question Acceptable Cylinder Compression - Lycoming O-235-C1

[Kenlsa]

I have a 235 C1B. As the one you are looking at is no longer in a certified aircraft, I think it is worth the price. The CH 200 is fully aerobatic with a 320 as it is +9G a/c. The "60" is the one to look at and if a bore scope is clear, it is a small job to remove the pot then a flex hone and rings with a valve lap while you are at it. This is an easy job. While the pot is off you can see some of the cam lobes to inspect for cancer.

These motors are costed at; bare core trade in at 22k with a zero timed motor at 65k plus! These are spendy motors.

The core is worth more than the whole plane.

Damn, might buy it myself and I will have a spare donk!

Ken

[sseeker]

I have a 235 C1B. As the one you are looking at is no longer in a certified aircraft, I think it is worth the price. The CH 200 is fully aerobatic with a 320 as it is +9G a/c. The "60" is the one to look at and if a bore scope is clear, it is a small job to remove the pot then a flex hone and rings with a valve lap while you are at it. This is an easy job. While the pot is off you can see some of the cam lobes to inspect for cancer.

These motors are costed at; bare core trade in at 22k with a zero timed motor at 65k plus! These are spendy motors.

The core is worth more than the whole plane.

Damn, might buy it myself and I will have a spare donk!

Ken

 

The CH200 is fully aerobatic with certain modifications done during the build phase. I wasn't able to confirm these were done. Having spoken with several CH200 builders - none of them do aerobatics despite having the mods done. There were questions raised about the structural integrity even with mods. Unfortunately not being the builder means I'd have to hire a LAME to complete all of these "quick jobs".

[Flightrite]

Don't forget that even though the O-235-C1 has adjustable valve clearances, there's no screw adjusters on the rockers, as in most other engines.

 

The clearances are adjusted by purchasing longer or shorter pushrods - another added hidden cost, just to simply get correct valve clearances.

 

That's actually incorrect. The 235/290 are the only Lyc that has adjustable tappets, the varying length pushrods are for hydraulic lifter engines.

[derekliston]

Don’t know why I am buying into this but anyway, here is my twopence worth. Flightrite is correct in saying the 0-235 has adjustable tappets and does in fact have adjusting screws on the rockers. Another thought, I don’t know where you are at with the engine but if it hasn’t run for a while I would give it a decent ground run and do the compressions again while the engine is hot. You may well find that the compressions improve. 60/80 is the minimum acceptable but 70+ is more normal in my experience.

[old man emu]

Normally the "psi" is not used.

 

There's no real need to identify the units used in a measurement when everyone knows what units the measurement is taken in. We all understand what is meant when someone says they were book for doing 80 in a 60 zone. Quoting the units of measurement in this case is a bit like the "f" in "use".

[Flightrite]

Don’t know why I am buying into this but anyway, here is my twopence worth. Flightrite is correct in saying the 0-235 has adjustable tappets and does in fact have adjusting screws on the rockers. Another thought, I don’t know where you are at with the engine but if it hasn’t run for a while I would give it a decent ground run and do the compressions again while the engine is hot. You may well find that the compressions improve. 60/80 is the minimum acceptable but 70+ is more normal in my experience.

 

I agree. If the owner was amicable I would habe run the engine hard for sometime. I bet the comps would have improved ?

[facthunter]

In normal circumstances flying the plane before doing a leak test is best but IF there's corrosion it can completely pug up the rings and jamb them in the grooves. You still have the dubious camshaft condition that will put metal everywhere if it's corroded. Scope it, pull the worst looking pot and inspect the camshaft. Where pistons stop affects where the corrosion is . This motor has sat for too long, also checking parts within allowable limits is not a zero time procedure, so that's misleading... Allowable limits are not limits for a new engine or one with over 2,000 hours to run to a NEW??TBO.. Nev

[Thruster88]

I presume it's this aircraft?

 

https://www.planesales.com.au/details/Listing/Single-Engine-Propeller/6041/2009-Zenith-CH200-Aircraft

 

This would be a great aircraft with RAAus rego for anyone with the skills to maintain what is arguably the best little piston aircraft engine ever made. Some fun facts about the lycoming 0-235, 2400 hour TBO, certified in 1942 so in continuous production for 78 years with only minimal changes. Can any other piston engine beat the tbo or production record?

[sseeker]

You'd need to strip a fair bit out of the plane. The MTOW is 680kg. Even with the proposed increased MTOW with RAAus, a LAME is still required to maintain it. At least that's my understanding if the proposed changes. If that were the case, I'd buy it and wait for that weight increase!

[Thruster88]

Yes I forgot about the LAME still required for over 600kg bit.