Van's Air Force
Don't miss anything! Register now for full access to the definitive RV support community.
Rv 4 engine choices
- Thread starter Rule91
- Start date
Scott Hersha
Well Known Member
I’m wondering how you would get 180 hp out of an O-300. Stock hp is 145, with 7:1 compression ratio. Are higher compression pistons a possibility with that engine? If so, probably not as smooth, but it’s an interesting idea. You would have to modify that beautiful RV4 cowl……..
Continental also has that IO-360 six cylinder, 200 hp engine - now we’re talking.
Way too heavy.. I love my O-360 180hp RV-4…. But it’s really really sweet to fly a light nose 320 -4.. what’s that O-300 weigh? Nothing like devaluing the plane like going off trail with the engine..
Stepping g outsise what’s accepted as normal poweplant wise on any RV kills its value! Saw an RV8 once some years ago for sale that had a Conty 470 (I think it was that size) sat for sale for ages, would have been like having a house brick tied to your lower lip! 0320 FP is the sweet spot for a 4
Thanks all o-320 it isStepping g outsise what’s accepted as normal poweplant wise on any RV kills its value! Saw an RV8 once some years ago for sale that had a Conty 470 (I think it was that size) sat for sale for ages, would have been like having a house brick tied to your lower lip! 0320 FP is the sweet spot for a 4
Have a fixed pitch O 320 - can’t go wrong with that combo.
rag
Active Member
I flew my RV4 with a O-320 150 HP fixed pitch prop (pacesetter) and slick mags for about 2 years, then installed high compression pistons (160hp) and flew for 7 more years. Changed to Catto prop, flew for a few more years, then changed to Lightspeed ignition. Flew this combination for about 18 years, discovered a cracked case, which created an opportunity to upgrade. Changed firewall forward to Dynafocal mounts, long gear, O-360 180 HP, E Mags and another Catto prop. I have been flying this combo for 5 plus years. I really thought long and hard about going to a O-320 with lightweight accessories and a constant speed prop - but did not want the complexity, weight and maintenance of the constant speed. So... I went to the O360 and fixed pitch. The weight difference between the original O-320 and the O-360 is about 10 pounds - due to the lightweight accessories I installed on the O360.
My conclusion?? - you can’t go wrong with any of the above combinations. The speed differences and climb differences are a combination of a number of variables, which make it verydifficult to provide comparisons. I am very happy with the current combination. It is simple, reliable and performs well.
I think someone who is contemplating a re-engine project for their RV4 can pick any of the above combinations and be happy with the performance. One can watch the engine market and see what opportunities come along - in other words - keep an open mind to any of these combinations.
My conclusion?? - you can’t go wrong with any of the above combinations. The speed differences and climb differences are a combination of a number of variables, which make it verydifficult to provide comparisons. I am very happy with the current combination. It is simple, reliable and performs well.
I think someone who is contemplating a re-engine project for their RV4 can pick any of the above combinations and be happy with the performance. One can watch the engine market and see what opportunities come along - in other words - keep an open mind to any of these combinations.
Roadjunkie1
Well Known Member
I elected to go with the O-320 160hp Lycoming from the outset as it was lighter and performance was better than anything I had previously flown. Oh: and it was less expensive! Put on a beautiful Bernie Warnke Almost Constant Speed prop (RIP, Bernie...) and that RV grin turned into a permanent thing! Cruising at a gentle 2400/19 (that she seems to like best!) going a cool 175 true sipping 7-7.5 an hour.....how does one beat that? Will she do 200? Um....yeah but she likes to suck down 10 gallons an hour to do it. 175 is just fine with me with a fixed pitch prop. I'm used to flying a J-3 Cub, for crying out loud! And she feels perfectly 'balanced' with the O-320 up front. Yeah: can't go wrong with that combination..... And with a Landoll balancer she is SMOOOOOOOOOOTH.......... 
Aside: talking to an Air Force jet jock who flew a bunch different rides: we decided the F-16 was the RV-4 of the Air Force stable of aircraft!!
Yes, indeed! Love my -4!!
Aside: talking to an Air Force jet jock who flew a bunch different rides: we decided the F-16 was the RV-4 of the Air Force stable of aircraft!!
Yes, indeed! Love my -4!!
Roadjunkie1
Well Known Member
Depends on the mission, I guess. High-altitude cruising would be a pretty good reason to have that.......
Anyone flying a turbocharged single with the engine in front should have an ejection seat.
Ed_Wischmeyer
Well Known Member
My RV-4 was 160 HP and a Cruisemaster (I think) prop. I had it repitched to be less of a cruise prop, but... after converting the RV-9A from fixed pitch to constant speed, I know that would have done great things for the RV-4 performance. Extra weight, though...
n82rb
Well Known Member
I have done side by side, literally in the air in formation, between a 320 wood prop 4 and a 360 constant speed version. mine is the 360 constant speed and a good friend has a 320 with a very well suited wood prop. during a formation takeoff, i have to pull the power back after rotation to keep in formation with him. however, once level, I only have a couple of knots over him in top speed.
i get a shorter ground roll, higher climb rate. but that comes with a higher fuel burn, higher maintenance cost, and purchase price.
one other big factor is i can slow down in the pattern real easy, he has to manage speed a lot closer as a slick fixed pitch RV-4 does not like to slow down. the down side is my glide ratio with that prop is like a manhole cover.
his handles a bit better due to a bit lower weight and better cg placement, mine is a bit nose heavy. the trade off there is i can put a lot more weight in the back seat and stay in the cg range. most fixed pitch RV-4's will go aft at around 200lbs or less.
