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Don Potter Racing Cam?

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Don Potter was the best Datsun engine builder and unfortunately he passed away.  He build Frank Leary's Z car the beat the Datsun race team for many years winning national championships.  He build the highest horsepower, reliable Datsun engines period with many of his cars to this day holding track records at Road Atlanta, etc..  He was an expert mechanical engineer, machinist, race car repair/engine builder.  He had his own cam grinding machine and fabricated every part in his engines.  During his life many people wanted to copy his cams as they provided great power thru a wide range and were very streatable cams.  HIs motors put others like Rebello racing to shame.

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Thanks for the info, I had no idea!

 

One of the reasons I love HybridZ is I always learn something.

 

Anyway, the guy that's sell the cam, is reproducing them using a original #360-09 Don Potter cam profile.

 

No specs, other than a .535 lift.

 

He claims this cam should create 243hp at rear wheels in your 2.4 liter motor if you run 12 to 1 compression. For larger motors, you will get a larger number.

Edited by Z-Dreamer

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Anyway, the guy that's sell the cam, is reproducing them using a original #360-09 Don Potter cam profile.

 

No specs, other than a .535 lift.

 

He claims this cam should create 243hp at rear wheels in your 2.4 liter motor if you run 12 to 1 compression. For larger motors, you will get a larger number.

Hmmm... that doesn't sound sketchy at all.

 

Wonder if he has permission from Mr. Potter's estate to use his name on this...

Edited by TimZ

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Here's the sketchy part, along with much of what the guy writes in his ebay ad - "The lift is .535 Don would never tell the duration of his cams. If your the lucky winner, I will let you know the duration."

 

Pretty easy to replicate a machine part, duration would have been easy to determine.  Power comes from the combination of parts, not just a cam profile.  The guy's selling snake oil and magic.

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Saw no mention whatsoever of head work, or anything else that would suggest a properly built high performance motor. I did notice that it has Mikuni 40s on it, wouldn't those be too small to make that kind of power, or am I mistaken? 276whp would be a lot of power for a 2.8L.

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He unlikely has permission but I doubt his wife has the resources to stop him. Don was a great engine builder but poor business person and his wife never new how much all the part he left to her were worth and I heard most were sold at a bargain.

 

Don created way more horsepower than all other engine builders in Datsun's' thru his custom cams but also thru his custom porting.  He ported the head so that it created an ideal flow and twisting which enabled great power but with a very smooth power band and not the typical rough idle of hot rod cams.  Don did get over 276 HP on 2.8 engines.  In fact I know one friend with a DL Potter 2.8 and that car is over that HP and consistently will beat most V8 cars.  Again Don built the fastest Datsun engines so what most of you have seen in other builders 3 liters is often what he got out of a 2.8.  Don built a lot of winning autocross cars where they had to keep stock induction so the HP was via all his internal tricks that made them always faster.

 

Don's engines even the 3 + liter motors ran great often with smaller 40-44 side drafts and did not need as much fuel as other engines.  If he is replicating Don's cam it is well worth the cost.  One thing I know is that on his more aggressive cams you need to find a super strong valve spring as that was one of the areas of weakness, you might want to change the springs periodically to avoid an issue.

 

I am not sure if anyone can recreate his engines as so much was in his porting and unless you can copy that porting work you might only have part of it?  Right now there are not many great builder that can get that much power from all engine with no fancy induction as Don did; right now I think Datsun Spirit is the next best option.  Also 12.1 on the street seems a little high but 11 to 1 is doable. Also if you do not know the way he ideally set the timing, etc. you might have to play around with it a lot to get it to ideal power.

Edited by primaz

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Don created way more horsepower than all other engine builders in Datsun's' thru his custom cams but also thru his custom porting.  He ported the head so that it created an ideal flow and twisting which enabled great power but with a very smooth power band and not the typical rough idle of hot rod cams.  Don did get over 276 HP on 2.8 engines.  In fact I know one friend with a DL Potter 2.8 and that car is over that HP and consistently will beat most V8 cars.  Again Don built the fastest Datsun engines so what most of you have seen in other builders 3 liters is often what he got out of a 2.8.  Don built a lot of winning autocross cars where they had to keep stock induction so the HP was via all his internal tricks that made them always faster.

276HP at the crank or at the wheels? This guy is claiming that at the wheels, which, if you assume 15% driveline loss, is about 325HP, or about 116HP/L. That's been done, but that's a lot of power from an L, and not a number you're going to see with just a cam. It sounds like this guy is claiming that with just the cam, no head work, or anything else. He listed everything else, so if it had other engine work done, I think he'd have said so.

 

 

By the way, since it sounds like Don Potter built a lot of engines, does anyone know where they all ended up? You would think someone would have come forward by now and documented what he did. Would be a shame to lose that info.

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My problem is, how do I really know it is really a Don Potter pattern?

 

The seller says he will provide a cam card with all the specs, but how do you verify that it is the Don Potter grind that Randy Welch won 3 solo autocross championships with, if there are no available Don Potter cam specs?

 

If it can be verified as legit, then I would order one myself!

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OK, I've been conversing the seller (Steve Bonk) and he says he bought the rights and patterns for the cams he sells from Don Potters widow.

 

Steve Bonk says, he purchased at least one of every grind Don Potter had from his Widow. And that people who are part of the Datsun scene, know him and his reputation.

Edited by Z-Dreamer

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An anecdote... I went to ONE MSA show in the early 90s. When I was there, I walked down a row of fairly crappy looking Zs, all had triples on them. Most were 40s, a few 44s or 45s. On every windshield was a paper that had the specs on the car, none of them was claiming less than 300hp. That was the last car show I went to.

 

I think DP's cams are good. Are they "super cams?" Probably not. But to say that they're very very good cams is not out of the realm of probability. The guy was a very well respected engine builder. You're not going to get there without the rest of the build, particularly the head work. If the cam price was reasonable, I'd do it.

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OK, I've been conversing the seller (Steve Bonk) and he says he bought the rights and patterns for the cams he sells from Don Potters widow.

 

Steve Bonk says, he purchased at least one of every grind Don Potter had from his Widow. And that people who are part of the Datsun scene, know him and his reputation.

Well that sounds better.

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The Isky L6 grind is 270 duration and .540 lift.  I suspect the Potter cam has a little more duration and steeper ramps, meaning more duration at .050 lift.  It's more money, but potentially a bit more performance too.  

The Isky is $140 for the regrind, but that doesn't include the cost of your own supplied core and shipping both ways for those who aren't local to Isky.  

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Ok cool it's.540. I think the duration at .050 is 236. I always like going straight to the source when possible. It saves money. And Ron will tell you what you really need. He doesn't push his product. I called him and told him that I needed a new cam. After talking with him a while he felt that I had a valve spring problem. At no point did he try to sell me springs. He just gave me spring specs that would cure my problem.

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Isky has a .535" regrind for $140. It would probably do great in most L6s. Why pay almost tripple the price?

 

According to Steve Bonk, many people are not aware of this, but the same lift and duration on 2 cams can be completely different acting cams in a engine. This cam has very fast ramps, allowing in more fuel and air than a similar sized cam.

Edited by Z-Dreamer

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Yes but buying the most expensive cam doesn't always yield the best results. Get the right cam for your application. Not the right cam for someone else. Talk to Ron at isky. He can recommend a good cam. He will tell you that his $360 new cams aren't as good as his $140 regrinds. Racer brown is another old school datsun cam you should research.

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Yes but buying the most expensive cam doesn't always yield the best results. Get the right cam for your application. Not the right cam for someone else. Talk to Ron at isky. He can recommend a good cam. He will tell you that his $360 new cams aren't as good as his $140 regrinds. Racer brown is another old school datsun cam you should research.

 

Price is subjective, Don Potter did supposedly study under Ed Iskederian and Harvey Crane.

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Yes but buying the most expensive cam doesn't always yield the best results. Get the right cam for your application. Not the right cam for someone else. Talk to Ron at isky. He can recommend a good cam. He will tell you that his $360 new cams aren't as good as his $140 regrinds. Racer brown is another old school datsun cam you should research.

Agreed - I'm sure that Mr. Potter had some really good grinds for specific applicaitons.  The rub for me is with just the lift number I have no way of knowing if that application is compatible or even close to compatible with my needs.  

When I talked with Ron I was able to give him some very detailed info about my engine and needs and we ultimately ended up with the L6 grind.  Without that insight I have no idea as to whether the Potter cam will work for me or not.  My guess is that it was designed for high compression NA applications so it likely wouldn't work at all for me, but I have no way of knowing.

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