camshaft timing?? right or off a tooth
 

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

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.

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

"Dot to dot" is not good enough.

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.

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

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.

put a vacuum gauge on it and see whats happening.

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.

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.

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.

if it were off a tooth I think it would be way down on power, not just sound "off"

Also with it a tooth off the cranking compression would be higher or lower than the other motor depending on which way it is off because the intake closing would would happen way sooner or later

well embarrassed to say , the issue was all TIMING....I thought timing was set, but was way off...
time for a test ride, after a year of rebuilding this boat from stringers, transom, new motors.......
then........

new project, update dash............

Haha hey we've all done that at some point. Glad to see if figured out may be a chilly test ride but at least you can get a test in before it gets really cold!

Yea,,,,,thank gosh,,wasnt looking forward to pulling motor,,,but think all is good
,suppose to be in low 60's this weekend...
Next will be ,,after little time on motors , start to ''run'' see where we are....speed ..rpm etc..
I think i will have to reprop boat. I have 4 blade intimators 26 p
have been told i will need 28 or 29's....and a bravo style prop...
Flash..out

Sometimes the easy chit just doesn't seem possible but another example of process of elimination starting with the simplest first. Your not alone. Been a handful of these this season.

I thought that I would have to reprop also. The old engine and drive set up ( no box and 1 1/8 lower ) turned 5400 RPM ( 650 HP with 1.5 to 1 and a 28 pitch 4 blade Bravo prop ) 6000 RPM with the drive ratio at 1.5 to 1.
With the new engine and box I now turn the same prop at 6100 RPM
I just bought a new BBlades labbed Bravo 4 blade 28 pitch modded for my boat.