Hello all!


I have been using this forum off and on for the past few years and find it a wealth of fun and information that has helped numerous times; so I decided to join. Thanks for having me


Here's my issue:


I just replaced my crank main and connecting rod bearings to solve an oil pressure issue. since the engine was out of the truck, I decided to pull the crank and replace the rear main seal as well as installing a new timing chain (mine was worn!). Well, I reset base timing with all the rockers loose and am looking good. So, once the timing was good, I went to re-torque the rocker bolts (18-25ftlbs) and noticed that when the valves are closed, the respective rocker for the closed valve is loose and can be wiggled by hand. I'm sure that the lifters drained while the engine was upside down on the stand (oil on floor) and hope that when I prime my new oil pump it will help fill the lifters back up.


Once the lifters are pumped back up, shouldn't the valve trail tighten up? I'm expecting to hear valve chatter for a few minutes after start up and hoping it will go away; is this a safe assumption?


All of my parts are stock (lifters, push rods, rockers, and the like) they are the originals--no Hi-Po parts here at all.


Was I OK to just torque the bolts down? I never saw a special procedure in my service manual and from what I understand, the valve train is self adjusting. is that correct?


I just want to be dead certain that I'm on track for a successful repair here because I do not want to fool with the rocker covers once the engine is back in the truck! that passenger side one is a PITA because of my A/C and heater box!


Thanks for the insight...

 

Welcome to FTE, lots of good people here.
Which engine do you have?

 

sorry about that... it's a 351M

 

They are stand mounted rocker arms so yeah, just tighten them down to the proper torque.
EDIT: You're correct on the torque, the factory manual calls for 18-25 ft/lbs.

 

So, is my original assumption correct? Once the lifters pump back up; the slack and chatter will be gone from my valve train?

 

Yes, they're hydraulic lifters so once the engine starts and builds up oil pressure, the lifters should quiet down.
If you want some peace of mind, prime the lube system with a drill before you put the valve covers on.

 

Outstanding. Thanks for the help. Once I get everything back together and running, I post an update.

 

The manual also suggests tightening down certain rocker arms at certain crank positions. I don't remember what those positions were, but I just rotated the crank until the load was off the rocker arm. then rotated more and tightened some more. and again....


x2 on the "loose" rockers. after the oil starts pumping, the lifters will "lift" and the slop will go away.


If you do prime the system with a drill, remember that the rotor spins counter-clockwise

 

I agree with priming the system but just some food for thought I was told not to do this by my teacher in Engine class because it will wash away all the assembly lube you put on those new bearings. Either way I'm sure it will be fine just thought I would mention it.

 

If it's like a 302, then you want the cylinder at top dead center with both valves closed, when you torque them. You at least want to be darned sure that the valve is closed when you torque its rocker, otherwise known as the lifter preload adjustment. There are other methods to ensure the valve is closed, like adjusting the intake when the exhaust is opening, and adjusting the exhaust when the intake is closing - if I remember correctly...

 

The 302 has stud mounted rocker arms and are adjustable, the 351M-400 has pedestal mounted rocker arms and don't have any provision for adjustment. You just torque the pedestal mounting bolts and done.

 

Mike is right about M block valves having no adjustment unless machined for studs.

J ballan has a point about the break-in lube possibly being compromised.

If you have OCD or **** about these things, you can do one of two things:

1. Put a #1 - with a crayon, white out, etc, on the balancer at TDC (0). Put a #2 180 degrees from that. A #3 mark goes 90 degrees (down) from that or 270 degrees from TDC (0).

With the balancer at TDC, torque rockers to spec on cylinder numbers 1 (intake and exhaust), #4 intake, #3 exhaust, #8 intake and #7 exhaust. Turn the crank clockwise 180 degrees such that the mark you made on the balancer (#2) is lined up with the pointer. Torque #3 intake, #2 exhaust, #7 intake and #6 exhaust. Turn the crank clockwise again 270 degrees such that the #3 mark you made is lined up with the pointer. Torque #2 intake, #4 exhaust, #5 intake, #5 exhaust, #6 intake and #8 exhaust. Done!

Too many moving parts?

Option 2:

Rotate the crank such that no valves (intake or exhaust) are fully open. Torque all to specs and you're done!

Either way you do it, be sure to pour some break-in oil down the pushrods, and on the rockers after you set the valves and before firing her up.

 

Well, the engine went in yesterday and the truck is back on the road. I had no issues with valve chatter, it was up and running a few moments after the timing was dialed in, and seems to be running pretty well. I did prime the oil system for a good 5 minutes with a drill prior to start -up just to be sure!


Thank you all for your help with this issue and keeping my truck in the wind!

 

Thanks for the update, glad it all worked out.

 

Good work-did pretty much the same job on mine, but not yet finished