Hi there,
This past winter/spring I finally finished up the 360 rebuild in my truck. The one thing I didn't replace in it was the pushrods and rocker arms. Unfortunately, during the rebuilding process the pushrods were mixed up (It wasn't properly taken apart.. had everything been properly labeled.. probably wouldn't be typing) and I sort of "missed" the proper pushrod assembly process when it went back together. The truck has a tap or two... bad / intermittent compression in a few cylinders. My friend and I both have a hunch its all because they were never set up properly.

Anyways, I need to check the Rocker arm to Valve clearance in each assembly to see what is in and out of spec (along with measuring each pushrod) The problem I have is that my book (an original shop manual) does not have the ranges listed where it should be. Does anyone know the range or what the clearance should be? Also, what is a good method for collapsing the lifters? Or should I just locate the proper tool for the job? Thanks!

 

If you're running a hydraulic cam, the push rod should depress the lifter plunger about .020-040. A solid cam setup will call for the lash to be set at .025 ( hot) With a hydraulic lifter collapsed, the valve clearance should be .100-.200

 

Ahh, I guess I should have mentioned that. It is a stock cam and lifters, nothing special. Whatever was stock in a 360 for 1970 is what I have. So, with that setup, the rocker arm to valve clearance is .100 - .200? So then I assume that if my clearance reads .060 or .250 I may need to change the pushrod length?

What you're saying about the lifter plunger... when I go to compress them at TDC they should only go down about .020 to .040? I am a bit confused on that one.

Sorry for all the questions...

 

I guess I should have been clearer. With a hydraulic cam, when you bolt down the rocker shafts, the push rods should only depress the lifter plungers .020-.040. This is kinda hard to check with rocker shafts. While I was posting before, I got out my Motor Repair Manual and that .100-.200 is what it said pertaining to checking the lash on the rockers with a hydraulic cam and non-adjustable rockers. Depress the lifter plunger all the way down and , using a feeler gauge, there should be .100-.200 clearance between the valve stem tip and the rocker tip. If you happen to need longer pushrods, I have a set to sell that I bought for a 390 overhaul, turns out I didn't need them. They are .060 longer than stock length.

 

I was wondering if there's anything to check for on rocker shaft-to-bore clearance? It just seems like a couple of my rockers could be loose.

 

If you mean checking for wear in the rocker shaft, then yes, just remove the shaft and dis-assemble it, any wear will be obvious. I've seen lots of shafts that were serverely worn under just one or two rockers. Come to think of it, just remove the rocker shaft and you can slide the rockers back against the springs to check for excessive wear. Or you can do them while on the motor, checking them one by one while the valve is fully closed.

 

But how much it too much wear? I guess if you can see any wear at all it's not good. Could be why I can hear valve train noise.

 

Yes, that could be your problem, if the shaft is worn to the point where the lifter can't take up the excess clearance in the rocker to tip then you will get "lifter" noise.

 

The only way to cure it is to install new rocker shafts or longer push rods.

 

Getting back to the question I had asked, I did notice in the shop manual that there were feeler guages used. I guess I have to pick up a set of those. From what you are saying, when the lifters compress, they should go down .020 to .040. I think I see what's going on now. The other question I had remains a mystery. Is there some sort of tool I need to compress the lifters. In the shop manul, they have a tool to do the job, is this something I can buy? Or is there another way? Thanks!!!

 

The lifters should be able to compress just by hand by pushing on the push rod, no?

 

Check this thread


https://www.ford-trucks.com/forums/s...B%25252Blifter

 

What I said was , when you bolt down the rocker shafts , the pushrod should depress the lifter plunger .020-.040. As the rocker, pushrod, and lifters wear, this amount of "preload" should take care of the slack created from the wear in all the various parts of the valve train. To check for .100-.200 clearance between the rocker tip and the valve stem tip, really doesn't require a feeler gauge , this amount is about equal to a little under1/8 to a little under1/4 inch.