Inliners International Forums General Discussion MOPAR Flathead crankshaft crossdrilling?

How do you crossdrill a 230 crankshaft? Where do the new holes go? I'm having trouble visualizing where the new holes go, does anyone have a diagram or something that I could look at?Is this something I can do on my own? Thanks.

-Jeff

I have a 230 that has been cross drilled. I had a machinist do it for me. I do not remember exactly how he did it. The crank has to be cross drilled at the #2 and #3 mains. Those mains has to supply oil to 2 rods each, where #1 and #4 only supply one rod each. This is why most all rod burn out's occur at 2,3,4,5 rod bearings. I do remember that there are 2 holes in the crank passing the main hole to supply oil to those rods. I also remember that the holes in the main bearings don't align well with the hole in the block. They need to be matched up to get full flow of oil. The oil groove in the main bearings are very shallow. They need to be made wider and deeper. My engine holds over 80 lbs. of oil pressure. It will turn 6000 rpm's with no problem. It has been running 5 years now and is showings no signs of wear. Checked rod bearing after the first couple of years. They showed no signs of wear.
Hope this helps.

it sure does!

I'm still confused.... I see that the #2 and 3 mains have 2 holes each(to rods 2&3, and 4&5 respectivly). Where does the cross drilling go, or which oil passages does it connect? THanks.

-Jeff

The best I remember, the two holes in the crank at the main journal are drilled so the two holes suppling the rods are connected. That way when either hole (rod holes) pass the main hole oil is supplied to both rods at the same time. You do not drill any new holes in the crank. You drill through the existing holes at an angle so that it will exit into the other rod hole. You are just creating a new passage way between the rod holes. Hope this helps.

That helps a great deal. I get it now. Thanks Hud I.

Hey Pa,

You forgot to tell him about enlarging the oil grooves in the main bearings to help increase the flow to the newly crossdrilled ports.

We've got a real bad habit of not drawing out or keeping notes on such things as the crank cross-drilling. I think we take a "let's see how this works" attitude and once its buttoned up and works well, we're happy!

I think Hud I (my Dad) will declare - We're HAPPY with the crossdrilling!

Hudson

Well, I'm afraid I'm a little confused about it... is there any chance of a diagram?

I've been looking into this and I think I'm going to slightly enlarge the oil passages to the #2 and #3 main journals and groove all mains on the crank on top of cross-drilling it. I may add grooves to all the cam journals too after hearing about similar problems with it. I still, of course, need to find an engine...