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Discussion Starter #1
Hi,

As you've probably seen in former posts, I bought 77 ex California which I have timed, Spica tuned and fitted 2x piece exhaust manifold to and done a Cat delete.

How beneficial would it be to change the intake cam ONLY to a 10548 in combination with re-timing both?

Still finding the car a little sluggish.

Thanks, John
 

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Premium Member
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It will help, difference will be subtle.
 

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It gives you a nice little extra urge all across the range, you feel it mostly in the low and mid-range as more torque. Not huge but for sure worth it. 10548 is what Australian cars would have had in period though we never got them in our cars. the other good things are (1) Alfa quality in the cam and (2) stock base circle so you can use regular shims, no need for thick ones since it doesn't have a small base circle.

Andrew
 

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Discussion Starter #4
Thank you Guys! I have sourced 2x now so will change both and post my impressions when done.
Should i keep timing std do you think?
 

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Richard Jemison
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Those LCs might be safe as an instal position, But tou should always check for Piston to valve clearance.
As well the factory LC for these 10548-01 cams was .99.5 intake and exhaust.
If you have P to V clearance those LCs "Should" give you the best street (lower RPM ranges) Torque and HP. But that small a BC has to be checked for P to V clearance.
If you are looking for enhanced mid to high RPM output retarding the cams to 102 intake and 104 exhaust will provide that.
Below is a copy of my PDF file I send my cam customers on cam set-up and checking P to V clearance.

CAM SET UP NOTES
Piston to Valve Clearance Check This is very important since when cams are advanced the piston clearance reduces dramatically, and Lobe re-design can effectively advance the valve opening. Set Intake and exhaust cams at initial LCs as indicated by provider`s set up instructions, and lash settings. By running the .040 plastic wire-tie between the Intake valve & piston, and .070 - .080 on the Exhaust side you can check if there is any interference and see that you have adequate clearance between piston & valve. If by turning motor over by hand you feel some interferance using a .040 thick wire-tie, (or .070 on the Exhaust) but the motor continues to roll through, you are at the limit! YOU MUST ROLL THE MOTOR OVER OVER BOTH FORWARDS & BACKWARDS TO BE SURE THERE IS CLEARANCE AT THE LIMITS!! REMEMBER, WHEN OFF THROTTLE THE CHAIN TENSION REVERSES!! If it locks up, retard the cam on the intake side, (or advance on the exhaust side) to get more clearance. and try again until the clearance is found. Each hole on the vernier sprocket changes the cam timing 1.5 degrees at the cam (3 degrees at the crank). I suggest as a test to find this limit, you advance the intake cam until you do find the minimum needed clearance, and permanently mark that point on the cam cap. That will be the point where the cam must NOT be advanced past. Then do the same with the exhaust only retarding it until the limit is found. Timing initially is dependant on design of cam lobe. Aggressive large duration cams will be more retarded.(intake) and advanced (exhaust) because of ramp & valve lift in order to fit in a engine that is already assembled and valve relief's not designed for large cams. Tighten and install lock nut on intake and bolt through sprocket and cam nut. Inspect carefully. Roll the crank over by hand to verify timing. When the intake cam is at the limit, or LC setting whichever is less advanced. You are there!
 

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How beneficial would it be to change the intake cam ONLY to a 10548 in combination with re-timing both?


You might also think about this combination: stock SPICA cam on the exhaust side and a 11.1 Centerline cam on the intake. I'm running that now on my year-old build with Motronic pistons, Webers, and headers and am very happy with how this combination works. Centerline says the 11.1 cam (I think its timing is [email protected]) works well with a stock Spica so if you want a little more punch than a 10548 cam, this might be another choice. Right now we're still running with 102/102 which is quite workable, although Richard's recommendation is better.
 
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