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Potter Cam markings


88dangerdan

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Trying to find out some information on this Potter Cam. Pulled out and L28, N42 block/N42 head out of a '75 280z earlier and removed valve cover and saw this. Apparently an "A" regrind. Haven't had any luck researching the numbers that are stamped on it. Only thing I come up with references a #360, and there's not that much about that. Can anyone enlighten me on what these numbers might stand for. Thanks Daniel

20180821_184816.jpg

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It'll be difficult to find any specific info for duration, as Don Potter was pretty secretive about that stuff I believe.  His camshafts are generally regarded as some of the best, and his engines won a lot of races.  Great find!

 

Lift is easy to measure:

(Lobe height - lobe width) * 1.5 = cam lift

 

If you have a camshaft grinder in your area, they might have a "cam doctor" machine, which can measure duration and such.  

Edited by ryant67
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Thank you for your response. What little information I have found, says the same about how secretive he was about the "duration" of his cams. The kid I picked it up from said it ran when he got it. He removed and kept the triple webers that were installed. I might just through some round top SU's on it and swap it into my 260Z and see how it runs. I've been wanting to paint my engine bay for a while now. This just might be the added motivation I need...lol

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Is the head stock? It might be worth looking closely at it.

 

Don Potter cams were not like Crane or Comp Cams. You had to know about him. So, the chances are better that it was a more serious build if it had a Potter cam. That might have included head work.

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8 hours ago, theczechone said:

if you want more info find Steve Bonk on facebook. I dont think he is on HybridZ but i think he bought the rights to the Potter grinds from Don Potter's wife after he passed. He would have more info on it. 

 

FYI - Steve regularly posts in the "Church of L Series" group

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  • 1 year later...
On 8/27/2018 at 11:38 AM, theczechone said:

if you want more info find Steve Bonk on facebook. I dont think he is on HybridZ but i think he bought the rights to the Potter grinds from Don Potter's wife after he passed. He would have more info on it. 

There  is not an ounce of truth to this statement. I am Don Potter's widow. Steve Bonk purchased some camshafts from me after Don Passed away. I was told he was purchasing them for his own use. Don had built some equipment for Bonk before he died, so Bonk was a customer. If I had known Bonk intended to attempt to copy, mass produce, and sell the resulting knock-off product as being DL Potter Engineering products, I would have never sold anything to him.  Believe me, Don is rolling over in his grave right now! I was unaware until tonight when I stumbled across this forum on the internet that Bonk was still selling these camshafts as being  DL Potter Engineering cams. When I first became aware that he had made copies of those cams and was selling them as being DL Potter cams in 2011, I sent him a registered letter asking him to stop marketing his cams as being DL Potter cams. He agreed to change his advertising to clarify that these are unauthorized copies. obviously he has not abided by that agreement. I consulted an attorney regarding this matter at that time, and was advised that it would be a very long and costly lawsuit that I would no doubt win, but it would not be worthwhile, because Bonk probably does not have the financial resources to pay a judgement of the size that would most likely result from such a lawsuit, and I didn't have the financial resources at that time to finance such a lawsuit with little or no hope of ever even recovering my legal fees. 

 

The cams Steve Bonk are selling not being ground by him. Bonk does not have the engineering background to even understand what made DL Potter Engineering cams so good. Bonk took the cams he bought from me to another camshaft grinder and had the profiles copied, and the copies produced. He did not understand that there was much more that went into producing those camshafts than just having the profile specs. When I pointed out to Bonk that the cams he was selling were not even convincing copies, since they looked nothing like DL Potter Engineering cams, and anyone that was familiar with DL Potter Engineering cams would immediately notice that, he told me that he wasn't going to attempt to exactly copy Don's cams, because some of what Don did to produce his cams was very labor intensive, and cut into profits too much. Bonk told me that the trademark item, the center-cutting of the cams, had no value other than cosmetic, which is absolutely not true. As a side note, he would also have a very difficult, if not impossible, time finding someone that is capable of duplicating some of the work Don did to his cams. 

 

After reading the comments I've seen on this forum tonight, I think it's time to revisit the legal issues here.

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  • 4 weeks later...

That's too bad about what's going on. I bought some items from his widow as well. She was very nice and helpful, I guess that's her above! I believe I bought a fuel injection manifold, cam, coolant restrictor, and oil pressure valve from her and ironically at the time she was also selling a Camdoctor which I thought about buying but it would be a table top souvenir at best.

 

 

 

 

 

Edited by josh817
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