Race Cam selection

[blykins]

I'm not trying to toot my own horn, so please don't take it that way.

However, I don't generally give out camshafts specs on race cams, because most guys post publicly on forums, and that's where all the "experts" come to demonstrate their knowledge. LOL

I have an extensive history of doing camshaft dyno tests as well as in-car camshaft swaps to find better ways of doing things.

Most guys will say, "I'm very happy with the cam so-and-so ground for me..." but most guys have never tried multiple camshafts on the same day, or at any time at all.

I will say that I'm the only one that has an FE turning 7500 rpm with a hydraulic roller. That's not because I ask around and have people grind cams for me. It's because I spend a lot of time looking at camshaft specs, the overall engine combination, and do lots of dyno testing.

I was approached by a custom cam designer who told me that he would like to earn my camshaft business. I told him that I was working on a particular combination, I already had a camshaft for it, but I was willing to test them both. I gave him the entire catalog of engine data, and even gave him my camshaft specs, but my cam bested his by 28 peak hp and 10 average hp.

One of the members on my Cleveland forum also approached me, telling me that they had a custom camshaft ground for them by Cam Motion. He told me that it made good horsepower but it was soft on the bottom. I had a camshaft ground for him that produced the same peak hp, but also gained him 20 hp at 3500 rpm.

If you have been on the FE Power forum and saw Jay Brown's new cylinder head project, Blair Patrick provided Jay Brown a camshaft for his project. I saw the issues and actually fronted Jay another camshaft to try that was 12° SMALLER than the previous cam and netted the engine more peak hp and torque, as well as up to 20 hp at lower rpms.

Would love to earn your business.

If the other guys are telling you that you need a single pattern camshaft, or a 114-115 LSA because you have Webers, you should walk away.

[1795]

Going only with well known and respected race engine builders/cam designers, who have experience with SBF's and Webers. Brent, I look forward to seeing your specs off-line and for those of you wondering, I will not be posting Brent's specs online.

Jim

[1795]

It is interesting to see the variety of flow numbers that people get from SBF heads. Found a chart online that listed results from a variety of manufactures.

https://www.google.com/url?sa=t&rct=...1SqRFtb-QkdRfS

The results vary significantly from a stock 289 head at 166 cfm Intake (.600) and 125 cfm Exhaust (.600) to a Kasse SVO head at 374 cfm Intake (.600) and 273 cfm Exhaust (.600).

When I was discussing my heads with the engine builder at Cobra Automotive he was saying that their ported race heads are producing over 300 cfm at .700 intake. Heard from several people that my heads in their old form with flowing about 260 cfm at .700 were the limiting factor in my engine. In addition, you have to factor in the carburetor's flow capacity, as while the head might be able to flow a certain cfm, a restrictive carb system will have an impact and the head can only flow what the carb provides.

I have settled on getting cam options from three sources based upon my discussions with them. They are Brent, Cobra Automotive and Shelby Racing Engines. Dema Elgin supplies the cams for Shelby.

Should be able to make a decision soon, as I need to get this engine together.

Jim

[talos]

Just remember, you get what you pay for. Mr. Blykins had a special camshaft ground for my side oiler with the combination I had given him and the results I was looking for. It was perfect for what I wanted. A lot of people asked for my cam specs. His years of experience is worth the investment alone. I went through two previous cam grinds with unsatisfactory results, from other sources, before he assisted me.

[1795]

Thanks for the input. Money is not a consideration, they are all within a $100 of each other. It's just sorting out which one will be the best one for this application. Without going into specific grinds, the lifts for intake and exhaust are all in the low .600's, but from there the departures begin. LSA has a range of 6 degrees between lowest LSA and highest. There is quite a variability in duration @.50 and in lobe shape.

Have to consider multiple factors in determining which one. All of the people giving input and making recommendations are well respected with years of race cam development; there are no slouches in this group.

Jim

[blykins]

Unless you have advertised durations, .200" durations, and .050" durations, the lobe shape would be undefined. I purposely do not give out all of that information.

[cycleguy55]

Originally Posted by blykins

Unless you have advertised durations, .200" durations, and .050" durations, the lobe shape would be undefined. I purposely do not give out all of that information.

Having that information would allow someone to reverse engineer your cam designs. It's certainly understandable why you wouldn't be giving that out.

[eschaider]

Originally Posted by blykins

... Most guys will say, "I'm very happy with the cam so-and-so ground for me..." but most guys have never tried multiple camshafts on the same day, or at any time at all.

This^ and a lack of understanding of the significance of lobe profile aggressivness and the effect of different profiles not just on intake and exhaust cams but on opening side and closing side dynamics makes significant differences in the personality and performance of the target engine — and we have not even gotten to cam phasing yet ...


Ed

[1795]

Originally Posted by eschaider

This^ and a lack of understanding of the significance of lobe profile aggressivness and the effect of different profiles not just on intake and exhaust cams but on opening side and closing side dynamics makes significant differences in the personality and performance of the target engine — and we have not even gotten to cam phasing yet ...


Ed

Ed,

Yes, it is a very dynamic situation and there are a multitude of engine factors that are effected by a small change in any aspect of the cam design. The engine is a system and has to be treated as such. All parts working together to achieve a desired outcome.

Jim