If you get the cylinder where you are replacing the valves springs at TDC using an indicator through the GP hole it can be done without compressed air. Just be sure the crank doesn't turn on you while releasing the spring retainer clips. This method has been used by others.

 

Robin,
Im sure you could and many others could, but you must agree you need some basic knowledge of tools and engine nomenciature. It would be real easy to get in over your head without it, and not know it until its too late. JMHO.

 

Mexicof250, tappets are the piece that rides on the camand push the tube. I def think you should pull the heads. Very easy job

 

I agree with you Bob. It's not for the in-experienced. But if you have no compressed air or GP adapter and need to get it done, say a collasped spring, it is another method. And if you are doing all of them and work in firing order you only have to turn the crank 45 degrees.

 

So, I'm just trying to breathe this all in . . .

If I take off my heads, I'm looking at ~100 bucks per new head gasket, each side right? And that's just to look in there . . . over 200 bucks + my own labor, just to look inside and wonder what I'm looking at . . . seems a bit pricey.

I'm going to suggest the following and see who agrees or not.

I pull off valve covers. IF, IF, IF . . . I find another bent pushrod, I note which cylinder it is, I replace it, replace all my valve springs, close up and start driving again. IF I get another problem, then I first check if it is the same cylinder, and if or if not, progress to search for other issues.


My reasoning for that: First, cheaper. Second, if I have driven 5000+ miles in between every bent pushrod occurrence, it seems to me that something must happen in a moment of driving rather than there being a problem in the cylinder. It seems more logical to me that something happens at one moment in time which bends the rod . . . because if I had an identifiable issue in one of the cylinders, wouldn't I see another bent pushrod within the next 100 miles I drive?


Maybe this is NEWBIE, naive, non-mechanic talking . . . but it seems somewhat logical doesn't it? And it seems to me that if I replace the pushrod and drive the truck . . . I'm not likely risking the entire engine. I suppose something could be going wrong in the cylinder that needs to be checked out . . . but again, if it goes 5000+ miles before bending again, doesn't that exclude the likelihood that the problem is the cylinder?


I'm inclined to buy into valves floating for one reason or another . . . and the moment of float comes at some point in my driving habits that goes over the edge of tolerance. So I'm thinking the heavier duty springs with a new pushrod might just solve the problem.


I've driven 15k miles since the first bent pushrod. So what are the chances that if I replace the springs and the bent rod now, that I'm going to do any more damage to my engine than has already probably been done? (Correct me if I'm wrong) So I'm thinking my gamble is either everything stays nice . . . or in another 5000 miles I have to go in again . . . and then I can identify if it is the same cylinder or not . . . And then maybe I'll have more cash saved up for head gaskets.


Opinions on this please?

 

Well the engine i spoke of only thew the push tubes every 7000 or so and the cam was junk. Your call i say pull the heads but thats what i woulddo if it was me

 

Sounds like a good plan to me. If you're bending a different push rod each time, it probably isn't cam related. If you are bending the same one each time, at least you'll know where to look after another 5,000 miles or so.

 

Replace the bent push rod, leave the valve cover off, start the engine and check the valve lash on the valve that had the bent push rod. If the valve lash is good put the valve cover back on and drive and monitor. Excessive valve lash could indicate cam of lifter damage. The lifters are hydraulic so it won't show minor damage, but if this has been going on for 15,000 miles, I believe you would see some extra clearance at the valve.
You should also change the engine oil, and look for any signs of metal in the old oil.

 

Huh, I didn't know I could do that. The Haynes manual has me unplugging wiring terminals and taking apart a bunch of stuff on top of the engine. I can start the truck with all this apart/off?

What is "valve lash" ?? And how do I know whether it is good or not?

How do I determine if there is extra clearance at the valve? I have some precision measuring instruments, do I just measure that cylinder relative to the 3 other ones?


Changing the oil is a good idea . . . would metal in the old oil suggest a cam getting destroyed?

 

If you re-connect the electrical harness, yes, you can start it with the cover off.

Pop

 

This happened to a friend of mine.....as soon as the bent push rod was changed and the mechanic started it up WHAM.....same rough running. R&R of the head led to the discovery a bad lifter.

 

[quote=mexicoF250;9041480]Huh, I didn't know I could do that. The Haynes manual has me unplugging wiring terminals and taking apart a bunch of stuff on top of the engine. I can start the truck with all this apart/off?

What is "valve lash" ?? And how do I know whether it is good or not?

How do I determine if there is extra clearance at the valve? I have some precision measuring instruments, do I just measure that cylinder relative to the 3 other ones?


Changing the oil is a good idea . . . would metal in the old oil suggest a cam getting destroyed?[/quote






Valve lash, is the clearance between the rocket arm and the valve stem.
Measure it with a feeler gauge, with the engine running slide the feeler gauge in between rocker arm and the valve stem. use a .020 feeler gauge, you will feel the drag on the gauge as you slide it in and out. compare it to other valves. If it has excassive clearance you will feel it.

You should see metal in the oil,( put some of the oil on a paper towel it should show up if it is there) or use a clean magnet it will attract the metal. Let the oil set after you drain it ( 1 hour should be enough) then pore the oil into a different container, the oil left in the bottom of the first container should have the metal at the bottom.