Topic: Valve to Piston clearance

[andyman]

Hey guys!
In the 350/400Four engines, which clearance valve to piston is possible in this engines IN and EX?

Greets and thanks!

Andy

[turboguzzi]

assuming you use racing springs, would go for 1mm min.

[andyman]

i use stock springs

[turboguzzi]

not really scientific, but maybe make the valve reliefs a bit deeper by a few more tenths... say 1.3 - 1.4mm?

after you run it a bit, remove head or use a borescope to check if there are "kissing signs" on the pistons

[754]

Wel if you are making them deeper , can't you just use clay and check them.. take the guesswork out

[andyman]

Now i have IN 1,5mm and EX 1,4mm, Webcam Stage1 Camshaft.

In the instruction i read clearance between piston and valve should be 1,3mm IN and 2mm EX....?

[johno]

When your screwing the ol girl to the redline and beyond I wouldn't be too stressed about wether 1.3mm or 1.8mm valve to piston clearance,  I would be extremely stressed about how good the valve springs are.
Do yourself a favour put in some better springs, at least shim them up .040" or .050" and then you can enjoy life at the fast end 

[MRieck]

When your screwing the ol girl to the redline and beyond I wouldn't be too stressed about wether 1.3mm or 1.8mm valve to piston clearance,  I would be extremely stressed about how good the valve springs are.
Do yourself a favour put in some better springs, at least shim them up .040" or .050" and then you can enjoy life at the fast end 

I agree....it's worth the 60.00. Worn, stock springs probably have 25 to 30lbs on the seats. You'll make more power with better valve control.

[andyman]

You mean aftermarket springs from CMS or Kibblewhite springs?

[MRieck]

You mean aftermarket springs from CMS or Kibblewhite springs?

Kibblewhite

[andyman]

ok thanks