Camshaft choices

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manoa matt
Posts: 9
Joined: August 11th, 2009, 11:18 pm

Camshaft choices

Post by manoa matt » October 21st, 2009, 11:23 pm

Below is the specifications of the engine I'm building for a fast road car (1978 124 Spider) Also seen in my post "Block choices for road engine" in the General discussion - road section. I came across some Weber 44 IDF's so I'm going to use those instead of the 40mm Solex carbs.

1592cc head
Stock intake and exhaust valves,
Abarth "blue" valve springs,
Factory Fiat "waffle" manifold
Dual 44mm Weber IDF downdraft carburetors
40/80 Alquati intake camshaft
Stock Fiat exhaust camshaft
Adjustable cam pulleys
Fiat stock 79-83 electronic ignition distributor
4-2-1 exhaust manifold with 2.25" straight pipe back to free flow muffler

I'm still working out how I will increase the compression ratio. I think with the 1592 head and 2L block and some shaving of the head and decking of the block I can get the compression close to 9:1 Otherwise I'll fit HC pistons.

I've recently come across some Abarth camshafts that are stamped 068, timed at 50/68 and 64/43 The nose profile is rather "blunt" when compared to the Alquati cams. The Abarth cams also appear to be forged as opposed to the Alquati cams which are billet.

How would the Abarth cams perform when compared to the Alquati cams given the engine specifications? Too aggressive? Only use the intake, or both? Also what are thoughts on shaving the head and decking the block?

thanks,

Matt

Guy Croft
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Re: Camshaft choices

Post by Guy Croft » October 22nd, 2009, 8:55 am

The 068 is a much more powerful cam setup and would fine with your motor, get the CR as high as your gasoline will allow, 10/1 or more.

GC

FiatRally
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Joined: February 11th, 2013, 6:37 pm
Location: Cape Town. South Africa
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Re: Camshaft choices

Post by FiatRally » March 18th, 2013, 6:24 pm

I have a question on the Abarth 068 camshafts! I always thought that the inlet and exhaust cams were exactly the same!
Is the profile different for the inlet and exhaust cam?
Is the duration not exactly the same?
GC_75

Guy Croft
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Re: Camshaft choices

Post by Guy Croft » March 24th, 2013, 6:00 pm

the 068 profiles are same inlet and exhaust, however a difference in running clearance would account for the difference in actual duration.

GC
Guy Croft, owner

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