Author Topic: Cycle Rama CR-575 Cams...TDC Lift Correction  (Read 3456 times)

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Offline Herko

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Cycle Rama CR-575 Cams...TDC Lift Correction
« on: Tuesday, November 09, 2010. 07:13:37 AM. »
Cycle Rama CR-575 Cams...TDC Lift Correction

Previous reported numbers------ .270 Intake TDC  .180 Exhaust TDC (two seven zero / one eight zero)
Correct numbers are------ .156 Intake TDC  .109 Exhaust TDC (one five six / one zero nine)

In defense of Wes Brown (designer of the cam) he was issuing the TDC lifts as given to him by Andrews Products (manufacturer of the cam). A few phone calls and some digging by Andrews. Andrews was very helpful and found where the problem was...incorrect hand written and verbal numbers. AP manned up and took the responsibility here. Chit happens. The "at-the-cam" data was pulled from the AP data base and the correct TDC lifts were derived.

The other cam specs remain the same:
Intake 15/35 .575Lift   230Dur 100LC
Exhaust 49/07  .560 Lift   236Dur 111LC
OVLP 22   

Good thing is, no one bent a valve due to "under"-stated TDC lifts.
And, the Cycle Rama CR-575 was/is more user friendly in builds than previously thought with the initially reported TDC numbers.

Great cam Wes.

WFOLarry, thanks for encouraging this inquiry.
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Offline Max Headflow

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #1 on: Tuesday, November 09, 2010. 07:20:28 AM. »
Herko,

Thanks for looking further into this.. I'm sure it helps builders to know what is allowable. It would me if I were using that cam..  My questioning wasn't to pick on anyone but make sure those first numbers were correct. They didn't make sense to me..

It does look like a good cam to me..

Thanks,
Bruce
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Offline HD Street Performance

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #2 on: Tuesday, November 09, 2010. 07:59:55 AM. »
Thanks, good call and makes a lot more sense

Offline Herko

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #3 on: Wednesday, November 10, 2010. 06:14:03 AM. »
Thanks gents.
Glad it worked out like it did.
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Offline baggerslimm

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #4 on: Wednesday, November 10, 2010. 10:16:53 AM. »
Hey John, have you tried this in an 88" yet??

Offline R.Bingham

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #5 on: Wednesday, November 10, 2010. 11:33:33 AM. »
Hey John, have you tried this in an 88" yet??

Its not available for an 88 :emsad:

Offline Herko

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #6 on: Wednesday, November 10, 2010. 02:31:39 PM. »
Earlier this year CR had some made with the early chain sprockets and the .875 inner journal.

Slimm, have not tried one in an 88.
As you know, heads would have to accommodate the .575/.560 lifts.
Would be very worthy of a try in an 88 or 95 IMO.
Has good advance (al a 204) but with higher lift.

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Offline mike 120

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #7 on: Wednesday, November 10, 2010. 05:07:05 PM. »
What is the base circle dimension of this cam? Is it the same as the SE 255?

Offline mike 120

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #8 on: Friday, November 12, 2010. 03:25:54 PM. »
Anyone?

Offline Herko

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #9 on: Friday, November 19, 2010. 01:11:34 PM. »
What is the base circle dimension of this cam? Is it the same as the SE 255?

-.020 or .630 Radius.
Stock being .650 Radius
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Offline mike 120

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #10 on: Saturday, November 20, 2010. 01:16:02 PM. »
Thanks Herko, want to go with perfect fit pr's, got to get the math right lol

Offline HD Street Performance

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #11 on: Saturday, November 20, 2010. 01:20:38 PM. »
Might be surprised the stockers work.

Offline Ken R

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #12 on: Wednesday, April 06, 2011. 09:10:11 AM. »
I put my stock pushrods back in (instead of adjustables).  After re-installing the rockers and eating supper while the lifters settled down, I went back and checked to be sure the pushrods could spin at TDC of the compression strokes.
 
Intake pushrods, no problem.
Exhaust pushrods, takes quite an effort.  They spin, but must be gripped very tightly to ge them to move.  Both the front and rear are the same.  Are the lifter pistons at the bottom of their travel?
 
The .02" difference in base circle shouldn't make this much difference.  I'm thinking that the lifter pistons have +/- .1" travel. 
 
That was last night.  I'm going to check again today and snip out the exhaust pushrods if they're still that tight.   Will report back.
 
Ken 

Offline Ken R

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #13 on: Wednesday, April 06, 2011. 12:45:20 PM. »
Checked, cold engine and warm engine.  Both exhaust pushrods spin.  Easier than last night.  This time, I just rotated the engine (rear wheel, 6th gear) and felt of the pushrod as it went up and down.  In the middle of the "down", I could spin the rod.  Same thing on front cylinder.  I guess I'm good to go. 
 
I suffer paranoia about my engine work.  Several builds of my own and repairs for other people came out fine, but I still get paranoid. 
 
Ken
 
 
 
I put my stock pushrods back in (instead of adjustables).  After re-installing the rockers and eating supper while the lifters settled down, I went back and checked to be sure the pushrods could spin at TDC of the compression strokes.
 
Intake pushrods, no problem.
Exhaust pushrods, takes quite an effort.  They spin, but must be gripped very tightly to ge them to move.  Both the front and rear are the same.  Are the lifter pistons at the bottom of their travel?
 
The .02" difference in base circle shouldn't make this much difference.  I'm thinking that the lifter pistons have +/- .1" travel. 
 
That was last night.  I'm going to check again today and snip out the exhaust pushrods if they're still that tight.   Will report back.
 
Ken

Offline BVHOG

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Re: Cycle Rama CR-575 Cams...TDC Lift Correction
« Reply #14 on: Wednesday, April 06, 2011. 02:17:23 PM. »
Checked, cold engine and warm engine.  Both exhaust pushrods spin.  Easier than last night.  This time, I just rotated the engine (rear wheel, 6th gear) and felt of the pushrod as it went up and down.  In the middle of the "down", I could spin the rod.  Same thing on front cylinder.  I guess I'm good to go. 
 
I suffer paranoia about my engine work.  Several builds of my own and repairs for other people came out fine, but I still get paranoid. 
 
Ken
 
 
 
I put my stock pushrods back in (instead of adjustables).  After re-installing the rockers and eating supper while the lifters settled down, I went back and checked to be sure the pushrods could spin at TDC of the compression strokes.
 
Intake pushrods, no problem.
Exhaust pushrods, takes quite an effort.  They spin, but must be gripped very tightly to ge them to move.  Both the front and rear are the same.  Are the lifter pistons at the bottom of their travel?
 
The .02" difference in base circle shouldn't make this much difference.  I'm thinking that the lifter pistons have +/- .1" travel. 
 
That was last night.  I'm going to check again today and snip out the exhaust pushrods if they're still that tight.   Will report back.
 
Ken
That's not paranoia, that's attention to detail.
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