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Discussion Starter #1
I have a couple sets of cams, and both have casting marks and 'dings' on one cam, and in the same places.
My questions - do the casting marks indicate intake / exhaust, or ?
Why are the third, forth and last numbers messed with?
Is this a coincidence?
DSCN4413.jpg
numbers messed with and round mark
DSCN4403.jpg
No mark no deformed numbers
DSCN4408.jpg
cam on other side, same round casting mark.
Numbers are messed with but not as easy to see.

What do you know about the lower two cams?
Thanks
Jim
 

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JR....
look at the heel of the cam in the first pic...
Looks like the base circle has been turned down.
 

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Alfa used cast blanks for various series cams (101-105 and so on). The cams were ground to a specific use profile, and the cast in numbers were often ground away and other numbers stamped, to indicate a specific profile.
All factory cams seem to use a "pretty-close" bottom circle measurement. This makes it easy to check on a possible regrind by just measuring that bottom circle.
RJ found me a real odd GTAm cam some time ago, not useful for any application, but quite interesting. A lot of numbers were remarked, and it carried plenty of lift, with a standard bottom circle. We had it reground to one of his more practical configurations. The bottom circle is still standard.
 

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Richard Jemison
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Regrind

No I don`t think it has been reground. On the 1st pic the BC of the lobe on the right is odscured by a casting line.
If measured the BC should be 1.080-1.085 if stock
 

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Someday, RJ, you can guess to me why these vary that tiny amount. It seems to go beyond a manufacturing tolerance, as you can find (I think I sent them to you once to profile), factory NOS 101 10 mm racing cams, in the factory box (!) with that variation between the two cams.
"They just made 'em that way!"
Those were stamped over the casting numbers.
 

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Question to the cam guy's> I am fairly new to Alfa's and have been learning about them as much as i can. I am in the market for a 105. One thing i was curious about was when sellers of these cars advertise upgraded "euro cams". I know its not uncommon to seek more power and better sounds from there motors. I'm not sure what "euro cams" means? More power? Emissions issues?
Any help would be great.
 

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I am in the market for a 105. One thing i was curious about was when sellers of these cars advertise upgraded "euro cams". I know its not uncommon to seek more power and better sounds from there motors. I'm not sure what "euro cams" means? More power? Emissions issues?
The cams used on carbureted 1750's in Europe carried part number 10548. They are slightly hotter than the cams used on the Spica engines we got here in the US.



Yes, you get a bit more power. I strongly doubt you would encounter emissions problems - again, they aren't all that radical.

The camshaft chart on the Centerline website at: http://www.centerlinealfa.com/tips/images/p51.pdf shows how the 10548 differs from its US counterparts (the 10502032 and 10520032).
 

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Webers work much better with 10548's than with the US cams which Alfa never fitted to a carburetted car.
 

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Richard Jemison
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10548 cams

If your car is running with std US cams, you only need to change the intake to a 10548 as the engine will make better torque with the USA exhaust cam.
 

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Discussion Starter #13
Thanks RJ,
I'm running a SPICA system and have sets of both cams. When I do the top end I plan on replacing the points dizzy with a non-point system. What would you recommend? (or is this a new thread...)
 

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Discussion Starter #15
One more question...

If your car is running with std US cams, you only need to change the intake to a 10548 as the engine will make better torque with the USA exhaust cam.
OK, really two questions but both related.
I'm going to be doing a bit of work on my Spider this weekend (trying to cure an oil leak) so while I got the wrenches out.......
Question one - should I replace my 10548 exhaust cam with a stock cam? (I have a pair on the bench)
Question two - should I set these both to stock timing marks? (I have the centerline templates and feel comfortable using them to change things a bit)

Right now both cams are 1054803 2001 and set to factory marks.
I drive with vigor, but not on the track or over 90 mph.

Thanks!
Jim
 

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Gotta subscribe to this one. I have a pair of 10548's in my 1600. I thought about changing the exhaust cam to a 1750 SPICA cam I have. Would it be worth it? What would I gain/ loose?
 

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Richard Jemison
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cam timing and other

You get benefit from the 10548-01 only because of the minor lift improvement and the small increase in duration that results from that lift. The lobe design is no more than a larger 9.6mm stock cam.

As I have said many times, both the 10548-01 and it`s smaller stock cousins have lobes designed for gentle lift and closings, and reduced wear to keep the cars out of the dealer`s shop through the warranty period. These are not "performance enhancers" just as the "S" cams in the V6 application where the only change is again only an enlarged intake lobe.

The correct timing of all the carbed Alfa`s was changed in a TSB from 102 (the stock mark) to 104 (both in & ex). That basically means the cam`s marks are positioned just outside (toward each side of the head) of the 102 mark on the cam cap. The marks should basically match the outside edge of the cap mark with the leading edge of the cam mark. This reduces the inherant excessive overlap due to the slow ramp rate. As well the wider LSA improves the valve timing events for better power (increased power stroke and combustion pressures).

However you set up Alfa stock cams the valve events won`t be as good as they can be because of lobe design.
Not until the TS did Alfa make an effort to improve the lobe profiles used on the intake and exhaust sides. Though the ramp rates are still slow (for the same reason as earlier versions) they do have less overlap and a different profile on each side to improve timing the valve events.

It amazes me the foolish manouvers used by engine "builders" to sell costly modifications to gullible Alfa owners for increasing output for non racing engines. It always seems to start in Europe. Big valves, Reducing the size of the exhaust seat/valve, small stem valves and their related parts etc. In an all out racing engine "some" of this is useful. In a performance street motor none of it is appropriate.

Here`s a perfect example forwarded to me by Bill Theobold.

2.0 Nord Trackday/Rally/Race Head – Big Valve | Classic Alfa Romeo spare parts and accessories

$6000.00 and 185 crank hp. Pitiful. Requires relocating the spark plug, inserting larger seats, all the components for converting to large valves with small stems and still makes no more HP than Ed`s stock size valve head using 40mm emission Webers.

If you have pi$$ away money go ahead and buy the Bling!
 

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Discussion Starter #18
Thanks for the quick reply. Sounds like I won't gain any real benefits from changing out the exhaust cam. You mention the TSB changed the timing to 104 on carbs, same on SPICA ?
Thanks again.
Jim
 
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