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IO-375 Pros/Cons

704CH

704CH

Well Known Member
Hey guys, I wanted to ask thoughts about pros/cons of the 375 from Aerosport. Any recent updates from those flying with specifics, there should be a few of you out there.

My understanding is this is a 360 with a longer stroke providing more than the 180 hp, you can get 195 or 205 depending on the compression. Also, no roller tappets on this one. Same size/shape mounts, uses same prop etc..

So what does this mean to the engine and TBO? Same amount of Metal producing 15-25 more hp ?

I would assume more friction in general due to the loner stroke.. Which means more heat and more wear right? Also, you have a heavier crank that is turning since you have longer stroke. What does all this mean?

Pardon my ignorance but I am at the early stages of looking at engines and wanted to get thoughts or feedback from owners.

Thx
 
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I ordered a IO-375 at Osh Kosh this year....can't comment on its operation yet.

FYI - I ordered mine with Lycoming cylindars and roller tappets.... I think the up charge was around $2k.
 
I have one

I only have about 30 hrs. on a 0-375 with 205 HP in a 7A. Aero-sport, you won't find better folks to deal with. 3 blade Catto turns what Craig said it would.

I'm still tweaking the airframe, have the wheel pants and fairings on. I'm seeing about 210 MPH wide open now at 1000' AGL. (Afraid of heights) I think someone with a cleaner and straighter air frame would see even more. Engine runs great, oil temps a little high at first, but now about 180-210 depending on OAT, CHT about 330-340

I really like mine. I was flying a 9A with a 0-320 that I built 9 years and 900 hrs. ago. The biggest shock for me was the increased fuel flow. (What is that old saying, how fast can you afford to go?)

Larry
 
Don't know

I have two 10" skyviews, but I don't have the red cube yet to measure fuel flow. I've never had a plane before with EGT and CHT, so I haven't started experimenting with the correct % of power yet. Before I just pulled the mixture until it started running rough and slowed up a little , then pushed it back in a little. (I'm from the stone age)

Jason is correct about the roller tappets. Bart said that I could upgrade to the roller tappets but I didn't.

Larry
 
I'm flying one...

The IO-375-M1S from Bart and Sue at Aero Sport is one of the best decisions I made on the entire airplane! Smooth as glass and just over 200 HP with 8.0:1 pistons. (yes that's right, 8.0:1) I'm running horizontal induction with the Superior cold air sump and dual P-Mags.

The speed box average for my -7 at 8500 is 184.75 kts. (Whirlwind 200RV prop) That's 212.46 mph in case you don't have a calculator handy.

Aside from the fact that the engine performs GREAT, Aero Sport could not be better to work with! They are always there to help and are just super people!

The real question: If I build another one, would I buy the same engine?
Answer: Without even thinking about it!!!

- Peter
 
Sig600 said:
You just needed the power to haul that panel around!!!
Click to expand...

...and your question is?!? :D

Yeah I saved weight where I could so the panel could weigh a bit more than average. My empty was 1133. I'll take it based on everything that ended up in this bird.

- Peter
 
Flyingguido said:
Peter,
What do you figure on for the weight, with accessories, of the engine?
Thanks!
Click to expand...

Good question... Bart can give you an estimate based on how you want to configure it. If I remember right, the cold air sump actually saved me a little and the Pmags were a wash with the regular mags that came off. I don't recall ever asking how much mine weighed but I would guess 315 lbs or so.

- Peter
 
propeller?

You may wish to consider what propeller you will use if you choose that engine. As well as right pitch, does it matter to you whether the engine/propeller combination has been tested and approved? Hartzell for example (as I am sure you know) publishes approved combinations (some with operating restrictions).
Bill Brooks
Ottawa, Canada
RV-6A finishing
 
Hartzell doesn't have this engine listed yet for approved combos on the website. However I will be using their 72" BA prop on this IO-375M1S engine with the 8:1 and dual lightspeed ignition. I flew an aerosport power O-360 with LSI, hi comp pistons and the same prop for 700+ hrs and had zero issues. (except for the hub slinging grease at the start which hartzell fixed on warranty) The published op lims for rpm and MP combos were a non factor for my style of flying with the previous set up and i expect the same here. I'll add to the kudos for aerosport customer service :)

C-GRVT said:
You may wish to consider what propeller you will use if you choose that engine. As well as right pitch, does it matter to you whether the engine/propeller combination has been tested and approved? Hartzell for example (as I am sure you know) publishes approved combinations (some with operating restrictions).
Bill Brooks
Ottawa, Canada
RV-6A finishing
Click to expand...
 
C-GRVT said:
...does it matter to you whether the engine/propeller combination has been tested and approved?
Click to expand...

It's a plain crank with no pendulum absorbers. IF the Hartzell guys or another qualified engineering team actually instrumented a metal prop on a 375, I'd expect restrictions similar to those for all the rest of the plain-crank motors. Some of the restrictions are in operating ranges where most pilots, lacking a warning, will run in blissful ignorance.

Something fatigue resistant like a fixed-pitch maple core Catto is a pretty safe bet. Personally I would not buy an untested metal blade combination under any circumstances.

Yeah, yeah, I know, it's your right to be experimental. Do what you want, but remember...the laws of physics vary for no man.

Avweb story from Marc:

http://www.avweb.com/news/motorhead/193075-1.html
 
Tested with older Hartzell . . . I think

If I recall correctly, I believe Bart told me that the 8:1 375 had been tested by Hartzell with the older Hartzell prop (not the current one sold by Vans). I believe he said it ended up with exactly the same restrictions as the 360 for that prop. I tried to verify this with Hartzell but never got any answer from them.
 
Dan,

That is an interesting article. I wish that it would have resolved more completely at the end to illustrate the data findings given the tested prop types for that set-up. As usual, you contribute great info to the forums and it is appreciated.

what prop do you have hanging on the -8?


DanH said:
It's a plain crank with no pendulum absorbers. IF the Hartzell guys or another qualified engineering team actually instrumented a metal prop on a 375, I'd expect restrictions similar to those for all the rest of the plain-crank motors. Some of the restrictions are in operating ranges where most pilots, lacking a warning, will run in blissful ignorance.

Something fatigue resistant like a fixed-pitch maple core Catto is a pretty safe bet. Personally I would not buy an untested metal blade combination under any circumstances.

Yeah, yeah, I know, it's your right to be experimental. Do what you want, but remember...the laws of physics vary for no man.

Avweb story from Marc:

http://www.avweb.com/news/motorhead/193075-1.html
Click to expand...
 
picture of pure joy!!!!

rcpz15.jpg


aerosport sent me this pic of my engine in their build area for Christmas. I have to wipe tears of joy from my eyes as I type this... sniff snifff....
 
Gonzo24 said:
rcpz15.jpg


aerosport sent me this pic of my engine in their build area for Christmas. I have to wipe tears of joy from my eyes as I type this... sniff snifff....
Click to expand...

That sure makes a nice Christmas present!! :D I have one of their engines, though I only have 40 hours behind it, it sure prrrs like a kitten. I think they do a great job!
 
Dan Langhout said:
If I recall correctly, I believe Bart told me that the 8:1 375 had been tested by Hartzell with the older Hartzell prop (not the current one sold by Vans). I believe he said it ended up with exactly the same restrictions as the 360 for that prop. I tried to verify this with Hartzell but never got any answer from them.
Click to expand...

Hartzell will never give an answer regarding a non-certified engine. Their lawyers won't let them.

:D
 
N941WR said:
P-mags are about 1.5 pounds lighter than a standard mag. Replace two, save 3 lbs. off the nose. It does all add up.
Click to expand...

Thanks Bill! Maybe it was the cold air sump that was the wash on weight...as I said I can't remember how it all came out in terms of what it weighed but I'm sure happy with the engine!

- Peter
 
Did they raise the price on the 375 within that last couple months?

I thought last time I checked, they were about $2,000 cheaper then currently listed?

merry xmas...
 
Yep sad to say it looks like aerosport raised prices across the board. By a fairly large percentage. Same seems to be true for classic aero.
 
IO-375 Prop testing

It's pretty twisted when you start quoting yourself!

Dan Langhout said:
If I recall correctly, I believe Bart told me that the 8:1 375 had been tested by Hartzell with the older Hartzell prop (not the current one sold by Vans). I believe he said it ended up with exactly the same restrictions as the 360 for that prop. I tried to verify this with Hartzell but never got any answer from them.
Click to expand...

I went back and looked at my records (I have this thing where I type up notes right after I have a phone conversation with a vendor) and Bart did tell me that the 375 had been tested. Here is an excerpt from my notes from 14 December 2009:

I asked him about any propeller testing that had been done and he said that Hartzell had tested one of their props on the "low compression" 375. (He didn't mention which prop but said it ended up with the same continuous operation RPM exclusion range as the 360 engine so it must be the older bladed prop.) Basically the indications were that the 375 didn't seem to be any different from the 360 from a prop standpoint. Vibration characteristics appear to be the same as the 360. Bart mentioned, as an aside, that they used to use "re-pitched" metal props for the test clubs. In all of the various engine testing they had done over the years they had had two prop blade failures. He said it is unbelievable to see. The engines just start shedding parts. Usually, nothing is salvageable.
Click to expand...
 
twisted

Dan,
Now you just have to start asking yourself the questions too!




Dan Langhout said:
It's pretty twisted when you start quoting yourself!



I went back and looked at my records (I have this thing where I type up notes right after I have a phone conversation with a vendor) and Bart did tell me that the 375 had been tested. Here is an excerpt from my notes from 14 December 2009:
Click to expand...
 
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