i have heard two sides to this connecting rod oil groove deal.

one is to have a .500 WIDE slot in the top and bottom of the main bearing journal machined .010-.012" DEEP.

the other is don't wast your time.

i am going to build my first NON STOCK engine and wondering if this is a must do or not. i was going to do it on my 350 engine and the machine shop laughed when i told them. they said it would not hurt anything but will do nothing for oil flow so i did not do it. i have never had any trouble with this engine. this engine is a very mild build, just a little more than stock. the engine i will be doing now is a 455 with roughly 475 HP + or - and hope to be in the 550 torque range.

also wondering about the oil restrictor issue. is this necessary?

 

this machine shop does have alot of experience with oldsmobile engines. mostly boat 455 engines.

 

I don't care for the slot. It is hard enough to keep up oil pressure when the rod side clearance gets big, and commonly on rebuilding rods the shop will cut .002" from each side of the rod, giving .008" more side clearance per pair. This alone results in a lot of oil leaking out, and I prefer not to cut the sides if I can avoid it. I have been using small cam bearing holes for decades and the newer bearings often come that way already. I don't know if that helps either, though. The restrictors probably come from the realization by suppliers that they can't sell a hole, so they make up restrictors to sell. I like the Melling 22HV pump but also use at least the Toro pan, with the hump flattened, and 7-8 qt. is better. Hope this helps.

 

It was dreamed up by someone who sold rods for a living. A little machine work increased the sales price.

Same guy. Need I say more?

Norm

 

thanks

 

For what it's worth: I am a firm believer in good machining tolerances and the correct parts.

I have never slotted the rods or used oil restrictors.

I use a HV pump, 7 quart pan, and a windage tray.

With blueprinted tolerances, I have 70 PSI cold, 25PSI at hot idle, and 60 PSI at cruise, with 15w-40 oil.

 

Hey;Machining the grooves in the rods would not be to your advantage,you could cross drill the other mains or machine/grind lead-ins. IMO that would be money better spent. If you want even more life out of your crank & brgs have your crank nitrited. Also I think it was Milton who posted an article on those oil restictors a week or two ago. Happy Motoring

 

Good way to weaken a crank.

Norm

 

i thought that cross drilling the crank was a good thing for a high performance engine. i know that some of them are from factory. maybe that is why only some of them are and not all of them. i would have thought that if they could on half of them they could on the rest of them.

 

Hey;Cross drilling the mains is a performance modification & Hi Performance cranks are usually drilled. Olds cross drilled the #1 main along with drilled blind holes(can't remember how many) to recieve and disperse oil. I thought maybe you were looking for some mods that would benefit your crank. As far as cutting the rod journals goes, it is a Hi Performance mod and one I would not recommend.
As far as weakening it,that can be debatted both ways. I have only seen one crank broke in two pieces at the center (main #3) threw the cross drilled oil hole (it was a ford 351W) Happy Motoring

 

Do you?

Norm

 

if i understand cross drilling correctly then number 1, 3, and 5 are cross drilled and the rest are not. please correct me if i am wrong. i don't know everything but my wife said that i come across that way in my typing. she makes fun of me on that and my misspellings and lack of capitol letters.

 

hay, i just noticed that you are talking about the mains. i was talking about the rod journals. i may be way off base. just fill me in.

 

Hey; Only #1 was cross drilled from the factory. Cross drilling is were a hole is drilled threw the main journal intersecting the con rod oil feed hole.
#2,3,4,5 are not cross drilled from the factory. #1 main is the farthest away from the oil pump, that's part of the reason they only drilled #1.

 

My bad : Do not machine any grooves in the ROD journals. Happy Motoring