Petrolheads pop quiz

[Tappy]

ok can someone tell me the difference between both cams perfomancewise , i'm just a novice in this and would like to understand wich are the best choise and how they perform (where the differences are)


cam set 1 : Cam deg In 15 / 55, Cam deg Ex 57 /13, Cam lift * 9.9mm

cam set 2 : Cam deg In 13 / 45, Cam deg Ex 49 / 9, Cam lift * 9.4mm

thanks for clearing this out !!

[Tappy]

no one ? i'll trow in a link to Modifying & tuning Fiat Lancia twin-cam engines.pdf book

[Tappy]

i'll kick up this post ones more , because i just can't believe that i know equally as much as you guys (nothing:)) on this matter

But i'll rephrase it this time , if you had to choose should you take lancia cams over fiat cams ? i've heared that the lancia ones are a bit more "sharp" , but i'm not sure what that means

[rlux4]

Well Tappy, your knowledge matches mine on this subject. But it didn't feel right just to leave you dangling out there all alone, so I thought I'd say at least something.
I have rebuilt engines in the past, but never built one for performance, so all I know about cam mods is terms like "street", "3/4 race" and so forth. I never raced, so I never had the need to get educated on it. However, if and when you do get an answer here it will add to my knowledge base and that's a good thing.
Ron

[mdrburchette]

Tappy, I know so terribly little about cams but I'll try to help you.
I'm assuming Cam set 1 is the Lancia cam? So,( Cam deg In 15 / 55, Cam deg Ex 57 /13, Cam lift * 9.9mm)
9.9 mm cam lift is talking about the camshaft lobe and how far it opens the valve.
In 15/55 is talking about the duration in which the valve is open and closed, so the intake valve is open for 15 degrees and closed 55 degrees.
By comparing the numbers of the two sets of cams, it looks like the Lancia cam would be more aggressive because it has a higher lift and the intake and exhaust valves will be open for a longer period of time with more overlap (as intake closes, exhaust opens with a small period where both are open).
Clear as mud? Now you know as much as a girl.

[Tappy]

thx both Im like 24/7 on the forum (imangine how bored i am) because i cant get to my car if my mechanic has no time 3 weeks now

Thx denise for the explanation , however the cam set one is the fiat cam set not the lancia one :s , but i guess i understand it some more now , i've read about it in the tuning book but its to much info in a foreign language for me (i'm just a cook)

[mdrburchette]

I guess these are stock cams, right? What is the 15/55 cam out of? A high performance cam benefits performance at higher rpms and a stock cam is more efficient at lower rpms. I don't know if you'll see much difference in using the Lancia Beta cam over the Fiat cam, but in Guy's book, it shows the 1608 Fiat cam (26/66) had 2 bhp more than the Lancia (13/45).

[Tappy]

yes they are stock , the 15/55 schould come of a 132 DB 000 2l fiat engine (132/argenta) the other cams of a 1981 lancia beta

Just got a message from my mechanic and we're of for fixing tomorrow , i keep you posted , neverteless i trie to install the block mounted dizzy and the alquati manifold so i can easely change the cams in the future if desired

I hope to get my fiat on a test bench when finiched to see howmuch Hp it actually gets , then i can see in the future when i do some mods what the effects are

[TulsaSpider]

Cam choice is always a debate. It's cam lift, (the amount (height) the valves are opened) duration, (the amount of time the valves are open), overlap, (the amount of time that the valves are open at the same time) and on and on it gets incredibly complicated. I guess it's good you only have 2 to choose from, not 50! Plus the Fiat valve train is all solid we don't have to choose between hydraulic, solid, hydraulic roller, solid roller, single profile, double profile........etc... I am like the others on here I have swapped cams and heads and carbs on Chevys all my life but never owned a Fiat until this year. The rule of thumb is the bigger the lift and duration the higher the horsepower and lower the torque. and vice-versa Torque literally is twisting power. Torque is what you feel when you get planted to the back of your seat when you hit the gas. Horsepower gives you speed. Personally since you will have the carbs for it I would go with the taller cam, after all you are trying to make the motor breathe better and after all it's just a fancy air pump!! But like I said I haven't cracked one of these open as of yet, I don't have the $$$$ to do that, but I would love to see if I can get her keeping up with some of the "modern" cars one of these days!

[SpiderHead]

I really am loving the stock cam. But I drive like a grandpa, so it suits me...

Think of it in terms of booze. Everclear has tons of kick, but it sucks @$$ when compared to a good bourbon.

-Ryan

[brad131a4]

Well if you look at the profile of the good street cams for fiats and lancias . They are in the 40/80-80/40 profile. These are what Bayless , Vicks and International sell for street performance cams. Most of the time you can get away with just running the intake side of the cams and not loose much in power over running both. Duration is 300 degrees lift is 10.35mm. If needed I can copy the specs for you.