borna

Hello all,
I need to replace a bronze bearing on the connection rod with needle bearing. What is correct process of doing that? Do you have to press fit the needle bearing?

Thanks
Borna

pe reivers

the needle bearing outer shell is a light press fit in the connecting rod. The press fit influences the needle radial clearance, so ask your bearing supplier first about the needed dimensions. A final play of about 0.01mm would be ideal in my point of view

buck1856

My Feedback: (49)

i just rebuilt my sachs engine and the rod bearing fit into the rod loose.then you put the piston over the rod and you insert the wrist pin or piston pin into the piston and through rod.it should only be a steady snug fit.its the piston pin that takes up the slop in the bearing.if its to tight or snug it will heat up and burn.pe reivrs said it right about the clearance.

KenLambert

My Feedback: (107)

it's simple if you have the right stuff, check out the pics

KenLambert

My Feedback: (107)

pics

Ralphbf

My Feedback: (27)

To replace a bronze bearing on the connection rod with needle bearing, don't you need a hardened
crankshaft journal?

borna

Thanks guys, Finally I'm getting some response on this.
I do have a small lathe and a mill so I'm having all the right tools.

Ken, thanks for the pictures. would you please explain these

1. What procedure you used to take out the bronze bearing? Do you grind it or somehow pushed it out?
2. What is the ID of the connecting rod and what is the OD of the bearing?
3. Is the diameter of the crank pine is same as the ID of the bearing?
4. Did you have to use a light press to fit the bearing inside the connecting rod?
5. Where did you purchase the needle bearing?

I guess to answer the Ralph is you don't need to harden the crankshaft pin as long as you use 10% or more oil in your fuel.

However I want to harden the crank pin so I can use less oil. What procedure do you recommend to do that?
I was thinking to get some Kasenit and do case hardening of the pin?

Thanks
Borna

jpanhalt

Hi Borna,

You have mentioned using Kasenite before for hardening the crank pin and did not get any specific replies to that suggestion. My experience with Kasenite is that you will roughen the surface of the pin and/or change its dimensions enough that it would need to be re-ground before it would work as the inner race for the needle bearings. Also, the heat necessary to get hardening might loosen it, if it is a press fit. I suspect replacing the pin would be a lot easier, but I have not done that myself. John

KenLambert

My Feedback: (107)

drill out the pin and replace it with a hard ground pin the proper size to match the bearing and pin. it takes more than a small lathe and mill to do a precise job , when you bore the rod to fit the bearing you don't wanit to change the stroke or be off center very important fact

borna

ok how about if I don't use Kasenite and just harden the whole crankshaft or atleast of part it? This way I can avoid drill out the pin and replace it with a hard ground pin?

But I guess there is a disadvantage of doing that?

Borna

borna

Hello all,
Just completed the conversion of GMS 120 from Glow to Gas.
also changed the bronze bearing to needle bearing in the connecting rod anf harden the crank Pin.

Next week I will test the engine. Here is the competed picture.

http://www.floridaame.org/discus/mes...tml?1189378581