850 Cylinder history.

I have read the history of the changes and improvements for the heads and transmition and would like to know if there were any changes to the cylinders for the 850. I have a 75 850 MK3 and unknown cylinders (bought in 79 but still not installed, just now getting to the rebuild) and would like to know what if any changes were made and what to look out for. I have done searches but could not find anything on cylinders changes or improvements. Looking to see what this brain trust can come up with.

Thanks

Chuck

Not much to change there. Tappets were all the same. Stock bores were all the same. It's a big frickin' hunk of cast iron and should be more or less identical to all its brothers.

Chuck, as far as I know once they stopped making the 750, the 850 barrel came out in one edition right up to the close of production with the Mk3. The only thing I suggest to look out for, is the 2 front studs. These commonly break through to the pushrod tunnels. There is a possibility of oil wicking up the studs to leak around the gasket joint. The remedy is to remove the studs, clean the the holes and stud threads, apply Loctite stud sealant and retorque them in.

Mick

According to the parts books, the original 1973 850 MkI/IA cylinder block part number was 063823.
For 850 MkII/IIA-on, the part number changed to 065704, however the difference in part numbers could have only been down to the MkI/IA cylinders being painted silver, and the MkII/IIA ones being black?

I'm guessing that the casting number 063850 was the same for all the 850 cylinders, unless anyone knows different?

I'm guessing that the casting number 063850 was the same for all the 850 cylinders

Click to expand...

.......and those bored 750 like mine bought from Norvil end of 2002. Have never seen another set but there must be a few about.