[quote="Scolopax"] ...I have had no regrets about any cash that I have ever put in to flying, upgrading and feeding these wonderful machines...../quote]

For the most part, I don't either.
But I do regret spending money when I don't feel that I got my money's worth.

In my case, I fly alone and light a good part of the time,
so I don't think the extra power that a Ponk engine would provide would be a good return on the investment.
(esp since it's not approved for mogas).
Obviously most everyone else feels differently...
and that's fine, more power to them. ( get it?)

I've had the same experience as nearly everyone else here. Steve build my O-470-50 and it has been flawless. The carb ice issue some have had baffles me as I have had zero carb ice issues in 250 hours of flying Utah, idaho, & Montana in sun, rain and snow.

The timing of this thread is tragically apropos. My A&P just sent me this picture of my ~650 hour O-470L during the annual. Due to some cylinder wear causing excessive burn, I wanted to be sure the bottom end was as solid as I thought it was before even considering future top end work, and my gut feel was to have him pull lifters and inspect those, as well as the cam. This is just the right side lifters, cam is getting trashed (waiting for a pic of that).

I always knew when I got to major OH time it'd likely be a 'Ponk, but was hoping for several more years of enjoyable flying before then. On the plus side we found this on the ground, rather than in the air over the Colorado mountains, or flying kids around the local area. This could have been MUCH worse. Unfortunately this will probably take the place of my planned panel upgrades next spring, but I'll end up knowing I can trust what's up front.

[emoji15] that sucks.

colopilot wrote:The timing of this thread is tragically apropos. My A&P just sent me this picture of my ~650 hour O-470L during the annual. Due to some cylinder wear causing excessive burn, I wanted to be sure the bottom end was as solid as I thought it was before even considering future top end work, and my gut feel was to have him pull lifters and inspect those, as well as the cam. This is just the right side lifters, cam is getting trashed (waiting for a pic of that).

I always knew when I got to major OH time it'd likely be a 'Ponk, but was hoping for several more years of enjoyable flying before then. On the plus side we found this on the ground, rather than in the air over the Colorado mountains, or flying kids around the local area. This could have been MUCH worse. Unfortunately this will probably take the place of my planned panel upgrades next spring, but I'll end up knowing I can trust what's up front.

What oil were you using? Sorry to hear about your situation, like you said, glad you found out about it on the ground.

Pponk Time! -YA BABY!
Steve builds such a nice smooth engine.
Mortgage the house or whatever you gotta do. Its worth it!

G44 wrote:What oil were you using? Sorry to hear about your situation, like you said, glad you found out about it on the ground.

I use XC20/50 with Camguard, so all good stuff. Unfortunately too little too late, this is the result of the engine sitting for a prolonged time. No other corrosion was present anywhere and it was in Montana, so we thought it was OK during the pre-buy. The cam damage was likely done before I ever got to it, if this had been found by the previous owner before cranking the engine they might have got away with new lifters and been done but that didn't happen. It ran quite strong and I was happy with the engine, so this is doubly frustrating having to tear down a great running 470. My A&P noted this would probably just result in gradual power loss as the cam lobes ground down, but the reality is it'd just take a little bit of metal in a bearing to spin it and blow things apart.

RockHopper wrote:Pponk Time! -YA BABY!
Steve builds such a nice smooth engine.
Mortgage the house or whatever you gotta do. Its worth it!

Yeah, I have already been talking to P-Ponk and MT props today. I need to call around to a couple Ponk rebuild shops just to compare, but I doubt there would be much difference in cost between them. My Mac 2A34C203/G-90DCA-8 prop is not authorized for the Ponk naturally, so if I do this upgrade I have to replace that too. MT is a little more but actually competitive with Mac and Hartzell, so I would probably do a two blade composite in that event.

This was a wholly unplanned exercise and I haven't even had the plane long enough to build up an overhaul kitty, so at the moment it's academic while I sort out the more practical bits. But if I do this I am going to make a fire breathing monster out of it, and spend many more years getting my money's worth in entertainment value since I will never see the investment back.

Anyone have experience with America's Aircraft Engines out of Tulsa? I got a pretty good vibe talking to them about the P-Ponk -50 overhaul, and they are $3-4k less than going to P-Ponk directly for the same work. They can also put the C206 higher compression pistons in for an estimated 300HP, basically for the cost of a DER doing some paperwork (if I have the newer rods, which I don't yet know).

What oil did the previous owner use? Same as you?

G44 wrote:What oil did the previous owner use? Same as you?

It varied, but in some cases yes.

FWIW here's a link to the "engines" page from Pponk's website: http://pponk.com/engines/
Lots of information there re what the mod consists of, which engines are eligible,
approved props, authorized engine builders, etc.
I see that they install 7.5:1 pistons in the -50 engine, just a whisker more than the 7.0:1 in the stock 470.
I guess it's not approved for mogas because no one spent the time & money to get that approval,
or maybe Knopp's just one of those guys that doesn't accept mogas use.