Cometic head gaskit

[allencr]

allencr : mate im just a little confused, you are asnwering my question or asking one.

Asking a few and answering one.

Soft?
I don't know what 'soft' means Just old & tired & in need of refurbishing, the often HG complaint of 'leaking oil'. Head alloy mostly made of recycled beer can aluminum, overheated once really bad - big time, overheated a little daily, piston hammered from the rod knock, many years of severe service from in-town daily driving stop&go with a poor cooling system or the regular HG problem from Toyota's marginal design & bad maintenance & never being re-torqued, some, many or all of the above?

45 degree?
don't know what '45 degree' or what 'smooth at first and the rough for the final' is trying to accomplish. Give it some 'bite' to hold the gasket in place? Same as the valve and cross-hatch for consistency? Diagonal so it will hold better?

Reused - Sure, no more or less then any other gasket can be reused.
Totally depending on previous use, quality of manufacture, design, surfaces being joined and preparation! There isn't any magic in the spray on shit except that is consistant, easy & applied evenly on the entire gasket. Personally I like clean & dry fire rings with a slight smear of non-harding goop/cement around all passages for water & oil, not enough to squeeze out a large blob that'll get loose.

[The Real Roadrunner]

soft is used to descride the surface density of a head. if you drop a ball bearing on it from 7" it should bounce back atleast 4". if it only bounces back 1" the head is generally screwed.

cheers
linden

[allencr]

soft is used to descride the surface density of a head. if you drop a ball bearing on it from 7" it should bounce back atleast 4". if it only bounces back 1" the head is generally screwed.

cheers
linden

Joke/put on, or corrosion?

[The Real Roadrunner]

WTF? its got nothing to do with corrosion.

in laymans terms a its like the head has been anealed (same as what you do with copper head gaskets) and once it reaches this state the head is rubbish.

you cant just go grab any old head and get it decked and expect it to be fine, you have to check if its worth reconditioning or not.
the first test is to drop a bearing on it to check surface density if it doesnt bounce high enough or dents the surface the head is fucked no two ways about it.

cheers
linden

[jeffro ra28]

What linden is speaking is true. Once its soft, its never the same again and screwed. Even if all the valve inserts and valve guides are removed and its re-heat treated. Most of the time if it gets re- heat treated the the head is hard again, but only for a short period of time. And is in a worse state for straightness then to start with anyhow.