Oil grooves
 

My engine rebuilder ‘forgot’ to put oil grooves after lineboring the mains. Maybe he forgot to do the big end bearings as well.
Who’s got a picture of the right grooves ?

Henk

Re: Oil grooves
 

Henk, while that might seem catastrophic, the bigger thing to check is to make sure the well was cut at the parting lines first. FWIW, many engines with cast bearings during that era did not use oil transfer grooves.

Personally I use the KR Wilson groove cutters which automatically cut using the cap bolt holes as the datum. I have included two segments of factory prints on a PDF below that will show you the basics of how they should look. Hopefully this will help you.

.

Re: Oil grooves
 

Brent, thanks for sending the drawings ! Do you have ‘m for the middle and front mains also ? And, if it’s not too much trouble ... the big end bearings ?

Going through the trouble of pulling the engine in a - what I believed - freshly restored car, is urging to do things right this time.

Is there any proof early bearings didn’t have grooves (my engine is early 29) ? The engine ran about three hours and I can spot some wear already (the shiny spots).
What would you do ? Put grooves in or not ?

Thx for the help,

Henk
For about three hours in total

Re: Oil grooves
 

Re: Oil grooves
 

What I would do is not fair to ask because it would be a simple fix for me since I already have the tooling. Using a micro-grinder and a carbide bur is very tedious, so that changes the game totally IMO.

As for spotting wear, in all liklihood, the bearings were not burnished when the crankshaft was being fitted, so high spots are likely to be found, and that is what you are seeing being worn. Also remember, when the carbide bur is cutting the bearing, it will make the edges be proud anyway so I would recommend if you are going to cut them, you also run the engine on a stand to wear the high areas and then re-clearance the bearings prior to installation in the vehicle.


Bob, I don't think so. The prints that I have all show the same one-direction pattern, ...and if you use the tool such as the KR Wilson to cut them, it only cuts in the one direction. I also have some pouring mandrels that have the shape made into the mandrel so when the bearing is cast, it will form the groove for you during the casting process.

Feel free to give me your opinion too on the grooves, but I am of the mindset where the grooves are only there to refill the wells on each side mostly when the engine is not operating, ...and it is the micro-scratches on the journal pins that actually catch as it enters thru the drain tube and then disperses that oil around the bearing while the crankshaft is rotating. Naturally I am certain that the crankshaft pin picks up some oil from the grooves as it rotates, but I'm not sure how much.

Re: Oil grooves
 

Brent,

Should I send the engine to you ? Or should I refund your ticket to Holland Bringing the Wilson tool ?

Henk

Re: Oil grooves
 

The block picture may not be the best it's original babbitt
The caps are NOS, what you would get at the dealer if you were pouring the mains, the factory put the oil wells in already
When I had my engine apart in the 80s I found the rear main crumbled at 3000 miles, there were 2 other people that had the same place do their shortblock they had not been put in the car yet so we had a look ,the first one had oil grooves and wells but the wadding was still in the pipes blocking any oil from the valve chamber the second engine they hadn't even bothered with even drilling the holes let alone oil wells and grooves

Re: Oil grooves
 

Re: Oil grooves
 

The oil grooves are necessary for the oil to remove the heat. Oil serves two purposes: Removng heat; keep the parts separated via an oil film.

Re: Oil grooves
 

While oil does remove heat, it also has to have a pathway to get an even film of oil to all of the bearing surfaces otherwise it will take the path of least resistance and likely neglect a portion of the surfaces causing uneven wear.

The basic model A engine predated designs that started to use engine oil to actually help cool the engine with oil around the exhaust valves and other parts of the top end. The engines that superseded the model A finally started using oil pressure in places that needed it more rather than just gravity flow from the valve chamber.

Re: Oil grooves
 

I would agree with that. I am not sure the quantity of oil flow with a gravity system is sufficient to actually carry away heat without being heated itself.

Re: Oil grooves
 

Hi Henk, Have you considered that maybe he did not "forget" the oil grooves? Do you have any pictures you could post. Rick.

Re: Oil grooves
 

Richard,

I could take pictures of the rear main cap as well as the font cap. But, there is nothing to see ... just Babbitt, no grooves at all. What’s your thought in saying ‘maybe he didn’t forget ...’ ?

Henk

Re: Oil grooves
 

My answer may cause some heads to explode ! I did hundreds of Babbitt and align bore jobs with no grooves in the caps. If those bearings where align bored and there is clearance the oil will go there. I hit submit with trepidation. Rick.

Re: Oil grooves
 

I recently dismantled a B engine after 40,000 miles of use by the former owner. It had no grooves whatsoever, but it did have the oil wells at the parting lines. Keep in mind that the
Model B had pressure to the main bearings so maybe the grooves were not so critical. Any comments?

Re: Oil grooves
 

I’ve said this same thing before and was immediately dismissed and attacked by the “experts”. The oil grooves are not needed.

A lot of industrial engines run splash oiling, have higher compression, run all day long at 3600 rpm, and usually don’t even have rod bearings. They run aluminum rods right on the crankshaft, and do not have grooves. If an engine is setup properly, grooves aren’t needed.

Re: Oil grooves
 

Does not matter A or B it works just fine. I did not use the X grooves in the rods either. I bought rods from Pauls Rods in St Louis. I had him put annular grooves in my rods. He liked the idea but felt his customers would not go for it. Anyone who studies the history and evolution on Plain bearings might come to the same conclusions. An article in Scientific American got me thinking about this and reading Federal Mogul and Maquay Norris bearing books and working on hundreds of engines from 1910 EMF factory race car to fairly modern engines. My own souped up B engine had NO shims, no grooves. Still going strong in Texas. I was not lucky enough to find and buy any Ford tools. My Father and I had the shop. We made our own molds and I used a Kwik way Line Boring bar that was made for Ford blocks. The rails and bar was marked for A, B and V8. I had the alignment fixtures that use the bolt hole to line the bar and it worked every time. I had a very complete Automotive machine shop including Crankshaft grinding. Rick.

Re: Oil grooves
 

To Henk, I would rethink the "Machinist forgot the oil groove" thing. Go find the machinist and talk to him. Rick.

Re: Oil grooves
 

Rick,

Now I am the one really getting nervous. It makes perfect sense to me if there were no oil grooves in the caps ! The wells themselves will take care of the oil distribution into the lower cap won’t they ? I can live with that.
What about the uppers parts of the crankshaft bearings ? Did they have grooves ? Or is that a myth too ?

Please don’t leave me alone on this subject ! I really need help in determining what to do ... can’t sleep at night !

Henk
The Netherlands

Re: Oil grooves
 

The worst that can happen is that is explodes into a thousand pieces at an inoppertune time.