Arctic Cat update

[scottessex]

So far I have not melted anything on the arctic cat, after 3 sets of pistons,
I can rebuild the top end in my sleep!
The last go round I re jetted extra fat, and I retarded the timing 7* for a total advance of 18*btdc.
Right now the water temps re 125-130*
EGTs are around 900* (a tad cool on purpose)
power is reduced by the timing I can tell, I had to take one degree of pitch out of the prop, but the engine is running very smooth and stable.
I have around 1.5 flight hours on the engine this time, a couple more hours of staying close to the runway, and I might venture off over some hay fields.
so far so good. keep your fingers crossed.

[Friendly]

I hope you whip that sucker inline!!! thanks for the update.

[Earthboundmisft]

Scott, good job man. Now that Im flyin, I can say I have experienced the constant concern about an engine out. It is on my mind more than I would like. Keep a tuned ear for a change in tone, your first clue.

[GrantR]

Keep a tuned ear for a change in tone, your first clue.


Not really. I think when Scott's 582 seized there was no warning. It seized hard enough to tweek the crank. Sort of like when you runover a stump with your mower and it suddenly stops!

[scottessex]

Exactly Grant, kinda like I hit some bad air or something. :)

[All_In]

Good news Scott, we all hope you got it this time. Keep us informed!

[RotoPlane]

It is surely sounding good to go. Oh, Scott.....don't forget to PM me on what my one piston expense share is.....you have probably saved me many headaches!

[pwongkit]

Hi Scott ...What model of the Arctic Cat that you are talking about? I got one the model is 1998 Arctic Cat ZR 600 EFI L/C cool Do you think OK for the gyro power?:der:
pwongkit

[Passin' Thru]

It is surely sounding good to go. Oh, Scott.....don't forget to PM me on what my one piston expense share is.....you have probably saved me many headaches!

And I committed for the other one. We're all pullin' fo' ya!:usa2:

[pwongkit]

Scott...any update for the Arctic Cat engine?:boink:
pwongkit

[scottessex]

No update this weekend, I was out of town. :)
The engine is a 1991 530 from a mountain cat EXT single pipe.

[scottessex]

UPDATE!
So far so good, engine has been running fine, no problems.
BUT since I cannot leave anything alone. I had a brand new
Hirth muffler assy, so I made brackets and straps, and mounted the Hirth exhaust just to see how it worked.
No difference in EGT temps or RPMs, It DID flatten the torque curve, seems to start building power around 4k rpm instead of 5k. also not near as peaky on the pipe.
I think I will stick with the hirth muffler, as it is quite a bit lighter, and smaller too.
Now to dial in the jetting, I am still running slightly rich on purpose.
I'll post pics later.

[All_In]

That is good news Scott!!!

[Friendly]

What are the hours on the engine now Scott?

[scottessex]

This is where it gets sad....... I only have about 4 hours on the engine, most of the flights have been 10-15 minutes. I'll stay over the strip just in case.....then land and check everything over to make sure nothing has loosened up etc.

The last 3-4 weeks have been extremely busy and hectic here, have not had too much time to fly,
Nothing planned for this weekend, so I might get an early morning flight in, Plan to venture out some, if nothing else just to put more time on it.
I did end up changing the Radiator, prop, exhaust, etc, I think I have it where it is going to stay now.
everything has been consistent so far as water temp, EGT, etc. no hickups.
I should be like Mike (earthbound misfit) and should have 40 hours on it by now, but it just has not worked out that way.

[All_In]

I vote for more flying and less work Scott, but my vote rarely counts...

[scottessex]

I'm with you John, If I can keep people I know from going to the hospital, getting married,
Joining the military, having birthdays.......But then what would I have to do? :D

I am trying to get to the less work-more flying part of my life.

[scottessex]

Having trouble with the normal photo hosting site, testing to see if this works.
engine pics (http://picasaweb.google.com/scottessex89sx/ArcticCatEngine?feat=directlink)

http://i568.photobucket.com/albums/ss122/scottessex/IMG_1301.jpg
http://i568.photobucket.com/albums/ss122/scottessex/IMG_1302.jpg
http://i568.photobucket.com/albums/ss122/scottessex/IMG_1303.jpg
http://i568.photobucket.com/albums/ss122/scottessex/IMG_1304.jpg
http://i568.photobucket.com/albums/ss122/scottessex/IMG_1305.jpg
http://i568.photobucket.com/albums/ss122/scottessex/IMG_1306.jpg
http://i568.photobucket.com/albums/ss122/scottessex/IMG_1306.jpg
http://i568.photobucket.com/albums/ss122/scottessex/IMG_1307.jpg

[Earthboundmisft]

Scott, the photos look good. Your engine install looks clean, I like the exhaust. Whats with the 45s between the carbs and filters? Are you looking for cleaner air? I remember my old Z1 900 with KNs. I could change the RPMs by moving my legs, affecting the airflow.

[RotoPlane]

Yes, those are clear photo's of a well laid out installation.....wish mine was to that point. Thank you....they will be useful for me ;).

[Friendly]

I am so glad you are getting to fly instead of rebuild engines. Thanks for the great photos. If you still have that B box from Bensen Days send me an email. I sent you one about the BMW drive.

[scottessex]

Misfit Mike, the 45's are on there to control the back spit from the carbs. Most 2 strokes have some back spit when the reed valves, rotary valve close, the column of air bounces back and reverses causing fuel to be spit back out of the carb, Normally this is contained in the airbox or resonance chamber. The old Hirth that I had used tubes between the carbs and filters, they called the velocity tubes. Anyhow, my thought was that any back spit would be contained in the elbow and sucked back in the carb, Rather than being spit into the air filter and traped or evaporated. I thought that may have been contributing to my piston burning adventures.
It may not make any difference at all, but it cannot hurt.

They are made from vacuum cleaner elbows with a rubber 2 1/2" drain coupling. :)

A

[Earthboundmisft]

Ahhh-so, have you ever watched the reverb with a timing light? Freezes the action ya know. Pretty cool

[scottessex]

Flew again tonight, held it at 6400rpm for a whole 10 minutes, and the water temp stayed right at 130* (the arctic cats do run cooler than the rotax's, 125* thermostat compared to 160*)
The engine is running really really well.
I have been venturing out a little farther each time, At first I was kind of hesitant to fly beyond gliding distance of the runway, since I have had so many engine failures.

But all in all it seems to be really sweet, flying is FUN again! :D

[Brent_Brown]

Good to hear your back flying.

[RotoPlane]

Every time I see "Arctic Cat Update"....I cringe before I pick it.
But lately it has all been GOOD news!
I am glad flying is fun again Scott!!
Looks like you really have found the gremlin......

[Timchick]

Good news.

[All_In]

Buddy that is good news, I'm so glad you figured it out!!!

[StanFoster]

Scott- I am glad you have been getting some flying time in. You deserve some airtime after all that you have been through. Stan

[Friendly]

So how many hours is that on the motor.

[scottessex]

So how many hours is that on the motor.

Only about 40 minutes more than the last time you asked. :D

I had to take the dog to the vet, and fix the wife's car, Her fuel filter clogged up. No biggie. So I flew in the evening.

[Friendly]

Only about 40 minutes more than the last time you asked. :D

I had to take the dog to the vet, and fix the wife's car, Her fuel filter clogged up. No biggie. So I flew in the evening.

I'm just making sure you are not sneaking in hours without telling us. 40 mins, sounds like I am doing a good job. I sent an email to the party we talked about, no answer. I know you're on the job.
Keep that pretty wife of yours happy.

[lanichol]

Flew again tonight, held it at 6400rpm for a whole 10 minutes, ....The engine is running really really well.

Nice install Scott. Now that you have a few hours, would it be possible to look at the top of the piston through the spark plug hole with a Small Diameter Video borescope (http://www.sears.com/shc/s/p_10153_12605_00980726000P?mv=rr) to see the burn pattern?

An idea might be to take pics of the pistons before any adjustment for comparison. Over time, you might get the perfect tune.

[Passin' Thru]

Scott, did you ever learn anymore about that "up-side-down" ignition advance curve? :eek:
I suspect that may have been the root of your burned pistons?

[scottessex]

Pete, Neil explains it here. http://www.rotaryforum.com/forum/showthread.php?t=25695&page=4

Apparently the 2 strokes do back off the timing at high RPM.
I have learned that it is a love/hate relationship with 2 strokes. :)

Larry, I still have it a little rich so I can watch the pattern on the pistons, I'll take it down one jet size at a time and keep an eye on it.

Mark, I'll keep you posted on my time :) I won't sneak any in on you.
Let me know if you find anything out.

[Passin' Thru]

Ah-Hah! So the ingition should retard as the pipe comes on and starts ramming the cylinder! The way Niel explains it makes sense, but my shade-tree mechanics understanding is waay behind the curve!:D

[RotoPlane]

I don't think of Pete as a "shade-tree" anything and wish I had at least his gyro knowledge. It's kinda funny but I use to think of myself as a shade-tree aerodynamicist….then I was told that I used Mary Poppins aerodynamics. Now, I don't think that is as good as shade-tree….but I rather like the title cause she floats around, using no apparent power……;).

[WHY]

Scott, did your wife get some of that BP gasoline with salt water mix in it??

Tony

[All_In]

Bro will it ever end? With everything you got going on, we need to get you a helper? = more flying time.

Glad your are in the air at all!!!

[scottessex]

Thanks guys, at least the one thing I have found out about German cars....They are easy to work on, it is almost as if they planned the car out before they built it. :)

Now She wants to quit her job and go back to school.... I want to quit my job and fly and build gyros, One of these days I'll figure out what I want to be when I grow up. :D

[All_In]

I vote for you flying and building gyros!!!

[scottessex]

I need to send Her back to school so She can get a good job, and I can stay home. :)

I updated the pictures on page 2 of this thread in case anyone is interested.

[Friendly]

That was some big files Scott, thanks for the quality photos. That really is a clean looking installation. Wow.

[scottessex]

Whoo hoo! Flew again tonight, I hate to make this like a facebook thing...But everything went well, I tried out the new radio and helmet. Everything was working fine.
I saw a mini thunderstorm dumping some rain to the north, so I came back and landed, still hearing thunder, it was the right decision.

Yes mark the files are huge, but they should show good detail. :D

[All_In]

Yaw Mon, easy living you be fly'n!

Way to go Scott and glad to hear it all worked except the weather!

[Friendly]

Whoo hoo! Flew again tonight, I hate to make this like a facebook thing...But everything went well, I tried out the new radio and helmet. Everything was working fine.
I saw a mini thunderstorm dumping some rain to the north, so I came back and landed, still hearing thunder, it was the right decision.

Yes mark the files are huge, but they should show good detail. :D

Hope you know I was bragging on your pictures not complaining. I like the large files. I think you may have a winner on your hands now.
you know the 800 is 160hp don't you?????:)

[scottessex]

The HP thing is way over rated as you know, I figure with the detuning you will lose 30-50% of the "rated HP" After flying the rotax 582 for a couple of years, and then flying Joe Pires 503 ultrawhite, I would have to say that I am right in between as far as power goes.
The 530 Arctic cat was rated at 97HP with dual pipes... with the single pipe mountain version that I am using, plus the retarded timing, Hirth Exhaust, and seat of the pants, tell me it is around 60 HP.
The engine only cost me $500......... :D

I would love to see some pics of the Arctic cat zl 1000 4 stroker drive end.

[jcarleto]

Can't beat a $500.00 engine. But it starts to sound a bit like a Mac with all the specialization required to keep it running right on a gyro. I have to be the first to admit that a good-running Mac is also tough to beat.

Congratulations on your results thus far. I wish you continued success.

[lanichol]

Scott,

Is it correct that the carb settings have not change after your recent overhaul? You have only retarted the timing? And the piston wash looks good vs burning a hole in the piston? How interesting.

[scottessex]

Yes Larry, that is correct, the last overhaul/piston replacement, everything was left the same, the only thing that was changed was the ignition timing. Stock timing was 25* btdc, I have reduced it to 18* btdc. I have since changed the exhaust pipe to a Hirth aircraft exhaust system.

[Earthboundmisft]

You still runnin cheap gas?:boink::painkiller:

[scottessex]

You still runnin cheap gas?:boink::painkiller:

Wow! That hurts! :)
No cheap-o gas for me, I am getting 93 octane at the local station, and have been checking it, never seen it over 5% ethanol.

The $500 was a joke, yeah the engine only cost $500, and then another $500, then $100, then $300, then $500 and then, $500, and then...........:lol:

[Earthboundmisft]

I,m stickin with 100LL, and will inspect more often. What interval do you suggest? I am finally over the increments of 100 dollar bills, and enjoying the rewards. I may add some gingerbread though...

[scottessex]

Don't add too much "bling" you'll gain weight and loose performance. :)

I'd still change the plugs at 25 hours, check the crank and bearings at 300.
Pull the exhaust at 150 and check the rings for deposits.

[Earthboundmisft]

Got plugs for this weekend, and I thought I would bring my borescope.
Smoke system shouldnt weigh much...:D

[scottessex]

Flew again this evening, I decided to venture out away from home.
Flew up to Hollonville buzzed a couple of local strips, flew over the peach orchard,
Flew back around the nature preserve behind our strip, south to Concord, over the horse farm, and back home. The engine seems to like running between 6000-6500 for cruising.
I came in for a nice butter smooth landing in front of the hangar. Mama Gyro had the grill fired up. Life is good.

I was told by some Arctic Cat guys to change the piston pin bearings at 100 hours.
They are cheap, about $8.00 each and a top end gasket kit is only $35. so that is not a problem. I'll just keep up a good inspection schedule.

Thanks to everyone for all the encouragement too keep going on this project, I think it will work out well.

[Friendly]

you are "Da Man"

[StanFoster]

Scott- Glad to see you are getting some flying in. I can understand your apprehension. Now go catch up some flying! Stan.

[RotoPlane]

This is really looking good Scott....makes me happier than you know! Some of that happiness is because I have one too ;). Change those bearings "every" 100 hours? Hurry up with the 100 hours to see if the bearings really, really, really needed replacement ;).

[GrantR]

OK now since it is running right it is time to make a cross country to Americus! You are 70 air miles :) I need a gyro buddy to fly with!

[scottessex]

Update! Still running strong! I had today off, so I decided to fly this morning before it gets so blisteringly hot. I had a nice flight, really hazy though not good for pictures.
:) :) :)

[StanFoster]

Scott- Glad to see you are getting some flying time in without having to haul it home. Lots more fun that way!


Stan

[Friendly]

Thats great news Scott. I hope you have hundreds more trouble free flights from the cat

[scottessex]

I still have the 650, but the 530 is running so well.........I cannot bring myself to start over with another one. Plus I have the 2 seat project with the Honda engine....Stay tuned. :)

Whats the ETA on the Weber?

[Friendly]

Maybe three more weeks if things go well for me. Tony is about ready to start tuning his.
I am waiting for ATI to give me a quote for a custom damper so I can finish the Bellhousing measurements for dept of cut.

Thanks for asking. I look forward to your Honda build.

[Passin' Thru]

Update! Still running strong! I had today off, so I decided to fly this morning before it gets so blisteringly hot. I had a nice flight, really hazy though not good for pictures.
:) :) :)

Every positive report I read about this engine puts a smile on my face. :)

[scottessex]

Me too Pete, makes me smile every time I have a "scheduled" landing!

[RotoPlane]

These good engine reports make me especially happy ;). Thank you Scott for those engine photos's....I downloaded them this time....

I've been looking at the possibility of not using carbs and injecting fuel directly into the cylinder. One thing I have not been able to verify yet is if the injected oil will still be able to leave the crankcase and lube the pistons, without help from the fuel....

[scottessex]

Well Ed, rather than "reinventing the wheel" Arctic cat has been using fuel injection on their sleds for years....might be worth checking out, many of the new sleds are also using direct injection as you are talking about.

[RotoPlane]

I knew about injecting fuel into the intake but I didn't know about ones that injected into the cylinder at the same time as the spark. I'll check that out and see if they are simpler than mine….thanks Scott.

[Not Yet]

Ed, you might be interested in this

SEMI-DIRECT INJECTION
Add to this picture the Bombardier-Rotax creation of Semi-Direct Injection (SDI), which employs low-cost hardware to achieve most of what DFI delivers. SDI has been used successfully for several years on Sea-Doo watercraft and appears suitable for snowmobile engines as well. The main reason that SDI works as well as it does is that development of two-stroke scavenging flows has achieved good separation of fresh charge and exhaust flows – essentially stratifying the air motion in the cylinder. By injecting fuel selectively into a part of this flow, far upstream in two of the transfer ports, fuel can be kept from reaching the exhaust.
While the SDI systems offered on 2004 Ski-Doo models are quite advanced compared to the first Sea-Doo injection systems, Bombardier SDI is still at a fairly early stage in its overall development. Company engineers are optimistic that further gains are possible within its simple concept. While full DFI can add 20-30% to the cost of an engine (this is true of Diesels as well), SDI might be achieved at cost similar to a carburetor system.
How about adding catalytic converters to our current fleet? Carbureted or TBI two-strokes lose too much fuel to their exhaust for the application of catalytic mufflers. The more UHC the catalyst must burn, the hotter it operates. DFI and SDI engines, with already little UHC in their exhaust, can be further refined by catalyst use if standards tighten again.
Rotax 2-TEC 600 HO SDI
Right now, four-stroke engines can (and do) meet sled emissions numbers even with carburetors, but reaching higher levels will require the greater accuracy and self-tuning features of electronic fuel injection. Further, a four-stroke’s combustion has to be more intense than that in a two-stroke in order to make equal power while firing half as often. This higher temperature combustion naturally produces more oxides of nitrogen (NOx), while a two-stroke’s natural EGR (inevitable recirculation of exhaust gas from one combustion cycle to the next) lowers combustion temperature, making the two-stroke naturally low in NOx. Any change which raises an engine’s combustion temperature (higher compression ratio, turbocharging, &c) also raises NOx production.

and this

MARCH 11, 2002 - 14:25 EST

Bombardier Introduces 800 2-TEC SDI Engine for 2003 Ski-Doo Snowmobiles

A two-stroke engine with lower hydrocarbon emissions and better fuel economy

Bombardier launches the Rotax(R) 800 2-TEC(R) SDI engine for Ski-Doo(R) snowmobiles and by doing so introduces semi-direct injection two-stroke technology to the market. The 800 2-TEC SDI engine offers as much as a 50% reduction in hydrocarbon emissions
and up to 25% better fuel economy than traditional carbureted snowmobiles, while delivering performance equal to that of a conventional two-stroke engine.

A central computer in the Rotax 800 2-TEC SDI engine monitors ambient temperature, altitude, engine temperature, throttle
position and RPM, then makes adjustments to optimize efficiency and performance. A knock sensor works with the computer to prevent
problems by retarding ignition or enriching fuel/air mixture if itsenses the engine is running too hot. With no choke, an operator
can just press the electric start button and go. Easier to operate, this engine is a no compromise alternative for
snowmobilers.

[All_In]

Way to go Scott!!

Glad to hear no more problems!!!

[RotoPlane]

Thank you David for this information. I knew about EFI but I didn't know about SDI or DFI for snowmobile 2-cycle engines.

I now know that SDI injects fuel into the transfer port, bypassing the crankcase (where synthetic oil is recommended). This makes more sense than EFI which injects fuel into the intake port. Both require a computer to keep the air/fuel ratio optimum for operating conditions.

The 2011 Ski-Doo's (Bombardier) DFI is a nightmare of complexity but I understand that it works well. The reason I like the idea of direct-injection through the Suzuki 600 heads and in time with the spark, is the simplicity….outside of the need for high pressure timed fuel pumping. For an engine that runs mostly at say 80% power, no computer or air butterfly valves are needed because air/fuel ratio doesn't need to be controlled. Power/rpm is controlled only by the quantity of fuel delivered to the cylinders. Low power is pumping more air than needed but that is not for long periods of time. I think I have solved the starting problem and can use kerosene….like Stan, and it's safer.

[scottessex]

Just wanted to let everyone know, still running strong! I had to re adjust the idle air bleed screws, it was loading up at idle, must be the cooler temps. I have been trying to fly regularly, had a great flight tonight about an hour before dark, I love the cooler temps, I was climbing out at 800 fpm. I did shoot some video, still trying to edit and upload. :) So far this engine is running sweet!!!! :D :)

[RotoPlane]

In the past, each time I saw this thread appear with your name on a new post….I used to cringe….but the last few posts have brought me happy feet. So glad you are happy with that engine Scott and thanks for this update!

[PW_Plack]

...it was loading up at idle, must be the cooler temps...

Scott, it's great to see success with this engine!

But when temps cool, it will tend to run leaner, not richer. Is there a compensation circuit of some sort that's overdoing it a bit?

[Friendly]

I know you must be a happy camper, How many hours is it now? Thank you for the update!!

[scottessex]

Paul, you are correct, I "miss spoke" :) I had to turn the idle air screws in about 1/4 turn, it acted as if it was running out of gas not flooding, but just at 2000 rpm. Other than that the engine has been running great, I am very happy with it.
I have flown a 503 dominator, and this one previously had a 582, and from the seat of the pants I would have to say it is right between the two as far as power goes.
You can here the engine here: Untitled on Vimeo (http://vimeo.com/31737690)
Sorry Paul, it is un-edited.

[gyro]

sounds good Scott....now fix them shakn blades:boink:

[scottessex]

I am working on the shaky blades... They were super smooth on the Soma, they have always had shake on the Dom, I cleaned them, strung them, and then added a shim to get somewhat smoother. Still work to do. :)

[Friendly]

It sounds like the engine is not straining a bit. Looks like you may have a winner. That is pretty country. Nice to see it in HD.

[scottessex]

Mark, I have 21 hours so far...I know that is lame, I put 100 hours on my Soma the first year I had it.
But I have been busy with the house and work, at least the gyro has been ready to fly when I have had the time. many of my flights are short, 15,20,30 min.

[Passin' Thru]

I liiike it! :whoo:

[Friendly]

Mark, I have 21 hours so far...I know that is lame, I put 100 hours on my Soma the first year I had it.
But I have been busy with the house and work, at least the gyro has been ready to fly when I have had the time. many of my flights are short, 15,20,30 min.

Its not lame,Scott
I only got to fly 3 or 4 times this whole year!!. I hate it when work gets in the way of play time, don't you?

For a 2 stroke , its good to know it can sit and still go out and fly when you want it to do so. Keep posting. There is a lot of people wishing you success for this engine.