ATR Hydraulic Roller Camshaft - Degree Measurements

[Spooling]

I do not understand how you got a Lobe Seperation Angle of 109*

Searching for a calculation I found this here:
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Add the advertised intake duration and the exhaust duration. 276 + 272 = 548
Divide the total number by 4. = 137
Take the new total and subtract the printed Lobe Separation Angle (LSA) = ?
Multiply this number by 2. You end up with the final overlap angle = ?
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I have been basing all of my measurements off of the cam cards Cam Timing at 0.050" Lift for the Intake Valve of 104* using the Intake Centerline Method.

Why is the Lobe Separation value of 109* not "Clearly" defined on this cam card?

Last time I ran this cam at 6A - I noticed it was kinda "soft" down low. If what you guys are sharing with me is indeed true - it is because I had it advanced almost 6*

I really do appreciate in a BIG way the assistance you guys are taking the time to share with me...

Many Thanks !!!

 

[Spooling]

Here's my earlier complaint about it being soft down-low:

http://www.turbobuick.com/forums/threads/old-atr-214-210-roller-camshaft.386913/

 

[Spooling]

I had some free time today – and re-evaluated my measurements – all along, not re-measuring TDC with the piston stop repeatedly – like I did last time, assuming I set TRUE TDC one time, and using the degree wheel to get back to that position, I would make subtle changes again.

Again, all of my data was collected from the Intake Lobe of the # 1 Cylinder, and again, the Cam Card defines Maximum Lift at 104* ATDC.
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At 0 (Straight-Up) on the crank gear - I measured = 108.75* ---> ~ 5* Retarded
At 2A (2* Advanced) on the crank gear - I measured = 107.0* ---> 3* Retarded
At 4A (4* Advanced) on the crank gear – I measured = 105* ---> 1* Retarded
At 6A (6* Advanced) on the crank gear – I measured = 102.5* ---> 1.5* Advanced
At 8A (8* Advanced) on the crank gear – I measured = 100* ---> 4* Advanced
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Again, all of this is based off of the Intake Lobe of the Camshaft ONLY.

I also researched *Lobe Separation Angle* (LSA). This is the measurement ground into the camshaft between the Exhaust lobe centerline and the Intake lobe centerline.

All of my measurements were taken off of the Intake Lobe and were taken using the Intake Centerline Method at 0.050" as the instructions suggest.

Hence to calculate the Lobe Separation Angle (LSA) from the data printed on the cam card:
Note: Intake CenterLine = ICL, Intake Opens = IO, Exhaust CenterLine = ECL, Exhaust Closes = EC
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ICL = (Duration/2)-IO = (214/2)-3 = 104
ECL = (Duration/2)-EC = (210/2)- (-9) = 114
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Lobe Separation Angle = LSA = (Duration @ Max Intake Lift + Duration @ Max Exhaust Lift) / 2
LSA = (104 + 114)/2 = 109
--------------------------
Thus, the average of the centers is the LSA.

I do not do this everyday – yet it is interesting to me, and in actuality, I am just trying to learn and better understand and essentially visualize the “big picture”.

My assumption was correct – with regards to the Rollmaster Crank Keyways ground at different angles, as I measured that with the crank gear on a piece of paper (reference attached pic).

So, back to my original question, if I decided to install this camshaft “straight-up” – it is apparent that I must select 4A on the crank gear which yields a Maximum Lift on the # 1 Intake Lobe at 104* - exactly as that defined on the cam card.

Again, many thanks for everyone’s valuable input.

 

[Mike Licht]

max lift will not happen at 104 since as Mr. Bison explained the lobes will varie from the card somewhat. Why don't you check the exhaust lobe and see where that is if you want to know more about the event timing. What is the suggested ICL in the motor?
Mike

 

[Spooling]

max lift will not happen at 104 since as Mr. Bison explained the lobes will varie from the card somewhat. Why don't you check the exhaust lobe and see where that is if you want to know more about the event timing. What is the suggested ICL in the motor?
Mike

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Mike - I am trying to set this camshaft to obtain "Maximum Lift" as measured using the Intake Centerline Method - where 2 values (measured in degrees) are obtained at 0.050" before and 0.050" after MAXIMUM Lift - hence this is an "average" value based on the 2 numbers recorded - concerning where maximum lift is measured on the intake lobe for that cylinder (#1) that I had my dial indicator attached to.

This is as defined in the instructions accompanying the degree wheel kit I have.

Thus, to set the cam timing of this camshaft as close to that value defined in the cam card (104* Intake) - it appears as if I need to set the Rollmaster Timing Chain Set - variable crank gear to position 4A.

Thoughts?

Many Thanks !!!

 

[fastblackracing]

spooling, you mention the engine seemed kinda soft with this setup before. advancing a cam helps the response and low end torque over a straight up position----but only a lil bit it wont make a cam thats too big work great. Your cam is already advanced 5.5* at 103.5* icl adancing it further wont help your cause much if any, the real answer is you probly need a smaller cam, this is why a 206/206 roller works so well on a motor like yours but I understand the need to work with what you have. Retarding the cam will only make your car even more sluggish down low.

 

[Spooling]

Thanks for your recommendation - yet to tell you the truth, I think I had other issues which were creating or inhibiting my inability to "spool-up" immediately off of the line issues.

When I first installed this camshaft using that holding device installed from the rear of the engine behind the camshaft block-plug, was really pleased with the camshaft manners. It was only after this rear holding device created a catastrophic event forcing me to buy another 214/210 camshaft and scrub the metal out of my shit that I started feeling some "softness" in this design.

Again, many thanks for sharing your opinion.

 

[Spooling]

This cam with 104 degrees Intake Lobe Centerline will actually be centered at 102 degrees ATDC when installed 2 degrees advanced – which is kinda what and where I was hoping for - in terms of measuring Maximum Lift on the # 1 Intake Lobe...

Concerning Lobe Separation Angle (LSA) being at 109* and that my cam being ground 5* advanced already - such is true that most camshafts have a certain amount of advance ground in. "Ground-in advance" can also be found by subtracting the intake lobe centerline from the lobe separation.
Ground In Advance = LSA – ICL = 109-104 = 5*
Yet again, I am certain the cam card would show this number if that is where they wanted you to degree your camshaft at - to obtain maximum lift – yet they clearly state MAX lift on the intake at 104* NOT 109*
After all of this, I then decided to read what Crane Recommends - in terms of their degree’ing procedure – rather than that which is recommended by Comp Cams – and Crane states that they recommend that you measure at .050 off of the “base” of the cam as the ICL Method (Comp Cams Method) the cam’s lobe “rise” and “fall” may not be symmetrical, so I did exactly as Crane suggested and I measure:
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At Dot-to-Dot (0*): Intake = 22* and 121.5* (cam card says should be 3* and 31*)
At (2A): Intake = 23* and 124* (cam card says should be 3* and 31*)
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WTF - now I am totally shaking my head and thinking that this cam could be the source of my car being “flat” down low in the RPM spectrum and never running correctly - like it did with the first 214/210 I had.
I tried to call Lonnie and Kip to see if they ever had a bad batch from Crane and I could not get in touch with either, and of course Crane is not available either.
Nobody answers their phone or E-Mail except for good old reliable Nick.

I have my shortblock assembled already and am presently in a "holding pattern", and I really want to use this camshaft as my shortblock is ready to accept this assembly, and my shit is all new and already assembled and - I simply cannot drill any holes in this block now to allow for another retaining (holding) device for another camshaft - if I decide to toss this thing in the trash can.
Kinda a bummer Christmas present don't you think?

 

[Nick Micale]

............... Your cam is already advanced 5.5* at 103.5* icl adancing it further wont help your cause much if any, the real answer is you probly need a smaller cam, this is why a 206/206 roller works so well on a motor like yours but I understand the need to work with what you have. Retarding the cam will only make your car even more sluggish down low.

This is a great cam grind, and actually is my favorite all-purpose, street/strip cam from high 11's to high 9's!

It has been used with turbo's from a TA-49 to GTQ-70's and has great mid-range torque and pulls way in the high 6000 RPM range.

I found 2 old ATR cam cards from my files, and they are identical to the card you sent me Ed. One card is from a high 9 sec. GN with a 109 build and a 70 mm turbo.

Both cards show handwritten notes when the cams were degreed, and one was advanced 3 deg.

There are a couple possibilities here Ed, the cam could be ground wrong, or the Rollmaster gear markings are off?

If you send me the cam, we can degree it in one of the engine builds we have in process, and if it still shows screwy readings, we can check it with a Cam Doctor to verify each lobe being in the right position.

Have a merry Christmas, we can get this sorted out for you!