Installing Rotax Ricks 670 Muffler on a 670

26 posts in this topic

Posted

Has anyone installed Ricks 670 in an Avid MK-4 and his Muffler system?

I would like to know how involved it is.

                Thx Marv

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Posted

Hi Marv

I was hoping some one would respond to your question.

This forum has attempted to gather  Rotax 670 information for years but there has been very little feedback from what I have seen.

I fly a Kitfox and many others who have Avids would consider replacing our 582's with 670's if there was more feed back to back up Rotax Rick's claims.

I purchased the exhaust from Rotax Rick 2 years ago  that was to fit inside the cowl of a Kitfox with a 670 and it would not come close to fitting when I mocked it up with my 582 which is virtually the same size as a 670.

That exhaust ended up in Alaska and the new owner thought at first it would fit without modifications in his Kitfox and then months later told me it would not fit.

Currently there is a Kitfox for sale in Florida on Barnstormers for 15K that has a newly installed 670 with 17 hours.

I called the owner just to ask how the 670 install went and he told me the exhaust  did not fit as promised and he had to modify it.

He sent photos and the muffler is installed right to left like a 582 kitfox exhaust.

The photos that Rick sent me of a flying Kitfox which had the exhaust he promised to send me had the muffler oriented front to rear.

I would be possibly be flying a 670  today if the exhaust would have been as promised.

I know this is a long and round about way to answer your question.

I assume the Avid 670 install would be upside down as it is with the 582 so the exhaust would not be the same as the Kitfox install.

Rotax Rick is a very friendly and helpful and loaned me the puller to install my RK 400 clutch.

I feel he knows his Rotax engines but something is missing when it comes to the exhaust fitting on the few cases I know of.

Herman

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Posted

Thx for the reply,

I will update after the holiday.

This was a 4 month project with  a A-m-I mechanic and a aviation school involved.

I just wanted to know if anyone has completed a 670 install and exhaust.

Having problems loading the pictures.

Exhaust was mounted side to side.

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Posted

I had a 670 in my Avid MKIV when I originally bought it.  The expansion chamber had been cut, turned and brazed in several placed and it fit inside the cowl (inverted engine) but the muffler was outside the cowl, hung under the plane.  The original ownner had tried the 582 pipe and said the engine didn't run worth a hoot. If you are good at welding or brazing, maybe just plan on having to build your own from a snow machine pipe.

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Posted

Here's Fred Storch's w/ the Siminoni and pipes. Anybody have any experience with the Siminoni? http://avidsimonini.blogspot.fr/?m=1

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Posted

There is over 20 plus hrs installing the pipe on my Avid.

What started out as a 8 hr install,turned into a fitting and welding challenge.

 

Rotax Rick is a super nice person to deal with.

Having Raced karts for many years I new on a 2 stroke engine I would not get the performance out of the 670 with out the tuned pipe.

 

Here are some pictures of my plane and engine.

 

First you can see how low the exhaust sits below the cowl.

 

securedownload-6_zpsa45aace1.jpg

 

Front view

 

securedownload_zps8549ba47.jpg

 

Now 3 views with the cowl off.

 

securedownload-2_zps0fae0524.jpg

 

securedownload-2_zps0fae0524.jpg

 

securedownload-4_zpsf25a375b.jpg

 

During first flight,Got the temp up plane seemed to roll about 3-4 seconds and it was air born.

Had to release back pressure so I could find the horizon.

This will be a great plane once I get it on some amphib floats.

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Posted

A couple more pics.

 

securedownload-5_zpsd0e04cb3.jpg

 

Pic before the install.

IMG_20130614_160852_126_zps8dd81b38.jpg

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Posted

I did not use the oil injection on this engine.

I decided to just add add oil to the wing tanks and just shake the wings to mix.

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Posted

Wonder how your coolant temps will be with no cowl lip and the muffler disrupting the airstream at that point.  Please  keep posting on your experiences with this engine setup.  Quite a few of us are interested in how the 670 works out.  Jim Chuk

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Posted

Jim,

We had to redirect and seal off the radiators to get the temp to stay in range.

I am having the lower cowl enclosed for the reason you stated.

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Posted

Alright Marv, looking good!

:BC:

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Posted

Another picture.

 

securedownload-3_zps371cb04a.jpg

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Posted

One other note,I never got off the phone with Rick that he didn't answer my questions completely. Marv

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Posted

Been along time with this install.

This is what we did to the lower cowl.

As you can tell we have not painted it yet.

IMG952015031095153457810_zps3dhd1lpc.jpg

IMG952015031095153510268_zpsvak78r7j.jpg

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Posted

I just ordered 8.50 x 6.00 22 inch tall Wessler tires and tubes for the plane.

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Posted

With the 670 you push the throttle forward let the tail raise and you are flying.

                              Marv

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Posted

your cowl work looks great .much cleaner. how many hours do you got on your engine now?

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Posted

your cowl work looks great .much cleaner. how many hours do you got on your engine now?

There is now 57 hrs on the 670.

Waiting for spring to put floats on.

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Posted

Did your cooling issues deminish with the cowel extension?

 

My Rotax Rick 670 is being built and I'm more than excited to get her installed into my Avid MkIV. 

 

How many hours have you clocked so far?

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Posted

I have a 670 installed on my KF 4. Mounting the muffler was the most difficult part of the installation. It required cutting and re-welding the "arm" to get it to fit in the cowling. it also required some mounting brackets. 

The work was definitely worth it. The 670 has 70+ hours on it now and is running great. The performance increase over the 582 is remarkable. Flying in CO from a field that is 5288 above sea level in the summer with the 582 is a bit lacking, especially with two guys. With the 670 the climb and speed increase is much much much better. 

The picture below is not my plane but is the reference for how my exhaust is installed. Works very nicely. 

You're going to love the 670 once you get the jetting and prop pitch set correctly. Rick is always pushing to run these engines over rich. That's the only thing I disagree with him on. I have my 670 tuned to be right on at field elevation but remember as we climb up, the mixture will be more rich. Just tune it like a 582 with the next size jet up. I ended up with that and the plug color is a nice light chocolate color, with minimal carbon buildup. The RAVE valves that everyone complains about is not a problem with Rick's engines. He uses the HO spades and they hardly move anyways with the power band we are running the 670 in. Prop it for 6350 ground static. On take off you'll hit 6500 and that's almost perfect. 

 

one last thing, ONLY RUN AMSOIL INTERCEPTOR! it's not that expensive especially if you find an independant amsoil dealer. The cost is 40% less than their stated retail price. 

My buddy became a dealer and re-sells to the 6 guys on the field. He makes enough to cover the dealer fee and we all get awesome oil for a reasonable price. 

image3.jpeg

image1.jpeg

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Posted

Nice report. Thanks.   Lou

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Posted

I like your gearbox sight tube.  Very Cool.  Ingenious..

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Posted

I never ever promised to any of my customers that my custom 618/ 670  exhaust would fit in a Kitfox without some mod to either the exhaust or cowlings. 

There is 6 different Kitfox models & guess what, the exhaust needed for each model is different.  I sell  4 different styles of 670 exhaust systems. 

A side mount, Rear mount, ( Gyro ) a straight & a Kitfox.  Every 618 that was installed in a Kitfox had a re welded exhaust.  Rotax never made a Rear mount style exhaust for the 618 .  Only a side mount exhaust.  Were working right now on modifying the customers 582 exhaust with hopes to see 82 + HP. 

I'm sorry if some misunderstood but I never promised a exhaust that would not require some changes.

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Posted

"CAUTION "  A rich mixture is safe !!!!!  You can not trust a EGT gauge in a RAVE Valve engine.  The only jetting change from a 582 to a 670 is a 15K2 needle set on the second clip from the top & a 180 Main jet.   As for plug colors Chocolate  Brown is NOT LIGHT TAN. That's far to  lean.  Remember the oil is in with the gas . 

Never think you can run a 670 below a 175 main jet.  Rarely on the low end some engines ( 5% ) need the 15E5U needle that leans the low end. 

I want to add one more thing.  Rotax makes 3 different angle Y pipes . ( Manifolds )   Straight, slight angled & a steep angle that has s a cut flange to slide over 1 bolt in each cylinder.  That gives you several options on installing your exhaust.  Keep in mind the 583, 617, 618, 643 & 670 all have interchangeable Y pipes.

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Posted

Another picture.

 

securedownload-3_zps371cb04a.jpg

Huge muffler.  Looks like it would have fit better by turning it around and putting it in a belly pod.     Just a nobody, just sayin...   :.)

I'm thinking of buying a Kitfox with a 670 and I'm still evaluating the pros and cons.

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