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By MoonShadow - 17 Years Ago
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I'm setting up my new engine and want to know how to set the cam. I had it a 0 degree advance before and was lacking low end torque. I am thinking of a 2 degree advance (?) to try and improve the launch. Is this the right direction? Should I go to 4 degrees? Cam Specs are: Int Exh adv duration 274 274 Lift @ .50 226 226 lift @ lobe .296 .296 lift @ Valve .456 .456 centerline 110 degrees at TDC I intend to order another cam for my next engine but will run this one for now in my McCullouch blown 272. Any suggestions? Chuck in NH
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By Hoosier Hurricane - 17 Years Ago
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Chuck: A 272 with that much cam isn't going to have much off the line torque, no matter what you do. However, advancing the cam is the right direction for what you are trying to do. A little extra valve clearance will also help. John
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By suede57ford - 17 Years Ago
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Did you build the motor with fairly low compression for the blower? The cam is streetable, but your cubes are way down, combined with low compression, and the mild cam it is going to be soft on the bottom end A centrifigal blower does not make any power until the rpm goes up either. If you are going to the effort to advance the cam, you may consider more like +4 as you may not be able to tell a difference with +2. I use a lot of initial timing, 18-20 deg, and limit the total advance 32-34 so that some of the low end is regained, yet it is not too much timing when the boost comes in. I also have a MSD BTM that knocks some timing out when the boost comes as well. A larger crank pulley, or smaller blower pulley, would bring the boost in earlier and help too.
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By MoonShadow - 17 Years Ago
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The 272 is 40 over and decked and balanced with ECZ-G heads. I have a 4" and a 5" pulley for the McCullouch so I have a little boost adjustment. The 4" puts out 6-8lbs of boost with the improved impeller. The last engine was a 40 over 292 with the same set up and cam. It had no torque at low end. Wouldn't break the tires loose for anything (except maybe wet pavement). I've got a big 292 block coming in the fall (3.875 bore) and will probably build it this winter. Just want the little 272 to scream until then. Is there a better cam for this setup?Chuck in NH
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By Hoosier Hurricane - 17 Years Ago
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Chuck: The best help you can give that 272 is a higher stall speed converter. John
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By MoonShadow - 17 Years Ago
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I'll be putting in an AOD with a 3000 stall converter this time. Chuck
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By MoonShadow - 17 Years Ago
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Just for clarification on the timing advance I've attached a sketch of a crank gear, actual dot locations may not be correct. If I want to advance the cam by 2 degrees am I correct to move the crank pulley from the stamped dot to the 2 degree adv location (imaginary dot in red) and also relocate the timing chain to the 2 degree adv tooth (imaginary dot in red). Thanks, Chuck in NH http://3eagles.hypermart.net/images/Timing.jpg 
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By charliemccraney - 17 Years Ago
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Chuck, you got it. I had lost my instructions when I degreed mine. Couldn't figure it out. Had to call Mummert. Is this one of the repro blower cams he offered several years ago? The specs are curiously similar to mine.
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By MoonShadow - 17 Years Ago
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It is one of his blower cams. I just couldn't get used to the idea of missing the timing to get it set right. We'll see how this one runs. Chuck in NH
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By Ted - 17 Years Ago
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Ditto on the four degrees of advance. Two degrees typically doesn’t show a step change in performance unless the camshaft is already borderline in being too big. I’m assuming the camshaft was originally degreed in? If not, then it’s a stab in the dark on the advance as you don’t have a baseline to really base it on. A compression ratio check before and after the cam advance change will also validate the change by showing you an increase in cranking compression but if this is being done on an engine stand, then 'never mind'. And John is right as usual in that a higher stall converter will undoubtedly be the best bang for the buck in this case.
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By MoonShadow - 17 Years Ago
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I did degree the cam and it came out to the 108 centerline as advertised. The engine is on a stand so cranking compression isn't a current option. I'll go 4 degrees advance and see what happens. We all know what a pitiful low end, even with 3:80 gears, the old engine had. It was a 40 over 292. Thanks again, Chuck in NH
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By charliemccraney - 17 Years Ago
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I think there were some other issues with that other engine, though. I had the same cam in my 60 over 292 and the low end was good. But it did (and still does with 17 more cubes) feel like it comes on between 1500 and 2000.
Was yours at 108 in the 0 advance keyway of the crank gear? I had to use the full 8 degrees of advance and mine is still retarded 2 1/2 degrees. This makes me believe that it was quite retarded in the old engine, though I never degreed it. I compared the cranks and the keyways appeared to be indexed about the same.
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By MoonShadow - 17 Years Ago
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Yes it was in at the factory specs and 108 degrees. All seemed to check out ok. The crankshaft, after checking for TDC, has 16 degree advance in it. I think thats normal? I know the old engine didn't have the best compression (100-130) but still think it should have run better. Came on strong after 2500 though. I have another, non blower cam, or unknown lift. I think while I have the Block on a stand I'll check it out too. I hope to ground hop the engine in a few days and see what it has for compression at 4 degrees advance. Chuck in NH
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