A number of performance parts suppliers sell cam chain/gear sets with 3 keyways allowing you to either advance or retard the cam timing. According to them advancing cam timing will result in increased low end power etc. Anyone have an opinion on this topic? Like... is it a good idea or not......

Ken

 

Doubtful, unless you have an all out application and are going for the last hundredth at the track. I'd leave it as is, epecially if yours is stock.

 

when I was building my engine the machine shop somehow put mne in the retard slot and caused all sorts of problems, puking gas out the intake, valves slapping pistons, all sorts of nasty shiite. Put it back to OEM slot and it started right up. I wouldn't fool with it unless you are absolutely sure of the results.

 

I would degree the cam and use the slot that best matches the cam manufacturers spec. The specs they give usually work out best.

 

I like the ones that have the eccentric, so you can get it right on the specs. I always install mine "straight up"

 

Unless you have a specific need to change cam timing, go straight up.

Larry
code5coupe

 

It is a fine tuning aid. You can juggle the timing to help you determine what specs you want in the new cam. Advancing the cam ROTATES the torque curve, toward lower rpms. Rotating means that it also reduces the torque at higher rpms. Of course retarding the cam works exactly the opposite. There is no point in buying a new cam and installing it advanced or retarded, unless it is done as a part of a comprehensive tuning program. If you think the cam isn't right for you, buy the cam that is.

RACE ON!!!

 

I bet there are not a lot of folks that do take the time to degree a cam to start with.
It has been my experience that they are almost always off by a bit.

 

You should ALWAYS degree your cam on the mockup. This is where you will find you have interference or now or need to make a change to the timing setup to get the cam "degreed" properly.

ALL manuf. of cams have different methods of grinding cams. Sometimes I do not even think they know themselves. Been told one way and found it to be something different. What I am talking about here is whether or not the cam has the 4* ground into it that some here are talking about or not. Some companies do, some do not.

Some other things that you MUST realize when putting a cam in is your relying on SEVERAL things to be right in order to get your cam in at the CORRECT angle.

(1) The keyway in your crankshaft relative to TDC
(2) the keyway on the crank sprocket
(3) the pin location/bolt holes on the cam sprocket
(4) the dowel pin/bolt holes on the cam itself
(5) shouldn't be an issue, but can be if your not using new stuff and that is timing chain stretch. that alone can put you off SEVERAL degrees.

But as you can see your ASSUMING a bunch when you just slap the cam in at the 0* mark.

The absolute proper way to do it is DEGREE THE CAM. The manuf. of the cam will give you a specific angle that the cam should be degree to. My latest cam is 104*. This is degrees required for the intake valve to travel from .050 before and after max lift for my cam.

If you get anything other when you degree your cam from the number specified, you NEED to adjust it. You adjust it by using the different keyways on the crank. Most nowdays have 3 setting. 4* adv; 0*; and 4* retard. REMEMBER that 4* on the crank will only change the cam 2*! Its a 2:1 ratio.

Some of the better timing chains have a hex-adjust setup or have MANY keys. I like the one that has many keyways. Basically it has 2* increments or as mentioned above, you can make adjustments as little as 1*.

There is no excuse not to degree your cam. Its the heart of the motor!

 

ALWAYS-ALWAYS-ALWAYS degree the cam.

street engines or race... there is MUCH to be gained by properly timing the valve events.

if you have no idea of what you're doing, put it in ''straight'' up....if you know you're building a torque monster (all l98's) advance it at least 4*....if you're gonna buzz it 8 grand+ on the strip, retard it at least 4*...
record what you set it on so later on you can fatten up the bottom or the top by changing the cam timing.
moving the cam will alter valve/piston clearance--not usually a problem with street cams and pistons, and on race motors you should check clearance in advanced and retarded positions so that you can safely reset later without hitting the pistons

btw- i just did a bbc a couple days ago and the 4* marks moved the cam 8*...don't know where the guy bought the set but it was true rollers and looked ok...without degreeing it things would have been weird