R/C Tech Forums

R/C Tech Forums (https://www.rctech.net/forum/)
-   Onroad Nitro Engine Zone (https://www.rctech.net/forum/onroad-nitro-engine-zone-71/)
-   -   Liner breakage on .21 engines ? (https://www.rctech.net/forum/onroad-nitro-engine-zone/167581-liner-breakage-21-engines.html)

Spillertwo 06-11-2007 08:44 AM

Liner breakage on .21 engines ?
 
Hello,

I would like your opinion on this problem:

last weekend I broke two liners in half of two different motors. It looks like this
http://i17.photobucket.com/albums/b9...o/IMG_0098.jpg

The engines where a Novarossi 35 Plus 21 and a JP FX 21 R03.

Both engines were in excellent condition.

I never had this happen to me in three years time.

The only fundamental thing I changed was that i ran the Sirio 2013 exhaust on both engines. Normally I run the Novarossi 2052 exhaust all the time.

Do you think the exhaust can cause such breakage ? Because two engines in a couple hours time is a bit far from bad luck.

Or do you know of other reasons why a liner would break in half ?

Best regards

duneland 06-11-2007 09:55 AM

Wow! That is some serious carnage! Can't imagine how the exhaust could be at fault though. Exhaust change would affect tune and powerband, but don't see how it could cause that.

Kemorc 06-11-2007 10:01 AM

woah... so italian mills do break like that too! I've seen one STS sleeve do the same thing.

lance04 06-11-2007 10:10 AM

hmmmmm. is it possible if the sleeve is modded a little bit too much until the sleeve is very thin on certain points? of either that engine was making way too much power hahahahahhhaa

Kemorc 06-11-2007 10:24 AM

dono man! But for some reason the metal weakened... not cool to see on any engine.

Corse-R 06-11-2007 01:22 PM


Originally Posted by Spillertwo (Post 3388090)
The engines where a Novarossi 35 Plus 21 and a JP FX 21 R03.

Both engines were in excellent condition.

I never had this happen to me in three years time.

Uhm.... haven't seen this in many many years, last time I saw this, happened to a 11port .21 engine (was a Cipolla, if my memory serves me good).

Never knew what happens with those ultra-high port engines and the yours (AFAIK, your two engines are 7+2 ports).

I can only aventurate an answer for you, maybe is true, maybe not, but... logical, tells that's possible. Let's see:

On those engines with such high number of ports, the metal thickness between ports is very reduced and suffers a lot the high temperatures, crankcase robs heat from the sleeve, but with such low quantity of metal to transfer the heat, it weakens and after some time it fails by the weakest part, the metal between ports (this is exactly where your sleeves failed).

Many years ago, the port craze finished (8,9,11 and up to 13 ports were available) and until few months, haven't seen a 9 port another time, but seems that old metallurgy problems still predate them.

Could be quicker, could be powerful, but they still suffer the reliability problems like the high competition engines, who have a short but very intense life. I feel so bad for you.

My advice, change them for some 7 port sleeves, maybe will not be so quick, but... will live longer.

Spillertwo 06-11-2007 01:47 PM

Thanks for the advice Corse-R on changing from 9 ports to 7 ports but the problem is that the Novarossi was indeed a 9 port engine but the JP was a 7 port engine.

In defense of your argument though, the JP was a highly tuned 7 port engine so in fact it could be that it was just as weak as the stock 9 port engine.

The thing that keeps me puzzling though is that the engines failed so close together of each other while they are so different. The JP had done only half the mileage of the Novarossi and even the Novarossi hadn't done that much racing. Both engines were only used in national championships and never for simple training. I am afraid it will remain a mystery why they died.

Now I am going to buy the 359 race .21 Plus 2 edition pack. It contains the new 359 race engine and a training engine which also isn't that bad if i hear the rumours.

Hope engine failure leaves me alone in the coming months because if it happens again then the racing season 2007 is over for me. Those things just cost to much money for a non sponsored driver.

One last question though, if you would buy another racing engine today in .21 classe what would you buy (for competing in national championships) ?

Corse-R 06-11-2007 01:56 PM


Originally Posted by Spillertwo (Post 3388681)
Now I am going to buy the 359 race .21 Plus 2 edition pack. It contains the new 359 race engine and a training engine which also isn't that bad if i hear the rumours.

Hope engine failure leaves me alone in the coming months because if it happens again then the racing season 2007 is over for me. Those things just cost to much money for a non sponsored driver.

One last question though, if you would buy another racing engine today in .21 classe what would you buy (for competing in national championships) ?

The Nova 359 is a great engine, but... still a 9 port engine (in fact, the JP Eagle R.9 and this are cousins).

The Ninjas are going very good, are comparatively cheap (if we can use that word on On-Road engines) and they're quick and durable (I have a pair and I'm very satisfied with them). if you have guts and finger to control it, the Mario tuned version will be a serious beast looking what it did with the Off-Road.

On-Road racing is a matter of horsepower, but other things are key for putting that power on the ground (perfect clutch adjustment, clutch and clutch... said you... Clutch? :D ).

Grab somewhat with a true 7 port sleeve.

German Muscle 06-11-2007 03:06 PM

the high port count isnt is whats causing it. something else is. this is the first time ive ever seen a sleeve cracked in half. so you want whats left of the 35 plus 21?

quietstorm76 06-11-2007 04:25 PM

Check the piston for dings, cut, gouges(spelling) etc. I've seen this a few times and everytime the piston caught a port.

wallyedmonds 06-11-2007 05:17 PM

its the pipe.
iv seen this before.

Winner's Circle 06-11-2007 05:38 PM


Originally Posted by Spillertwo (Post 3388090)
Hello,

I would like your opinion on this problem:

last weekend I broke two liners in half of two different motors. It looks like this
http://i17.photobucket.com/albums/b9...o/IMG_0098.jpg

The engines where a Novarossi 35 Plus 21 and a JP FX 21 R03.

Both engines were in excellent condition.

I never had this happen to me in three years time.

The only fundamental thing I changed was that i ran the Sirio 2013 exhaust on both engines. Normally I run the Novarossi 2052 exhaust all the time.

Do you think the exhaust can cause such breakage ? Because two engines in a couple hours time is a bit far from bad luck.


Or do you know of other reasons why a liner would break in half ?

Best regards

I broke two cylinder liners on a 35 plus 21 over a 4 race period. I have no idea why they broke.

M7H 06-12-2007 04:16 AM


Originally Posted by wallyedmonds (Post 3389173)
its the pipe.
iv seen this before.

on a dutch forum where "spillertwo" also raised this question, a remark came about somebody trying a Ninja pipe on his R&B, and engine temp. went up to 150C (300F)

As the Sirio 2013 really works well on the Sirio AAC based engines, like R&B XenonR, this pipe might well be not really suitable for ABC type of engines.......


All times are GMT -7. It is currently 02:46 AM.

Powered By: vBulletin v3.9.3.6
Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.