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By jcacciag - 11 Years Ago
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Is there a way to verify that the cam timing gears and chain were properly installed on a recently rebuilt engine without dissasembly . I had a 312 engine (60 over)rebuilt, stock cam and it does not have anywhere near the power the orginal engine had. The engine idles smoothly and does not backfire. It has slow throttle response compared with old engine.. The engine has ignition knock on hard throttle and I have moved ignition timing around trying to eliminate that but still present under full throttle and power suffers even more.. Under full throttle the power seem to come back around 3500 rpm. I am using the same carb (holly 600 )and distributor from the old engine. Could cam timing be the problem? How would if run if it was off ?
The old engine idle was never ran totally smooth at idle so it may have had a performace cam but I am not sure.
57 tbird aod
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By Hoosier Hurricane - 11 Years Ago
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You post a '57 Bird on your signature. That is good. A quick and dirty method to determine camshaft position is this: Take off a valve cover, and turn the engine over until either #1 or #6 (depending on which cover you took off) exhaust valve is open. Then turn the engine by hand slowly until the exhaust valve is closing. Place a straight edge across both valve spring retainers and continue turning the engine until both valves are open the same amount as indicated by the straight edge. At this point the timing pointer should be pointing very near the TDC mark on the pulley. Should be within 4 degrees, depending on the accuracy of your judgement of the valve openings. I said it is good that you are working on a Bird, since the damper ring on passenger cars often slip and the timing marks are wrong. Bird marks are on the pulley and cannot slip.
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By jcacciag - 11 Years Ago
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John,
Thanks for the response , I will do the check you outlined but even with the old engine the crankshaft marks were off. I just assumed the damper slipped. I always had to ignition time the engine with a vac. gage or just advance until it spark knocked then backed off because when I timed by marks it ran poorly. Have you had any experience with cam timing off and how would it run?
Joe C 57tbird
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By Hoosier Hurricane - 11 Years Ago
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Is this a T-Bird? Marks can't slip on a T-Bird damper. The only experience with timing off was a friend's '58 Ford with a very loose chain (332 engine). It had no low end power, the faster you revved it the better it ran. Oh, I also had a friend with a newer Bird with a 460 engine. Information leaked out that the factory set the cam 8 degrees retarded to meet emission standards of the day. The trick was to put early 429 sprockets in them to advance the cam. The car was a dog before the change, would spin the tires after.
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