| Russ' Restoration | -- 06-13-2011 @ 12:48 PM |
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I just installed a fresh EAB (with an after market cam)in my hardtop. Someone else did the rebuild. This engine only has 75 to 85 lb.s of compression ( I'm thinking it should have 110 to 120 on a fresh motor).No power at low end, I pulled plug wires at each cylinder. Cylinders 2,3,5 and 6 can be pulled with no change in engine,indicating to me low vaccum in those cylinders. I want to degree the cam using a degree wheel. I need to know how would I advance or retard the cam gear, is there a kit with eccentric bushings or is there another method. Thanks' Russ
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| Stroker | -- 06-13-2011 @ 1:09 PM |
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Most flathead cams are installed "straight-up", as the timing gears (unlike chains), are pretty precise. Your cam supplier may have eccentric bushings available, but in order to use them, you will probably have to enlarge the bolt holes on the aluminum timing gear on a vertical mill (simply reaming them out with a drill isn't accurate enough). An aftermarket cam with substantial overlap and a narrow lobe angle will kill static compression, as well as low rpm torque. It may be that you simply have "too much cam" for your application. In order to properly degree the motor you will, of course have to pull both heads, or at least the intake manifold to get a dial indicator on the valve assemblies. Won't do you much good unless you have a timing card for the cam however. I'd guess the timing card will reveal the issue before you ever take a wrench to the motor. Advancing a cam will sometimes help overcome low-end torque issues, but it's just a compromise. A cam with less duration is a better choice.
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| supereal | -- 06-13-2011 @ 2:33 PM |
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I believe that "degreeing" the cam is likely the least of your worries. Unless your aftermarket cam is a press on type, such as the very early Fords, it is almost impossible to get them out of time. The camshaft bolts are staggered to allow only one way to install the timing gear, and the marks on the crank and timing gears are clearly marked to be matched at installation. Your compression is very low for a "fresh" rebuild, and the cylinders without power are adjacent, 3 and 2, and 5 and 6. I'd pull the heads and see what is wrong. If the cam is out of time, all cylinders would be affected. It is possible to mix up the plug wires, particularly on adjacent cylinders, but that doesn't explain the low compression. I've seen too many bad "rebuilds" to think your problems are minor.
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| 37RAGTOPMAN | -- 06-13-2011 @ 5:29 PM |
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RUSS before you pull it apart. DO A LEAK DOWN TEST on the cylinders.this will tell you if the valves are leaking. if they are , you will hear the air escaping though the exhaust, the exhaust valve is leaking, if you hear air coming out the carb, the intake valve is leaking, and if you hear air coming out the oil breather the rings ,might be a issue. hope this save you some work, 37RAGTOPMAN
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| Russ' Restoration | -- 06-13-2011 @ 5:31 PM |
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I beleive your right on the button. I think I will go back to the stock cam. Thanks'
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