How much fuel do you have through yours? I know www.ultimatehobbies.com has the rods but it's not on their website. You may have to call them. $30US.

I have about 2 gallons through mine, but after I spoke to Andrea Rossi from Sirio, he told me is best to change conrod after
break-in, and after measuring conrod bushing and crank pin Diameters I found out I was on the limit of safe play. I posted those measurements somewhere in this thread.
I will contact Ultimate Hobbies, thanks a lot.
AFM

If you buy from Trinity heres their site. Last time I looked they had most sirrio parts.http://www.shopatron.com/index/158

Why Andrea told you the best is to change conrod after break in when he mentioned it's a joke to replace the conrod after break in the Sirio forum????

Author Topic
Salvadori Racing


Brazil
12 Posts
Posted - 04/26/2004 : 05:38:55
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hi andrea,

do you suggest run a conrod only for break-in the engines, once the break-in period put more stress ond this piece???

some drivers here are buying a new conrod separately and running them only when they're breaking in their engines, then they store the conrod and run it only for break in a new rebuild kit or a new engine....

is it worth????

Cesar Salvadori Jr.
SALVADORI RACING

Andrea Rossi


41 Posts
Posted - 04/29/2004 : 14:55:24
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I consider a taking joke of the customers saying that once completed the brake in you must change the conrod.
Probably your friend has had bad experience or has purchased bad quality products.
Make brake in and than run your engine with the same conrod and you won't have any problem.
Ciao

Maybe I did a bad Break-In process, or I had a bad batch conrod (I'm not the only one, ask Uriah Murnan about conrod issues with Sirios).
So in my case it was safer to do so, and after checking my conrod and crank measurements, he was right, I need to replace my conrod.
I would suggest that everybody check their masurements and decide upon them. Every engine is different, and every run condition is also different (fuel, temp, etc.etc.)
AFM

Hi guys, for your records below is the official answer I got from the factory concerning conrod life for the Sirio S12. Also I did measurement to crank pin on a new stock engine and found that it has 4.428mm.
Hope it helps everybody
AFM

"The right play between crank pin and conrod bushing is 0,04 - 0,05 mm. I don't know if you're able to check it, but I suggest you change the conrod every 2-3 hours running.
The life of the conrod depends mainly on the fuel you use, as the lubrification and the right carburation keeps your engine running well for long time."

Regards,

ANDREA ROSSI
Lavorazioni Meccaniche srl
Via Meucci, 3 Seggiano di Pioltello Mi Italy
Tel +39 0292160235 Fax +39 0292160581
Visit our Web Site at :
WWW.STAR-MOTOR.COM

From calculations on my last post about conrod life, according to Sirio factory, one should change the conrod between 0.4756 to 0.7133 galon !!!!!!!

How come??? Well, if a 75cc tank lasts an average of 5 minutes, one makes 12 tanks in 1 hour, which is 900cc. So according to Sirio that says change conrod after 2 to 3 hours running, that means change conrod between 1800cc and 2700cc of fuel. Now if 1 galon has 3,785cc, that means the lifetime of the conrod is less than one galon.

In my case, my engine is over 2 galons, so I'm way past the conrod's life span, which i verified with the measurements of my last post.

So if in a Break-In process one consumes apx. 1000 cc of fuel (about an hour), it souds good to me to change the conrod after it and then get your 2 to 3 hours of safe racing time.
AFM

My evo 2 conrod has .07 mm play after .5 gallon! It was really tight for before break-in so I guess it does take it's toll. I managed to get 2 new s12 con-rods.

Where did you get those conrods??
AFM

After reading a post by Andrea Rossi in the Sirio's web site, this is the correct Break-In procedure for the S12's

1.- One (1) tank in the bench at WOT with very rich setting of HSN, avoiding it to go on 4 stroke.
COOL DOWN
2.- Three (3) tanks on the track with very rich setting of HSN, and tuning the HSN at the end of third tank to get almost full power.
COOL DOWN
He says after that, the engine will give more power after every new tank.
3.- For 20% Nitro, use .20 head shim and N° / Glowplug.

Which means that Break-In should be done with more or less 300 to 500cc of fuel.

AFM

if the con rods are damaged so easily during breakin has any one had a problem out of them after replacing it? i would thing hard core racing would be more punishment than break in. i am lookin at getting a sirio are they good but trouble?

Sirio S12 Evo2 is a great engine, it can race head to head with any of the new Nova based engines, very stable engine, holds high temps, new carb is the best i've seen. The problem with the conrods is that we've been doing a bad Break-In process (to long), using same procedure as with Nova engines. If one follows the procedure i've posted a couple of posts back, shouldn't be any problems, but still beeing a very high revin' engine one should change conrod every 2 to 3 hours running as stated by the factory. Best of all is that price is the most affordable of new crop of engines, and i think that is what you are looking for, by reading your posts on other threads.
Check www.speeedtech.com I thikn it is $190.00
And yes, Break-In puts more strain on engine than racing, because everything is more tight and usually most people do it wrong, four stroking the engine, so you have additional strain on conrod bushing.

AFM

where is the proper break in, you said it was on here?
i want a nova killer i want to be different.

If your budget allows it, and wan't to be different, you can get a Murnan modified Sirio Evo2 at: www.murnanmodified.360k.com
or a Mauro Collari Sirio at www.werskracing.com

AFM