cam/pushrod question!!!!!

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Aug 29, 2004 | 07:09 PM

dennyjr47

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cam/pushrod question!!!!!

i have a 351 m ,changed the cam,lifters,valve job,timing chain ,i keep bending pushrods,exhaust worse than intake.the new cam lift is.280 in.&.295 ex. the stock lift is .235, is that my problem??????? the lifters collapse normal .020-.060,i am lost..when the heads r resurfaced is that .010 or less?????that would give me .070 more lift on ex.& .060 on the in.,is that the problem???????

Aug 29, 2004 | 11:18 PM

74 F100 351m

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From: Okla.

What kind of rocker arms do you have on it? If they are roller rockers you might have a problem with the roller going over the edge of the stem of the valve. This will bend the stem of the valve and make it bind. This will bind the tubes.

Aug 29, 2004 | 11:54 PM

grclark351

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From: chicago burbs

if you have stock rockers they may not be able to travel as far as the cam is trying to push them. check the coil springs for binding at max lift too. check the contact patch on the tip of the valve stem, it should be centered. you can adjust the contact patch by altering the length of the pushrods. if it's rocker bind, Crane Cams adjustable stud kit might help. or a set of bolt in pedestal roller rockers?
to find the lift at the valve, take the lobe lift and multiply by the rocker ratio. i'm getting .484"/.510" on the new cam and .406" stock. .510" in a Cleveland should not cause problems, are M/400's more sensitive to lift increases?

Aug 29, 2004 | 11:57 PM

dennyjr47

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standard rockers w/ fulcrum.since the rockers are non-adjustable i thought standard pushrod 9.500 was too long,possible??????//

Sep 3, 2004 | 01:52 AM

solaratomic

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From: Millbrook, AL

Go to Bubba's M-block webpage and go under the parts reference section, then go to the internal engine parts section it should tell you at what point the stock springs reach coil bind. That sounds like your problem. Unless your heads were set up specifically for your cam I think your binding your springs. That'll bend a pushrod everytime.

Sep 3, 2004 | 01:59 AM

solaratomic

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From: Millbrook, AL

Here's the link to his webpage, by the way this webpage is an all around great source for M-block information. Couldn't have built mine without it. WAY TO GO BUBBA!!!!!!

http://home.earthlink.net/~bubbaf250/index.html