Scooterotica

Just replaced my head gasket and torqued the cylinder head nuts to the correct torque.

I seem to recall reading somewhere that they should be checked after a certain milage. Is this right and if so after how many miles?

I thought after a couple of heat cycles is normally enough

Thanks, Burnside.

I just run mine around the block and get the cylinder head hot. and let it go cold. Do the same again,when the cylinder head goes cold I then re-torque the cylinder head nuts,thats it.

I know this will get an whole load of flake but I don't re-torque mine anymore. When I started I never had a torque wrench that went down that low so I never used one. When I came back into scootering I read how important it was so I checked a few but they never moved so I have abandoned the idea.

Tractorman wrote: ↑Sat Oct 10, 2020 9:02 am I know this will get an whole load of flake but I don't re-torque mine anymore. When I started I never had a torque wrench that went down that low so I never used one. When I came back into scootering I read how important it was so I checked a few but they never moved so I have abandoned the idea.

I largely agree, as I have never re-torqued. With any engine I am building, I also ensure absolutely first class threads, genuine OEM type rolled studs with heavy duty, hard washers & torque up to a higher figure in conjunction with Copaslip type grease.

I torque up in three stages (say, 5 lb/ft initially, then more etc)

However, the fundamental cure for head leakage is to eliminate the weak link. I have not used head gaskets since the early 70's & will not do so again.

I have stripped down many an engine in my time & have never found evidence of the head gasket having effectively sealed. They always leak, even if that appears as 'only' a little weep.

Why have the grief of sealing either side of a gasket when, if it is discarded, having to seal up just the head to barrel?

It's a no brainer IMHO

However, the fundamental cure for head leakage is to eliminate the weak link. I have not used head gaskets since the early 70's & will not do so again.

Interesting. Is that with standard Lambretta cylinders and heads, or "special" ones?

MightyGem wrote: ↑Sun Oct 11, 2020 8:54 pm

However, the fundamental cure for head leakage is to eliminate the weak link. I have not used head gaskets since the early 70's & will not do so again.

Interesting. Is that with standard Lambretta cylinders and heads, or "special" ones?

Works for any type of head but the important thing is that the contact surface is perfectly flat. Large sheet of emery, a flat surface , paint the gasket face with a felt tip and slide the head in a fugure of 8 motion until all felt tip removed

MightyGem wrote: ↑Sun Oct 11, 2020 8:54 pm

However, the fundamental cure for head leakage is to eliminate the weak link. I have not used head gaskets since the early 70's & will not do so again.

Interesting. Is that with standard Lambretta cylinders and heads, or "special" ones?

Any engine that I build inevitably has the head modified to suit the engine. So the heads are all "special"

Just as the whole head/barrel/crankcase are all optimised to function as an assembly.

TBH I'm uncertain that any proprietary head deemed to be correct for any barrel/piston is ever going to be spot on, so volume & squish corrections are inevitable, requiring form tools & fixtures on a lathe. As that is being done, then the head may as well be spigotted to the barrel to ensure a seal.

The days of "bolt on power" are long gone, because even in the World of RB20 racing where modification is limited, there is still a lot that is achieved via careful blueprinting.....