race engine oiling
 

Hello all.

There have been some fascinating references to oil system improvements for high rpm engines here.

Cross drilling cranks and opened up oilways have been hinted at..

I am sure many would be as intertested as I am to learn the details about these, if the experts would be so kind as to share their knowledge please...

Kind regards
David

An old trick to improve oiling of the crank and rods is to use 2 lower halves of the main bearings (the lower half has the oil groove in it) so that you end up with 360 deg oiling.
Similarly...you can do the 360 deg groove trick to the rod bearings.
Don't forget to champher the edges of the rod bearings to feather the oil flow outwards.
Cross-drilling the mains or rod journals....tear-dropping the trailing edge of the oil holes.
Re-drilling the oil passages to larger sizes.
Using a high volume (not high pressure) pump.
Using a full bypass filter system (this uses a second oil pump - belt driven - to filter the oil) this takes the load off of the internal pump and improves flow.
How we doin' so far??
Bob

Thank you, Bob/

I appreciate the information.

Would it be possible to get the numbers etc to actually do these things please?

Kind regards
David

DAvid...it's not so much a number thing....more like machining (expensive) or getting the correct parts.
To 360 the crank bearings...you would purchase 2 sets of main bearings and only use the grooved halves.
To feather the rod bearings...you machine the bearing shells so that they have what looks like the viens in a tree leaf (big groove down the middle and smaller ones leading at an angle to the outside).
These grooves have to be in the correct direction to do any good.
For a larger oil pump...try a turbo pump...more output on both sides.
Full bypass oil systems are like the ones you find in big deisel rigs (semi-trucks). Probably big bucks.
Cross drilling the crank...also feathering the oil holes in the direction of flow....machine shop...$$$.
Get Waynes engine rebuild book....read it...understand it.
Talk to old time racers who had to do everything themselves because hot rod type parts did not exist.
Don't limit yourself to just cars...look at what the bikes have done...also boats and airplanes.
Good luck
Bob

- Turbo pump to avoid oil gathering in the sump
- Turbo piston squirters
- Cam housing oil line restrictors
- Crank Shedding

Found at Rennlist.com:

Subject: Oil - What's it good for?
Date: Fri, 14 Nov 2003 07:17:40 -0800
X-Message-Number: 10

Neon brings up a some good points - Oil has basically 4 functions:
1 - To prevent metal to metal contact in moving parts;
2 - to assist in carrying heat away from the engine;
3 - to clean the engine parts as they lubricate; and,
4 - to form a seal between the piston rings and cylinder walls to prevent
blow by of the combustion gasses.

Porsche recognized that their engines are in essence oil cooled and enhanced
the cooling in the 2.2 liter motors by adding squirters off the main gallery
aimed at the bottom of the pistons to cool the piston crowns.

Later, in the early 80's, in their twin turbo TAG F1 engines (1,500 cc's -
over 1,000 hp at 4 bar), they did a real neat trick - going through the
piston crown with a 13 mm diameter end mill, they routed out an area just
behind the piston rings. Then two 10 mm holes were drilled under the piston
180 degrees apart which functioned as the entrance and an exit for the
injected oil. The hole in the piston crown was plugged with a really big
washer (nearly the diameter of the piston 83 mm by 13 mm) and welded into
place using electron beam welding.

It worked this way. As the piston came down to BDC a spigot just off the
main oil gallery "docked" into one hole and injected oil filling the piston
with oil by force, which made the piston an internally, oil cooled, piston.

If anyone would like to see picture of this piston - gimmie a shot off
line - I don't have a web site and don't want to clog the system with an
attached piston picture.

DOUG
It musta worked - they won a ton of GP's in the 80's with that motor and a
number of World Championships.

Thanks guys.

I assume the crossdrilling is intended to increase the oil flowinto the crank at each end...so is in these two main journals, to similar sizes as the existing drillings.

Now about the case oilways, they look rather adequate to my eye, compared to lots of other race engines, do they need opening, and to what sizes please?

I am familiar with the teardrop entry idea for the crank oil holes but have never seen the leaf-vane or herring bone pattern cut into the rod bearings.. is this Ok as these run at somewhat high shear velocities on the early 2 L cranks... this may be an issi=ue, or do synthetic oils tolerate high shear aretes well please?

I plan to use low viscosity synthetic..as I use in in other race engines... any probs?

I assume that simply fitting the large tirbo squirters and a big pump is OK, tho' I have in mind to replace the case maount oil cooler with a big remote, and fit a large filter in place...

Thanks for advice again..

Kind regards
David

David...I was thinking the same way with the filter idea.
A full flow filter instead of the engine mounted cooler.
Should work...and the filter mount is sold by acompany already (have to look it up, can't remember them right now).
The extra work to rod bearings would be an experiment...perhaps not necessary with Porsche engines.
The oil viscosity is another issue...I usually use quite heavy oil...50W or 20-50W...and have used up to 100W (aircraft type) in very hot weather.
The hydraulic wave effect in the bearing journals is what keeps the whole engine working.
If there is enough oil at the right pressure, the metals of the bearings and races never touch.
We have tried all sorts of combinations...high pressure (washed out the bearings)...silicone instead of oil (worked great but leaked everywhere)...and even oil/additive mixes (Wynns friction proof works best in air-cooled engines).
Bob

Another thing I cannot find is an old-fashioned disc type oil filter.. or are these now frowned upon?

They were very nice to see the metal particles after the race!

Kind regards
David

Do you mean Racor/oberg filters ? These filters are great in a fully developed oil system