There's a hole in my T8!
 

Ok you guys, I need some advice! (from people that know)

My SP4 suffered a major blow up last year and to cut a long story short, the whole bottom end was replaced with a slightly used late 851 unit.

The engine was rebuilt by Alvins in Edinburgh (since gone bust) and now suffers a nasty oil leak at the back of the rear cylinder.

After much investigation eliminating breather problems, it became clear that the oil was coming from the base gasket at one particular point.

I'm now resigned to the fact that the motor needs another rebuild but I wanted the original SP4 cases and gearbox put back anyway.

My question is: On the crankcase rear cylinder, just in front of the right/rear stud, there's what seems to be an oilway on the crankcase. What's puzzling is, the 851 cylinder at that point is solid (nowhere for the oil to go - just completely blanked off). Can anyone shed any light on this? Is it unique to the SP4 therefor making the 851 crankcases incompatible with SP4 barrels?

I can post a few images as soon as I find my boody USB cable!

Obviously, I don't want to run the engine if an oil feed/return is being blocked off.

Any info on this would be greatly appreciated.

Cheers

Fred

my old . . .
 

748 SPS used to weap a little oil from that rear gasket - we managed to (in situ) lift the rear cylinder slightly and seal it with some liquid gasket stuff - never leaked again!

Khushy

Hi, The oilfeed is for the 900 two valve motors (common part) it's not used on the 4 valvers,but it's still under presure. It's ok to blank it off with a grub screw thus doing away with the chance of it leaking!
Steve