Hey all,
I have a 1980 F-150 4x4, 302, c-6 auto. I'm getting a bit of "valve slap" when the engine is under load. It goes like this: Warm the truck in park, then engine almost purrs...a minor tapping sound you can barely hear. Rev the engine to 2K in park, sounds great, just a little tapping sound (except for the $$!!* belt squeal that is)
Put the truck in drive and it sounds as though I have an exhaust leak with a metallic edge. Thats the best description I can come up with. Since I have headers with the pipes welded to the collectors and have checked all mounting bolts, I'm guessing its not an exhaust leak.
Can anyone give me a ballpark idea of the cause of this noise? I don't want to be driving down the road and hear a massive "crunch". Could it be a bad lifter or maybe a bent pushrod?

I appreciate any ideas on this one.

Dave S

 

It could be a bad lifter, but it probably is not a bent push rod, since it would make the noise all the time. How many miles on your engine?

 

If you have a lot of miles on it, watch out for the nylon gear on the cam shaft they do have a tendancy to let go throwing of valve timing and bending valves and pushrods. My daughter was driving my 81 LTD when the gear let go and bent every valve and pushrod in the engine (she "wasn't going fast").

 

the engine has boo-koo miles on it, at least 150K. I know its ready for a rebuild/overhaul/junkyard trip. I'm debating on replacing the lifters and hoping for the best.
If the nylon gear on the cam is gone, can it be easily replaced, or is that an engine pull situation?

DS

 

The timing chain and gear can be replaced with the engine in the truck. The waterpump and timing cover have to come off (there are 4 bolts through the oil pan) and you will need a puller for the harmonic balancer. A manual will help a lot.

 

Well, I went to my local autozone and they have generic lifters for $3.50 each. They have a 1 year warranty that the motor may not live to see (lol). I guess I'll go ahead and replace all of them and see if that solves the problem.
If not, I'll go the cam route. I'm just needing the motor to stay alive for a few more months until I can save the dough for a used rebuilt replacement.
On the bright side, I am using this situation to impress upon my kids the need to take care of a vehicle. The P.O.'s of this truck had no idea of what maintainance is. They almost destroyed a really good truck.

Heres a basic list of what I think I'll need to change lifters. Please add/erase anything that will help me with the job:

1. Lifters (duh)
2. manifold gaskets
3. valve cover gaskets
4. gasket sealant
5. Big breaker bar to turn motor

anything is appreciated as always,

Dave S

 

Old lifters tend to get a varnish build up on them and can be very difficult to remove from their bores, so I would recommend that you pick up a lifter remover tool. I believe they have them at Jegs and Summit. If you do not aready have one I would suggest you pick up a shop manual, Chiltons, or Haynes repair manual because there are a little fine details you need to be aware of when you do a job of this nature for the first time. I would also replace the timing set at this time, so you will need a harmonic balancer puller and installer. A lot of Auto Parts stores either rent or loan these tools out, so you do not need buy them unless you want. Don't forget you'll need to have a torque wrench to reassemble the parts you remove. Good luck with your project.

Jim

 

Also if the lifters are hard to remove, spray some carb cleaner on them and let them sit overnight. Try pulling them up and if they still don't come out, soak them in more carb cleaner. A tool would be helpful too, but I just removed the lifters on my 78 302 and the carb cleaner really helped out.