MTFCA Forum

I have never been able to get the search function to work on this website, so if this question has been asked and answered a million times already, make it a million and one!
The friend's Coupe engine with the piston problems has what appears to be almost new rod bearing Babbitt. Hurray! Something done right on this car - finally! Someone has also drilled the rod caps for oil dippers/scoopers. The hole is already through the cap and the Babbitt, so I'll have to stay with the dippers. But - the hole in the cap is only 1/8" and the one in the top of the rod that goes down through the rod's Babbitt is only 7/64". These both seem rather small to do much good, especially the rod cap's 1/8" hole, the one that does all the scooping. I should think it would need to be larger. It is chamfered, but seems too small to do much good. I also would have drilled the hole at an angle to take advantage of the dipper's angled inlet. The caps on these pistons are drilled vertically. Oh, well. Too late now to change. 'Gotta live with it.
The question: Would it be advisable to open up the cap's 1/8" hole to the next size larger or is it too risky with negligible gain? If the consensus is to enlarge that hole, should I drill through the Babbitt down through the cap to avoid chipping the bearing material?
Marshall

Don't mess with the rod holes leave them as is. the caps can be drilled a little larger from the out side and chamfer the babbitt with a much larger drill bitt by hand.

Holes in the cap, or web, and a Dipper will do no good, unless the rod has a X Groove System.

The holes in the web should be 3/16, and drilled on both sides of the web.

The cap should be drilled with 3/16 hole, and not over 1/4.

With out the X Groove, oil can not enter the bearing. It would be like trying to put water in an up side down grass, until you relieve the pressure in the glass, to make it flow through.

The dark rod is a spun poured rod of about 1930, from the clawson & Bals Co. The gold rod is one of ours we took to swap meets.

Herm.

Thanks, guys! Need X-grooves in the Babbitt in order to make the dippers functional? I was afraid of that, Herm. Nice work on your rods! Too bad you didn't do this engine. I'd sure like to find the numbskull who did: 0.020" valve clearances, loose as a goose rods with UNADJUSTED 1/8" stacks of shims, oddball aftermarket pistons with rings that can't be found, etc. And the thing still ran smoothly, just no power.
Marshall

I have pulled down engines with odd pistons in them, you have to remember at one time nothing was availible, I have seen plenty of Ford 292 or 312 piston in them that may be what you have. Hope this helps.