Cross-drilling the crank ?

[andyjboy]

Looking through the invoices for engine work on the short-stroke twin-plug 2.5 litre from my recently-aquired 914/6 GTR race car, I came across an entry:

"Cross drill crank & groove #4 main brg"

- I don't remember seeing any references to this proceedure before - is this a worthwhile/recognised modification & what is it specifically aimed at reducing/preventing ?

Is the #4 main bearing most prone to oil starvation/failure ?

[MBEngineering]

HI andy have a look hear;

Crankshaft cross drill

this should shed some light on the matter;

regards mike

[andyjboy]

Thanks Mike - I ran a search here & found a few threads on the topic.

Opinion seems to vary as to the merits of such a modification for road use but since this was a racecar spending much of its time at the higher end of the rev range then i guess it was money well spent.