Fait 124 Using Shims less Than 3.20mm
Posted: May 12th, 2013, 3:03 pm
I had posted on the forum March 1, 2013 regarding a Fiat 1952cc twin cam bare head with an unidentifiable ID # that I got from an internet auction site. Never found what it came from!
I did find an excellent high performance machine shop in Millsboro DE, just a few miles from my home. They were able to machine the head with the oversize valves that I had purchased from Auto Ricambi along with (Isky) high performance valve spring set.
I am using a set of 1608 cams with original cam towers from a 197xs Fiat 124. I had them on my original 1800cc head and they fit fine. But I have found out that the oversize valves are longer than the original valves. The shim sizes I will need to get the proper clearances will range from 2.80mm to 3.30mm. Csaba @ Auto Ricambi contacted Guy Croft for me to get some info. Csaba let me know that the smallest shim I could use was 3.20mm. Csaba suggested I get the machine shop to cut the cam followers down.
This is what I have come up with. I need to cut the cam tower top current height of 3.0mm by 0.40mm leaving me a 2.6mm dept to hold the shim. I will need a clearance for the In/Ex from 0.41mm to 0.53mm. Using the 3to1 rule I should OK - the shims should not pop out.
I don’t want to have to buy a set of reground cams just to make it work.
I could use two sets of gaskets!!!
Your comments and thoughts are must welcome.
Camie
I did find an excellent high performance machine shop in Millsboro DE, just a few miles from my home. They were able to machine the head with the oversize valves that I had purchased from Auto Ricambi along with (Isky) high performance valve spring set.
I am using a set of 1608 cams with original cam towers from a 197xs Fiat 124. I had them on my original 1800cc head and they fit fine. But I have found out that the oversize valves are longer than the original valves. The shim sizes I will need to get the proper clearances will range from 2.80mm to 3.30mm. Csaba @ Auto Ricambi contacted Guy Croft for me to get some info. Csaba let me know that the smallest shim I could use was 3.20mm. Csaba suggested I get the machine shop to cut the cam followers down.
This is what I have come up with. I need to cut the cam tower top current height of 3.0mm by 0.40mm leaving me a 2.6mm dept to hold the shim. I will need a clearance for the In/Ex from 0.41mm to 0.53mm. Using the 3to1 rule I should OK - the shims should not pop out.
I don’t want to have to buy a set of reground cams just to make it work.
I could use two sets of gaskets!!!
Your comments and thoughts are must welcome.
Camie