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Questions for the camshaft Gods #2808923 08/14/20 04:34 PM 08/14/20 04:34 PM
Joined: Jul 2008 Posts: 607 Boise M Moparteacher OP mopar
Moparteacher OP mopar M Joined: Jul 2008 Posts: 607 Boise	Bonjour! I have two flat tappet camshafts. Different manufacturers, one solid, the other hydraulic. different applications but same engine series (BBM). I have found both camshafts have a a base circle that drops .001" approximately 50 crankshaft degrees (25 camshaft degrees) prior to the ramp. Q. #1. Is this drop prior to the ramp what is referred as the heel? I think the answer is yes, but seeking a second opinion is always a good thing. Q. #2. What's it's purpose? To put oil under lifter base? Q. #3. When mapping a camshaft should the dial indicator be zeroed at the base .000, or the drop (heel) prior to the ramp? I assume the base and not the heel, for valve adjustment EOIC puts the lifter at the base and not the heel. Q. #4. What is the typical length of the take-up ramp on a solid (mechanical) 7, 8, 15* of camshaft degrees??? And, again is this measured from movement zeroed on the heel or zeroed on the longer base? OK, Thanks.

Re: Questions for the camshaft Gods [Re: Moparteacher] #2808946 08/14/20 05:21 PM 08/14/20 05:21 PM
Joined: May 2004 Posts: 12,383 Taxes & Virus's R-US, NY Dragula I Live Here
Dragula I Live Here Joined: May 2004 Posts: 12,383 Taxes & Virus's R-US, NY	Never studied a cam that close, but your conclusions seem reasonable. I know Ray Barton would be able to tell you the answers to your questions... If you go roller, you will never have to worry about any of that....And considering all the flat tappet cam failures I have seen in the last few years, I don't think there is an engine oil out there that will allow one to live anymore in a performance world... '70 Cuda,...605 EFI Hemi Street Car (6.20 best pass, 1.33 60ft) https://www.youtube.com/watch?v=WYw6RA-k5Bk (6.25 at 108.75mph from inside car) https://www.youtube.com/watch?v=3zQEb9uxFng (6.25 at 108mph from outside car) https://www.youtube.com/watch?v=JCvfzsC4NgM (9.9) '66 Barracuda AWB Stretched nose Blown 440 Car in build stage '71 Duster Drag Car 400 Low Deck 512 best 6.002 at 115.44mph https://www.youtube.com/watch?v=Znuo3jMUXTk

Re: Questions for the camshaft Gods [Re: Dragula] #2809003 08/14/20 08:01 PM 08/14/20 08:01 PM
Joined: Jul 2008 Posts: 607 Boise M Moparteacher OP mopar
Moparteacher OP mopar M Joined: Jul 2008 Posts: 607 Boise	Ya, I've got a roller, but it's 260/260/108 and even with .028" lash I don't think it'll clear But It's going over the weekend just to get mapped, if nothing else, and then it'll probably come back out and onto the never-going-to-use-it shelf. I'm running 16 Smith Machine Composite hand grenades so no worries about flat lobes. Although I've probably just jinxed myself.

Re: Questions for the camshaft Gods [Re: Moparteacher] #2809007 08/14/20 08:13 PM 08/14/20 08:13 PM
Joined: Aug 2003 Posts: 43,119 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,119 Bend,OR USA	I ran a similar solid roller in my old pump gas duster, it was 260@.050 int. lobe with .420 lobe lift and 266@.050 on the x. lobe with .409 L.L. ground on 108LSA installed at 106 and later at 107 ILC. That rascal ran really good in that motor with both 9.25 to 1 compression ratio with a set of big valve 906 heads and a low deck Eddy six pack intake with a set of 1970 440 six pack carbs. at 511 C.I. and ended up later with 1.0.78 to 1 comp. ratio with a set of Indy SR M.W. ports and a 400-3 intake with a 1050 CFM Holley Dominator carb with 517 C.I. Last edited by Cab_Burge; 08/14/20 09:56 PM. Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Questions for the camshaft Gods [Re: Moparteacher] #2809036 08/14/20 09:06 PM 08/14/20 09:06 PM
Joined: Mar 2011 Posts: 3,069 Michigan A A727Tflite master
A727Tflite master A Joined: Mar 2011 Posts: 3,069 Michigan	Originally Posted by Moparteacher Bonjour! I have two flat tappet camshafts. Different manufacturers, one solid, the other hydraulic. different applications but same engine series (BBM). I have found both camshafts have a a base circle that drops .001" approximately 50 crankshaft degrees (25 camshaft degrees) prior to the ramp. Q. #1. Is this drop prior to the ramp what is referred as the heel? I think the answer is yes, but seeking a second opinion is always a good thing. Q. #2. What's it's purpose? To put oil under lifter base? Q. #3. When mapping a camshaft should the dial indicator be zeroed at the base .000, or the drop (heel) prior to the ramp? I assume the base and not the heel, for valve adjustment EOIC puts the lifter at the base and not the heel. Q. #4. What is the typical length of the take-up ramp on a solid (mechanical) 7, 8, 15* of camshaft degrees??? And, again is this measured from movement zeroed on the heel or zeroed on the longer base? OK, Thanks. 1). The drop is called a clearance ramp. The heel and the base circle are one in the same. 2) To slow down the lifter on the closing side to prevent valve bounce. On the intake side it is to promote stabile valve opening. 3) At true base circle, but I guess it depends on what you are trying to map. Lift, duration, what? 4) I would imagine that depends on the design (hydraulic, solid,roller) intended use, spring pressure,,etc.

Re: Questions for the camshaft Gods [Re: A727Tflite] #2809050 08/14/20 09:52 PM 08/14/20 09:52 PM
Joined: Jul 2008 Posts: 607 Boise M Moparteacher OP mopar
Moparteacher OP mopar M Joined: Jul 2008 Posts: 607 Boise	I was always under impression that the clearance ramp was a gradual rise at the entry to the lobe to take up valve train clearance on a mechanical grind. Typical hydraulic grind not having such a clearance ramp. Or are we talking about to different ramps? One that dips on front of the lobe and a second for solids that has a slow take-up at the entry to the lobe? I'm mapping a hydraulic flat tappet as I write this and this one has "dip" coming off the intake lobe as well as the dip in front of the lobe. But the dip coming off the lobe is about .0009' and the dip in front of the lobe is .0011'. Difference is meaningless I'm sure, but interesting non the less. Thanks

Re: Questions for the camshaft Gods [Re: Moparteacher] #2809051 08/14/20 09:57 PM 08/14/20 09:57 PM
Joined: Jul 2008 Posts: 607 Boise M Moparteacher OP mopar
Moparteacher OP mopar M Joined: Jul 2008 Posts: 607 Boise	Yep, it's there on the closing of the exhaust ramp as well but much more significant at .003" and for an extended time. OK, learned me sumptin' new. Cool. Thanks.

Re: Questions for the camshaft Gods [Re: Cab_Burge] #2809815 08/17/20 03:34 PM 08/17/20 03:34 PM
Joined: May 2017 Posts: 72 WI B Brewzer67 member
Brewzer67 member B Joined: May 2017 Posts: 72 WI	Cab, Do you recall what kind of numbers that combo pulled? And also what kind of head flow numbers you had for that cam to use? That sounds really close to the combo I am running in my 526" except I am using the TrickFlow 270's with some port work. I haven't had it to the strip yet but it behaves remarkably well around town for that kind of combo. 13" of vacuum at idle with a reasonable convertor in front of it. Response-wise it amazingly snappy through the entire RPM range.

Re: Questions for the camshaft Gods [Re: Moparteacher] #2809858 08/17/20 05:53 PM 08/17/20 05:53 PM
Joined: Aug 2014 Posts: 562 Ohio L lockjaw-express mopar
lockjaw-express mopar L Joined: Aug 2014 Posts: 562 Ohio	Call Mr. Porter at Porter Racing Heads...he knows everything there is when it comes to camshafts! Buy one from him, and you will be very happy! I did, am I ever impressed!

Re: Questions for the camshaft Gods [Re: lockjaw-express] #2809884 08/17/20 07:19 PM 08/17/20 07:19 PM
Joined: Oct 2006 Posts: 1,264 New York, USA Chargerfan68 pro stock
Chargerfan68 pro stock Joined: Oct 2006 Posts: 1,264 New York, USA	Originally Posted by lockjaw-express Call Mr. Porter at Porter Racing Heads...he knows everything there is when it comes to camshafts! Buy one from him, and you will be very happy! I did, am I ever impressed! I agree 100% with the above. Never dissappointed and expectations have always been surpassed. 1.50 60Ft. , 10.75@ 127MPH Hauling 3900 LBS.

Re: Questions for the camshaft Gods [Re: Brewzer67] #2809944 08/17/20 09:12 PM 08/17/20 09:12 PM
Joined: Aug 2003 Posts: 43,119 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,119 Bend,OR USA	That cam was used in that block with two different stroke cranks, 4.25 and 4.300, and five different sets of heads, ported big valve 906,eddy RPM CNC ported by MCH, a set of ported 440-1 and I ended up using a set of Indy SR M.W. heads. The 440-1 heads made 775 HP at 7000 RPM on Oregon pump swill and the SR heads made 725 HP at 7000 RPM on the same dyno two weeks later, both sets of those heads had 76.0 CC chambers so the compression ratio stayed the same. The fastest and quickest my 3450 Lb. Duster ran with that last combination on Oregon 91 octane pump swill was 9.996 at 134.7 MPH at Woodburn, OR in late July IHTHs Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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