Clanking noise near oil cooler (AR230HO)

[wajetter]

Split the head from the block.
Head gasket is showing a potential leak spot at cyl 1, which may explain low compression. In addition to valve lash being too tight

 

[wajetter]

Took the crankshaft to a shop that specializes in polishing and grinding. Findings:
- The main of the crankshaft is not exactly straight, the shaft itself is bent.
-Cyl 4 journal diameter is 4/1000 less than #3
- Cyl 4 journal itself is not round, it is oval.
So, looks like a new crankshaft is needed

 

[wajetter]

Ordered a new #4 rod assembly, Green pair of bearings and a crankshaft.
The place I ordered from is Northern Crankshafts in New York. They recommended the Green bearings.


@Brad_Ct have you dealt with matching a new rod to old crankcase and rods with their bearings?

 

[Brad_Ct]

Ordered a new #4 rod assembly, Green pair of bearings and a crankshaft.
The place I ordered from is Northern Crankshafts in New York. They recommended the Green bearings.


@Brad_Ct have you dealt with matching a new rod to old crankcase and rods with their bearings?

I have not and have wondered about the same thing. For some reason Yamaha bearings are by color and would guess that correlates to if they are standard, .010 over etc.. If the place you are buying the crank from recommended green bearings I would think all the rod bearings should be green. I know for main bearings the color is on the outside of the block and they are not always the same, you can have 1 different than the others. When you get the new crank I would measure both the rod and main journals on the old and new one to see if there is a difference between the two. You might also want to use plastigage to verify clearances.

 

[wajetter]

If the place you are buying the crank from recommended green bearings I would think all the rod bearings should be green.

I ordered only the pair of green bearings for #4 ,not others. Sounds like I'll need to buy the plastigauge and measure clearances for all main bearings and all journal bearings.

 

[Brad_Ct]

I ordered only the pair of green bearings for #4 ,not others. Sounds like I'll need to buy the plastigauge and measure clearances for all main bearings and all journal bearings.

If you don’t have one go buy a decent digital micrometer, they are not that expensive and will give you more exact measurement.

 

[wajetter]

If you don’t have one go buy a decent digital micrometer, they are not that expensive and will give you more exact measurement.

I have one from Harbour Freight. But, I have hard trouble trusting it.