• Become a Subscribing Member today!

    J3-Cub.com is the largest community of J3-Cub pilots, owners and enthusiasts. With over 1000 active members, we have fostered a vibrant community and extensive knowledge base.

    Access to the J3-Cub.com community is by subscription only. Membership is only $49.99/year or $6.99/month to gain access to this community and extensive unmatched library of knowledge.

    Why become a Subscribing Member?

    • J3-Cub.com hosts a library of over 13 years of technical discussions, J3 data, tutorials, plane builds, guides, technical manuals and more.
    • J3-Cub.com also hosts an extensive library of J3-Cub photos.
    • You will also receive two J3-Cub decals!

    Become a Subscribing Member and access J3-Cub.com in full!

    Subscribe Now

C-85 Stroker Tach Markings

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Stearmann4

Well-Known Member
Supporting Member
Joined
Mar 17, 2007
Messages
758
Reaction score
47
Guys,

My IA has some questions about the legality of the stroked C-85 installation. I know it's still just a C-85 which is authorized as per the TCDS. I'm also turning a new Sensenich 76AK-42 metal prop which is also on the TCDS. I think his question is what are the limitations imposed because it obviously has more power than the A-65 it replaced.

I know the tach must have a new red line to replace the previous 2,300. I don't have the TCDS in front of me, but I believe it was 2,575? Other than that, I'll have to sift through the Don's Dream Machines paperwork for a better explanation that will clarify it or him.

In any case, I was looking for an easy explanation to articulate to him that just because it can make more power doesn't mean I can legally apply that much power, etc. I'm guessing that it might be entirely possible that my current engine/prop combination might exceed the TCDS specified limitation of 2,550 rpm static? Does that mean at full static throttle I can't exceed that rpm? The only solution i can think of would be to re-pitch my beautiful, brand new 42 prop. I'm hoping very, very hard that this isn't going to be the case.

lastly, after going through the paperwork that DDM provided thee original purchaser of the engine, it has 2 STCs, one for the conversion of a series of -12 engines to -8s, and also another STC for installation of O-200 an crank, connecting rods, and pistons in a C-85. Stapled to the STCs are 2 accompanying 337s from the original purchaser's FSDO with he and his ill-fated Cub's registration number. Since the C-85 is on the TCDS I was under the impression that an STC wasn't required. I also called DDMs to see if I needed to get the 337s applied in my name and for my Cub. He said it wasn't required, but why then was it provided in the first place? Any other C-85 stroker owner's inputs or experiences would be greatly appreciated.

I promise, I started out just asking about range markings on a tach and just got carried away...

Mike-
 

Latest posts

Back
Top