 are starting to be hard to find, so I used the stock -12 accessory housing and made block-off plates where I removed the starter and generator. So mine will be a little heaver. Also look at the brass crankcase vent 90 deg elbow at the front right side, replace with a aluminum one from Aircraft Spruce. New Slick mags a lighter weight than some of the older mags. Bob said his engine weights 185 lbs, I haven't weighted my engine yet, but should weigh about 187-188 lbs.
For extra power, Bob used the 0-200 crank and rods, cam, and jugs with C-85 Pistons for the higher compression ratio, but then he had a set of pistons made with a little higher compression ratio. I might be wrong, but I thing he is running 9.5 to 1 C/R now with Total Seal rings for less compression loss around the rings. Dan R.

Added-- I think, in the Cont overhaul manual the total weight with all accessories is 219 lbs if I remember, I need to look that up to make sure.
Bob is also running a custom made aluminum oil tank on his engine for a weight saving over the stock steel oil tank.

[Cherokeedriver]

Wow Dan! Great writeup and pics! Thanks.