Stock cam replacement
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Joined: Jun 2000
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Stock cam replacement
I have an '82 300-6 4x4 F150 with quite a bit of valve train noise. I pulled to valve cover to adjust valve lash, found the rocker arms had been tightened all the way down and was still able to turn all of the push rods. So I cleaned it up and put it back together. I drive it every day.
The manual has a valve travel spec of .0247" (or something close to that). If I use a dial indicator and find it to be less than that, then my cam lobes had worn out - right?
There is a process is the manual for cam replacement with the engine still in the truck, but I wonder how hard it is to pull the the cam followers/lifters (a magnetic tool is specified in the manual). Has anyone out there done it?
Engine has good compresion (155psi+), runs smooth, does not use or burn oil(except on start-up a little), but seems to be down on power. It has 200,000 miles on it.
I can't afford a new motor right now, so is the cam change the way to go? Should I rebuild the whole top end at the same time? Help me out here guys - thanks.
The manual has a valve travel spec of .0247" (or something close to that). If I use a dial indicator and find it to be less than that, then my cam lobes had worn out - right?
There is a process is the manual for cam replacement with the engine still in the truck, but I wonder how hard it is to pull the the cam followers/lifters (a magnetic tool is specified in the manual). Has anyone out there done it?
Engine has good compresion (155psi+), runs smooth, does not use or burn oil(except on start-up a little), but seems to be down on power. It has 200,000 miles on it.
I can't afford a new motor right now, so is the cam change the way to go? Should I rebuild the whole top end at the same time? Help me out here guys - thanks.
Postmaster
Joined: Jul 1999
Posts: 3,172
Likes: 4
Stock cam replacement
First of all , you have hydralyic lifters so all you have to do is torque the rocker arm bolts to spec , there is no means to adjust the valve lash if the lifters are functioning properly . For 200K miles you have great compression . The smoke on initial start up is worn valve stem seals . If its lacking in power or down on power from what you have been getting , when was the last time you did the routine maintenance type things ? Some people have had good luck using some Marvel Mystery Oil to quiet noisy lifters , it sure wont hurt to try some . Your engine barring severe abuse is very solid . Whats the oil pressure like ? It is possible to remove the cam while the engine is still in the truck but you will have to remove the radiator and possibly the A/c condensor ? The cam runs pretty much the entire length of the engine so you have to make enough room to pull it straight out .
Paul
Paul
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Joined: Nov 1999
Posts: 780
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Stock cam replacement
Gee, that 300 is just now well broken in!
Magnetic lifter tools work just fine.
With the coil disconnected, pop the rocker cover and mash down on the pushrods--Ford specs .060 clearance with the hydraulic lifter bottomed out.
After it's bottomed out, displacing the oil inside the lifter (essentially turning it into a mechanical lifter), do as you suggest and check your lobe lift with a dial indicator. It wouldn't surprise me if it ain't what it used to be...
You might want to replace that cam with a mild aftermarket Torquer or RV-type unit anyway.
And, as the post above suggests, replace those valve seals. And since your doing that anyway, buy a matched spring and retainer kit along with the cam--the original springs are basically toast by now anyway; pun intended, heat kills springs.
Use a 3-ft. piece of 3/8-in. allthread into the front of the cam as a handle.
Eddie
Magnetic lifter tools work just fine.
With the coil disconnected, pop the rocker cover and mash down on the pushrods--Ford specs .060 clearance with the hydraulic lifter bottomed out.
After it's bottomed out, displacing the oil inside the lifter (essentially turning it into a mechanical lifter), do as you suggest and check your lobe lift with a dial indicator. It wouldn't surprise me if it ain't what it used to be...
You might want to replace that cam with a mild aftermarket Torquer or RV-type unit anyway.
And, as the post above suggests, replace those valve seals. And since your doing that anyway, buy a matched spring and retainer kit along with the cam--the original springs are basically toast by now anyway; pun intended, heat kills springs.
Use a 3-ft. piece of 3/8-in. allthread into the front of the cam as a handle.
Eddie
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