Broken Rod

[Greg Rowe]

I started this topic trying to understand if we all have a rod issue and if so how do we get it to the OS engineering department 

This motors have become expensive to purchase and rebuild. 

This is not to question Rules or violation of  any rules

Greg 

 

[Grimracer]

It would be best to check the fit of the rod bushing to the crank pin.. BEFORE you run it again. Take a 1/8" wide length of note book paper and place it in the rod hole. if you can slide the rod on the crank pin without breaking the paper you should be good to go. if not you will have to clearance the hole in the rod.

One more thing I see in the pic.. is a piston that is VERY stressed. I suspect this could be due to the lower bushing coming apart but i can tell you my 4 year old piston looks nothing like that.

It took me 8 years to break an OS outboard. And when I finally did it was the case that let go. LOL.. No hard feelings for that motor. It won a ton of races!

Grim

 

[SayMikey]

B. Engine Specifications 1. Engines must be standard factory production with a minimum of 100 units available for sale to the general public. To be eligible for the International Regatta the engines must have been offered for sale to the general public not less than ninety (90) days prior to that year's International Regatta. 2. The powerhead and lower unit must be of the same manufacturer and model. 3. The engine external parts shall remain as originally manufactured, but any part from a manufacturer’s outboard may be replaced with any other outboard part for the same size outboard from the same manufacturer, the exception being that slide valve exhaust adapters may not be used with carburetor equipped engines. 4. The following exceptions will be allowed in the Sport Outboard Tunnel specifications: a. Adhesives (loctite), set screws and jam nuts. b. Any carb linkage arms. c. Any motor mount. d. Any glow plug, fuel brand and mixture. e. Any type steering arm.

   All I can say is I spoke with the IMPBA Tech Director this weekend and he asked me about it. His interpretation of the rule is only os outboard parts go in OS outboards,same with K/B

 

[dave roach]

So the OS speed rod is a OS factory part the same rod that is in the OS air cooled engine.# 3 in the IMPBA rules

 

[SayMikey]

So the OS speed rod is a OS factory part the same rod that is in the OS air cooled engine.# 3 in the IMPBA rules

If thats true the rod is ok a RG sleeve not so much

 

[topfuel443]

Except for the key word "external" in the rule #3. RG sleeve is totally legal in IMPBA in my opinion. RG Piston and Sleeve is from the same manufacturer (OS), and its an internal part, so rule #3 doesnt apply. Rules can be so silly. 

Sorry to derail your thread Greg. 

 

[RonShaw]

Here is the latest rod I found broken

i race this stock engine at the SC fall national in October 

View attachment 97643

Greg,

Looks like you were led down the wrong path. There is only one rod available for the OS OB. As usual, Dave leads everyone away from the very people that support this hobby, to eBay, again with misguided info. The 23755020 part number was ALWAYS the part number for the rod only for the Outboard. The 23755024 has always been the part number for the rod and clips for the Speed that included the same rod and clips used in the Outboard engine. A few months ago, OS discontinued the OB rod only offering so the number that includes the clips and rod is the only way it is available. I had OS send me a letter so anyone ordering the new part number would have proof that the new rod/clips part was the OS factory replacement number for the OB as required by NAMBA rules. I had both in stock until the rods ran out, but the 23755024 rod.clips are always in stock on my site, at a price probably lower than what you found on eBay. I have reduced the prices on engines and parts as low or lower than anywhere else you can find them in hopes it helps the tunnel boaters. Thanks. 

https://www.novarossi.us/products/os-stock-outboard-engines-and-parts-new-and-used

 

[RonShaw]

Just so you know,If you go to a national event and get torn down you will be booted if found using internal parts that do not  come in a outboard version of that motor.

Exactly right!!

 

[RonShaw]

Maybe ask Ron Shaw as he deals in OS outboards and has parts.

Brad

Thank you Brad for supporting the local dealer. 

 

[RonShaw]

I have had two stock rod braking in the same place.That's why i use the speed rods

Dave

Same rod Dave. 

 

[Carl Van Houten]

Keep a check on your Dead Swing on your O/S engines. These engines have to turn way up to perform like they should and so a rod that starts showing signs of mileage should be replaced before it becomes an issue.

Info for any new outboard guys: The original O/S outboard engines came with "C" style wrist pin clips and the new engines now come with "G" style wrist pin clips. Both are legal in all events but the "G" style is MUCH easier to deal with. Always wear eye protection when removing these clips as they can put your eye out if they pop out while you are removing or installing them.

-Carl

 

[Andy Greene]

Keep a check on your Dead Swing on your O/S engines. These engines have to turn way up to perform like they should and so a rod that starts showing signs of mileage should be replaced before it becomes an issue.

Info for any new outboard guys: The original O/S outboard engines came with "C" style wrist pin clips and the new engines now come with "G" style wrist pin clips. Both are legal in all events but the "G" style is MUCH easier to deal with. Always wear eye protection when removing these clips as they can put your eye out if they pop out while you are removing or installing them.

-Carl

So for those not in the know of all the things to know  ,  can you elaborate on " dead swing " and how someone goes about checking this Carl ?? 

 

[Carl Van Houten]

Hello Andy,

When I have finished running my engine for the day and after I have flushed it out and oiled it up and also before I put the glow plug back in, I like to take a moment to rotate the flywheel completely through TDC by hand and feel the amount of pinch I have in my piston and sleeve. I am feeling first how hard it is to pass over Top Dead Center and also I like to feel if the piston and liner is developing a long fit or a short fit. I do this to monitor my engines overall fitness as it breaks in and though out its life. Then I like to turn the flywheel up onto TDC and rock the flywheel back and forth to feel the amount of dead swing it has. Dead Swing is the distance the flywheel can rotate back and forth without moving the piston. Everybody has their own amount of tolerable dead swing before it is time to go into the engine and check things out really good. I know some people who disassemble their engine completely every time they run it. I'm just not going to do that...to each his own there. This is just a way to get a general evaluation of  what condition your engine is in without taking it apart. I also like to rotate the piston off of TDC to listen to and feel the bearings. If you do this every time you clean up your engine it can alert you to issues before you have a part failure.

-Carl

 

[Greg Rowe]

Carl thank you for the info this is why i started the thread 

This was to inform us rookies playing with expensive toys and not break them to the point its not fun.

So i believe you answered the rod issues at least for myself

I just wore the internals beyond there useful life

So thank you for the information

Greg

 

[Greg Rowe]

Hi Ron thanks for correcting the rod confusion 

I know i have the correct parts as i purchased them from you last month so i can start fresh for our nitro race in January 

And thanks for keeping the prices affordable.

Hope to see you at a pond somewhere

Thanks Greg Rowe

 

[Charles Perdue]

Judging from the wear marks on the piston and where the cracks are occuring in the rods, you have a crankshaft pin that is not square to the cylinder bore (like the end of the crank pin being tilted down when the crank pin position is at top-dead-center). It is trying to rock the piston front to back in the sleeve, in line with the crankshaft center. Since it cannot do this it is flexing the rod near the big end causing it to crack.

If you keep putting in more rods without changing the crankshaft you will keep breaking the rods.

Also from the severe wear pattern on the piston, you are not getting the performance from this engine that it is capable of because of excessive drag between the piston and cylinder wall caused by this same condition.

Just my 3 cents worth ( It was 2 cents before but we have inflation to compensate for)

Charles

 

[RonShaw]

Hi Ron thanks for correcting the rod confusion 

I know i have the correct parts as i purchased them from you last month so i can start fresh for our nitro race in January 

And thanks for keeping the prices affordable.

Hope to see you at a pond somewhere

Thanks Greg Rowe

Thanks Greg. Glad I could help. Good luck at the race!!!

 

[Carl Van Houten]

Charles could be right. If you hang another rod on that crank It could be a repeat performance if the crank journal is bent. If that were my engine it would be a hand full of cracked and crumbled aluminum and not just a cracked rod and trashed bushing. My luck is not that good. I had a ball in my top end bearing snap in half and drop down into the crankcase and once the crank and rod and piston got finished chewing on it, there was nothing salvageable but the carb, flywheel and PTO housing! It was REAL NASTY...That engine had a brand new piston and sleeve in it too. I had no warning that it was coming. It was just a freak thing I guess. That was quite a while ago and thank goodness I haven't had another issue like that to happen.     

 

[Greg Rowe]

Hi Ron thanks for correcting the rod confusion 

I know i have the correct parts as i purchased them from you last month so i can start fresh for our nitro race in January 

And thanks for keeping the prices affordable.

Hope to see you at a pond somewhere

Thanks Greg Rowe

 

[Greg Rowe]

Thanks guys all the input is helpful

But i have 3 broken rods all in the same place but in 3 different engines.

I will say all 3 were well used 

For me i wii replace the rod when rebuilding from now on 

I also think i will start pulling the pto cover and check the rod after racing

Thanks for the comments