Safe installed height for GC triple valve springs

[Abarthnorway - Remi L]

Hi Guy!

I need some advice:

When doing the valve seats on the Fiat 128 race according to Your specs - the valves are now 1.8 mm deeper in the head.
I have not yet got to measure the installed valve spring height.

I am considering whether or not to install an extra valve spring shim (1mm) to reduce the increased height

For Your information:
Valve springs: GC Triples
Cam: steel billet - 10.5 mm actual lift
Max revs: 8000 redline + possible overrev :-)

So the question is as follows:

What are the maximum safely installed height of Your triple springs when using the standard inner spring base?

Thanks once again!


Best regards

Remi Lovhoiden


I do not have any pictures of cam/head/springs etc at the moment, but some pictures of block build underneath:




Intake valves back cut 30` on left, std on right




Bracket for oilcooler mounted




Sump baffle fitted, along with new oil pump and upgraded spring




Bottom end soon finished - note new longer hex bolts for oil pan as we now run two gaskets + baffle.




New Yokohama slicks finally fitted size 175/50-13

[Guy Croft]

Remi, hi

you're wise to check, but actually you can go to 40mm if need be, but based on your valve tip heights I figure this:

std X19 tip ht 41.5mm nominal
your tip height 43.3mm
your valve tip to spring cap underside (outer spring) say 3.5mm
outer OE spring base 1mm
your installed height outer spring is 43.3-3.5-1=38.8mm

The GC 3VSR 'box' (coil bind) at 22.7mm compressed height with OE valve cap and the inner spring base fitted, so to figure out if the installed height is going to be tall enough for your cam you do this sum:

22.7 + cam lift + 2mm safety clearance, which gives minimum safe installed height 35.2mm, you have some in hand there. You can pack them up but I wouldn't bother.


GC