Naming of parts - cams and valvetrain

GC porting, development, valve and seat work, combustion chambers, cams, head construction, etc
Post Reply
Guy Croft
Site Admin
Posts: 5003
Joined: Sun Jun 18, 2006 9:31 am
Location: Lincoln, UK
Contact:

Naming of parts - cams and valvetrain

Post by Guy Croft » Mon Jun 26, 2006 10:10 am

1. The 'top hat' shim or 'lash cap is often used to take up the clearance that is created when changing from standard cams to competition cam. Competition cams often have a smaller diameter base-circle. Top hats just sit on the valve tip with a good, but not necessarily tight fit. Best material is alloy steel like En36 which contains nickel and case-hardens well to say 15 thou deep, allowing for finish grinding, and thus resists wear without becoming too brittle.
Top-hats must not bear against the collets or the fretting will severly damage the valves and spring caps. Fitting requires great care - always do a dry run without them and take measurements then fit them and re-measure. If the clearances are not reduced by the thickness of the top-hat, one has become dislodged.

2.Identifying the different sections of the camshaft. This is a Fiat 8v TC cam, where there are no separate bearings, the cam runs direct in the housing.
Attachments
Slide36.JPG
Naming of parts - camshaft..
Slide36.JPG (53.34 KiB) Viewed 7708 times
top hat.JPG
Top-hat shim.
top hat.JPG (15.18 KiB) Viewed 7586 times

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest