87 mercruiser i/o 170 rocker arm adjustment

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SHANEWHITLEDGE

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Rocker arms seat on/in rectangular pedestal on the head with a 1/2 bolt. And ive been told you just tighten each to 24 ft/lbs with tourque wrench and thats it, that theres no adjustment or set procedure, on this type head( 460 ford) any remarks??????????? JUST REALIZED ALSO THAT I DIDNT MARK WHICH PUSH ROD WENT WHERE WHEN HAD HEAD REDONE AND PUT THEM BACK IN NOT KNOWING WHICH ONE GOES WHERE. ANY CERTAIN LENTH DIFFERENCES OR MEASUREMENTS TO GO BY TO KNOW WHICH ONE GOES WHERE?????
 
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Bt Doctur

Bt Doctur

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Re: 87 mercruiser i/o 170 rocker arm adjustment

you just posted, give us some time to find the info
 
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stonyloam

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Re: 87 mercruiser i/o 170 rocker arm adjustment

You are correct, valve lash is set by pushrod length. There are 4 different lengths, and are supposedly color coded, but I suspect the dye is long gone. There is a measurement procedure (page 3a-11 of the manual), but it is kind of a pain. What I would do is pull all the pushrods out and line them up to see if they are all the same length. They are at least 0.300 inch between the different lengths, so it should be pretty easy to see. If they are all the same length, you are good to go. If a couple are different then you will have to find out which hole they go in. Good luck. If you need to make a lifter collapsing tool, there are a couple of threads here where the guys made them. BTW it is 20 ft lb, and must be done with the valves CLOSED. Covered in the manual. It is also esential that you retorque the HEAD bolts after the engine has been run up to temperature.
 
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SHANEWHITLEDGE

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Re: 87 mercruiser i/o 170 rocker arm adjustment

Ok........ All my push rods are the same length and i followed the manual perfectly to torque spec on all rocker arms. But three of the rocker arm still have to much play in them to be right. Definately would be more than the required clearance of .110"-.210" if i were to use lifter collapsing tool. Appears that at least one has more than that just pisking up on the valve end of the rocker arm. So if i correct i possibly should replace the lifters.????
Motor seems to run quite well though. Just trying to make things right.
 
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SHANEWHITLEDGE

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Re: 87 mercruiser i/o 170 rocker arm adjustment

Ok........ All my push rods are the same length and i followed the manual perfectly to torque spec on all rocker arms. But three of the rocker arm still have to much play in them to be right. Definately would be more than the required clearance of .110"-.210" if i were to use lifter collapsing tool. Appears that at least one has more than that just pisking up on the valve end of the rocker arm. So if i correct i possibly should replace the lifters.????
Motor seems to run quite well though. Just trying to make things right.
 
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stonyloam

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Re: 87 mercruiser i/o 170 rocker arm adjustment

A little over my head now, but section 3A-12 of the manual has a pretty through discussion of the lifters. Is it noisy?
 
nola mike

nola mike

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Re: 87 mercruiser i/o 170 rocker arm adjustment

SHANEWHITLEDGE said:
Definately would be more than the required clearance of .110"-.210" if i were to use lifter collapsing tool. Appears that at least one has more than that just pisking up on the valve end of the rocker arm. So if i correct i possibly should replace the lifters.????
Click to expand...
Well, you should try collapsing them first. If they're already collapsed, there's your problem. If not, maybe it's a push rod issue. Not sure what would cause and increase in clearance like that though.
 
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SHANEWHITLEDGE

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Re: 87 mercruiser i/o 170 rocker arm adjustment

Motors not noisy but do hear some clatter from valve cover. And and i suspect that #1 exhaust lifter is collapsed but dont know how much force it takes on push rod to collapse it to check that. Just seems that the rocker should be tighter than it is when torque is properly set. You can physically wiggle it and two others. But rest seem right. And even if i had the longest of the four sizes of push rods (8.715") listed that could be used i dont believe it would make up the diff. Thanks for the help. Guess i try to compress and then remove, disassemble, clean and rebuild all if i find any collapsed
 
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fmalott

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Re: 87 mercruiser i/o 170 rocker arm adjustment

are you sure you followed the manual on the torquing of the rocker arms at 20 ft lbs
#1 piston at TDC(firing) torque #1 intake & exhaust
#2 intake
#3 exhaust
#4 intake
rotate crankshaft 360 degrees one complete revolution then torque
#2 exhaust
#3 intake
#4 exhaust
 
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SHANEWHITLEDGE

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Re: 87 mercruiser i/o 170 rocker arm adjustment

Ok guys thanks for all your input on my problem. Today pulled off rocker arms and push rods( all same length) and i took side cover off(lifter cover under i.m.) and just by feeling tops of lifters there are four that are collapsed. So guess thats my valve clearance problem, i probablly just replace them all. (new set of 8 $27.00 ebay) and see how it goes from there. Any special treatment needed on new lifters before installing??????????
 
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stonyloam

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Re: 87 mercruiser i/o 170 rocker arm adjustment

For reassembly of a lifter the book says fill half full of oil then reassemble, so it sounds like you would want to put oil into the new lifters. It also says lubricate the cam lobes and the entire lifter with engine oil supplement or engine oil. Once you get it started make sure oil is coming up through the pushrods.
 
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