750sf3 Engine

Skeeta

Skeeta

Junior member
Location
Coolum Beach, QLD
Are some engine head bolts used for oil galleries(hollow) and the cap nuts metal and plastic(cap yellow) there significance ?, different lengths I have found
Thanks
Skeeta
 
The studs aren't hollow but oil runs down front right stud into hole in crankcase. When I rebuilt my engine earlier this year I found previous mechanic had fitted base gasket upside down and gap was on left side. Copper washers keep the oil in.
 
Two front central head/barrel studs are oil galleries, carrying oil to the slots in the top centre surface of the head (which mates with the top cam cover). It's imperative that these slots are open to the oil that comes up those centre studs and travels into the rocker pivot pins and rockers to feed oil to the cams. Some cam covers seem to have the holes too close to each other (front-to-rear) which in turn squeezes the studs against the open slots, effectively blocking the oil flow (ask Tippie on this forum!!  :o ). We use thin wire bent at 90 deg fitted between stud and head to ensure that the slot can't be blocked. May even have to elongate the holes slightly to ensure an open flow.

Yellow top nuts were introduced on the SF2 to replace the solid flat-topped SF1 and round-topped SF0 (and prior) versions. Not sure why, aesthetics?
 
The drain on the front right stud is nowhere near as important as the two front centres (see my previous post). I rebuilt an SF1 on which Luigi had forgotten to drill the drain in the cases from the right front stud that (supposedly) feeds the RH outer main bearing and starter freewheel needle roller. Motor had not suffered any ill effects, but I drilled the hole anyway (no easy feat!).
 
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