flashgordon

hello,
i am trying to determine if the cam is off a tooth .i just assemblied and installed a pair of 547 in boat. Just build two 547's , second motor runs,sounds great, first motor , runs but has always sounded OFF. i have replaced or changed everything, swapped carbs, new dist, had new wires, checked with ohm meter, swapped msd boxes, plugs, checked rockers and lash, so i am finally thinking cam is off a tooth. i was told that from TDC, rotate motor 360 degree, rockers should be in same position. So i measure exhaust, it has 040 of travel, and intake has 138 of travel. That would mean cam is off a tooth. not really looking towards pulling motor, but need to resolve issue.
ANY COMMENTS PLEASE>>>>>......thank you

dereknkathy

as you rock back-forth thru tdc, you should see both intake and exh valves moving equally. one just closing, other just opening. most common chain-gears is 38-19 teeth. so, roughly 20 degrees off for 1 crank tooth. so if the point they match is 15 to 20 either side of tdc, cam is off. you won't really see the 2 to 4 degrees some cams are indexed off on purpose.

vintage chromoly

iTrader: (3)

You need a dial indicator, a magnetic stand and a degree wheel.

"Dot to dot" is not good enough.

flashgordon

hello vintage,,,i have all that
first motor , i lined up dot to dot, degreed cam , it read as card said, then i took off chain and lower gear, advanced it 2 degrees with crank gear. this is where i think the cam got off. second motor, i advanced it 2 degress, then degreed cam, and all numbers were off 2 degrees , which would be correct. the second motor runs and sounds great, first motor runs,,but just doesnt sound right,,or respond good.

fordf350

I only mention this because I was guilty of it. Are your plug wires one off on your distributor cap?

flashgordon

GOSH,,,i prayed to plug wire god , that that was the issue,,i have triple checked, so did buddy...but, it sounds like motor has a dead cylinder, pulling wires off cap,,5/7 cylinders hardly makes a difference. someone suggested a vacum leak.

sutphen 30

put a vacuum gauge on it and see whats happening.

Tinkerer

I would think that if it was off a tooth then there wouldn't be any cylinders that acted different than the others. The valve timing would be off the same on all cylinders. How big is your cam? How much valve to piston clearance did you have? possible slightly bent valves due to piston contact. As said do a compression test. Pull the engine and make sure everything is correct before you do real damage.

flashgordon

the cam and lifters is a solid roller, 714 lift 286/294 isky cam and red ball lifters.
compression test was 170-180 on motor, other motor which is fine was same compression.
both motors are new everything. clearance valve to pistons, not sure, dymanic speed, very reputable shop, did all machine work , also they got all my parts. they , ron ,picked out the cam.

KRAUSMOTORSPORTS

iTrader: (2)

I'll degree in a few times. double, triple, quadruple check. Also if the motor has ever had a line bore it will change things too. Not by much but it does. Usually set your cam advanced 2 degrees as it will usually breaks in not much longer. I just went Dot to Dot for ****s and giggles to see how far the Cloyes double roller was off. I'm 6* advanced. Not from the Cloyes but from the line hone. Just food for thought. But when you degreed it you would have noticed the timing difference. Hope you get it figured out.