older dart 360 heads
 

I have a set of older Dart 360 heads..and i had to have a few valve guides re-pressed in the heads due to they lost there press fit.
During the conversation with the builder he claims these heads are on "there way out".
My question is.. the way i see heads are they are a casting with other components added to them.
Am i wrong here thinking that the aluminum isnt going to go bad.. unless u have some catastrophic failure which damages the head beyond repair right? All the other components the valves the springs,guides, retainers,locks..all are replaceable.
How is a head on its way out?..if it hasnt had catastrophic hole blown in the head?..and all the components attached to the head are repalceable?
I know the heads are older lower technology but they seem to get the job done.

Your thoughts would be appreciated

Thanks

Keith

360's
 

Keith,
I was Sure that I covered this,but maybe Not?
The Aluminum Gets SOFT,from Fatuege(sp)and when that Happens,things start Falling out?Guides,Seats and so on?
Trust me when this starts happing,It DONT get Better!!!
I know this is Not what you want to here,but does happen.
Later
G 8)

It comes from the heat, when the heads are first cast, they are heat treated, then machined. After yrs. of use and the constant heat ups and down it draws down the temper of the alum, making them get softer.

JMO

Zip.

is it possible, practical, &/or cost effective to reharden them?

360's
 

Yep,Zip.
I beleive its referred to as Heat Cycling?
As far as Heat-Treat?Yes,It is a Option.And I had that done once also,trying to save a Set of R/M Dart Heads.This was about 30 years ago and the Cost was 160.00 or 180.00 ?BUT,then of course you have the Expence of another Valve Job and resurfaceing,and so on?
I know its Hard to PULL the PLUG,but sometime you have to just do it!!!
If I had to do it all over again?
Go with a New set of Bare castings that You can use your Parts in.
SORRY!
Later
G :(

heads
 

Ok i see what u mean... i have a line on a newer set if dart 355 cnc'd heads,, have like 50 runs on them. Im gonna run these heads for a little while..save some cash and swap to the newer heads. And my jesel setup will bolt right up