On many of the antique engines I've worked on, lubrication for the top of the connecting rod bearing was accomplished with a simple hole. This allowed the splashed oil to migrate into the bearing.
Would there be any advantage using this technique for a T rod? It seems a couple of small (1/8") holes could be drilled on either side of rod base, close to the "H" section, allowing oil to the top side of the bearing without weakening the rod at all. Thoughts?
I think it would be a good idea. Better than the X rod idea.
The boys at Antique Engines in Escondido do just that. The holes are drilled either side of the H section into the Babbitt. Interestingly the hole appears as a single hole in the Babbitt. :-)
The only problem I can see is rotational force. That would prevent most oil from entering the holes.
Agreed Jason, but just about every old splash oiled engine I've worked on depends on this type of oiling. Almost all of them run within the rpm's of a T engine so with the amount of oil being thrown around in a four cylinder engine, it should be quite dependable.
What about putting the hole in the cap with a dipper? No Xing the rods but just a hole and dipper. That should force oil into the rod at a decent pressure.
Actually, I planned on doing both. Although I managed to set up my lathe to "X" rods in the past, it was a real pain and I'm not totally sold on "Xing" anyway!
I have thought about how a single spiral grove might help oiling. What are your thoughts? I don't like the idea of Xing. Too much surface area removed. But a single spiral groove not so much.
There's another, simpler way. A straight, shallow groove that runs across the bearing but does not go completely to the edge. The groove normally goes in the center, crossing any oil holes, such as where a dipper is. This allows the oil film to be spread across the surface and more or less get "trapped" and do its job.
I've noticed that all of my rods have no "Xing" at all, although I've seen it in other non Ford engines. I see no special grooving techniques mentioned in my Ford literature either. Not saying that it's not a good idea, just maybe overkill for such a simple engine.
During the Teens, 20's, and 30's, hundreds of oil groove patterns were tried, from very conservative, to bearings that looked like Swiss Cheese. It was found that the best pattern is the X Groove system, for a dipper rod.
George, a straight, shallow groove that runs across the bearing but does not go completely to the edge. These are used on Pressure oiling only. The reason they don't work is, it would be air locked, and it needs pressure to keep the well full, and also dirt would build up in the dead end pocket, and would keeping going around with the crank. That is why you also need pressure to keep the pocket flushed out, and clean from dirt.
Holes in the web are not made to pick up oil, but to let oil, and air to escape. With out X Grooves and dippers, web holes are useless. You can't get oil in, as there is oil on the way out.
Some time is 1927, Ford seen the error of his ways. He came out with X Grooved, dipper rods, for Model T's. Also after that all Model A's, and B 's were also Dipper, and X Grooved.
You can't put the right kind of X Grooves in a Model T rod with out boring the rod out for enough depth, or all you will end up with is chicken scratching.
Jason, the only way you can loose bearing surface in a rod is to start shorting the oil to it. The bearing surface of a rod is the oil molecule between the Babbitt and shaft. When the Babbitt touches the shaft, that is when the bearing surface goes. I don't know of a rod burning out for getting to much oil.
Rod cap and hole, with a dipper, would be of very little help, as there is no place to use the dip pressure, without oil grooves.
Chevy like wise started X grooving sometime in 1928, on the 4 cylinders, and from 32 to 36 Chevy used X Grooving, and in 1937 went to a narrower rod and a different groove system, because of the width of rod, but still had oil dippers. Just lately, I have seen a set of rods with X Grooves in the cap only, but all it will do is cut oil capacity.
Before I got rid of all the records we had on rods, we had spun poured well over 33,000 Model T rods. All had deep an wide X grooves, two holes in the web, and one in the cap. They also have broached part lines because of Spinning. We have never, ever gotten one of our rods back for failure, or just a rod core to pour.
The first pictures are 1932, and 1934 Chevys
Then a Model A, Spun Poured.
Then a Spun Poured Model T.
The last two pictures are a Clawson & Bals Spun Poured rod and this has a broached Babbitt hole.
If they come out in order!
It was explained to me today that with the dippers and X'ing the holes at the top sprayed oil up into the piston oiling the wrist pin. The oil being forced thru the rod from the dipper is under pressure and forced out and up.
That's just not true, Mark.
Herm, What is your preferred method for X grooving your rebabbitted rod bearings?
Herm, thanks I was thinking it was not.
Herm, Beautiful work and great information. Thanks, Scott
Herm, I was kind of hoping you'd chime in on this. You removed any doubt on the matter......so I'll be planning on "Xing" my rods after all. So, is the idea of drilling a couple of holes in the top portion a good idea, allowing oil to "flow through", or just losing precious lubrication?
I've always thought that it's kind of interesting that in the case of the Model A Ford, the "dipper" is not a separate piece, but is actually part of the connecting rod casting itself. To me, that's an indication of how important Ford thought "dippers" were, at least during the four-year period of the Model A Ford,....harold
Delete my last question........I just closer at the pics of the T rods and saw that a hole HAD been drilled.
Thanks again everyone!
.....oops,.....meant to say,.....connecting rod CAP casting.