K&b super pro

Any run these before? I just got this motor and it's never seen fuel . Gonna try it out sunday .

Ran one on my leecraft with the stock exhaust. Did not run faster than a stock redhead but with the pipe it should be awesome.

The cranks are a bit brittle. We would draw them down and hardly ever had issues after that.

I'm simple what is draw them down ? I hope this set up runs good .i want a novarossi but im a broke ass boat racer

michael faszcza said:

I'm simple what is draw them down ? I hope this set up runs good .i want a novarossi but im a broke ass boat racer

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That Nova Rossi 46 is one Bad Boy. I have had many 7.5cc engines and this Nova Rossi takes the cake by far.

When my racing buddy saw mine he ordered one. Actually I am ordering it for him tonight. He don't use the internet much.

Okay, drawing down a crank is easy. Pull the crank out of your engine and put it into an oven sitting straight up (I use an old toaster oven)

and set it to 450 degrees and let it sit there at that temp for 4-5 hours, don't open the door or don't leave it unattended because that is hot for any toaster oven. Once the time has lapsed, turn the oven off (don't open the door) and just let it cool down on its own. It will draw the rockwell hardness down enough to keep it from snapping the journal off. Why K&B didn't draw the cranks down at their factory is a mystery but they elected to sell them as they were. They knew the cranks were too hard. We snapped a sack full of them before we started drawing them down. We later learned that there was an ugly split among the owners of K&B about that time and a lot of operating capitol was pulled out and was most likely the cause of some of the things that were done that just did not make sense to us.

-Carl

I'll try that in the am but will the crank drop out without yaking bearings with it ? And i would end up using a conventional oven

michael faszcza said:

I'll try that in the am but will the crank drop out without yaking bearings with it ? And i would end up using a conventional oven

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Mike hope your conventional oven is gas. Electric would cost you enough to buy a N/R 46.

With K&B parts you never know if the crank will drop out in your lap or if the bearings have a press fit. K&B's tolerance window was a bit wide at times. If you pull it apart and the lower bearing is press fit, you should just put it back together run it and pray that the crank will hang in there until you need new bearings. If it makes it, just draw it down while you are replacing the bearings. That's what I would do. Its a gamble but it may hold until then. Just don't hang a huge prop on it because that would be playing Rushing Roulette with that situation for sure and if your like me...luck is for everybody else. LOL

If it goes lean while you are running it, well...just be careful not to let that happen or run the tank completely empty.

Ray is right! But I don't pay the power bill. Dang baby that is a high power bill...WOW. LOL

While i am at this point what is a better rod .the dogbone or the aluminum block rod ?

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The dog bone rod will bend if you blow off and take a big gulp of water and the engine will go sick. I have had it happen and I took the engine apart at the pond and did not see it at first because it was so slight and I didn't actually see it until I got it home and took every piece apart and laid it out on my table. I like the fact that it will bend some before it breaks instead of coming through the case but when it does bend it can put you out of a race. The other rod its stronger and most of the time you will find that a fracture will originate from the oil hole on that rod. After a weekend of hard racing you should pull that engine down and inspect the rod with a magnifier around the oil hole. When I used to run the K&B 45 engines, I would replace the rod after a couple of gallons of fuel to keep out as much dead swing as possible. Excessive dead swing will snap the journal off that crank real quick.

Another thing I would recommend to do before you reassemble that engine is to take some fine sandpaper like 400 grit and lightly sand off the sharp edges around and inside that crank window then step sand the edges up to 2000 grit. It only takes a small radius to stop a fracture from originating from sharp edge. The window and journal are where it will most likely fail. Clean it good before loading your bearings and you should be good to go.

I still have so many old K&B engines and parts in my shop I could start a K&B business myself. LOL.

-Carl

Carl Van Houten said:

The dog bone rod will bend if you blow off and take a big gulp of water and the engine will go sick. I have had it happen and I took the engine apart at the pond and did not see it at first because it was so slight and I didn't actually see it until I got it home and took every piece apart and laid it out on my table. I like the fact that it will bend some before it breaks instead of coming through the case but when it does bend it can put you out of a race. The other rod its stronger and most of the time you will find that a fracture will originate from the oil hole on that rod. After a weekend of hard racing you should pull that engine down and inspect the rod with a magnifier around the oil hole. When I used to run the K&B 45 engines, I would replace the rod after a couple of gallons of fuel to keep out as much dead swing as possible. Excessive dead swing will snap the journal off that crank real quick.

Another thing I would recommend to do before you reassemble that engine is to take some fine sandpaper like 400 grit and lightly sand off the sharp edges around and inside that crank window then step sand the edges up to 2000 grit. It only takes a small radius to stop a fracture from originating from sharp edge. The window and journal are where it will most likely fail. Clean it good before loading your bearings and you should be good to go.

I still have so many old K&B engines and parts in my shop I could start a K&B business myself. LOL.

-Carl

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Probably a better chance of you starting a K&B business that MECOA ever producing a 7.5 engine again.

JD

Well it's going back together I'll be testing it saturday .just wanted to say thanks for all the help

Anytime. I had thousands of hours of enjoyment running the K&B outboard. I would get a new engine and take it apart and cut in my timing numbers and match ports and polish the inside of my engines for hours on end. Now, you can buy a Nova Rossi 46 and the moment you pull that engine out of the box, it is already better than anything we used to do to our engines back then. It actually allows you to spend more time testing and enjoying your boat and working on your setup. I would like to see a US manufactured engine come out that could compete with the performance of an "out of the box" Nova Rossi 46 engine. The Nova Rossi is just a beast of an engine.

-Carl

Ron

Give Carl 50 bucks. LOL

Well...I don't look to get $50 bucks from anyone but if I did get some money for saying what is obvious, I would put it towards another back up engine.

Hello Carl just removed my .82 crank from the oven 4-1/2hrs at 470*f standing upright..

David Ashcroft said:

Hello Carl just removed my .82 crank from the oven 4-1/2hrs at 470*f standing upright..

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Now you have done all you can do to avoid the K-Boom factor. I would clean the journal with some 2000 grit paper, wash it, dry it and get that engine back together and get some fuel through it!

-Carl

Drilled the oil passages a tad larger and put a chamfer to the entries.

Anything to help it i guess ha.