Degreeing a Cam, or not.....

[PRH]

There's a few heavy hitters involved with that build.

If you subtracted 100hp for not having the “heavy hitter” blessing, then took another 10% off for installing the motor in the car, then knocked 2.5 tenths off for track elevation, and assumed the race weight was 3600lbs.......the ET’s achieved so far by the OP(12.30’s) are still over 1 second off what one would expect to see out of that basic combo.

That would be about a 11.25@117........ which shows 445hp@3600lbs.

 

[Kent mosby]

tdc tool arriving on Sunday. This is my cam card. I don't see anywhere that says this is supposed to degreed in either advanced or retarded mode. So I should be 108 on intake CL 116 on Exhaust CL. I hope to complete this on Sunday for checking where it is installed.

 

[RustyRatRod]

There's a few heavy hitters involved with that build.

It can still be duplicated.

 

[RustyRatRod]

tdc tool arriving on Sunday. This is my cam card. I don't see anywhere that says this is supposed to degreed in either advanced or retarded mode. So I should be 108 on intake CL 116 on Exhaust CL. I hope to complete this on Sunday for checking where it is installed.
View attachment 1715762536

Yes sir, actually you do, you just don't know it.

Look where it says "Lobe separation". 112. Now look where it says "Intake center line". 108. That means when it's installed "right" it will be 4 degrees advanced from the 112 LSA. It might be there. It might not be. Since it was not degreed, you just don't know.

 

[Kent mosby]

So, After confirming TDC. I would then check the Intake CL and it should be 108. If it is not, or very close (1* off maybe) then I would have to correct it by changing the gear orientation to get the 4*. I would have thought that it would be ground so that when installed at "TDC" the 4 * advance would be built in. Maybe not. Thus why I should have checked in the first place. Live and learn.

 

[oldkimmer]

The crank key could be off. The timing marks could be off on the sprockets or the pin installed in the wrong place. Cam could be off also. Lots of variables. Kim

 

[George Jets]

So, After confirming TDC. I would then check the Intake CL and it should be 108. If it is not, or very close (1* off maybe) then I would have to correct it by changing the gear orientation to get the 4*. I would have thought that it would be ground so that when installed at "TDC" the 4 * advance would be built in. Maybe not. Thus why I should have checked in the first place. Live and learn.

Most performance cams have a 2° Advance ground into them already.

 

[George Jets]

Your Lobe Separation is listed at 112*, that is the average between the Intake Lobe Centerline of 108* and the Exhaust Lobe Centerline of 116.

4* on each side of the Centerline numbers, = Lobe Separation degrees at 112.

So far you are good.

 

[George Jets]

Thanks for this. I will do this next weekend (10 days) and post results.

Made up one of these 7" degree wheels today, from an aluminum sheet and a printed degree wheel.

Bolts on to the front damper of assembled engines, for reading valve timing events.

Can just glue on the printed degree numbers to the outter edge of the damper for some quick temporary testing too.

Example:

 

[Dartfreak75]

Made up one of these 7" degree wheels today, from an aluminum sheet and a printed degree wheel.

Bolts on to the front damper of assembled engines, for reading valve timing events.

Can just glue on the printed degree numbers to the outter edge of the damper for some quick temporary testing too.

View attachment 1715763566

View attachment 1715763567

View attachment 1715763568

View attachment 1715763569

Example:
View attachment 1715763570

Thats freaking awesome!! You are always so dang creative! Nice work my friend!

 

[RustyRatRod]

So, After confirming TDC. I would then check the Intake CL and it should be 108. If it is not, or very close (1* off maybe) then I would have to correct it by changing the gear orientation to get the 4*. I would have thought that it would be ground so that when installed at "TDC" the 4 * advance would be built in. Maybe not. Thus why I should have checked in the first place. Live and learn.

It is ground like that. The discrepancy you're checking for is what's in the timing set, cam and crank keyways. Even though the camshaft is ground with that 4*....or "whatever" the cam card says, that doesn't mean it will "match up" correctly with all the other parts to make it happen without some adjustment.

 

[RustyRatRod]

Most performance cams have a 2° Advance ground into them already.

No, most it's 4. ......BUT, some are different, so it's "whatever" is on the cam card.

 

[Kent mosby]

Here is what I have found. I used the TDC tool and My TDC lines up correctly with the 0 on the Balancer/Dampener. When I measure the degrees at .050 tappet lift, (.075 spring retainer lift since I have 1.5 ratio rockers), I have the opening at 4.5* btdc and it should be 15*btdc as measured on the dampener. The closing mark at .050 tappet lift is at 57.5*ABDC not 51*. Thinking I may have a flattened lobe I checked the LIFT of the spring retainer. I got .492 on the intakes of cylinder 1 and 5, Should be .517 inch. Exhaust was .502, should be .537 on #1 cylinder. Also thinking that my dial gauge may be off I measured a drill bit with calipers at .481 and then measured the dial lift and it was bang on. I am confused by this. Wrong cam?

 

[Dartfreak75]

Here is what I have found. I used the TDC tool and My TDC lines up correctly with the 0 on the Balancer/Dampener. When I measure the degrees at .050 tappet lift, (.075 spring retainer lift since I have 1.5 ratio rockers), I have the opening at 4.5* btdc and it should be 15*btdc as measured on the dampener. The closing mark at .050 tappet lift is at 57.5*ABDC not 51*. Thinking I may have a flattened lobe I checked the LIFT of the spring retainer. I got .492 on the intakes of cylinder 1 and 5, Should be .517 inch. Exhaust was .502, should be .537 on #1 cylinder. Also thinking that my dial gauge may be off I measured a drill bit with calipers at .481 and then measured the dial lift and it was bang on. I am confused by this. Wrong cam?

You loose some lift with factory rockers.

 

[Kent mosby]

The rockers are 440 source. Aluminum Roller Rockers/shafts - 1.5 Ratio - New-440 Source

 

[Kent mosby]

I forgot to say that I took out the valve lash to .000 on the #1 intake rocker and recorded lift of the spring retainer parallel to the valve CL.

 

[RustyRatRod]

Here is what I have found. I used the TDC tool and My TDC lines up correctly with the 0 on the Balancer/Dampener. When I measure the degrees at .050 tappet lift, (.075 spring retainer lift since I have 1.5 ratio rockers), I have the opening at 4.5* btdc and it should be 15*btdc as measured on the dampener. The closing mark at .050 tappet lift is at 57.5*ABDC not 51*. Thinking I may have a flattened lobe I checked the LIFT of the spring retainer. I got .492 on the intakes of cylinder 1 and 5, Should be .517 inch. Exhaust was .502, should be .537 on #1 cylinder. Also thinking that my dial gauge may be off I measured a drill bit with calipers at .481 and then measured the dial lift and it was bang on. I am confused by this. Wrong cam?

What are you using to measure lift with and where?

 

[Kent mosby]

Dial indicator on the spring retainer, making sure that there is no binding/hitting on the rocker arm.

 

[replicaracer43]

You will NOT have the exact lift at the valve as the cam card indicates. Almost no rockers are exactly there indicated ratio, seldom are all 16 the same, and you probably have geometry affecting you as well. Not to mention, if you still have the spring on the head your running, that will induce flex also

 

[RustyRatRod]

Dial indicator on the spring retainer, making sure that there is no binding/hitting on the rocker arm.

You cannot expect an accurate measurement, unfortunately. You need to figure out "something" to do about the hydraulic lifter plunger. I believe the only real way to do that is going to be removing the intake, valley pan and flipping a lifter upside down. Otherwise, the lifter plunger will give you inaccurate measurements, since it will compress. Maybe @IQ52 Jim Laroy knows an easier way. I cannot think of one.....unless you can reach through the valve cover area in the head and do it.

 

[Kent mosby]

You cannot expect an accurate measurement, unfortunately. You need to figure out "something" to do about the hydraulic lifter plunger. I believe the only real way to do that is going to be removing the intake, valley pan and flipping a lifter upside down. Otherwise, the lifter plunger will give you inaccurate measurements, since it will compress. Maybe @IQ52 Jim Laroy knows an easier way. I cannot think of one.....unless you can reach through the valve cover area in the head and do it.

They are solid lifters. I thought you could measure directly the lift.

 

[RustyRatRod]

They are solid lifters. I thought you could measure directly the lift.

Oh ok. Cool. Then in that case, you can do that. I'm sorry. I thought they were hydraulic. But as was mentioned, you won't get the exact lift, due to valve train angles and other variances. Also, I feel sure to get it dead accurate, your rocker shafts probably need relocating, like Mike at @B3RE offer the shims for.......BUT that's opening a whole nuther can of worms you don't need to get into right now, IMO.

 

[George Jets]

Here is what I have found. I used the TDC tool and My TDC lines up correctly with the 0 on the Balancer/Dampener. When I measure the degrees at .050 tappet lift, (.075 spring retainer lift since I have 1.5 ratio rockers), I have the opening at 4.5* btdc and it should be 15*btdc as measured on the dampener. The closing mark at .050 tappet lift is at 57.5*ABDC not 51*. Thinking I may have a flattened lobe I checked the LIFT of the spring retainer. I got .492 on the intakes of cylinder 1 and 5, Should be .517 inch. Exhaust was .502, should be .537 on #1 cylinder. Also thinking that my dial gauge may be off I measured a drill bit with calipers at .481 and then measured the dial lift and it was bang on. I am confused by this. Wrong cam?

Looks like your valve timing events are coming in retarded instead of on the degrees you desire.

Can move to cylinder #5 and check the @.050 valve events there to see if they are the same as #1, or if it is an isolated cylinder thing.

 

[replicaracer43]

Here is what I have found. I used the TDC tool and My TDC lines up correctly with the 0 on the Balancer/Dampener. When I measure the degrees at .050 tappet lift, (.075 spring retainer lift since I have 1.5 ratio rockers), I have the opening at 4.5* btdc and it should be 15*btdc as measured on the dampener. The closing mark at .050 tappet lift is at 57.5*ABDC not 51*. Thinking I may have a flattened lobe I checked the LIFT of the spring retainer. I got .492 on the intakes of cylinder 1 and 5, Should be .517 inch. Exhaust was .502, should be .537 on #1 cylinder. Also thinking that my dial gauge may be off I measured a drill bit with calipers at .481 and then measured the dial lift and it was bang on. I am confused by this. Wrong cam?

You cannot do it that way. The timing specs are based on tappet lift, NOT valve lift and you cannot figure it mathematically because you dont know your actual rocker ratio, not to mention your geometry will effect rocker ratio

 

[George Jets]

You cannot do it that way. The timing specs are based on tappet lift, NOT valve lift and you cannot figure it mathematically because you dont know your actual rocker ratio, not to mention your geometry will effect rocker ratio

Cam lobe lift x 1.5 ratio rockers = final lift.