merkfalc

Can anyone tell me how to properly check and adjust the valves on a 318 poly. I have never done a valve adjustment except on vw bug and that was about 12 years ago. I know I follow firing order getting #1 at TDC on the compression stroke and then do I check intake and exhaust at the same time? And where am I checking it at. Another stupid question but I'm learning.

David

duster_066

I'll take a shot at this. First I'm no Mopar expert so forgive if I ask whats a 318 poly?? If it's a LA318 small block and it's stock it should have hyd lifters which are non-adjustable. Even if it has had adjustable rockers added you still need to know if the cam is mechanical or hyd because it changes the procedure.

If you are sure the engine has a mechanical cam the adjustment procedure is fairly simple, and you are already on course by bringing #1 to TDC. Adjust both valve tips to rocker arm clearance to specs (feeler gauge between the valve tip and the rocker tip). Turn the crank 90' in the direction of rotation to bring #8 to TDC and adjust both those valves. Continue this procedure through the firing order, for an LA318 1,8,4,3,6,5,7,2 left bank (drivers side) is odd numbered cylinders right bank is even.

If you need specs you can find em online or...0.008" to 0.010" on the intakes, and 0.012 to 0.014 on the exhaust will work fine.

440roadrunner

Duster, a "poly" is the earlier 318/ other cid with the scalloped valve covers, often erroneously called a "wide block" because it looks big in the bay. The fact is the block itself is no bigger than an LA block. These were used in the B bodies up to I think through 67. You won't find them in an A body which would have had a 273 before the 318 LA came in 'em.

A "built" 318 poly. Note the scalloped valve covers:



A 318 poly valve gear:



What year model is it? I can probably look up the valve lash

It is IMPORTANT to know, ESPECIALLY a performance cam, does NOT exhibit the same valve clearance with the piston at TDC as it does when the lifters are on the "backside" (heel) of the cam

One easy way to do this on ANY four stroke engine, is remember EOIC

This means that you bump the engine so that

When an EXHAUST valve just starts to OPEN, you adjust the intake for that cylinder

When an INTAKE valve opens and is nearly CLOSED, you adjust the exhaust valve for that cylinder

If John K gets in here, I know he posted a chart on how to set "every 90 degrees" of crank rotation, but the method I posted is the one above.

Also, I do not believe in hammering yourself to death trying to adjust "running." Just warm the engine up, pull one cover, and set that side, engine off. If you are concerned about the engine "staying warm," you can always warm it up some more before you attack the opposite bank.

I use two feeler gauges, one for the specified lash, and one a few thou bigger. I set them so the specified gauge goes "in" but the larger does not.

It just ain't that hard.

duster_066

Ah, that's right I remember hearing about the "other 318." Never seen one. lol

merkfalc

I got them all adjusted except for the last one and it is toast! It is super loose and will not tighten up. I had 0 compression on that cylinder and it looks like the exhaust valve is not sealing. I knew it was that cylinder and the PO said he thought the valves might be bad and looks like he was right. So I guess I'll tear the head off, make sure there isn't any damage to the cylinder and install some new valves. Thanks for y'alls help.

David

440roadrunner

Good luck. If I live long enough, I may build a poly Just Because

robert 3176

robert 3176

hello my name is robert and i thank you for the info on the 318 poly