Cam blocks locators

Z

Zakredridge

Junior member
Location
United Kingdom
Hi
Should the locator dowels be used in the assembly and alignment of camshafts where
Cam blocks have been matched by milling/scraping metal away from the cylinder head to create correct alignment of the camshaft in the cylinder head ?
I want to repair the 8mm short studs threads, but the dowels reduce ability to use time serts with the shoulder in the top of the inserts.
Am I correct in the thinking remove dowels assemble and check correct positioning, tap with alloy bar for alignment, and re torque head?
Cheers Colin
 
Machine the collar of the insert so it fits inside the bore in which the dowel lives... re-fit dowel, done.

Without the dowels in these early heads, cam alignment is questionable at best, resulting in inconsistant valve clearances.

piet
 
I run a head without dowels and around 20 thou clearance on the later locating runners ( because the machinist didn't follow instruction)
As Piet says, it will play havoc with your valve clearance and valve timing because the axis of the valve stem is different to the cam pillar axis.
I get around it quite successfully by having scribed some fine marker lines around the outer cam pillars. However these pillars are billet machined, and the head is machined flat so it's repeatable.
 
The earliest-type heads often required a bit of fettling to obtain enough clearance for the bottom of the later cam bearing blocks. A great deal of interchangability resulted as the heads and bearings evolved, later bearing blocks were suitable for either dowel or channel/spigot location. But there was one run of bearings along the way that did not accept the dowels of the earlier heads!

piet
 
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