The Stovebolt Site Forums The Shop Area Engine Shop One noisy lifter

Introductions first, I'm 62, been around cars and back yard mechanicing for 45 plus years. Current projects are my 5.0 Mustang drivetrain powered 1990 Miata. Think of it as and old guys ultimate hybrid. Just put a set of 165 AFR heads on along with a set of Scorpion roller rockers. Started it last week, just need to clean up a few details and it's back on the road.

Other and more importantly this's forums specialty is the newest project, a 1951 3600 with original engine and a documented 43,800ish miles.

I've only had the truck a couple weeks and have been sorting out various issues, straighten bent tie rod (amazing how much better it drives), change fuel pump, new vacuum advance and other minor issues.

Now to the question, it has one noisy lifter, the intake on number 4 when set at 6 thou is noisy as all get out. Driving down the road at 45 it's all I can hear. I can tighten it down so it's as quite as it's neighbors but when I do it's at about .002 (hot engine). I'm tempted to set it there and just drive it and see what happens. But then the old burnt valve possibility makes me keep it on .006 and noisy. I'm using a standard flat blade feeler gauge (about 1/2" wide). My research tells me I should use a wire gauge, just don't have one.

So, anyone have an opinion on just tightening it down till it's almost quite and driving on?

I'll pull the rocker arms when I get a bit more time and see if I can figure out what's going on. I did check and oil is flowing everywhere it appears it should be.

Thanks in advance, Ron

If you're setting them at 6 hot there's no reason for it to be noisy unless maybe you have a lifter that's sticking??? Someone else may have more ideas than I do but I'd pull the pushrod and make sure the lifter moves freely in the bore.

To tight a setting on an intake is not a huge risk.
Intake valves are cooled by incoming gas so they seldom burn.
There may be some time the valve may not close completely during the warm up cycle or if the engine over heats but I think you would get back firing through the carb or some bad miss if this happens.
Never good on an exhaust valve setting it to tight.

Could the tip of the rocker arm that contacts the valve be worn and the feeler gauge is just touching the outsides of the rocker arm?

I would bet that is the problem.

Don Stocker said; "Could the tip of the rocker arm that contacts the valve be worn and the feeler gauge is just touching the outsides of the rocker arm?"

I had considered that possibility. Guess I'll just let it be noisy till I can pull the rockers and check things out.

Thanks All!

If you know the thread pitch of the screw, you can divide that out and determine how many thousandths each flat of the nut is. That's how I adjust the valves on my L134. I have yet to find replacement tappet adjusters and even if I did, taking the head off to get to it is way to much work for now.

On a L134 that will work. On an overhead set-up you would also need to calculate the rocker ratio into that.

Seems like 1.477 the right ratio.

Assume that the thread on the adjuster is 32tpi (.03125 per revolution) / 6 (sides on a nut) = .005 thou per nut flat.

Since the rocker increasing the lift ratio you would multiply .005 * 1.477 = .007 per flat

Snug the adjuster to remove all lash, then back the adjuster out one or two flats depending on the intake or exhaust.

Sound right??

Use a magnetic-mount dial indicator touching the top of the rocker arm inline with the valve stem instead of a feeler gauge to check the clearance. If there is a dimpled rocker face the dial will reflect the true clearance instead of bridging over the feeler gauge blade.
Jerry

Thanks guys, it'll be a while before I can get back to the Lit'l truck but when I do I'll update with what I find. I'll dig out the dial indicator and test pfarber and Hotrod Lincon's suggestions. I like both.

Was going to suggest that method, but most people don't have a dial indicator (HF sells them, with a mag base for $20).

I'm sure that if you set up your indicator, you'd find that you need to turn the adjuster 1 flat (.007) to be good enough. So why not save the $20 (and the drive) and turn the adjuster 1 flat? 2 flats for exhaust.

My Guess is if you adjust it to where it just stops being noisy and you are not getting a miss, popping or back firing it is good to go, as others have said probably a little wear on the rocker face giving you a false reading with a flat gauge.
Rich