Degreeing Cams

[justa03]

I know this topic has been covered a few times about the process of degreeing the 4V. So I put Crower stage 3s in my car about 4 years ago, car never ran right couldnt get it tuned right. Tore it apart almost 2 years ago and now getting back into it. In the process of degreeing the cams. I lined up all the dots and links for a base timing. From there I followed Comp Cams centerline method and my results are as follows, RH exh 118* int 103*, LH exh 107.5* and int 116*. According to the cam card centerline should be at 110*

Has anyone that has done this or experience with this have seen them that far off before? Im planning on shaving the keyway and using ARP camshaft bolts to torque the cam gears into place. The timing chains were tight as I had a clamp on each timing chain guide to tighten them. I checked and rechecked and kept coming up with the same numbers. Just wondering if I am doing this right or is something wrong? I also contacted Crower on this and was given Dave Crowers direct number and was told to check tappet lift at .006" and then valve lift at .050". Does this sound right to anyone one? Dave was telling me I have to check at .006" tappet lift to have zero lash and I am using MMRs solid lifter.

Any help or insight would be greatly appreciated. Thanks, Dan :beer:

 

[Bruha]

subin. Hoping you get it figured out.

 

[justa03]

Haha me too man def wanna get the car back on the road with some E and higher boost. Def isnt like degreeing a SBC thats for sure!

 

[Ironhand]

You have the part number for the cams? What's the duration at .050 lift?

 

[justa03]

The Crower part # is 62824-4, if your looking up the cam card on Crowers website you gotta type in 628244. Duration at .050" lift is 212/212. Durtation @ .050" lift at the valve is 228/228. The cam card shows centerline at 110.

 

[racebronco2]

I know this topic has been covered a few times about the process of degreeing the 4V. So I put Crower stage 3s in my car about 4 years ago, car never ran right couldnt get it tuned right. Tore it apart almost 2 years ago and now getting back into it. In the process of degreeing the cams. I lined up all the dots and links for a base timing. From there I followed Comp Cams centerline method and my results are as follows, RH exh 118* int 103*, LH exh 107.5* and int 116*. According to the cam card centerline should be at 110*

Has anyone that has done this or experience with this have seen them that far off before? Im planning on shaving the keyway and using ARP camshaft bolts to torque the cam gears into place. The timing chains were tight as I had a clamp on each timing chain guide to tighten them. I checked and rechecked and kept coming up with the same numbers. Just wondering if I am doing this right or is something wrong? I also contacted Crower on this and was given Dave Crowers direct number and was told to check tappet lift at .006" and then valve lift at .050". Does this sound right to anyone one? Dave was telling me I have to check at .006" tappet lift to have zero lash and I am using MMRs solid lifter.

Any help or insight would be greatly appreciated. Thanks, Dan :beer:

I have degree'd several engines so far. The numbers you posted are really close to the ones i have checked with one exception, both exhaust cams were really close to 118* and intakes were around 107*. Are you sure you didn't mix up the left hand side cams? The chains stretch causing the exhaust cams to open later or being retarded but i don't know how the chain could get shorter and advancing the exhaust cams.

 

[justa03]

I hope not. I had a valve job done on the heads at a machine shop and just got them back. He put in new valve seals and reinstalled the cams, followers and tappets. But I will def check that when I get back to my shop. So those numbers seem about normal to you before degreeing the cams? If so then did you just set the centerline where it was supposed to be via the cam card? As in my case I set the centerline to 110* still right?

 

[Quick Strike]

According to your cam card using the @ .050" duration, you should be at 110* on the intake centerlines and 118* on the exhaust centerlines. This gives you a 114* lobe separation with 4* of advance.

 

[Ironhand]

Intake Opens After TDC: 4
Intake Closes ABDC: 36
Exhaust Opens BBDC: 44
Exhaust Closes ATDC: -12
Overlap: -16
Lobe Separation Angle (cam degrees): 114

Be very careful how you do degree the cams. Depending on the cams, a piston with valve notches can NOT run as tight as 104-106 ICL. Since these cams are less in duration then you should be fine but you need to check your PTV Clarence regardless. You are aiming for .090-.110 on the intake side and about .100 on the exhaust side for a stick car. You can run tighter PTV clearances but that range is a good safe range.

 

[racebronco2]

I hope not. I had a valve job done on the heads at a machine shop and just got them back. He put in new valve seals and reinstalled the cams, followers and tappets. But I will def check that when I get back to my shop. So those numbers seem about normal to you before degreeing the cams? If so then did you just set the centerline where it was supposed to be via the cam card? As in my case I set the centerline to 110* still right?

The 118* exhaust and the 103* intake looks normal for used sets of chains. Set the cams according to the cam card unless someone whom you trust tells you different.

 

[Quick Strike]

Lobe Separation = (Intake Centerline + Exhaust Centerline) / 2

In your case we have the Intake Centerline (110*) and Lobe Separation (114*) from the cam card, so it goes like this:

114 = (110 + EC) /2. This translates to: 2 x 114 = 110 + EC. That reduces to 228 = 110 + EC. That translates to 228-110 = EC. That reduces to 118 = EC.

So the Exhaust Centerline = 118* for your cams as derived from the card. Exhaust centerlines increase in number as they are advanced and intake centerlines decrease in number as they are advanced. We know your cams are advanced 4* since the intake centerline is 4* less then the lobe seperation angle and the exhaust centerline is 4* higher then the lobe seperation angle.

You can trust the math and the formula - HTH ;-)

 

[justa03]

Wow thanks for the replies and info guys. Didnt get a chance to swing by my shop to make sure the cams are right in the LH bank since I had softball after work last night.

Quick Strike and Racebronco do both of you use the Comp directions when degreeing the cams? And according the Quick Strike I guess my numbers are closer then I thought, at least for the RH bank? Looks like I have some tweeking on the intake cam and then figure out whats going on, on the LH bank? Thanks again guys!

 

[racebronco2]

I have never used cams other then stock.

 

[justa03]

Did you use Comps centerline method to degree the stockers?

 

[Quick Strike]

Did you use Comps centerline method to degree the cams?

I did, and I used welding clamps (like you) to keep tension on the arm like oil pressure would. I also degreed in an extra 1/2* of advance from my cam card to account for the big chains stretch over time.

 

[justa03]

I did, and I used welding clamps (like you) to keep tension on the arm like oil pressure would. I also degreed in an extra 1/2* of advance from my cam card to account for the big chains stretch over time.

Like how you know it was welding clamps! :lol: Works and does the trick! So from what ive been told on here degree the intake cam to 110-110.5 and exhaust cam to 118-118.5? I def thought I was smarter at this until I started to dig into it but gotta figure it out sooner or later! Thanks again for the help so far! :beer:

 

[Quick Strike]

Nothing else works as well as a welding clamp! They do get in the way at times though. I'd shoot for 110* IC and 118* EC if using the old chains and 109.5* IC and 118.5* EC if the big chains are new. Also remember to take the 0.050" before and after CL measurements while turning the engine in a clockwise direction. I made sure to get them both in a single pull. I would stop at the 0.050" before and continue to the 0.050" after. Then I repeated it several times to make sure the numbers were the numbers. Then I filed a lot and repeated the process endlessly until one day everything was finally right!

 

[Quick Strike]

Also remember to start with the exhaust cams as the intake cam is turned by and dependent on the exhaust cam for position. If the exhaust CL is wrong the intake CL can't be right no matter what it is.

 

[justa03]

Haha so Im guessing that you filed the camshaft sprocket and used ARP bolts then?

 

[Quick Strike]

Haha so I'm guessing that you filed the camshaft sprocket and used ARP bolts then?

Yes, lots of sprocket filing and fitting. I have custom Comp cams with larger (then stock) ARP bolts. You have to take the exhaust sprocket off to get to the intake sprocket if there is not enough slack filed into the intake sprocket. That means re-degreeing and resetting the exhaust before seeing if you filed enough into the intake sprocket. That is when you realize you are in it for the long haul. Eventually, you get the hang of where to put the exhaust right each time. Then it is a matter of filing and refiling, checking and rechecking.

This is fun right? :shrug: