O-290 piston/ring sets
- Thread starter danal
- Start date
Jim,
Not to forget all the valvetrain bits needed for the conversion. I'm all about simple. Straight bore plated cylinders in standard size. 8.25 comp pistons with cast iron rings make for an good running 155 takeoff hp. and 145 cruise hp. If you really want to start swapping parts, find a O-340 crank and install with GPU 6.5 comp. forged pistons running just the top 3 rings. 315 cu. inch and 10:1 comp. I got a million combinations but not a million dollars. I'm just about quick and cheap, run what you already have kicking around.
Dana LaBounty
Chief cook and bottle washer.
"The Awesome Possum"
Bistro and Bait
Not to forget all the valvetrain bits needed for the conversion. I'm all about simple. Straight bore plated cylinders in standard size. 8.25 comp pistons with cast iron rings make for an good running 155 takeoff hp. and 145 cruise hp. If you really want to start swapping parts, find a O-340 crank and install with GPU 6.5 comp. forged pistons running just the top 3 rings. 315 cu. inch and 10:1 comp. I got a million combinations but not a million dollars. I'm just about quick and cheap, run what you already have kicking around.
Dana LaBounty
Chief cook and bottle washer.
"The Awesome Possum"
Bistro and Bait
biasplyflyer
Registered User
Norcal
I would be interested in a set of 7.5 or lower compression pistons w/pins & rings.
Why lower the compression and suffer reduced combustion efficiency? I'm curious. I just had pins made from H13 tool steel and the first batch of 8.5:1 pistons are in line for production. I'll have them ready to ship in 5 weeks. Rings are on hand as well as the pin buttons. Best option is to have oversize cylinders plated to standard and STRAIGHT BORED. Let you O-290 perform like a modern engine.
biasplyflyer
Registered User
Norcal
If you end up making 7.0 sets, please let me know. Don’t want to run a CR that high on 55 year old GPU cylinders with screwed on heads on an airplane my children ride in. Airboat would not be an issue...
Are there Lycoming cylinders made today that do not have screwed on heads? The better fuel available today allows for the compression increase and will INCREASE combustion efficiency. Lower CHT's and reduced RPM's for the same power output and increased reliability. No sir, I will not accept the downside of lower compression. Now if you want to turbo supercharge... I'll default to my experience building Cosworth Indy car engines back in the mid 80's and everything I've learned since.
The stuff I had made is just beyond compare to anything out there. The better ring control alone is reason enough to want these in an aircraft engine. Can't wait to get it built and dyno run. I'm thinking 165hp.
The stuff I had made is just beyond compare to anything out there. The better ring control alone is reason enough to want these in an aircraft engine. Can't wait to get it built and dyno run. I'm thinking 165hp.
To be fair if someone wants a lower compression piston they can pm me. There is a 12 piston minimum order and I would need you to make payment directly to the manufacturer. I had to front $4000 for this batch and don't care to put my money out on some ones word that they will buy a set.
gregory.andronaco
Registered User
Ukiah, CA
Hi Danal, Did you ever get these pistons made? Do you have four left for sale?
gregory
aerocomposites
KUKI
gregory
aerocomposites
KUKI
Greg, Ancient history. I did have a batch made and they sold instantly. I get request now and again for another set but have other projects
from decades past in the way. I may yet have another run done but not for a couple months. Just for bragging rights, they came out 2 ounces
lighter than the cast stock pistons. I'm going to have to come up with a different pin/button combo if I do this. I'm all out of O-290 buttons.
I'm thinking use O-320 buttons and have shorter pins made. The other option is go to double spirilox and lose even more weight. Any thoughts?
Now if someone wants to help lighten my project load I'll get on it. What do you know about late 70's Ducati 900's, then there's my Great Lakes
strewn about the shop and corners of the country. I'm only 57 and retired but I have a lifetime of projects to play with.
from decades past in the way. I may yet have another run done but not for a couple months. Just for bragging rights, they came out 2 ounces
lighter than the cast stock pistons. I'm going to have to come up with a different pin/button combo if I do this. I'm all out of O-290 buttons.
I'm thinking use O-320 buttons and have shorter pins made. The other option is go to double spirilox and lose even more weight. Any thoughts?
Now if someone wants to help lighten my project load I'll get on it. What do you know about late 70's Ducati 900's, then there's my Great Lakes
strewn about the shop and corners of the country. I'm only 57 and retired but I have a lifetime of projects to play with.
I did find GREAT rings for these pistons. Moly top, cast 2nd and stainless oil control.
Working on my Darmah SS custom. The renter I had when I lived in Burlington sold
a bunch of parts off my bike to someone in northern Vt., stuff like my Campagnolo wheels
with brake rotors and all, the fairing and other odd bits. So 30 years on I'm finally collecting
what's needed and freshening the engine. Cleaning up a pile of baskets.
Working on my Darmah SS custom. The renter I had when I lived in Burlington sold
a bunch of parts off my bike to someone in northern Vt., stuff like my Campagnolo wheels
with brake rotors and all, the fairing and other odd bits. So 30 years on I'm finally collecting
what's needed and freshening the engine. Cleaning up a pile of baskets.
A friend of mine just cleaned out a storage unit of a Ducati guy who recently passed away. Most of the parts were from the early 2000s. There was a set of Campy wheels but they were later, wider rims. I got some upper fairings but again much newer than our bikes.
In 1980 when I bought my 74 Sport, the original owner had installed the dual seat and painted the tank and fenders silver to match the Darmah look. Luckily the original single seat and side covers are untouched original.
It will be a few years till I open up my O-290 but might be in the market for pistons then.
In 1980 when I bought my 74 Sport, the original owner had installed the dual seat and painted the tank and fenders silver to match the Darmah look. Luckily the original single seat and side covers are untouched original.
It will be a few years till I open up my O-290 but might be in the market for pistons then.
WhiskeyMike
MEMBER
West Boxford MA
Steve, what I heard about this when I was running 135 hp in my J-3 Banner planes was that the O290-D2 was meant to run on 87 octane and when 100 low lead came out it was no longer really necessary to run the timing back to 23 from 25. In fact the banner guys in Florida set their timing to 27 with 100LL, or so they told me. It always seemed like they didn't run that great with the timing retarded and I think I remember setting ours back to 25, in Restricted Category.
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