Jump to content
Click here if you are having website access problems ×

VHPD cam clearances


Englishmaninwales

Recommended Posts

  • Area Representative

I guess it depends on exactly what Malcolm (OP) is asking for, but taken from DVA website:

Piston/Valve clearances

When contemplating a change of cams it is important to ensure that there is sufficient working clearance between the valves and the tops of the pistons on the 1.4 and 1.6 engines there is likely to be more of a problem than on the 1.8 where the piston is 1.4mm further down the bore. We have undertaken a clearance checking exercise on a 1.6K engine using the Piper #740, #835 and VHPD grinds, this exercise shows about 3mm clearance between the piston and the valve head for the #740 and 2.5mm for the #835 and VHPD, and a 2.0mm lateral clearance with 30mm inlet valves so these two cams should be safe to use without piston mods even with VVC sized valves. I cannot absolutely guarantee this clearance since it will vary with several factors, valve size, cam timing, amount skimmed from head and how much the valves are recessed into the seats, but in general these should be OK. Cams with 300 degrees or greater duration will need checking. It is not easy to enlarge the cut-outs in the pistons since they already come perilously close the the ring lands, any serious removal of metal would likely result in finding fresh air via the top ring.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...