Degreeing cam - need help

[mustangsilly]

I bought a 264-10 Clay Smith cam and double roller timing set from Classic Inlines. I am trying to degree the cam with a dial indicator and degree wheel using the .050 measurement on both intake and exhaust. But my readings are not even close to the cam card.
I have rechecked my setup three times. I found TDC using the dial indicator (the head is off). I get the same reading every time - +130 degree intake valve opening and +10 intake closing. The timing mark on the cam gear is lined up with the +4 keyway on the crank gear as recommended by Clay Smith Cams.
I know I'm doing something wrong, but damned if I can figure out what.
Also, I only measure .390 lift - the card says it's .480. I'm going bonkers trying to puzzle this out. Anybody got any ideas?

 

[addo]

480 thou lift will be at the valve, with an averaged rocker ratio around 1.5:1. So, you should be measuring closer to 320 thou at the lobe - maybe a hair more to account for breakin and any "dead motion" they allow for in the lifters.

As to the degreeing - are you turning your motor in the correct direction? Have you got 50 thou data for intake and exhaust (degrees BTDC, ABDC etc). What is the intake lift at TDC?

 

[64falconsix]

depends how your getting tdc if your useing the dial indicator to find out when the piston is at its highest point in the bore you could be way off because of piston dwell. it's the time that the piston does not move while the crankshaft is still moving which is several degrees. trying to find tdc with a dial indicator could get you in the ballpark at best but you really should have a piston stop, as for the lift the lobe lift will be different from the valve lift depending on your rocker arm ratio for example the comp cams 260h in my 200 is measured at the lobe .2933 x 1.5 rocker ratio is .43995 rounded up to .440 which is the advertised lift.

 

[Lazy JW]

You can use a dial indicator to find TDC if you take a reading with the piston down the bore a ways, such as .050", then go rotate the crank so the piston goes down and back up to the original reading of .050". TDC is exactly halfway between. Basically this does the same as a positive stop, you just have to note where the degree wheel is at the chosen reading.
Joe

 

[mustangsilly]

The numbers I get at the .050 mark are +130 on the intake valve opening and +10 on closing. Seems like TDC would have to be WAY off to get those readings.

Thanks for the feedback on the lift height. I didn't realize that was a calculated figure and not absolute.

 

[MustangSix]

Are you using a hydraulic lifter and taking measurements at the valve? If you are, your numbers will be off because the lifter may collapse slightly as it loads throwing your observations off. The .390 number at the valve could be the result of the lifter collapsing .100".

Set your dial indicator up to read directly from the lifter and you'll see a difference in lift and duration numbers. You can read cam lift directly (X 1.5 for valve lift).

 

[Does10s]

I've found that Clay Smith's cam cards are NOT very user friendly. I have never been able to get the numbers that they have written down! :x

Looks to me if you're at 130* and 10* then you're intake centerline is at 120*.

And I'm pretty sure that Clay Smith uses a rocker ratio of 1.6 on the cam card lift numbers.

Will

 

[mustangsilly]

I am measuring off the push rod, but the indicator should not provide enough resistance to depress the tappet center (I wouldn' think). I can't come up with a setup to measure directly off the lifter b/c it sits too deep into the block.

I pulled the gears back off last night and will experiment with different advance points to see if I can get closer to the cam card since I am also not sure if the +4 deg. recommended adv would throw the readings off.

 

[fphillips]

I've found that Clay Smith's cam cards are NOT very user friendly. I have never been able to get the numbers that they have written down! :x

Looks to me if you're at 130* and 10* then you're intake centerline is at 120*.

And I'm pretty sure that Clay Smith uses a rocker ratio of 1.6 on the cam card lift numbers.

Will

I second that.
Mike, can we please get more explicit info from Clay Smith on the cards? The valve event timing is pretty useless without knowing what lift they're measuring at. I seemed to determine that it was somewhere between .006-.012, but that exhaust differed from intake. My intake opening seemed to check out, but couldn't get the closing event real close. I then got tired of turning that wheel and moved on. Also, an explicit rocker ratio on the cards would be good - I think it's 1.6, too.

Frank

 

[wsa111]

Read this hope it helps.

http://www.compcams.com/Technical/Instr ... es/145.pdf

 

[AzCoupe]

Looks to me if you're at 130* and 10* then you're intake centerline is at 120*.

This is incorrect. You are trying to use both methods (@50 and Centerline) to degree the cam. You can't do that.

When using the @50 method, you do not subtract one number from the other to calculate lobe center. Even if you did, you would be assuming that the lobe was symmetrical, with its opening side being the exact same shape and size as the closing side of the lobe. Truth is, most lobes are asymmetrical, with the opening side of the lobe being much more aggressive and the closing side being more gentle. When using the @50 method, you must use the valve events to degree the cam, not an assumed centerline.

If he got those readings using the centerline method, then he is obvously doing something wrong. If you add 130+10 and divide by 2, it yields a lobe centerline of 70 degrees, which is impossible. If using the @50 method, he's saying the intake is opening 50 degrees BTDC, and closing 10 degress ATDC, again impossible. Either way, he's doing something wrong. More than likely the degree wheel is set improperly.

I'm not sure why everyone thinks the cam cards are not user friendly. It has everything you need to degree the cam, using either method.

If you are degreeing using the centerline method, and advancing a 264/110 the recommended 4 degrees, the centerline should be set at 106 (110-4=106). If the lobe center was 112, you would degree the cam to 108 (112-4=108).

If using the @50 method, you use the valve event numbers. The 264-110 cam card shows the intake opening at 22 degrees BTDC @50, and closings at 62 degrees ATDC @50. Using a 180 degree wheel, the pointer should read 158 (180-22=158) when the intake opens, and 62 when it closes. You can confirm the centerline or lobe center as well, 158+62=220 /2=110. However if you advance it 4 degrees, it would be 154 and 58 respectfuly (154+58=212 /2=106).

It also sounds like he is doing this using a hydraulic lifter, which is a definite NO-NO. You MUST use a solid lifter. Yes this means pulling the head, unless of course you have a solid lifter cam, which he does not.

If he's taking the dial measurements off the valve stem, or retainer (recommended), he must also make sure the indicator is parrallel to the valve stem, otherwise the reading will be incorrect. Also if using non-adjustable rockers, you need to use an adjustable pushrod, with the solid lifter.

Some people like the @50 method. While others prefer using the centerline method (off the retainer) as it takes pushrod and rocker deflection into account. It is generally easier to understand and do, with less chances of making an error.

Mike, can we please get more explicit info from Clay Smith on the cards? The valve event timing is pretty useless without knowing what lift they're measuring at.

I'm pretty sure it's @50, but I will call Clay Smith and confirm it.

 

[addo]

Surely you can add the event degrees up and get a total duration - that'll instantly tell if it's gauged at zero or 50 thou.

 

[AzCoupe]

Surely you can add the event degrees up and get a total duration - that'll instantly tell if it's gauged at zero or 50 thou.

Correct. Don't know why I didn't think of that.
The 264 cam has a duration of 214 degrees @50. However since duration is expressed in degrees of crankshaft rotation, and the cam rotates at half the speed of the crank, you need to divide by two. Therefore (380-214=166)/2=83 degrees, compared to (22+62=84). That's within a degree, thus confirming that the valve events are measured @50.

 

[addo]

I do it differently:

Intake: You add the stated number of degrees BTDC and 180°, and also add the stated number of degrees ABDC.

For this cam: 22°+180+62°=264°

Exhaust: Add the stated number of degrees BBDC and 180°, and also add the stated number of degrees ATDC.

 

[MustangSix]

I am measuring off the push rod, but the indicator should not provide enough resistance to depress the tappet center (I wouldn' think). I can't come up with a setup to measure directly off the lifter b/c it sits too deep into the block.

Certainly not enough pressure from the dial indicator, but the valve spring can create enough force to push the lifter thru its preload range.

 

[Lazy JW]

Surely you can add the event degrees up and get a total duration - that'll instantly tell if it's gauged at zero or 50 thou.

Some cam makers use .006", some use .004" for the "advertised" duration. Also .020" gets thrown in the mix.

The .050" number seems most useful to me but I like to know both the .050" and the lift at the advertised gross number.

Doesn't seem unreasonable for a cam maker to supply both of these numbers; why should a customer have to play Sherlock Holmes just trying to find basic information for which you already paid good money?
Joe

 

[Does10s]

Looks to me if you're at 130* and 10* then you're intake centerline is at 120*.

This is incorrect. You are trying to use both methods (@50 and Centerline) to degree the cam. You can't do that.

You're correct Mike! This is why I NEVER degree a cam without a book in front of me.

None the less....the Clay Smith Cam Cards are not user friendly.
I just did a Comp Cams in a 351W and their card used obvious numbers. The cam was perfect per the card. I've done 4 or 5 Clay Smith cams and while I like the cams, I have never had any of the numbers on the card match my calculated ones.
Also for what it's worth, I've only been workin on 250s, so I'm unable to easily adv. or retard the cam anyway!
Will

 

[wsa111]

All of the comments have been close to correct, however advertised duration as mentioned before is at .006-.007 or .004 depending on the cam manufacurer.
Clay smith cams only lists the duration at the advertised numbers.
For example the H-274-112 cam is 25/69 in. 69/25 ex.
Clay smith cams gives you the duration @ .050 with a 1.5 rocker ratio, but does not give you any timing events @ .050.
Not a big deal for the average user, but other grinders supply all the info.
I degreed the cam using the intake lobe center & my engine came out to be 3 degrees advanced @ the timing gear was at 0.
This could be an error in my engine-very common.
The intake centerline was at 109 which is 3 degrees advanced, fine.
I called George & got the events @ .050" intake open 3 degrees, intake close 39 degrees abtc, exhaust was exhaust opens 47 bbdc & exhaust closes -3 btdc.
This is not on the timing card.

Schneider cams gives both the advertised duration & the events @ .050 & even gives you the correct #'s using whatever rocker ratio you are using.

Using different rocker arm ratio's changes the events @ .050.

They also give you the events @ 2 degrees advance which they recommend.

Yes the clay smith timing cards give you just the basics.

I check camshafts both ways first the intake lobe center & then the events @ .050.

This is maybe an overkill, but the info on the cam card gives you that information to go both ways.

Be careful certain grinders advise you to advance the camshaft using an adjustable timing gear set other grinders already have the advance ground into the camshaft specs.

I also see where comp cams is offering a nitriding hardness process to stop the camshaft wear with the oils available today which lack the ZDDP additive.

I offer hardened nitrided dizzy gears which eliminate wear from the too soft gears available to us from the original ford gears to the junk aftermarket gears on the market now. Bill

 

[AzCoupe]

I sent an e-mail to Clay Smith, requesting all the info for the various profiles that I stock. Once I get it, I plan to make some new cam cards and/or post it on my website. Hence the info will be available.