new heads

[plumcrazy]

lookin around for a new set of heads. i plan on gettin bare
aluminum castings and assembling them myself. my question
is what would the affect of gettin .100 longer valves apposed
to standard legnth valves? just something i would like to know
to keep in the back of my head

 

[rrubel]

Well, the valves would open further, so there'd be a possible clearance issue with the pistons, plus the rocker arms might not seat right without longer pushrods...

Of course, some heads require longer valves, I *think* because they're a bit thicker, and everything kinda evens out.
[RICHR]

 

[SG4206]

Longer valves are only needed when you can not get the correct spring height installed for seat and open pressure.

 

[Tom Bryant]

Exactly as SG4206 said. You probably won't run into any length problems on new castings intended for street use as long as they are fully machined when you get them and you use the valves the manufacturer recommends.

Are you thinking of building your own heads because you want to use valves or springs of a different specification than those that come in the assembled heads or to try to save some money?

Tom

 

[Edmond]

Could you also tell us what specs you're doing the heads to?

2.02 intake?
1.6 exhaust?

1.6 roller rockers too?

 

[taegdh]

A tenth of an inch isn't going to do much difference because when you are reinstalling the rockers, you either use a certain amount of torque or play on the end of the the rocker, according to your manual. You might need to install a slightly taller spring or a circular shim at the bottom.