Connecting Rod and Bearing Oil Holes

[joelittel]

Aren't there supposed to be oil holes in the connecting rods?

My Brooklands shop manual (image #187) says that it is very important to line up the holes in the connecting rod with the holes in the bearing...

The rods say FIAT on them. Could they be from something other than a Spider?

[131lover]

These rods you have are from a much newer Fiat TC, probably Fiat Croma Turbo, Lancia Delta Turbo, the turbo models didn't have oil holes in the rods, they had oil squirts from the side of the block bottom!

You can have a machine shop drill them.for you and use them, they are a much stronger rod than the old bolt and nut,perfect for performance engine, there are ARP rod bolts available for these rods..

[joelittel]

Is drilling them necessary? I've noticed some bearings being sold no longer have the oil holes so I'm wondering if I need to worry about the oil holes in my connecting rods.

[vandor]

Not absolutely necessary. I've seen racers have conrods custom made and not have the oil spray holes.

[131lover]

I think that our Tc's are old and not so common in competition/performance anymore so all aftermarket rods and bearings are targeted for more common and newer TC's like Lancia Delta Turbos and Fiats never Turbo models now day's ..

I don't disagree it wont work because I haven't tried without rod holes but I know Fiat didn't do thing's without knowing it was needed for some reason!

No offense Csaba, I know you have tons of experience with Fiats and have far more knowledge of Fiats than me but It would be nice to have some confirmation/feedback from a racer who used the rods without holes for a few seasons!
I intend to use the Croma IE 2l rods who is the same as above turbo rod but with OE rod bearing oil holes in my engine, as far as I know all non turbo Cromas have holes in the rod until Croma mk1 was discontinued in late nineties...

More inputs in this topic needed, someone who actually tried without oil holes and have any experience please!!
Csaba: Don't you know anyone who tried it?

[Ramzi]

Ask the Wizard (Guy Croft). He will tell you the same.

[timinator]

Oil holes positioned to cool the piston are always a good idea for engines with higher rpm use or forced induction. The holes are a pain to drill and long ago people found it is much simpler to add a notch or two to the cheek of the big end of the rod. If you are only asking your engine to put out a stock "smog engine" level of power then don't bother unless you live in the desert south west or have ac. Fiat most likely stopped drilling them to save on machining cost.

I don't build race engines for my customers or myself without some type of piston cooling so I can't say from experience that it does not work. I just don't know of any performance engine that does not use piston cooling.

[fiatfactory]

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[timinator]

[quote][/quote]There is so much oil splashing around that the cylinder walls get more than enough lubrication.

The best engine power is always obtained with the least amount of oil on the cylinder wall. Windage trays, multi-directional baffling in the oil pan, crank scrapers, pcv valves or vacuum pumps, and piston oiling are all used to limit oil on the cylinder wall. Performance pistons are short skirted with thin ring packages these days in an effort to make more hp. Keeping them thermally stable is required. Running 30wt oil at 50psi while turning 7500rpm on a 100f degree day in So. California day is the norm for a performance engine these days. I stick with my statement that piston oiling is a good idea.