Rod side clearance oil squirting?

[miniv8]

Does grooving the connecting rod big end work for directing oil at the underside of the piston?

[PackardV8]

Does grooving the connecting rod big end work for directing oil at the underside of the piston?

Several of the '50s US OHV8s were built that way. How much oil got up to the bottom of the piston is questionable.

[Krooser]

Most modern US V-8's no longer have a "squirt hole" in the connecting rod... simple splash lubrication for the pistons.

[modok]

yes grooving the side fo the rod works to direct more of the oil spray towards the piston.
More than half of engines manufacturers have used this feature. honda, porsche, VW subaru, ect, ect
If it didn't work it would be a heck of a funny myth.

[Kevin Johnson]

Honda even used two per side.

[Geoff2]

I have been grinding three per side, for decades.

[mag2555]

Are you having wrist pin issue or looking to cool the piston better for pumping in boost?

[ptuomov]

The “nozzle” geometry is such that the rod side slots are much more likely to be oiling bore walls, not cooling pistons. The piston cooling oil spray needs a relatively narrow spray pattern and high flow rate.

[Kevin Johnson]

The “nozzle” geometry is such that the rod side slots are much more likely to be oiling bore walls, not cooling pistons. The piston cooling oil spray needs a relatively narrow spray pattern and high flow rate.

The same quantity of oil is being released from the bearing margins regardless. The slot(s) simply change the probability of where the droplets will land in order to do something more useful.

The Honda rod above (NA B-series) also used oil squirters for each piston. Jon Schmidt worked for Honda Performance Development and can attest that Honda empirically carefully checked modifications to engines on dynos thereby generating railcars of cores.

[ptuomov]

The “nozzle” geometry is such that the rod side slots are much more likely to be oiling bore walls, not cooling pistons. The piston cooling oil spray needs a relatively narrow spray pattern and high flow rate.

The same quantity of oil is being released from the bearing margins regardless. The slot(s) simply change the probability of where the droplets will land in order to do something more useful.

The Honda rod above (NA B-series) also used oil squirters for each piston. Jon Schmidt worked for Honda Performance Development and can attest that Honda empirically carefully checked modifications to engines on dynos thereby generating railcars of cores.

Understanding whether those slots spray the piston bottom or more broadly the bore wall is important to understand if hotrodding an existing engine. There are engines that have too much oil on the bore walls and have too little piston cooling. For those engines, I believe, a hotrodder cutting slots like this would be counterproductive.

[Kevin Johnson]

I think the hot rodder needs to carefully study the design and execution of the slots. Haphazard attention to detail will yield haphazard results. Below are two Honda piston and rod assemblies. In "a" the oil is aimed under the piston; in "b" it is sprayed on the cylinder walls.

honda a.jpg

honda b.jpg

[ptuomov]

I think the hot rodder needs to carefully study the design and execution of the slots. Haphazard attention to detail will yield haphazard results. Below are two Honda piston and rod assemblies. In "a" the oil is aimed under the piston; in "b" it is sprayed on the cylinder walls.

honda a.jpg
honda b.jpg

I believe that both of those slots will spray mostly cylinder walls (especially in a wet-sump engine) and such slots would be counterproductive in any engine that has oil control problems due to too much oil on the bore walls. The basis of this belief is the area vs. length of the slots as well as a guess of the flow rate out of the bearings.

[Kevin Johnson]

I think the hot rodder needs to carefully study the design and execution of the slots. Haphazard attention to detail will yield haphazard results. Below are two Honda piston and rod assemblies. In "a" the oil is aimed under the piston; in "b" it is sprayed on the cylinder walls.

honda a.jpg
honda b.jpg

I believe that both of those slots will spray mostly cylinder walls (especially in a wet-sump engine) and such slots would be counterproductive in any engine that has oil control problems due to too much oil on the bore walls. The basis of this belief is the area vs. length of the slots as well as a guess of the flow rate out of the bearings.

You need to look more closely at the slots themselves. One set has straight boundary walls and the other curved. If you are viewing them on a cell phone you will need to expand/magnify the image.

[ptuomov]

You need to look more closely at the slots themselves. One set has straight boundary walls and the other curved. If you are viewing them on a cell phone you will need to expand/magnify the image.

Both slots are too short and have too much area to produce anything else other than a general oil spraying mess, I think.

[miniv8]

Are you having wrist pin issue or looking to cool the piston better for pumping in boost?

No issues yet, but it is a low rpm deal with high boost, which is new for me.
Since we are spraying oil everywhere, I thought we might as well make a better use of it.

Looks like a good interesting topic, thanks everyone for your input.