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I'm overhauling my Continental A75 -9, the handbook is very superficial with rings position and there is no markings in the ring set.
I make a research on ring position in all possibilities, but I’m not comfortable with my conclusions, see image attached.
I appreciate any help to confirm it.
I would send this info to Mike Busch. To me it looks correct but its been to long since I have built any engines to listen to me, contact Mile and take the guess work out of it....
Tony
You are correct in the position of the rings. It follows both my manual and basic ring theory. I wouldn't bother with Mike, I don't get the feeling that engines are his best area of knowledge.Quote:
Originally Posted by Tasca
Quote:
Originally Posted by Aaron Novak
May I ask how you came to this assumption?
Tony
I have a J3 cub that use a VW version, but I don’t like the combination and the flight characteristics, I decide to go to original A65, a friend of mine had this A75 from his Luscombe, and in reality was only crankcase, crankshaft and camshaft, everything else was missing and most I bought from Fresno Airparts.Quote:
Originally Posted by 1600vw
I really like engines and I’m preparing myself to assemble the engine since it’s experimental aircraft and reading the overhauling handbook I found this … one of many, like there was a crankshaft gear to camshaft that seems to be correct ,until I try to assemble the mags, lots of research again and I found the correct gear is double in high.
Now there is only one detail, that is the correct push rod length, I have three different sizes !
This old engines has no parts number on it and I don’t feel confident on the AP that has close to me here in Brazil….
Thanks for the help of you all !
Tony,Quote:
Originally Posted by 1600vw
From his own "technical" articles and presentations. He has a very limited scope of knowledge on engines and engine theory, compared to others in the field. Nothing against him as a mechanic or businessman.
Rings with an inside bevel usually go up (for gas pressure to work on) outside bevels go down to act as an oil scrapper. I can't speak to the square ring but if they have no marking (up) or a 'pip' mark (dot) which goes up, it most likely doesn't make any difference. Regarding the different push tube lengths, that's how you get the correct collapsed lifter setting which is .030-.110 if I remember correctly. You need get the cam on the base circle or flat side, collapse the lifter and measure the free travel at the rocker arm with either a dial indicator or stack some feeler gauges. The travel should be between .030 and .110 if not change the push tube to a shorter or longer one. I like to have them around .050-.075 if possible but it doesn't always work out perfectly. I made a tool to put pressure on the rocker arm in order to bleed the lifter down. Hope this helps. Mike
Mike
Very important your post for me, this give me important clues to finish my engine the right way !
I'll make a pre-assembly and measure the gap. the lifter is new and consequently empty, can I measure this way ?
Many thanks to all the guys, I can't wait the day to fire it !
If there lifter is more or less dry that should allow you to check the clearance once the rockers, etc. are assembled. What you're shooting for is to get the hydraulic part of the lifter body in it's working range. Rocker arm. push tube, valve protrusion, all effect this which is the reason for different length push rods. You're measuring the clearance between the rocker arm and the valve stem.