Just a thought,

There is a Clevelands Forever Fourm member, Dan Jones, who is using engine sumulation software from Dynomation to spec cam shafts for some of his friends. He also ran a 351C dyno mule engine testing various intakes and head combinations. Dynomation is not free and it requires a lot of precise measurmentd data on intake and exhaust as input, but Dan seems to be satified with the results. Just a thought at another way someone with access to all the right parts could put together something of value to others.

Jerome

Jep, Ted. I knew that overlap thing and as I said, Isky RPM-300 has also that 114 degree LSA. It has more lift and the same advertised duration 270 /270 as our recent cam. And I read somewhere that folks are using more and more cams with more exhaust duration nowadays, so that is why that Comp Cams Thumpr interests me. But, how much is too much? Well, time will tell where we end up... again... .

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

Seppo.  Grizzly is spot on with his cam thoughts as a custom cam for a boosted application would be a better fit than an off the shelf cam for a normally aspirated Y application.  Blower and turbo cams have similar characteristics in that the lobe centerline is increased to reduce the amount of overlap and the exhaust valve typically opens earlier than normal to give a jump start to the scavenging process.  With that in mind, here are the specs for the cam in Randy Gummelt’s dragster.

 

Adv duration = 288° Int / 294° Exh

Dur at 050 = 254° Int / 260° Exh

Lobe centerline = 114°

Lobe lift = 0.350” Int / 0.346” Exh

 

This is a custom ground Isky cam and works well with fifteen pounds of boost and 7.5:1 static compression ratio.  A single dyno pull was made with this cam with a four barrel carb prior to installing the supercharger and even in this format the engine performed surprisingly well and especially considering how low the compression ratio is.  Here’s the link to the YBM article giving some more details on Randy’s engine including some dyno numbers.

8 Second Y Engine 

Lorena, Texas (South of Waco)

Guys,

What a pandoras box? I've always seen camshaft choice as a very personal thing as it is one of the big deciders in the engines personality.

Seppo from what I know about camshafts for turboed engines (and I know nothing) they do not like overlap. Turbo engines require higher exhaust pressure than intake pressure to work. overlap can allow the pressure differential to even out.    

The best camshaft for a turboed Y is a special. See a cam grinder.

Cheers

Warren

Grizzly (Aussie Mainline)

Ditto on the previous comments.  Camshaft testing is time consuming to say the least while also being expensive.  Besides just the camshaft swap, then there are a multitude of other variables that must be considered for each swap.  Some of these include moving the installed cam position around, intake manifolds, header sizing, lash settings, carburetion, jetting, and ignition timing to just name a few.

I’m currently dyno testing a 390 Ford and that test has evolved to the point of trying another camshaft.  That means that many of the other variables that were tried on the first camshaft must now be rerun with the revised camshaft.  But the only way to know for sure is to do the test as a computer program designed to calculate HP/TQ for a SBC is not going to be accurate enough in this case to define exactly what the results are going to be.

Lorena, Texas (South of Waco)

Engine Analyzer is good program to test camshafts and other stuff virtually, but needs a lot of input data and the most Y-Block Camshaft sellers don't have a lot of information on their sites.



...and other thing is port dimensions, lenghts and flows, huh.



More input info, more accurate result.





Hyvinkää, FI

Didn't someone have a virtual site in a previous post they could go to to see different HP's and torque numbers for different grind cams. May not be spot on but would give a ballpark figure.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

I agree that such a test program would be expensive, and I also think that even if Ted was given test cams for free, he should be paid by someone at his regular shop hourly rate to test them.  Changing cams and lifters in a Y block is a rather time consuming process.

John - "The Hoosier Hurricane"

I agree, this would be a very expensive test, money and time. We used the Isky 505T in my engine and although it has very poor idle , the thing makes good power. Now if someone could convince the cam grinders to provide there products to Ted for testing, he could give them some good data.

Glen Henderson



Freedom is not Free

Letohatchee, AL

Paul, i gotta agree with you, Teds imput and R & D is beyond all expectations, cams and results differ with head changes etc and think there are enough theory,s on what works best where. Merry Xmas to all.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia