Rod bearings, man I suck

858 Views 9 Replies 7 Participants Last post by curtisfox, 3 mo ago

Eric2.0

Discussion Starter · 3 mo ago

I finally got a rod and piston to put on this engine. I took out the other piston and rod to check bearing and journal condition. On the rod where the hell is the bearing? This is the rod that did not break, so the bearing has to be there, am I seeing things? It doesn't look like a Bearing on there.

Also are the rods and Pistons loyal to a side of the engine? Aka a left and right side. Plus my new piston has a number 2 inside it and both my old Pistons say number 1. New piston seems to be exactly like my old ones.... This is a learning experience, but fun. Pictures...

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scottlcy

· #2 · 3 mo ago

Eric2.0 said:
I finally got a rod and piston to put on this engine. I took out the other piston and rod to check bearing and journal condition. On the rod where the hell is the bearing? This is the rod that did not break, so the bearing has to be there, am I seeing things? It doesn't look like a Bearing on there.

Also are the rods and Pistons loyal to a side of the engine? Aka a left and right side. Plus my new piston has a number 2 inside it and both my old Pistons say number 1. New piston seems to be exactly like my old ones.... This is a learning experience, but fun. Pictures...
View attachment 128803

They don’t have rod bearings in a b or p engine.

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Eric2.0

Discussion Starter · #3 · 3 mo ago

Well

scottlcy said:
They don’t have rod bearings in a b or p engine.

That's a hell of a deal. The replacement rod I have has black scuffs and I can feel with my finger so it is either gouged or deposited on it. Hopefully just burnt oil spots. I hope it measures out in spec.

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Eric2.0

Discussion Starter · #4 · 3 mo ago

Well I decided to wrap this project up, I'm just not an engine guy, can't seem to figure out a micrometer, always wondering if they are accurate, am I doing it right ect ect. I didn't even mark the rod caps or take note of the orientation in the block.

I'm taking it all to a local engine shop so they can use it for parts for customers. I'm just lucky I don't have a ton of money I to this. Oh well. Goodbye Onan.

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Jancoe

· #5 · 3 mo ago

Regardless, that tractor is a good candidate for a repower. Why not try to source a used running onan to put into it?

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scottlcy

· #6 · 3 mo ago

Eric2.0 said:
Well I decided to wrap this project up, I'm just not an engine guy, can't seem to figure out a micrometer, always wondering if they are accurate, am I doing it right ect ect. I didn't even mark the rod caps or take note of the orientation in the block.

I'm taking it all to a local engine shop so they can use it for parts for customers. I'm just lucky I don't have a ton of money I to this. Oh well. Goodbye Onan.
View attachment 128808
View attachment 128807

I believe you’re over thinking it, it’s not a race car engine. Just put back together with what you got.

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k0jdd

· #7 · 3 mo ago

scottlcy said:
I believe you’re over thinking it, it’s not a race car engine. Just put back together with what you got.

^^^^
This.

The worst that can happen is it still doesn't run and then you proceed with the plan to give it away.

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Harry

· #8 · 3 mo ago

Evan, if at first you don’t succeed try try again. I agree with the others in your predicament. Take your time refer to the manuals on settings and ask questions here on the forum. I remember a few years ago during the winter I rebuilt a Onan CCK. I called Boomer once when I got stuck on something that he sorted out for me. But I can distinctly remember cranking this engine over and it immediately started and it purred like a kitten. What a great feeling of accomplishment and I believe you can get that feeling too. ✌ Harry

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DDudeinar

· #9 · 3 mo ago

Eric2.0 said:
Well

That's a hell of a deal. The replacement rod I have has black scuffs and I can feel with my finger so it is either gouged or deposited on it. Hopefully just burnt oil spots. I hope it measures out in spec.
View attachment 128804

I wouldn't worry too much about a few grooves in the bearing surface like that. I had a crankshaft resurfaced and ground .020 under on one journal and it still had some pits. Gentleman that did it is about 20 years older than dirt and had enough tools and experience to hand build his own engine from billet. I asked him about the grooves left in the journal and he looked at me and said "Do they stick out?" I said "No?" He said "Then it'll just be another spot to hold oil..." he kinda shrugged when he said that and moved on. This was on a much higher tolerance diesel, small engines like this Onan are far more forgiving.

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curtisfox

· #10 · 3 mo ago

DDudeinar said:
I wouldn't worry too much about a few grooves in the bearing surface like that. I had a crankshaft resurfaced and ground .020 under on one journal and it still had some pits. Gentleman that did it is about 20 years older than dirt and had enough tools and experience to hand build his own engine from billet. I asked him about the grooves left in the journal and he looked at me and said "Do they stick out?" I said "No?" He said "Then it'll just be another spot to hold oil..." he kinda shrugged when he said that and moved on. This was on a much higher tolerance diesel, small engines like this Onan are far more forgiving.

This is so true! When I was a kid( small Briggs on a motor bike sized). I took it all apart and filed all the high spots ( didn't have the money for another engine) That thing ran forever it seemed.........Curt

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