[DeTomaso] Valve Spring Shims

[fordmachinist at gmail.com]

Typically a cast iron head will not need them.
BUT...there is no doubt that big spring pressures can possible start digging in.
In a performance build, you will be shimming for correct spring assm. height and pressure. Then you might as well choose the HP (hardened) shims, and kill 2 birds with one shim.

TMeyer

Sent from my iPad

> On Oct 24, 2015, at 9:45 AM, John Taphorn <jtaphorn at kingwoodcable.com> wrote:
> 
> I am freshening up a set of heads recently acquired that had been sitting for several years.  However, previous owner thought them to be bolt on ready.  Upon dis-assembly, found there to be no hardened spacers under the valve springs.  Many years ago, I assembled a Cleveland head w/o shims and the rotating valve springs cut grooves in the cast iron seats.  I have always cut the seats deep enough for a shim since that experience.  However, perhaps the cutting issue was my failure to debur the springs' leading edge.
> 
> What is the consensus among engine builders - Shims or no shims, assuming proper spring height w/o them?
> 
> I'll probably shim these anyway as spring height is inconsistent, yet around 1.90""
> 
> Thanks
> JT
> 
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