04-07-2021, 05:47 AM | #21 |
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Re: Oil grooves
What myth? I posted a copy of both the cap and the block from the original Ford blueprints. It clearly shows that Ford engineers specified there are oil grooves.
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04-07-2021, 08:03 AM | #22 |
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Re: Oil grooves
Hello Henk:
Since no one has responded to your question here are actual pictures of what correct grooves should look like. This is correct babbitt also ,no lead. Most likely rebuilder didn't have tools to cut the grooves. http://www.jandm-machine.com/rebabbitting.html Last edited by J and M Machine; 04-11-2021 at 01:32 PM. |
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04-07-2021, 01:00 PM | #23 |
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Re: Oil grooves
Gentlemen,
Thank you for all the help ! Much appreciate it ! I now know how the grooves should run and their size, thanks to Brent. I would like to talk about oil grooves a little more, but my writing is interrupted all the time ‘cause this website makes me log in when I am ready to send and I then loose my writing. Annoying !
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04-07-2021, 01:08 PM | #24 |
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Re: Oil grooves
Now what I would like to add is some theory of flow mechanics. Everybody knows the phenonemum of aqua planing I guess. A function of car weight, speed, tire size, water film thickness and GROOVES. You would want to install slicks if you had a desire to end up in the ditch.
This is what happens in your babbitt bearings !
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04-07-2021, 01:14 PM | #25 |
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Re: Oil grooves
Oil pressure builds up in your bearing. To accommodate this, the babbitt is not finished very smooth ! It has a certain RMS roughness. The oil film will be a function of crank revolutions, roughness of the babbitt, bearing clearance and leakage ... (leakage is what grooved tires do !).
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04-07-2021, 01:23 PM | #26 |
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Re: Oil grooves
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I do not know what Ford engineers were thinking switching from the ungrooved Model T to the Model A, but it doesn’t make any sense to me. I would never cut grooves in the lower part of the bearing, the place where you want pressure to build up ! Maybe, for the sake of oil supply, I can imagine people wanting to cut an annular half a circle running from the oil entry point to the wells, but that’s it ! On the other hand Ford prescribed sufficient radial clearance for the oil to freely flow to the wells from the entry point. Not cutting grooves seems like a serious option ... Henk The Netherlands
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04-07-2021, 01:57 PM | #27 |
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Re: Oil grooves
Brent,
I hope I haven’t offended you ! Myth to me means the thinking within Ford engineering late 20-ies. NOT your valuable documentation ! Henk
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04-07-2021, 03:56 PM | #28 |
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Re: Oil grooves
Henk, To answer your question the block half of the bearings use a short longitudinal groove from the oil hole. This distributes oil across the face of the bearing. This works well, it just may be different than what others do. The oil creates an oil film and oil pressure from the molecules rolling over each other. Rick.
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04-07-2021, 04:19 PM | #29 |
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Re: Oil grooves
DO not compromise the oil system by NOT having the grooves to spec. Believe me not having oil grooves as designed will cause issues with wear and premature failure. Oil's function is to remove heat and separate the parts. This is irrespective of the oil system being pressurized, splash lube , gravity system, etc. If the engine rebuilder forgot the grooves he is obliged to make it correct -or- explain why the engine will run without the grooves. Much money was spent on the re-build I am sure.
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04-08-2021, 04:29 AM | #30 | |
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Re: Oil grooves
Quote:
Thx again. Hdnk
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04-08-2021, 04:48 AM | #31 | |
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Re: Oil grooves
Quote:
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04-08-2021, 04:57 AM | #32 |
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Re: Oil grooves
Rick,
The rebuilder also out felt in the groove holding the oilslinger. How do I get that out of the upper part of the bearing end with the crakshaft still in place ? Any ideas ? Henk
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04-08-2021, 07:37 AM | #33 | |
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Re: Oil grooves
Additional info added since original posting:
Quote:
I would try this old time idea normally used for installing rope seals. 1. I think that it should work to remove old FELT seal also by lowering crank and pushing out old felt then grab felt with puller... NOTE: Try pushing the seal BEFORE lowering crankshaft. With some luck the felt will not be glued into groove. 2. Or try screwing "cork Screw wire" into the felt and then pull out the felt seal. https://www.napaonline.com/en/p/BK_7...ABEgJIffD_BwE& Last edited by Benson; 04-08-2021 at 08:18 AM. |
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04-08-2021, 07:46 AM | #34 |
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Re: Oil grooves
Journal bearings work on the hydrodynamic principle, a fixed constant at .001 oil clearance per inch of shaft diameter...10 inch shaft? 10 thousandths clearance. With the hydrodynamic principal applied the journal basically floats on oil.As you can see by the illustration a certain amount of pressure is created when the principal is applied, providing oil flow through the bearing.
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04-08-2021, 08:03 AM | #35 | |
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Re: Oil grooves
Quote:
Additionally, I feel by using wells on either side at the parting line, you have the ability to have a reservoir of oil on both sides and the diagonal groove allows for the oil to contact the pin in more areas providing a greater amount of lubrication. How much additional longevity 'one would see between the two methods would be very difficult to determine. |
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04-08-2021, 08:09 AM | #36 |
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Re: Oil grooves
I have an engine that was rebuilt by Richard (Rick) Knight back when he was still doing that work and it is a terrific, great running engine. He had a very good reputation as an engine rebuilder "back in the day." YMMV
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04-08-2021, 10:02 AM | #37 |
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Re: Oil grooves
Thank you Boston Bruce. Rick.
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04-08-2021, 10:27 AM | #38 |
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Re: Oil grooves
Brent, It is not an "idea" it is a fact. I had my shop from the early70's until around 2000. I used hundreds of rods with circular annular grooves and babbitted and align bore hundreds of blocks with what I have described. Back when engine oil was more like road tar the grooves and oil wells served an important part of lubricating the bearings. If you look at the design of bearings and fluid dynamics and modern oil all those grooves are not such a good idea. It is not a maybe it will work, it does work and work well. Breaking up the oil film is not what you want to do. I am just saying bearing design and engine oil have progressed some since the 20'-30's. I worked on all kinds of engines from dirt track racers to indy and saw the evolution of oiling syste's first hand. If you machine for oil clearance and supply oil it will support the journal, it just does. I think what you do is just wonderful. You are lucky to have the KR Wilson tools. I came at this from a little different perspective. Rick.
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04-08-2021, 12:40 PM | #39 |
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Re: Oil grooves
Since I started this thread, I’d like to thank everybody for their contributions ! This may change the way of thinking about Model A Bearings, which is good. The original design - being a purist I hate to say this - Is not conform hydrodynamic theory ! Whatever you do, after rebabbitting and alingboring, LEAVE THE LOWER CAP ALONE !
Henk
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04-08-2021, 03:41 PM | #40 | |
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Re: Oil grooves
Quote:
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