Rods

[AndyBrown]

Do they break or just bend? If they break, is it common, uncommon or almost never??

 

[Mike Menter]

Andy,

The only case I heared of a bent rod was after a boat was stuffed real hard. Did this happen to you??

Mike

 

[Ron Olson]

**** Didn't see the byline. Oops.

 

[Tofastformellow]

they flatten the lower rod needle bearing after a hydrolock. throw crank away.

bend rods are pretty dam severe excersise.

i have seen the hole bottom end shatter cases included

jase

 

[RIGGERMORTISE]

Andy

I broke mine! It was still on the first tank and failed for no reason. The botom end exploded down the straight and sent the rod through the side of the case.

Dave

dead zenoah

 

[Mike T.]

Run one that has had rust damage to the bearing races and the bearing can eventually turn blue and break. All-in-all, rod failures are rare in Zenoahs.

 

[Bob Finn]

I've seen a few bent, and one that blew the bottom end bearing after being run with a bent rod. Owner said it " had never been dunked". LOL

 

[AndyBrown]

I was just curious, because the the Zenoah rod has about 20% less cross sectional area than the CMB 91 rod.

Considering the much larger bore and stroke of the Zenoah and the fact that some of them have been reved to 20,000 rpm, I'm guessing Zenoah is using some very good steel for the rod.

 

[Ken Retallick]

Andy,

The Zenoah rod does bend very easily if hydraulic locked. Having a large heavy flywheel would contribute to this.

Daves Zenoah that broke the rod was most unusual, i checked that engine out and there was no visible reason

for it. Just unlucky.

If you like i can try and find out what material they are using.

Ken

 

[EatMyShortsRacing]

If you like i can try and find out what material they are using.

Ken

I am guessing its steel.....

 

[RIGGERMORTISE]

If you like i can try and find out what material they are using.

Ken

I am guessing its steel.....

:lol: :lol: :lol: :lol: :lol: :lol: :lol: Craigs on cue as usuall! :lol: :lol:

 

[AndyBrown]

If you like i can try and find out what material they are using.

Ken

I am guessing its steel.....

LOL...

 

[Jim Allen]

I was just curious, because the the Zenoah rod has about 20% less cross sectional area than the CMB 91 rod.

Considering the much larger bore and stroke of the Zenoah and the fact that some of them have been reved to 20,000 rpm, I'm guessing Zenoah is using some very good steel for the rod.

Andy,

This case hardened rod (only the bearing ends) will bend or break if run for extended periods of time beyond 20,000, even when the hp is low. The fact that the wrist pin is a long distance down from the piston top doesn't help either. Also the rod is not a true "I" beam section & it is not guided in the upper end. I'm working on modifications now to allow 23,000+ rpm's.

Use with caution!

Jim

 

[Ken Retallick]

If you like i can try and find out what material they are using.

Ken

I am guessing its steel.....

But thats only a guess hey Craig??

The recent ones i have seen are copper plated, similar to CMB/MAC, so it is a carburising or nitriding steel.

 

[gil sonsino]

I'm working on modifications now to allow 23,000+ rpm's.

Wow I would like to see one of "those' screaming on straights.Our max rpm obtained are 17,100 with reliability using a tacometer on a SGX.

Gill

 

[RIGGERMORTISE]

I'm working on modifications now to allow 23,000+ rpm's.

Wow I would like to see one of "those' screaming on straights.Our max rpm obtained are 17,100 with reliability using a tacometer on a SGX.

Gill

Gill

just make sure you have the flywheel well locked on. Most engines that I have seen exceed 17000 tend to loose a flywheel. Maybe the taper is too steep or the flywheels become out of balance at that point.

just my 2c. I would rather get more hp but i prefer nitro so rpm always sounds good.

seeya

Dave

 

[NAMBA860]

i have lost a rod bearing on one and bent a crank on another

 

[gil sonsino]

I'm also a nitro boater but have been testing some Zen on riggers and mono's due to the fast growth of this class in my district.Thanks anyway for your input Dave.

Gill

 

[Scott Schneider]

:huh: Quote: Also the rod is not a true "I" beam section & it is not guided in the upper end.

This part: ... it is not guided in the upper end.

Excuse me, but it very much guided at piston pin end. As a matter of fact, the zenoahs have thrust washers that are on both sides of wrist pin needle bearing, and they run inbetween the piston pin boss's.

This design centers the rod on the crank end bearing journal.

:blink: Scott

 

[Jim Allen]

:huh: Quote: Also the rod is not a true "I" beam section & it is not guided in the upper end.

This part: ... it is not guided in the upper end.

Excuse me, but it very much guided at piston pin end. As a matter of fact, the zenoahs have thrust washers that are on both sides of wrist pin needle bearing, and they run inbetween the piston pin boss's.

This design centers the rod on the crank end bearing journal.

:blink: Scott

Sorry, my error Scott. Forgot about this after taking assembly apart. I guess I,m working on too many things at one time, but I will eliminate the washers & rollers when making the new rod.

Jim