Yet another cam question

BlpltGTV · #1 (**permalink**) 02-22-2008, 08:22 PM

So I pulled my valve cover off to see what cams I have. My intake is a 10502032000, and the exhaust is a 105020320001. Upon closer inspection, It looks like these are 1300/1600 cams, not a 1750 cam (either one). Is this correct? How much power could I gain (potentially) by going to a set of euro 2L cams with my stock SPICA injection? I know I can't get too crazy with the cams but there has to be a decent gain someplace. The engine is in good shape, compression checks out at 187,185,187,185. (Not bad for sitting 30 years.) This must be the reason the car feels gutless.

Thanks,
Will

**Bill S** · #2 (**permalink**) 02-23-2008, 06:15 AM

Gack, the intake cam is for a 2L Spica car, probably the worst cam you could have in there. The exhaust cam is correct for a Spica 1750 and not that bad of a cam although a euro 2L cam (10548) would be better. I've got a correct 1750 cam (same as your exhaust) I'd sell you for the intake for $50 if you want. You could probably find one local for just as cheap. Perhaps Mr. Jemison will weigh in with a better suggestion.

**Zunige** · #3 (**permalink**) 02-23-2008, 07:22 AM

Quote:

Originally Posted by BlpltGTV

... My intake is a 10502032000, and the exhaust is a 105020320001. ...

**Alfar7** · #4 (**permalink**) 02-23-2008, 08:08 AM

well, I suspect the cams are the same, but first check the lobe hight to see if they are really differnt. (Measure base to nose with a didgital or dial caliper)
If the exhaust is .3mm larger(.012) you might swap them to get the minute increase in lift & duration, but it`s hardly worth the effort.
As to the 10548 as intake it will add significant lift & duration but you only need it on the intake. The cam on the exhaust side is fine. You didn`t say what year your Spica car is, and some of the pumps wont have adequate fuel delivery at higher RPMs , but all can be adjusted to work with the cam until they are maxed out. I could be wrong

but I think `77 up and particularly `80 & `81 cars were the least performing versions.
"If you use a 10548' on the intake I would suggest setting it at a lobe center of 100, rather than the 102 as spec`d in Europe. The FI cars (Spica & Bosch) work better with less intake overlap, and the 10548 is a typical slow ramp cam. I have a single "as new" "10548" if you want to go that route. You also didn`t mention if you had a VVT sprocket.

**Bill S** · #5 (**permalink**) 02-23-2008, 08:40 AM

Quote:

Originally Posted by Alfar7

well, I suspect the cams are the same, but first check the lobe hight to see if they are really differnt. (Measure base to nose with a didgital or dial caliper).

BlpltGTV · #6 (**permalink**) 02-23-2008, 08:56 AM

The spica is a 69, bone stock, untouched. I have been thinking of putting some new cams in for a while (I knew there was something strange going on, drives fine, good compression, just gutless.) At this point, it looks like the car might become my AutoX as well as everything else car next year as the track car seriously needs time off and lots of $$ (paint and possibly an engine rebuild) thrown its way.

That said, currently I'm considering a set of Spruell headers, and the most cam I can run without having to send the Spica out to be rebuilt/modified. The valve springs are stock, so I really can't go huge. I'm less than inclined to pull the head off just to swap valve springs as its happy where it is and doesn't leak anything. (Kind of a "if its not broken, don't fix it" thing.) I'd like to go with a modern lobe design as there is a reason the design has changed over the past 40 years. The cam gears are stock, non VVT (I think the car was parked in the barn before VVT was invented)

On the missing 0, I double checked it and there were only 3 0s and a funky dimple in the casting, no clear 0 where there should be one. My digital calipers need a new battery, so I was unable to check them.

Will

**Alfar7** · #7 (**permalink**) 02-24-2008, 08:05 PM

For a 1750 motor I wouldn`t suggest a 10548. The motors need all the help they can get torque wise and the small ports & valves work better with more duration when valves are open higher.
Look at my website at cams like the 796 and 125 that will fit without modification, have reduced overlap & more .100 up valve duration.

BlpltGTV · #8 (**permalink**) 02-26-2008, 07:52 PM

Richard,
That was the type of suggestion I was looking for. It sounds like the your 796 cam is what I might be looking for. Do you have any idea of a rough best case scenario for hp gain over what I have? 5? 10? More? Honestly, the duration and lift #s for Alfa's is tiny compaired to what I see in the Datsun world. For the U20, the stock SU carb cam is a 256 duration, and .44" lift, the one for the Mikuni carbs, is a 280 duration with a .456, and my custom Isky is huge. 315 on the intake, 325 exhaust with tons of lift (I can't remember off the top of my head, its stamped into the cam.) I know very different creatures, but the durations are so much smaller on the Alfas. Its just an observation.

Thanks,
Will

**Alfar7** · #9 (**permalink**) 02-26-2008, 08:06 PM

With a 796 intake only you should see 10HP and more torque but it is a lot dependant on engine tune. The 796/776 will be your best bet. you will need to adjust the Spica. A stock `69 is a fair unit, but it will run out of fuel to mix with the additional breathing about 6000. But it will be much quicker getting there.