silver97Z

What do the cam numbers mean...ex. 213/218 @.050 112lsa

I did a search and didn't come up with anything useful. Can someone explain what the 213/218 means and what the differences are in different numbers...208/222...236/228...

What is the difference in different lifts? .50 or .620, etc.

And last, what does the lsa mean and what is the difference in 112, 110, 113, etc lsa?


Thanks!!!!! I did a search and didn't come up with anything useful.

RamAir95TA

Basic camshaft principle.

Your camshaft is responsible for opening and closing the valves in the heads. The intake valve opens first for a certain amount of time (called duration) and projects from the valve seat a certain distance (called lift). VERY generally speaking, an aftermarket camshaft (such as the hotcam) increases these numbers significantly, allowing more fuel and air to enter the combustion chambers.

For example, the hotcam specs are as follows: (218 / 228, .525 / .525 112 LSA )

The first two numbers are duration (see definition above). Intake valve is open for 218 degrees of camshaft rotation, while the exhaust valve stays open for 228 degrees. The intake (and exhaust valves in this case) both project .525" from the valve seat. The LSA is the amount of overlap, i.e., the amount of time that the intake and exhaust valves are open simultaneously.

That's a VERY VERY VERY simplified definition of how a camshaft works.

Mtrhds94Z

The above is basically correct except LSA is LOBE SEPERATION ANGLE[in degrees...]which is the angle seperating the center of the lobes between intake and exhaust... it isn't 'overlap'[which is the time that both valves are open at same time..]
Check this out it'll help:
http://www.compcams.com/information/...s/valvtim2.asp
Charlie

97Z-M6

no offence at all, but how can you have over a 1000 post on this board and not no the answer to that question. not that i wouldnt help or anything but i was just curious. because if you have a 1000 post on here, then must have read alot to have that many post.

i am not trying to poke, honest. after all you never know unless you ask.

silver97Z

No offense taken...I probably spend more time in the appearance forum than I do here...mainly because I can't answer most of the questions that are asked in here.

Although, I have learned a ton by reading posts on here but I've never read a post that actually explained what the specs relating to a specific cam mean. All the posts about cams are "Which cam should I pick," or "Help me pick a cam."

Brian

silver97Z

Oh...thanks for the replies so far...just one more question.

What is the difference in lsa? What I mean why would you choose a 112 lsa over a 113 lsa or a 114 lsa?

Thanks.

EviLBoX

Here's some pictures also if you're interested:

http://auto.howstuffworks.com/camshaft.htm

OldSStroker

Hmmm... No flame, but that's not quite accurate.

Duration is specified in crankshaft degrees of rotation, not camshaft degrees. Cams of course turn at 1/2 crank speed. That's why even big lobes use less than half of the cam lobe.

LSA or "lobe separation angle" is the angle between the centerline of the exhaust lobe and the centerline of the intake lobe, and is expressed in camshaft degrees. With a single cam-in-block engine like SBC or single overhead cam (SOHC) engine the LSA is fixed; it's ground into the cam. With DOHC it can be varied either during engine buildup or while the engine is running.

Overlap is the period when the exhaust is closing and the intake is opening and both are open at the same time. Generally more overlap hurts idle and low rpm power but helps higher rpm power.

97Z-M6

lobe separation angle=lsa - is the amount of degrees that seperates the exhaust lobe and the intake lobe, like if you were looking down the cam from one end to the other. like loooking down the barrel of a gun. and take the two lobes that are for one cylinder and you can see there set apart by and angle, and the lsa is the degree of that angle.

now the way that plays a part with choosing a cam is the more of a angle the better it is for nitros or a blower and the less lope the cam will have and the less cam surge it will have, and the more broad the power curve will be.

now the less the angle, you will have to rev a little higher, the power curve gets narrower, and more lope (duration plays a role here as well), the more cam surge you will have. (duraton here to)

the smaller the angle the more overlap

this just a small over veiw of lsa

hope this helps.

Toolman1

This is all I have don't know the brand