Reinstalling Pushrods on 72 Ford 351c *Torquing*

Before you reinstall the plugs, install the pushrods and get them properly set into the rocker arms.

As you rotate the engine, using a breakover bar on the crankshaft nut, you will see the pushrods rise and fall. When both pushrods are simultaneously in the down position on any given cylinder, then you are near top dead center on the compression stroke. You can check the mark on the pulley to be sure. This is when I take the slack out of them.

How you adjust them is up to you and your source of information.

What I do is to take the slack out of each cylinder as described above, and install the plugs. This gets me close enough to allow the engine to start. It will rattle like two skeletons doing the lambada, but should run.

Then I adjust each cylinder with the engine running. I first adjust to get the engine running smoothely and quietly. I don't use torque, nor do I take out the slack and tighten so many turns.

When the engine is running smoothely, I readjust each valve slowly and carefully: With the engine running, I tighten slowly until the engine starts to run roughly, indicating that I am holding the valve slightly off the seat. I mark that position and loosen until it quietens and then again starts to run roughly. At this point, I have loosened the valve until it no longer opens. Marking this point, I adjust the valve right in the middle of this angle.

It may not be fast, and it may not be the way the manual says to do it, but I see nothing wrong with the logic in doing it this way, and have never had any problems afterward.

I cannot say the same for the 'take out the slack and tighten x turns' methods.

The valve lifter works under dynamic conditions, balancing internal pressure in the filling lifter versus the mechanical pressure which the valve and spring present. It makes sense to me that such a device needs to be adjusted under dynamic conditions. (Messy, though)

I didn't think the Ford 351c had any adjustments. I remember the rocker fulcrum being bolted to the head with a bolt. The only way to adjust would be with shims or a file....

You need to install the rockers on each cylinder with both valves closed (compression stroke TDC) and torque the fulcrum to specs - be very careful to torque accurately on these. Make sure the torque spec yur are using is for the screw size your engine has - some of those engines were

5/16", some were 3.8". Once you do that, you need to check for proper valve clearance on each and every valve by compressing the lifter with a tool or lever. Check the valve clearance to be sure it is in range. You are basically trying to get the lifter somewhere in the center of it's travel. Your 351C valve clearances are set by installing a pushrod of std, +.060" or -.060". I don't have my specs handy but, IIRC, your valve clearance should be .060" >.115". Your manual should tell you correctly. Too tight and it will "pump" the lifter too easy causing misfire or piston contact at high RPM or too much and it may rattle at low RPM. Adjustment can also be made using a FordRacing shim kit for pedastal rockers but, I don't recommend using enough to make up for a pushrod change if you are intending any kind of performance driving or have a performance cam and springs. The shims are mostly for fine tuning. All out performance apps should use custom length pushrods or, better yet, studs and roller rockers. If the pushrod is physically loose with the piston at TDC compression, you have a problem. You should be able to easily spin the pushrod between your fingers or it is too tight.

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Correct, although there are different length pushrods for the 351c.

For high-rev 351c:s it is recommended to run with very little lifter preload, 1/4 - 1/2 turn. This is to avoid lifter pump-up as much as possible.

I have used a Crane shim kit to get as close to a 1/4 turn as possible on my 351c in my Pantera.

Thomas

|I didn't think the Ford 351c had any adjustments. I remember the rocker |fulcrum being bolted to the head with a bolt. The only way to adjust would be |with shims or a file....

If it has bolts, you just tighten the bolts down. If it has studs with nuts, then it's adjustable. Rex in Fort Worth

Your right. The rocker arms on my 351c are bolted to the head. The rocker sets then there is a fulcrum seat, a oil deflector and then the bolt. Now. Do I still have to go thru the half turn torque some then three quarter turn and torque some or do I torque to 20 with the cylinder I am torquing at TDC. Or do I just install the rods and tighten the rocker bolts to 20 without worring about who or what is at TDC?

Forget the 3/4 turn routine unless you have studs. If you have bolts, you must torque them and then check the clearance per my previous post. If all you want to do is the good 'nuff for guv'munt werk, then the 3/4 turn routine will get it running. The way it is done is get the cylinder on TDC compression. Spin the pushrod between your fingers as you run the screw down untill all the slack is out of the valve train and the pushrod begins to get harder to keep spinning. It should tighten another 3/4 turn to bottom the pedastal on the head. This requires getting a "feel" for it. Then, torque it. If you have to go 1 1/2 turns or more to bottom the pedastel on the head, the valve is going to be too tight requiring a shorter pushrod. If it goes less than

1/2 turn, you will need a longer pushrod.