Update! Lifters are fine, the mechanic is the problem.

[hoopty5.0]

I hate to keep posting questions related to the truck here, but at the same time, its still an SBF and I trust the info here more that elsewhere.

So after swapping the heads on my F-150 this weekend, I put the push rods and rockers back in. The plungers in the lifters don't move at all. When I set the lash on the fox, the plungers in the lifters could be pushed in slightly. The ones on the truck didn't do that. By this point, I had already put the intake back on, so I couldn't inspect them to see if they had collapsed or were just frozen.

My question is, should I prime the oil pump and try to pump them up and see if that helps, or do you think that the lifters are junk? This is a 160k mile roller 351 that is clean as a whistle inside.

 

[Noobz347]

Replace. Sucks that you have to burn a set of gaskets but how else could you be sure?

 

[hoopty5.0]

Replace. Sucks that you have to burn a set of gaskets but how else could you be sure?

I don't disagree.

But for the sake of my curiosity - Why would the truck have been running just fine before? Oil pressure was ok, nothing rattled or knocked. purred like one of my wife's bastard cats. ran as recently as 2-3 weeks ago.

 

[Noobz347]

Priming them certainly couldn't hurt anything.

 

[hoopty5.0]

Priming them certainly couldn't hurt anything.

The thought of pulling the cast iron GT-40 lower manifold off is unsettling. It weighs every bit of 70lbs!

 

[95BlueStallion]

Why not prime it and see. Worst case when you try to start it, it just turns over and has no compression cause you over tightened them...

 

[CarMichael Angelo]

And

Why not prime it and see. Worst case when you try to start it, it just turns over and has no compression cause you over tightened them...

And he speaks from authority on that...
( you can run and hide, but we all know the truth)

 

[hoopty5.0]

Changed the oil, pulled the distributor out, primed the engine.
The plungers are stuck solid.

Now please don’t think I’m trying to cut corners looking for someone to say, “screw it, see if it runs!” ...... I’m just genuinely baffled. Has the truck been running with stuck plungers and therefor solid lifters?

Luckily, I have the lifters from my blown 351 to use for further investigation. They had less than a thousand miles on them and were new before that.

Guess what? All 16 stuck like a pig.

So I got really curious and took one apart and cleaned it. Now, the plunger works.


Yes, I know the answer, yank the intake and replace the lifters. But how has the truck been running like this? Do they loosen up as they warm up? Someone has to know!!!

 

[RangerJoe]

I would installed the rocker arms and let them sit overnight. See if the spring bun pressure bleeds them down. They are probably full of oil.

Joe

 

[hoopty5.0]

I would installed the rocker arms and let them sit overnight. See if the spring bun pressure bleeds them down. They are probably full of oil.

Joe

Ahhhhhh. that didn't even cross my mind.

On second thought, the one I took apart from the old engine was full of oil too.

I feel like a dope now

 

[General karthief]

Your just trying to live up to your avitar

 

[hoopty5.0]

Your just trying to live up to your avitar

It’s there for a reason!

Funny though, after working on cars regularly for all these years (15 years since my first fox) I still run into new situations that I have no clue how to diagnose. It’s humbling!

 

[95BlueStallion]

It’s there for a reason!

Funny though, after working on cars regularly for all these years (15 years since my first fox) I still run into new situations that I have no clue how to diagnose. It’s humbling!

I had done two H/C/I swaps prior to assembling my current 347, and didnt have the rocker adjustment issue on either of them. Sometimes weird sht happens that perplexes you because you have been there before and it never came up.

 

[hoopty5.0]

I had done two H/C/I swaps prior to assembling my current 347, and didnt have the rocker adjustment issue on either of them. Sometimes weird sht happens that perplexes you because you have been there before and it never came up.

This thread really has me wondering now if I repeated your mistake on my mustang. nowhere in the rocker install instructions does it say that the lifters must be pumped up. I wonder if my valves are ever so slightly open????

 

[FoxMustangLvr]

This thread really has me wondering now if I repeated your mistake on my mustang. nowhere in the rocker install instructions does it say that the lifters must be pumped up. I wonder if my valves are ever so slightly open????

You don't need them pumped up for install I believe, that's only for measuring push rods. When measuring push rods you do not want the lifter to depress while cycling the valves to create the wear mark (solid lifter req'd for this). When installing the lifters, assuming you have the correct length push rods, you only need to tighten down to zero lash (can only twist pushrod with fingers), then torque to spec (18ft lbs within one turn?). This is of course for pedestal rockers.

 

[hoopty5.0]

You don't need them pumped up for install I believe, that's only for measuring push rods. When measuring push rods you do not want the lifter to depress while cycling the valves to create the wear mark (solid lifter req'd for this). When installing the lifters, assuming you have the correct length push rods, you only need to tighten down to zero lash (can only twist pushrod with fingers), then torque to spec (18ft lbs within one turn?). This is of course for pedestal rockers.

Yep. I read a few install sheets, all fall between 18-20 ft. lbs and 1/4-3/4 turn.

 

[95BlueStallion]

There are soooo many different techniques and specs out there. Thats what got me. Tried the "fail proof" ones off Youtube. Turns out...