Cylinder head refitting

[mr mugello]

Removed cylinder head to check if was blowing. Exhuast body had oily spray near barrel cowling area. Exhaust gasket was blown . No blow mark lines on gasket head face , but oily on bottom side of head,. Would this be just oil dripping when loosing the head ? My mugello kit has a 1 mm alloy head gasket. Can the head gasket be replaced with new when refitting head ? Is general use loctite thread nut sealant good to use on head gasket for head sealant use ? Thanks

[Scooterdude]

I've had a similar issue with mine but it was nothing more than some fuel that came out of the overflow pipes on my PHBH getting sucked through the fan and blown through the cowling, does look like a leaking head though but it's not.

I'm not sure about using stud lock as a head sealant though, get yer self a tube of stag wellseal off of eBay.

[mr mugello]

Thanks . These alloy head gaskets. Are they ok to reuse or are they like the exhaust gasket which needs replacing each time ? Thanks

[gaz_powell]

Strip off head, barrel and manifold, clean it all up.
Lap the cylinder (head, inlet, exhaust), cylinder head, exhaust flange/stub and inlet manifold (need to remove studs.

Reassemble with new gaskets, thin smear of grease on the base and inlet and as said stag wellseal on the head, torque all nuts up to correct tightness. Use decent thick flat and spring washers with deep nuts on the head.

Don't reuse gaskets unless it's an emergency

Good luck!

[mr mugello]

Thanks for advice. Not sure on what this lapping involves. Is this machining ?

[dazblakey]

https://youtu.be/cQHdXcqAo-k

[Scooterdude]

https://youtu.be/cQHdXcqAo-k

That video's not the way I'd do it personally, the way I learnt "back in the day" when working on air cooled Magirus Doitse (yes I know I've spelt the name wrong) was to put a small amount of fine valve grinding paste between the two mating surfaces I.e your head and barrel and "lap" them together until both surfaces turn a dull grey using a back and forth turning motion of about 90 degrees or there abouts and constantly turning the head clockwise or anti clockwise, it really doesent take very long.

[fluff34567]

The guy in the video is doing the initial blending to remove the machining marks. I use a surface table and 1000 or 2000 grit and make a quick 30 second run to find and high or low spots on head and cylinder then any lapping will be minimal between the head and cylinder

[mr mugello]

Not 100%sure head is even blowing. Might just Lapp the head. Looking like it's a engine drop to remove barrel I take ?

[dennis]

You might want to watch this,he does not scrimp on the sealer.
https://www.youtube.com/watch?v=KQgPSfJJK-c.
or look at the casa rebuild on youtube.