My Spada based G5 lookalike used a lot of oil on our 4,000 miles round Europe in August, so I thought it was time to look inside the engine.
Rust marks from where the piston rings had rested during a long layup by a PO, felt too deep to hone out, and clearly would have needed at least new rings, so remembering what a worthwhile investment Gilardoni barrels had been on my T3, years ago, I invested.
Comparing the lovely new items with the original iron lined Spada barrels, I see they do not have the cut out at the base of the pushrod tunnels, presumably to allow oil to drain, from there, down the skirt of the cylinder liner.
Is this a feature that has been considered unnecessary?
Or should I reproduce this feature on the base of the new barrels?
I’ve just checked. The base gaskets have a corresponding scallop cut in them as does the crankcase mouth.
So it clearly is to allow oil, draining down the push rod tunnels to return to the crankcase.
Without them it would appear that oil builds up in the push rod tunnels, unless it exits via the cam followers.
Maybe this has been found adequate and so the cut outs have been discontinued.
Does anybody have a later (post '81) original Guzzi round finned barrel, that does not have these cut outs?
I dunno the later sqaure barrels still have them, just about, as holes are different. It would help drain some of the oil past the cam followers, albeit they have longitudinal slots down the outside.