valve adjustment

[papa scoops]

any thoughts on valve adjustment 66 hi po with cobra lemans cam, hot/cold? running,off? fred

[shelbydoug]

any thoughts on valve adjustment 66 hi po with cobra lemans cam, hot/cold? running,off? fred

Off and cold. Iron heads add .002. Aluminum heads deduct .006".

You know how to establish zero clearance right?

[papa scoops]

add to what? me, dumbguy, my mechanic, smart guy.

[427heaven]

Those numbers are added to the valve lash because its cold. When the engine warms up the tolerances will shrink because of heat then theoretically you will have your valve lash that is recommended by your cam manufacturer. I adjust when its hot because that's the real number its going to run at then I don't have to guess about how close it is. A stock hipo can rattle along just fine not knowing any difference if its a few thousandths off one way or another.

[shelbydoug]

add to what? me, dumbguy, my mechanic, smart guy.

Solid lifter camshafts have a clearance specification given by the camshaft manufacturer.

The camshaft that I am using for example has a clearance given of .022". That is hot or more correctly with the engine at normal operating temperatures.

Now I happen to be running aluminum heads. Aluminum heads will expand when "hot" by .006" or more correctly when cold, they will be .006" smaller.

So the correct clearance to measure with the feeler gauge cold is going to be, .016".


Now an iron head will expand also and that is going to be about .0015". Using .002 is safe. So the cold clearance for an iron head with that cam is going to be .024". Got that part?


Next, you need to be able to determine zero clearance. You are going to insert the feeler gauge between the valve stem and the tip of the rocker arm. Then tighten down the adjusting nut just until you can no longer rotate the push rod with your finger tips. That is zero clearance.

Now here's the tricky part, IF you are using locking nuts with allen set screws in them, as you tighten down the set screw, you are going to open the clearance slightly. Enough to be able to rotate the push rod. The number is actually going to be about .001" of an inch.

Some will leave it there, but if you want to be dead nuts on, you are going to have to compensate for that by closing down the clearance with the feeler gauge another .001".


If you have got all of that, the Ford Shop manual has a specific order in which you adjust each valve. It's going to require you to use eight different positions of the crankshaft to adjust all 16 valves.

Some mechanics will tell you to throw that procedure away and just adjust each set of valves (1 intake, 1 exhaust) at top dead center of each piston stroke.

Now I've got to presume that Ford wouldn't have wasted the ink and paper to print the procedure on if it wasn't of significance. I consider it a text and the text as Gospel. If you want to be strayed by the dark side, I can't fight it's power. Do as you will. I go the straight and narow...on adjusting solids anyway.


Back in the olden days before electricity, racers could gain torque or rpm by adjusting the valves loose or tighter. Even if that works, you run the risk of snapping a rocker arm stud if it's too loose or burning an exhaust valve seat if too tight.

The normal inaccuracy you are going to have setting them at spec, is going to give you enough variation right there, so don't even think about this Vodo procedure of looser or tighter. Leave that to the Chevy guys who always needed to cheat anyway they could?


Oh, one other thing, specs are always given for an air temperature of 70 F. So if you choose to do this at 20 F or 100 F, expect some inaccuracies.

You are also going to get some people yelling from the cheap seats, booing as it were, that you need to do this with the engine running. Here's the word that you use with them. Poppycock.

Now go to it Pilgrim. Life's an adventure. So is adjusting valves. Let us know the new cuswords you invent while doing this. There's a good one I use after my finger tips are all raw and my back goes out from leaning over the fenders for too long. Decorum won't permit me to share those with you here. 


Oh. There are at least two versions of the 289hp Ford cam that I know of. Different clearances spece'd on both.

...and sure you can adjust them hot BUT them things IS hot and you better have asbestos finger tips. Trust me on this point. Oil temp is 210-220. Your pushrods won't glow but your finger tips will. You can compensate for a lot of things but you can't fix stupid. 

[NC TRACKRAT]

A good set of go/no-go feeler gauges really helps. If you set clearances cold as described above, you can check when hot without removing the valve covers (which usually makes a mess of a nice, clean engine compartment).  Just use a dowel rod or a stethoscope on top of the valve covers right above where the rocker arms are located. You'll hear the difference if one is either too loud or too quiet.  Make a note of the one/s that may need re-checking once the engine is cold.

[cob4ra]

I'm sure as many of us know that the stock pinch friction 5/8th nut will lose its ability to hold your gap ; especially if you've Made some 6000 + rpm shifts ! So being a watchmaker I applied some horological spidey sense! I found some thin locking nuts that take a 9/16th socket ; still short enough to fit on a stock stud over the stock 5/8ths ; adjust your gap with  the top 9/16th to tighten  little too much ; then loosen with a 5/8ths socket as it  fits over the smaller top nut and counter clockwise to adjust ; the two tighten together and say goodbye to anymore adjustments ! Better than polylocks as there is no clearance issues !,

[SFM6S087]

The official Ford "1965 Comet, Falcon, Fairlane and Mustang Shop Manual" says the factory spec for 289hp is: intake & exhaust .022 cold /// .018 hot

My 1966 GT350 Owner's Manual says:
Operating tappet clearance . . . . . . . .0.020in., hot (intake and exhaust)

Since I don't like burning my fingers I set for .022 cold.

Steve

[shelbydoug]

The official Ford "1965 Comet, Falcon, Fairlane and Mustang Shop Manual" says the factory spec for 289hp is: intake & exhaust .022 cold /// .018 hot

My 1966 GT350 Owner's Manual says:
Operating tappet clearance . . . . . . . .0.020in., hot (intake and exhaust)

Since I don't like burning my fingers I set for .022 cold.

Steve

Kinda' makes you want to consider a hydraulic lifter cam doesn't it?

[gt350hr]

  Phred,
    "For me"  the LeMans cam ran best @.018 HOT. When I bought 6S477 in '74 that was the cam in the engine. I tried different lash settings searching for "free" performance at the drag strip. .018 is what worked best for me. I use a bit different method to "run" the valves than those who use the "TDC" method. "I" adjust the intake valve when the exhaust begins to open and then adjust the exhaust valve when the intake valve begins to close from full lift. This more time consuming way ensures the lifter IS on the base circle of the cam. Once you "pick" a cylinder to start with , you can follow the firing order to the next one to adjust . I use a remove starter button to "bump" the engine to the next cylinder to adjust.  "My" .018 has drag on the feeler gauge when it's right.
    Randy

[s2ms]

I'm running aluminum roller rockers in my 66 and used to adjust the valves hot until I discovered the hot and cold lash were exactly the same, did the comparison several times with the same results. Now just do it cold.

[gt350hr]

  I found the same thing with aluminum rockers. The expansion as they heat up is the reason.

[sg66]

  Phred,
    "For me"  the LeMans cam ran best @.018 HOT. When I bought 6S477 in '74 that was the cam in the engine. I tried different lash settings searching for "free" performance at the drag strip. .018 is what worked best for me. I use a bit different method to "run" the valves than those who use the "TDC" method. "I" adjust the intake valve when the exhaust begins to open and then adjust the exhaust valve when the intake valve begins to close from full lift. This more time consuming way ensures the lifter IS on the base circle of the cam. Once you "pick" a cylinder to start with , you can follow the firing order to the next one to adjust . I use a remove starter button to "bump" the engine to the next cylinder to adjust.  "My" .018 has drag on the feeler gauge when it's right.
    Randy

This is what I've always done ^ but now wonder why I never went a step further and made a simple chart like Mopar guys (with correct firing order) and just turn the crank 90 degrees With a breaker bar rather than try to be exact with each bump. https://www.forabodiesonly.com/mopar/attachments/moparvalvecard-jpg.1715048444/

[gt350hr]

  That method is fine with smaller cams. Using the "factory shop manual" way WILL result in loose valves on aftermarket longer duration , higher lift  cams. I've learned a thing or two in 53 years of building "racin" engines.
     Randy

[camp upshur]

This is all pretty good, but perhaps needlessly made complicated. A valve can't get any more 'closed' than when on it's base circle.
The C7FE is a basic Sullivan symmetrical lobe.
I always put 4 paint daubs at each 90 on my damper, but that's not even necessary. Similar to the Mopar gouge posted, two complete engine turns in quarters with both covers off will catch all of the lobes at their nadir wherein they can gapped (remember they can't get any more closed). A couple of minutes!

Of course shoptalk of esoteric lobe assymetries, reverse radius inverse flanking, 'unique' accel/decel ramping etc etc preventing access to the base circle really do not relate except in the most rarified of arcane automotive circles.

Another poster alluded to the use of a jamb nut atop the crimped nut (like A Boss 302). For me this always worked best, usually using another 'crimped locking nut' flipped over. 1920's technology but simple and effective short of shaft mounts I found.
Many use poly locks successfully (and God bless em), sometimes though if not exactingly torqued/ or sometimes guys add and 'extra' 1/8th turn or so to perfect the clearance---stress can be placed upon the top threads of the stud and result in stress/strain breakage of the stud tip threads within the poly lock.
Again this shouldn't happen in theory if done exactingly but it can induce a problem.
Many ways to skin a cat!