O-320 HP increase options and prop questions
- Thread starter roxiedog13
- Start date
And now I need to retract that statement. With just a little Google searching I see articles that say dynos are not like rulers where an inch is always an inch. There are up to 30% variations between different dynos. That's interesting. This whole topic is interesting.
Paul Heinrich
PARTNER
Illinois & Wisconsin
I wasn't trying to offend or insult.
I don't doubt that a well-built, well-tuned engine will run better, longer, and stronger.
I don't doubt that a well-built, well-tuned engine will run better, longer, and stronger.
40m
SPONSOR
Shoreham, VT
12 inches in New York, is that about right Glenn? Here in Vermont and New Hampshire only 10. The water is different.
roxiedog13
Registered User
This is exactly the feedback I need, thanks so much . The 10:1 option definitely the way I am going now, it will force me to use Avgas 100% of the time, just means a little more of a work around on the back country trips.
Can you share which prop you are using to harness the additional power , RPM static and cruise, the aircraft and performance change from the original engine ? I'm running the 1A200 Borer now pitched 8245. I static this prop with the original 160HP combined with Powerflow exhaust at 2350-2400. Many are telling me the Borer is not the best choice for hither HP, I was simply going to adjust the pitch to keep the static and WOT in cruise within acceptable range .
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Are any explanations offered for the variation, other than inaccurate torque or RPM readouts? Atmospheric conditions or fuel composition, maybe??
roxiedog13
Registered User
This is the first suggestion I have read that the timing would change. Have any of the other builders changed the timing of the crank gear when upgrading their engine ? To be honest this is the first I have ever heard of a gear on the crank dealing with timing . Lycon nor others have mentioned this before, obviously I now have to investigate . I do plan to use the P-mag when I reassemble, may or may not go with a second. I was going to use a secondary standard magneto for now see how it works out .
Difference in dyno equipmet and manipulation of setup to achieve desired results.
My dyno report has mathematical adjustments for temp, humidity, and barometric pressure. The OAT was 98* and the servo inlet temp 150*. Not good for making power at full rich on a motor with less than 30 minutes total time, but that’s how it’s done. I’d be happy to share the report with you. You’d understand the math better than me! The value that stands out to me is the EGTs don’t vary at different rpms while the fuel flow varies greatly. It’s like they manipulated fuel supply to maintain 1100-ish EGTs. Like I said, interesting. I want to talk to a couple of guys next week to make sense of it all.
kase
SPONSOR
Billings MT
Gear came from Lycon. Advance is 3 degrees. Have you considered a 0340 crankshaft.?
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Yes Stewart, I'd enjoy looking at the dyno report. Dunno if you still have my email, it's gordon dot misch at gmail. Thanks for the offer.
roxiedog13
Registered User
Would you mind sending me a copy of the dyno report ? Assuming it is the upgraded O-320 with mods .
roxiedog13
Registered User
If I didn't already have an engine I would have gone the O-360 route but I really only needed to change cylinders, figured some cheap extra HP wouldn't go astray. That said my neighbor with
O-360 and the identical plane in comparison to my aircraft would be considered a poor performer. His plane is much heavier because of the engine, larger floats the large fixed pitch pawnee prop
and heavier aircraft overall. I break water in half the distance and climb better, even have a slightly better useful considering his fuel burden. He can cruise faster though , 115mph vs my 95mph.
My 172 is almost 150lb lighter , the bigger engine would have been heavier, required a bigger prop and bigger floats . For smaller lakes, I can already outperform his aircraft, I'm sure that gap would
close if he could use a Catto or other better prop. His aircraft is certified, he cannot deviate, mine is owner maintenance so I can put on experimental props.
PerryB
FRIEND
Chico, CA
Do your homework before putting a Catto (or any other lightweight prop) on a high compression engine. This subject was being discussed a couple years ago and some valid concerns were raised regarding the lack of flywheel in conjunction with the more pronounced impulse and deceleration cycles of the high compression engine. You might have some undesirable harmonics.
roxiedog13
Registered User
Thanks for the heads up, I did indeed read the comments in that thread. Seems there are actually pros and cons for both. The heavier metal props have a better idle , start better with less kickback however the high compression engines are thought to have caused tips to come off due to the hard pulses of high compression. The Catto , wooden composite absorb the high compression pulses better and appear to run smoother however they don't idle so well, have been known to kick back during start because of the lack of mass/flywheel. They save around 15+ lbs , in the event of a prop strike the crank does not get damaged like a metal prop.
I have not heard/read any comments that suggest the hard pulses from high compression pistons have caused a failure with Catto . I have read and actually witnessed a failed Warp Drive propeller from a high compression O-320.
Lots of stuff can get hurt even with a wood prop strike. If you understand the HP modifications you purpose are not cumulative, I would do them if that is what you want and leave the prop until you see how it performs with all the mods. The other issue not posted is CHT!! High compression pistons make a lot of heat. Do you have a 4 cylinder CHT/EGT? Fuel flow would also be nice. Do you really want you limit yourself to 100LL for all you flying?? I don't think P mags help HP at sea level (I could be wrong). In general high HP from small engines means shorter life. Just things to ponder, you have had great advice for others.
DENNY
DENNY
skywagon8a
MEMBER
SE Mass MA6
I realize that you are in Canada with different rules. I question your friends approval of that prop. If you look at the TC data sheet for that engine prop combination you will find that it is not approved with a long diameter.
Also he would get better performance by reducing the weight on the nose either with a lighter prop or by the addition of ballast in the tail.
roxiedog13
Registered User
Yes indeed, a prop strike is a prop strike, all things considered though, if the prop can absorb the energy and break the crank could be saved. Avoiding a prop strike is probably a good thing to do. I know the HP modifications are not cumulative, indeed they do overlap and I do understand the heat penalty and longevity . I do have a EIS engine monitor with 4 X's EGT, CHT , Fuel Flow, M.P., O.T, O.P, Carb Temp, OAT, RPM . I also have the cylinders done with a alodine coating that reduces heat and I have made
changes under the cowl to reduce heat. Baffles are going to be given special treatment and I have removed the vacuum pump a source of major heat. The P-mags are more effective at altitude I agree but they also do have a fuel savings component and run cooler , also idles MUCH slower which for floats is a good thing .
The 100LL thing is a biggie, price doubles immediately and availability is a PITA. Today I have to make the decision to go stock 8.5:1, 9.5:1 or 10:1 pistons. 10:1 I have to go 100% Avgas, most power most heat. 9.5:1 I can use a 50/50 mix most of the time and many use straight Auto to get out of a pinch once in a while. A little less HP and less heat. 8.5:1 I can still run 100% auto fuel, however I do get the major advantage of port & Polish plus flow balancing supposed to be 20HP over the stock , probably no additional heat so CHT not an issue .
As I'm writing this all down, I'm thinking the most advantage will come with port/polish and flow matching, and 4 new cylinders , likely 75% of the benefits. I was headed for 10:1 but thinking about this I may really stick with stock and see how this works and then if I want, switch to 10:1 later . I have another 6 hours to decide, time to dig in and make the decision.
roxiedog13
Registered User
That prop is approved on his 172 with O-360 . His plane is certified, he cannot deviate from that . I'm not 100% sure what the prop is, my mechanic simply said it was a BIG prop, similar or same as that found on a pawnee . I fund this , maybe that is what he is using : http://www.univair.com/propellers/mccauley/fa8452-mccauley-propeller/ it's 84-52 , would account for why he cruises so fast I suppose.
skywagon8a
MEMBER
SE Mass MA6
That's also why you can whoop him getting out.
roxiedog13
Registered User
This is what you posted a while back : The 1P235 prop is approved under Type Certificate number P12EA.
NOTE 9. Table of Propeller-Engine Combinations Approved Vibrationwise for Use on Normal Category Single Engine Tractor Aircraft
The maximum and minimum propeller diameters that can be used from a vibration standpoint are shown below. No reduction below the minimum diameter listed is permissible since this figure includes the diameter reduction allowable for repair purposes.
Model Engine Model
1P235/AFA Lycoming O-540 &IO-540 series, with one 5th and one-6th order crankshaft damper configuration (up to 260 hp @2700 rpm) Max. Dia. 84(Inches) Min. Dia. 77(Inches) Placards None
1P235/PFA Lycoming O-360 series (up to 180 hp @2700 rpm) Max. Dia. 78(Inches) Min. Dia. 74(Inches) Placards None
1B235/BFA Lycoming IO-360 series (up to 200 hp @2700 rpm) Max. Dia. 78(Inches) Min. Dia. 74(Inches) Placards None
This tells me that the 1P235 prop IS approved on the Lycoming 0-360 with the diameters indicated. You should not have to show that the engine and prop combination is approved on a TC'd airplane, just that they themselves are approved.
I'd say he is Not using the 84-52, looks to be for a larger engine . His would be max 78 inches for the 189HP and that does not make sense for floats, and yes this is why I can whoop him getting out of the water. When he had the O-320 and Borer I was still ahead by a margin. I have a much lighter aircraft, better floats, STOL, gap seals, VG's, bush seats, etc. Even then there was no contest really, all the mods, especially the lighter aircraft all add up. For the lakes he fly's from, his cruise is probably the asset, a quicker take-off is really no benefit . I do use smaller ponds and rivers that he could never dream of though, that's where the climb prop makes sense , for any combination.
skywagon8a
MEMBER
SE Mass MA6
Your Eddie Peck wide 2000s are a big improvement on their own. I used to have a stock 172N on 2130s which was a big improvement over the 2000s. This was particularly noticeable in my 1000 foot long pond. That was a really nice airplane which in a way I wish that I still owned. I was renting it out and someone wrecked it.
roxiedog13
Registered User
Eddy's floats are actually 2250 and yes, they are a major contributor to my stellar performance. My 1967 is one of the lightest 172's made , you have a head start from the get go . I'm still making improvements, next up is my options for pistons during the current O-320 rebuild happening now ( 10:1 vs 9.5:1 or stock 8.5:1) . Then there is prop , catto 84-37 vs the Borer 1A175 82-45 I currently have . I have to make the engine piston choice today, prop can wait until later .
WhiskeyMike
MEMBER
West Boxford MA
Someone else probably already mentioned this but dyno ratings do not take into account exhaust systems. The rating is for unfettered running without back pressure under ideal circumstances. Even the factory rating is such. IMHO the ratings are optimistic in real life, and I maintain that engines and planes are as individual as people. Is it luck? Personality? Who knows. 99% science, a little bit of art and good karma. Ive got two identical O360''s, one with and the other without flow balance. I'm not sure that the "without" doesn't run better. Different props. So many variables, air box tweaks, cowl fluctuations, maybe minor exhaust differences, prop balance.
Comment #2. If you're planning on mixing Avgas and auto 50/50, just exactly how well and with what system will you ensure a complete mix? Is it worth the work and risk? I would err on the side of... "OK with auto only" and then run what you need or like. I know -- I get 3 cents change from my nickel.8)
Comment #2. If you're planning on mixing Avgas and auto 50/50, just exactly how well and with what system will you ensure a complete mix? Is it worth the work and risk? I would err on the side of... "OK with auto only" and then run what you need or like. I know -- I get 3 cents change from my nickel.8)
Last edited:
Fortysix12
Registered User
RanchAero Grand Vista, Brooksville
So I run an E2D with 9:1's and new Lycoming cylinders. Heat is my biggest problem. Makes great power, who knows how much but I can hold my own. The higher the CR the higher the heat. In Florida with high temps summer it has to be managed. Richen and relax the climb. At cruise is not the problem , its the climb out. Out west same problem only worse. Leaning for power reduces my cooling from altitudes of 6 to 11k. just things to take into consideration when trying to make hp at 100mph. Cowling is tight and flow is to specs. Opened the carb to 14gph plus and flow tested to improve the cooling opotion . Maybe more. NO autogas, the stuff smells.
Last edited:
kase
SPONSOR
Billings MT
What c/r did you go with and what camshaft are you using?
roxiedog13
Registered User
I spoke with a really experience chap who buy these ported and polished cylinders by the pallet load, a engine rebuild shop in Canada. He put everything in perspective pretty much and basically advised the 10:1 on top of my port/polish and flow balance including the powerflow exhaust would really only add about 5hp over the stock pistons. Realistically I will end up in the 180HP territory with the mods I have including 8.5:1 and I can still use auto fuel. I'm going to use a 50/50 mix anyway for the most part to make sure I get enough lubrication, if I don't have the Avgas for back country trips now and then it will not matter, I won't be stuck .
I'm swinging a borer 82 45 now 2400 static and 2800 wide open throttle . My stock 160 with powerflow was already exceeding what a normal 160 would do. was probably 170hp. I will likely have to pitch the prop to 48 to get correct static and cruise RPM, will try it first and see how it pulls, then make some informed decisions. Will post the results once that happens, will be another month before I hit the water though, lakes here are still frozen.
I may get a chance to borrow a Catto 84-37 for comparison. It may pull through a climb and give better take-off but it will not compared to the Borer for cruise. the 37 catto max cruise is only 90mph if 100% efficient, I'd expect the Borer to be 100+ on this aircraft . Going to be an interesting experiment, will know in 5 weeks for sure.
roxiedog13
Registered User
Appreciate the feedback . Some claim over 200HP, I suppose with enough compression and RPM it is possible, just not practical nor is it dependable. From what I have seen the mods do not stack on HP in the way some believe, the majority of the mods overlap. Biggest gain is port, polish and flow balancing. My powerflow exhaust is supposed to be good for 15HP, 10:1 pistons 15hp and so on. In reality when you stack up a few of these mods the combos are not 100% cumulative the results are more overlapped. Even with engines claimed to be 185-190hp I have never seen one that swings the prop a O-320 will, not in normal RPM range anyway .
My new Lyc. cylinders are ported, polished and balanced, I opted to stick with 8.5:1 pistons , I am running a powerflow 4into1 exhaust and dual P mags. Even the addition of the powerflow popped my static RPM 100, I'm expecting about another 100 with the rest, in short about 175HP. Problem is the stock 160HP doesn't make 160HP with the original exhaust, likely only makes 150. The powerflow simply allowed the engine to breath a little better, liley making 165 HP . The other additions combine for another 10HP.
I'm already over redline with the Borer 82 45 at WOT, the engine will push 2800 , 2450 static. Before the powerflow the static was 2350 and 2700 WOT. I'm sending the prop out to have it pitched 48 see where that lands
and adjust from there. Certainly a lot more HP but still not a O-360.
