Early vs Late heads

[Jim LaGuardia]

While repairing a leak today, I found there are 2 types of heads and oil return tubes. While the seals are universal between the MK 1 and MK 2 designs, you cannot use a late head with an early oil return tube or vice versa due to tube design and machining of the tube bore.
On the MK 1 heads, the O ring is captured in a groove and the return tube has no lip on one end .
It seems 72 and later use the MK 2 heads and return tubes.
Too busy to take pic's, but thought I would toss out this scrap of info for those doing repairs on earlier Pinz engines.

[M Wehrman]

Pics please,I am curious about the o-ring difference.
Mark

[Jim LaGuardia]

Since you asked nicely..............
MK1 head


MK2 head


Oil return tube compairson, top MK1 bottom MK2


Right MK1, Left MK2

[M Wehrman]

Thanks,I haven't seen the smooth-tube version yet,must have been changed early.Thanks for the info. And I always try to ask for information nicely!
Mark