Rod/Crank Clearance Help...

Rod side clearance

I have a new set of Ali rods, 1" wide at b/e, I need to remove .035 to .040" do I remove from one side only.

 

i would chamfered the rod bearings to get clearence,ive never heard anybody cutting on the side of the big end of the rod .

 

Thank you for your reply, I had attended to the bearings. I discovered the prob, when i was checking fitment without bearings ?

 

half on each side..remember the pin boss..if you take for example if you need .030 clearance on rods 1 and 2 take .015 on rod 1 and .015 on rod 2 wich will then give you .030///// but if you take .030 off of rod 1 and the same on rod 2 that will be .060 think!!!!!!!!measure twice cut once

 

Thank you, will do.

 

When you take matarial off the big end of the rod, you are going to throw the balanceing off rember the big end of the rod, 100% of it is used to balance the motor.check to see what the rod whate is before and after so you can get an idea of how many grams you cut off, then you can deside if you want to take a chance.

 

Rotating assembly away for rebalance.......not willing to take that sort of chance.

 

balanceing is soooooo importen

I didn't think you would. smart move, any time you change brands of pistons rods wrist pins grind on crank lightin same you will change the balance of assy. and it's some thing you cant see thats wrong.

 

Thanks guys, this is how machinened the rods, i fitted them into the lathe jaws inside the big end, dti'd them.
Turned the cutting tool tip to cut on the side edge, not the tip nose, spun at approx 850 rpm & used the auto crossfeed.

I micrometered each one and took .030 off the inside edge.

On the last one I took .015 off both sides & reset the radius on the rod, for this one I machineed up an alumimuim(N Z) mandrel, drilled a hole to accept the cap dowel, bolted the rod to this, dti'd the face and used auto crossfeed.

To put a radius on the bearings to ensure plenty of clearance for the large radius on the crank, I used an old ali rod machineed a lip on the inside face, so as to hold it in the lathe jaws easier, and cut at 30 degrees.

Bench checked all and as of date still awaiting for balance to be completed.

Cheers all and thank you again for your advice, needless to say i was initially nervous about touching them.