Panhard crankcase front oil drilling reinstated
04/03/12 15:09
Next up to bring Brian’s engine up to date with the oil supply modifications is restoring the original designs original oil supply mods, but this time bypass all the negatives.
The later engines didn’t have this option, as can be seen here.
(insert picture)
The original engines had this oil feed visible above the camshaft bore at the very front of the crankcase, which is shown below. As the camshaft rotates this drilling is filled two times per camshaft revolution, and after this it passes underneath the bearing and jumps into the slingers. Some oil splashes back and passes through the main bearing, but the rest is accelerated by the slingers on the crank web, and passes through the big end bearing before exiting and splash lubricating the little end.
Unfortunately this hole is too small, and it led to a 50% reduction in flow rate over the rear, which is why I mod the front like so.
It might not be obviously apparent from this picture, but the hole size is now 6mm diameter, whereas the one above is just 4mm. This new oil feed now matches the camshaft aperture, so all openings, front and rear are timed equally. The 4mm diameter hole in the middle will have to be enlarged to 5mm, as the rear oil feed is actually 5mm in diameter, but at first it is more important to get the hole in the right position, and work from this.
Oil feed at 5mm diameter now, which is 50% bigger than OEM, but matches the rear bearing oil supply.
The later engines didn’t have this option, as can be seen here.
(insert picture)
The original engines had this oil feed visible above the camshaft bore at the very front of the crankcase, which is shown below. As the camshaft rotates this drilling is filled two times per camshaft revolution, and after this it passes underneath the bearing and jumps into the slingers. Some oil splashes back and passes through the main bearing, but the rest is accelerated by the slingers on the crank web, and passes through the big end bearing before exiting and splash lubricating the little end.
Unfortunately this hole is too small, and it led to a 50% reduction in flow rate over the rear, which is why I mod the front like so.
It might not be obviously apparent from this picture, but the hole size is now 6mm diameter, whereas the one above is just 4mm. This new oil feed now matches the camshaft aperture, so all openings, front and rear are timed equally. The 4mm diameter hole in the middle will have to be enlarged to 5mm, as the rear oil feed is actually 5mm in diameter, but at first it is more important to get the hole in the right position, and work from this.
Oil feed at 5mm diameter now, which is 50% bigger than OEM, but matches the rear bearing oil supply.