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Lowering guides to avoid follower contact.

1111 Views 1 Reply 2 Participants Last post by  TVS
Hi folks, Rebuilding engine, standard piston and liners. In relation to the head (1750 GTV) I am fitting new valves, guides, seals and followers and race springs as well as replacing chains,tensioners etc. Head will also be polished but not ported (to scared case it goes wrong) I am fitting AR.120.292S camshafts. I know I have to "notch" the head for lobe clearance but I have also read that the followers must be lowered to avoid follower /guide contact. I have got Jim K's book but cannot find a reference to this. (am I blind)

Can someone tell me how much lower?, are they stock guides? Sorry if this is basic but I need to be pointed in the right direction. :confused:
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Just a query about 'polishing' the head? You don't mean the inlet manifold/port do you? Because this is a sure way to reduce flow and reduce the chance of fuel staying in suspension! Defiantly not good on ether account! Improving the combustion chambers surface finish is always a good thing... and polishing the exhaust port or using a ceramic coating can defiantly give good results. But the Alfa twin cam head has a very short port in the head reducing the effects of heating from the exhaust gas - which may make this quite a bit less effective compared to a BMC A or B series engine for example.
It was me, I'd leave the ports alone and getting the valve seat widths and angles sorted - good for flow, reliability and cheap too!

Just a note on valve springs - can't help with the alfa engine but its worth using the recommended springs for the cams for the RPM you'll be spinning the engine up to. Over springing the valves only wastes power though friction and puts greater stress on the valve gear. Probably not such a problem with over head cams but if you're talking push rod engines...still, every little helps!

Just my couple of pence worth! Toby
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