Cylinder head tightening

[mr mugello]

When tightening the cylinder head, stickys book mentions to use a diagnol sequence. Do you torque one nut fully before then moving onto the next in the sequence. Or do finger tight with socket, then go round in sequence 1/4 turn on each nut till torque is reached ? Thanks

[Norrie Bodge]

Or do finger tight with socket, then go round in sequence 1/4 turn on each nut till torque is reached ?

I`d say you`ve already answered this one yaself m8

[mr mugello]

Thanks. Blowing heads are a pain !

[Norrie Bodge]

go across the 4 nuts as you tighten them
not around

[Muppet]

flat surfaces help, heads buckle with use and abuse; surface plate with 400 grit paper or lap head to pot with valve paste; clean n degrease assemble finger tight torque nuts in stages 5;10;15; more if not std; heat cycle n retorque

[gaz_powell]

http://www.vespamaintenance.com/engine/ ... index.html

This shows you the sequence (albeit a vespa)

14-16 ft/lb standard

16-20 ft/lb tuned

Make sure your studs are in good nick and tight and use good thick washers and deep nuts

[mr mugello]

Thanks . Job done. Engine rebuilt a few years ago, not by myself. Was showing signs what I thought to be blowing head , slight oil spray on the exhaust and barrel find. Head off shows no blow marks on gasket !

[Tractorman]

I would use 3 stages of torque wrench setting depending on the final head torque, for example on a 18ftlb final torque I may use 6, 12 and finally 18. This is just the way I was trained larger engines but it seems to work for me on Lambrettas.

[mr mugello]

Thanks. Good tips to know.