Valve Clearance a remote diagnosis

[Steve Douglas]

I am trying to help a friend out with a loud valve noise, this is being done remotely, via phone and emails, sort of hard to do. But, looking for ideas. it's a 62 T-6 with a later B engine. He said he had a shop do a tune up and them himself set the valves, #1 intake seem to be the one clattering. At TDC he set the lash at .004", then rotating the crank 90 degrees the gap opens up to .012, and at 180 degrees it increased to .022" I tried to explain the maybe he is setting at the wrong spot, but says the rotor is pointed at #1 and the timing make lines up with the case. Any thoughts????.
The car seems to run OK, just a loud clatter, from #1. All sorts of things come to mind: Broken valve spring, retainer hitting rocker arm, sticky tar residue on the valve stem, loose valve guide, broken lifter, worn cam, or????
He says it might have been increasing over the last 500 miles, but he is not sure if just is becoming more aware of the sound. The car sat for a 6-8 months over the winter with only a few drive of less than 150 miles since August of last year.

[WilliamVaughan]

Practice makes perfect. Tell him to put on some dirty clothes, develop a tolerance for working on his back, and get scientific with the crankshaft rotation. Forget the distributor. Watch the rocker arms move while rotating the crankshaft (ccw) in small increments.

And realize that rocker arm tips are offset from the top of the valve stem. The get a step worn in them that you can not see. If you don't take the rocker arm tip wear step into account you can get some wildly wrong and inconsistant feeler gage measurements.

[David Jones]

He needs to pull the valve train and inspect the push rod and maybe also drain the oil remove the sump plate and inspect the cam follower. At least that is what I would do simply because if he set all the valves the chances are he did not screw up if the others are OK especially if there is no issue with the opposite side.

[Dick Weiss]

Adjusting the valves requires the crank to be rotated 180 degrees; NOT @ 90.
Sounds like the crank is rotated backwards(?) giving those gaps listed--the gap should remain @ the same setting
while that piston is going thru its power stroke from TDC until it's near the bottom when the exhaust valve starts to open
before BDC. A broken valve spring may or may not affect the clearance unless the valve or guide is loose.
A straight or bent pushrod shouldn't be the cause unless it's not seated in its tappet/cam follower.

[Chip Flor]

Hello Steve,

I'm inclined to agree with Dick. It sounds like he is rotating the engine backwards. The engine direction and distributor direction should be turned CLOCKWISE. The firing order 1432.
It might help for him to see the intake valve close prior to rotating to TDC . That would make sure he is at the firing spot of that cylinder. Take a look at the degree wheel where you can see what valve is closing on the rotation before you reach top dead center.

Also agreeing with Dick, TDC and 180*degrees are the only place on the pulley where one of the cylinders has both intake and exhaust valves fully closed. Unless of course there is something terribly wrong with the motor.

What you describe is troubling. !f the valve is closed (at TDC or 180*) the adjustment can not grow and extra .022" at 90 degrees. To me this does not make sense. Its either fully closed or it is not. There is no in between at TDC and !80*

What is the clearance on the other cylinders? Is #1 way off by comparison? If so there is something horribly wrong here.

I'm hoping that this scenario is exactly as you initially surmised, that he is adjusting the wrong set of valves in the wrong firing order.

I hope this helps.
-chip

[Wes Bender]

It matters not which way the crank is turned. (Except if the distributor is removed. Right Vic?)
I prefer to turn it in the direction it is intended t run, but that's only because I adjusted M-B valves and the drive chain needed the slack taken up.

[Chip Flor]

1432 clockwise... 1234 counter clockwise. yea I too like to turn the same direction that the motor actually runs. (force of habit I guess).

[Wes Bender]

I adjust them 4321 because I can do one side at a time instead of going back and forth.

[David Jones]

I still say that it is unlikely that he adjusted just one valve incorrectly if the others are all correct, unlikely but possible.

[Steve Douglas]

I sent him all the information and I think he is turning the engine backwards, since Dick and others mentioned it.
Chip can you give Barney a call?? I sent you an email with his number. He's not very far away and just needs some guidance, I'm about 90 miles.

[jim hasbrouck]

I start with number one and go backwards 180 degrees, going 1234, doing one side at a time. I hope rotating backwards doesn't change anything. I don't see how it can, tell me if I'm wrong.

[Vic Skirmants]

I start with number one and go backwards 180 degrees, going 1234, doing one side at a time. I hope rotating backwards doesn't change anything. I don't see how it can, tell me if I'm wrong.

You're not wrong. Just don't do it with the distributor removed.

[Mike Wilson]

O.k. a shop did a tune up but didn't adjust the valves? Why not?

Mike

[Chip Flor]

Spoke with Barney (the person with the issue) last night.
He told me the valves were adjusted by two different shops. So the out of sequence adjustment is not a factor.
He also described that he measured the cam lobe via the adjustment gap for a full 360 degree turn (x 2 on the engine rotation) on the #1 intake.
As you can see the cam lobe is not concentric on the non lift end. It appears to be out of round or undercut (.004" - .014") .010".
He is going to plot out the other valves to see if #1 is different.
Here is his plot:

IMG_5343.jpg (82.14 KiB) Viewed 588 times

I asked him to pull the lower cover off and see if there is an abnormal amount of metal wear accumulated at the magnet.
He is also going to look at the cam while he has this cover off.

I truly do not have an answer here.

[Wes Bender]

Not to insult his intelligence, but I wonder if he's counting valves correctly.