Needle Tachs suck!

[C5Engineer 1170]

On my first full power run after my engine install I thought I was seriously over revving my engine so I added pitch until it read 6600 rpm on my needle tach. I installed a Tiny Tach when I did the engine install too and it was consistently reading 5700. I was 100% sure my engine was turning more rpms than that so I called Steve at Tiny Tach and tried all their tricks to get it to read correctly.. None of them worked. Steve and I was convinced I got the wrong model so he sent me out a new one.

In the meantime I tried to fly my plane and it was running like crap. It did not accelerate like it should and if you saw my other thread at around 50ft it would start losing RPM's. I was convinced I had a fuel starvation issue and have spent the last three days trying to track it down.

Fast forward to this morning. The first thing I did was swap in another fuel pump I had that I knew was good... Didn't change a thing. The next thing I did was pull my Tiny Tach off my Powered Parachute that I also knew was good. I hooked it up to the other coil so I'd have two different sources... at this point I had THREE tachs in my plane. I fired it up and went to full power and lone behold it read 5700...exactly the same as the other one. MY ENGINE WAS ONLY TURNING 5700RPM!!!!!! No freakin wonder it was running like crap it was severely overloaded. I took 4 degrees out and got it so that it was turning 6500 rpm static on the tiny tach. NOW were making some horsepower!!

I put the cowling on and taxied out. We had a 12kt wind straight down the pipe. I threw the throttle open and almost went through the back of my seat! I was airborn in 50ft and the engine purred like a kitten at 6300 throughout the climb. It climbs WAY better than it did with the old engine and never missed a beat. I flew it for 30 minutes.

LESSONS LEARNED... If you overload your prop enough a 582 with a 2.62:1 gearbox wont pull it. It's the same as lugging your truck...eventually it just starts shutting down. That's why I was losing rpms.. in the climb is when you have the greatest load on your engine. At 5700 I was barely in the powerband. When it was all said and done my needle tach reads 7100rpm at WOT!!! It's pretty much worthless now. I'm pretty sure I've been running my RPM's low this whole time, even with the old engine. I had to adjust my idle even after taking all that pitch out to slow it down.

Gotta love trying to troubleshoot a two stroke sometimes.. I went down a completely wrong path because of a faulty instrument. I should have trusted the Tiny Tach from the beginning. Anyways what a relief..this was driving me insane.

[horsepower 24]

On my first full power run after my engine install I thought I was seriously over revving my engine so I added pitch until it read 6600 rpm on my needle tach. I installed a Tiny Tach when I did the engine install too and it was consistently reading 5700. I was 100% sure my engine was turning more rpms than that so I called Steve at Tiny Tach and tried all their tricks to get it to read correctly.. None of them worked. Steve and I was convinced I got the wrong model so he sent me out a new one.

In the meantime I tried to fly my plane and it was running like crap. It did not accelerate like it should and if you saw my other thread at around 50ft it would start losing RPM's. I was convinced I had a fuel starvation issue and have spent the last three days trying to track it down.

Fast forward to this morning. The first thing I did was swap in another fuel pump I had that I knew was good... Didn't change a thing. The next thing I did was pull my Tiny Tach off my Powered Parachute that I also knew was good. I hooked it up to the other coil so I'd have two different sources... at this point I had THREE tachs in my plane. I fired it up and went to full power and lone behold it read 5700...exactly the same as the other one. MY ENGINE WAS ONLY TURNING 5700RPM!!!!!! No freakin wonder it was running like crap it was severely overloaded. I took 4 degrees out and got it so that it was turning 6500 rpm static on the tiny tach. NOW were making some horsepower!!

I put the cowling on and taxied out. We had a 12kt wind straight down the pipe. I threw the throttle open and almost went through the back of my seat! I was airborn in 50ft and the engine purred like a kitten at 6300 throughout the climb. It climbs WAY better than it did with the old engine and never missed a beat. I flew it for 30 minutes.

LESSONS LEARNED... If you overload your prop enough a 582 with a 2.62:1 gearbox wont pull it. It's the same as lugging your truck...eventually it just starts shutting down. That's why I was losing rpms.. in the climb is when you have the greatest load on your engine. At 5700 I was barely in the powerband. When it was all said and done my needle tach reads 7100rpm at WOT!!! It's pretty much worthless now. I'm pretty sure I've been running my RPM's low this whole time, even with the old engine. I had to adjust my idle even after taking all that pitch out to slow it down.

Gotta love trying to troubleshoot a two stroke sometimes.. I went down a completely wrong path because of a faulty instrument. I should have trusted the Tiny Tach from the beginning. Anyways what a relief..this was driving me insane.

Awesome, now its time to have some fun.Do you have a better cruise now or is a just more on the takeoff.I was just curious if the bluehead has more power because its the old one was worn out or do they put out a little more zip than the greyheads? Probably a little of both.Good job on the swap. Randy

[akflyer 1427]

Been there done that. Every needle tach I have seen is way off on the top end. I have seen, just as you have, a perfectly good kitfox or avid turned into an anemic piece of shit due to turning 750 to 1000 RPM low on take off.. hell, that is barely a good cruise RPM let alone trying to take off.

Glad you got it figured out! I used the hole my needle tach was in for the fuel flow meter. Best trade I ever did

[C5Engineer 1170]

Awesome, now its time to have some fun.Do you have a better cruise now or is a just more on the takeoff.I was just curious if the bluehead has more power because its the old one was worn out or do they put out a little more zip than the greyheads? Probably a little of both.Good job on the swap. Randy

Randy I just stayed right over the top of the airport for about 20 minutes so no good numbers yet. I did open it wide open to be sure it was not going to over rev in flight. I was staring at the tach and egts and realized it was getting really loud and I glanced over at my airspeed and it pegged at 100mph so I chopped the power. I'm getting about 6400 straight and level wide open and 1100 degrees on the EGT's. I'm still getting a little toasty at 4800-5000 which is where I cruise a lot when down low and slow so might drop the needle down another notch. I'm not exceeding 1200 but it's getting right up there. Some guys say you should run them like that to prevent carbon build up..what do you guys think? I'm trying to stick a tad on the lean side down here at Sea Level so it's not slobbering rich when I head up to the 3-4000ft MSL strips in the hills I plan on flying to alot this summer.

As far as the blue head vs silver head a lot of guys think the blue head is making a few more horsepower. I discussed this with the guy that built my engine yesterday and he agrees. He uses the same gearbox/prop to do all his break ins and he said a blue head just seems to pull harder and run better overall. I've never seen anything to back this up though. I can tell you that this engine is way smoother than the other one. I always thought my prop was slightly out of balance because I've always had a slight vibration. That is totally gone now and I'm still running the same prop and gearbox. I did replace all my prop mounting hardware and clamping blocks and I tore my gearbox totally apart..maybe that did it??? I'm thinking it's the engine itself though.Maybe I had a crank bearing on it's way out or something. I asked for a full report on my old engine when he tears it down just to satisfy my old curiousity.

Like I said I was using my needle tach exclusively on the old engine so I'm thinking I have been running the RPMs low for a while. I was getting 900fpm solo before so it could not have that low but I saw 12-1400 yesterday here at Sea Level, 50 degrees, and a 12kt headwind. I know this engine has more power but I don't think it's that much more. I'm thinking I was only running 6000 rpms or so before.

[akflyer 1427]

Randy I just stayed right over the top of the airport for about 20 minutes so no good numbers yet. I did open it wide open to be sure it was not going to over rev in flight. I was staring at the tach and egts and realized it was getting really loud and I glanced over at my airspeed and it pegged at 100mph so I chopped the power. I'm getting about 6400 straight and level wide open and 1100 degrees on the EGT's. I'm still getting a little toasty at 4800-5000 which is where I cruise a lot when down low and slow so might drop the needle down another notch. I'm not exceeding 1200 but it's getting right up there. Some guys say you should run them like that to prevent carbon build up..what do you guys think? I'm trying to stick a tad on the lean side down here at Sea Level so it's not slobbering rich when I head up to the 3-4000ft MSL strips in the hills I plan on flying to alot this summer.

As far as the blue head vs silver head a lot of guys think the blue head is making a few more horsepower. I discussed this with the guy that built my engine yesterday and he agrees. He uses the same gearbox/prop to do all his break ins and he said a blue head just seems to pull harder and run better overall. I've never seen anything to back this up though. I can tell you that this engine is way smoother than the other one. I always thought my prop was slightly out of balance because I've always had a slight vibration. That is totally gone now and I'm still running the same prop and gearbox. I did replace all my prop mounting hardware and clamping blocks and I tore my gearbox totally apart..maybe that did it??? I'm thinking it's the engine itself though.Maybe I had a crank bearing on it's way out or something. I asked for a full report on my old engine when he tears it down just to satisfy my old curiousity.

Like I said I was using my needle tach exclusively on the old engine so I'm thinking I have been running the RPMs low for a while. I was getting 900fpm solo before so it could not have that low but I saw 12-1400 yesterday here at Sea Level, 50 degrees, and a 12kt headwind. I know this engine has more power but I don't think it's that much more. I'm thinking I was only running 6000 rpms or so before.

Joey, if you temps at cruise are high, then you need to raise the needle to fatten it up! Glad to hear that you now have the power that you felt you always should have had.. but I bet you would have had that same performance with the grey head if it was turning the right RPM too.

[BryceKat 125]

After reading this post, i think i'm suffering the same problem by relying on a westach. So i ordered a tiny tach. The unit isn't here yet, but i was reading the online instructions http://www.tinytach.com/tinytach/pdf/Tiny_2A_Instructions.pdf

and was wondering how many sparks per revolution, and i think it's 4 on a 582 grayhead. Is that correct? Thanks, Bryce

[C5Engineer 1170]

Bryce call em they are very helpful and will make sure you get the right one.