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Rod bearing question on 390.
Ok, I have clevite 77 CB 760p .010 under bearings, but looking at my old ones, there's a V notch in the each piece and with the new ones, well, they don't have that notch. Obviously the rods have the notch in them too (I guess for oil evacuation/pressure relief? Anyway, what's the story?
Right ones or wrong ones? On the summitracing site I don't see any other 760 .010 model for clevite, sooooo...???? Thanks for the help. |
On the side of the rod cap mating surface I guess? Some rods have a hole in the rod near the top of the big end for squirting oil up into the piston area. Cooling\lubrication...
It is curious as to what the v notch on a 390 is for, perhaps the same thing? |
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Brent: Sounds like the V-notch is to match a rod or cap that has a groove across the parting line for squirting oil on the thrust side of the cylinder wall. If your caps or rods aren't grooved, the V-notched inserts are not needed. If they are and your bearings aren't notched, you can always file a notch in them. Just make sure you chamfer the edges.
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Tom, it sounds like I need them (see my pics above)? Is there a special part # or what?
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Make sure you get the rods facing the right direction when re-installed. Not only for the possible oil squirt effect but because the rod is chamfered on the side the goes against the crank counter weight edge.
Backward installation is known to happen. Initially on my engine build I put the pistons on backwards to the rod. When I got the rod installed right, the piston was wrong! Arrgggghhhhhh, those piston pin spiral locks are a nightmare to install. :LOL: So you gonna file some notches in the bearings? WHOA, does that sound scary or what! :D |
Brett: I'll have to do some research for you. Been out boring holes in the sky this afternoon and heading out to the movies now. I'll check the Ford manual and talk to my BB Ford guru and let you know.
Excaliber: Scary filing notches in bearings? Having massaged a fair number of beairng in race engines, I find it scary only if you don't know what you're doing. With the right info and the right touch, it should be OK.:JEKYLHYDE We'll get the right info and go from there. Later. |
Thanks for the help guys...More the merrier. :)
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Brent -
I don't think those notches have anything to do with oiling....it does seem that those holes are bigger than normal - is there a locating bushing that fits in there? Are those holes larger than the ones on rods that do not have the notches? Pat |
Brent,
The notches were originally put there by FoMoCo for lubricating the cylinder walls and pistons (squirt splash) with the intent to keep them cooler. It was designed to allow oil to be squirted through it if the matching bearings are used. Apparently, some bearing manufacturers decided to stop making them with squirt holes thinking it was not needed. Also, if they are used as original, it could lower oil pressure. Good Luck. :) |
Did you spin a bearing Brent? That cap looks pretty rough....
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It is the elimination of items such as this that are contributing to the flat tappet cam/lifter failures. Some types rods/engines used these notches, some types used squirter holes in the upper half--you need the oil off the big end of the rod to oil the cam/lifter area, distributer gear, and wrist pin bushing/small end of the rod-have any of these situations bitten any of you guys???
Go and read my responce several days ago about flat tappet/cam failure Jerry |
Bearing cap looks OK to me, appears to be just showing the normal markings left from the old rod bearing.
Good point Jerry! I wouldn't worry about loosing oil pressure if indeed that IS a oil squirt hole in the rod. |
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While I've seen rod bearings with "V" notches in the indicated location, the pistons & cylinders also get splash from oil running out from between the rods as the shaft rotates. The larger the gap between the rods (usually .025 max) the more splash. |
I thought you were smart enough to know about the little end hole...
What rods do you have? I haven't seen any with a hole as you describe...just curious. Dan |
Actually Ford decided not to use those little squirter holes anymore and had both major bearing manufacturers eliminate them as a cost savings measure.
Saving a penny per bearing means a lot when you make a few million of them. They were designed to squirt oil into the cylinder for skirt lubrication - - and have nothing to do with cam life. The vast majority of the oil sprayed around the crankcase comes through the rods side clearance area, and it is limited by rod bearing clearance. Testing proved that the squirters were not needed - - they were a leftover concept from the 50's when the original design work was done. Now on a Cup motor they put them back - - in the pan rail... |
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