Valve adjustment for dummies?

[ZIGGY]

Not that F-bird & MadBill need my endorsement, but they are absolutely correct. I learned from personal experience when I got past ancient cam technology.

[In-Tech]

Boz's method is just fine, I don't care how big or who's cam it is. I do the "just as exhaust starts to open" and "anytime the intake is on its' way closed" method. If you have adjustment problems with that, you better have a look for a base circle runout problem.

[ZIGGY]

In-Tech - thank you for the different view though I'm not smart enough to know what I was seeing. I don't often have (or maybe it's make) the opportunity to check cams. First time I recall an issue was with a "Corp" Cams tight lash FT some years ago. I remember I had to watch/feel the exhaust pr for movement and set intake on the instant, etc or I had variation on re-check. From then on I did 'em all that way and don't remember any similar issues since.

[Mick70RR]

If you want the 100% full proof "valve adjustment for dummies", do each valve one at a time.
What ever valve you are on, turn the engine over until the valve is at max lift, then turn the engine over 360 degrees and set that valve.
This puts you dead center on the base circle, with zero chance of being on the clearance ramp.

No need to turn the engine over 360 degrees, adjust the opposite valve in the firing order. I.E. for a 18436572 firing order get number 1 exhaust valve at maximum lift and adjust number 6 exhaust, then turn the engine over until number 1 inlet is at maximum lift and adjust number 6 inlet. Turn the engine until number 8 exhaust is at maximum lift and adjust number 5 exhaust etc.

[speedphreake]

Looks like I will be trying out a few different ways to see what works best for me.

[CamKing]

If you want the 100% full proof "valve adjustment for dummies", do each valve one at a time.
What ever valve you are on, turn the engine over until the valve is at max lift, then turn the engine over 360 degrees and set that valve.
This puts you dead center on the base circle, with zero chance of being on the clearance ramp.

No need to turn the engine over 360 degrees, adjust the opposite valve in the firing order. I.E. for a 18436572 firing order get number 1 exhaust valve at maximum lift and adjust number 6 exhaust, then turn the engine over until number 1 inlet is at maximum lift and adjust number 6 inlet. Turn the engine until number 8 exhaust is at maximum lift and adjust number 5 exhaust etc.

I was just trying to make it as simple as possible for "dummies". Didn't want to make them remember the Firing Order.
I'd never spend this much time on it, but when someone is having problems, I suggest this method to take out all variables.

[Boz-Race Engines]

Boz's method is just fine, I don't care how big or who's cam it is. I do the "just as exhaust starts to open" and "anytime the intake is on its' way closed" method. If you have adjustment problems with that, you better have a look for a base circle runout problem.

exactly, thankyou In-Tech

[Boz-Race Engines]

it would be nice if some people would actually have a proper practical look at something before knocking someone elses method

[cjperformance]

ICEO method is fine and you dont need to be too exact with the position to be around the right position on the base circle to have no issues with opening/closing ramps.

The firing order method works fine BUT only for stock/mild Flat tappet stuff, keep it for the stocky's IMO, too much room for error for performance use.

The 'one valve at a time' method is pretty much fool proof for any cam and if its your first time at tackling a big solid roller, do it this way.

Either way you go, if you are new at it, heres a few easy tips,,,

= get a marker pen and mark each rocker as its done so you cant get confused,

= remove the plugs as its so much easier to turn the engine over and find accurate positions,

= go a little easy on the tightness of the posi locks(if using them) many newbies overtighten them badly, then they crack!

= if you are not real great/sure with the 'feel' of feeler gauges, try this- if you are trying to obtain say .015" clearance,
adjust the rocker clearance to a .015" gauge, then verify it by trying to fit a .016" gauge in the clearance you set, if you can get it in you are set too loose, then try and fit a .014"gauge in, if it has drag on the gauge you are set too tight and were riding the valve 'slightly'.

[pdq67]

I'm going to say it again!

I lash solid lifter cams hot idling with my needed two feeler guages AND this is a "FEELIE" deal here to set them right, imho.

Now, hy-cams, the old again "FEELIE" twist the p/r between the thumb and index finger to set lash while again, hot idling, is the way I was taught to do it as a pup way back in the early '60's...

It's an oily messy way to do it, but it flat works by me.........

pdq67

[MadBill]

Maybe I was using cheapo feelers, but when I tried that, after a few rounds the blades were beaten down to well under the marked thickness..

[cjperformance]

Maybe I was using cheapo feelers, but when I tried that, after a few rounds the blades were beaten down to well under the marked thickness..

Lol, true, you cant use cheapies doing it this way,,

I have used the go-no-go feeler gauges before to set solid lifter lash with the engine running!! lol what a lovely job, takes all the fun out of performance motoring! Roasting hot oil splattering all over you and the engine bay, extractors etc, great stuff.

Not so bad on the typical old 60's muscle car cams where the usual .460"-.500" lift and obscene duration makes the valve action so lazy you can easily get the feeler in place.

BUT, try it on a solid roller with .700"+ lift and the typical valve accel rate that comes with it!!! not so easy any more..

[MadBill]

It took me a while to get around to the calculations but since I have, I'm going to share them, even though this thread has pretty much run its course:

I hate doing math in public, but I guess there's no way out, so here's a little analysis:
The biggest lobe in the ~ 8 year old Comp catalog at hand is a Pro Mod exhaust at 368° advertised. My guess (CK or someone may have a better number) is that we can add 30° to find the first thous. of ramp. Lets call it 400° duration @ 0.001". Assuming the intake lobe is 20° shorter, we get 348° advertised, 380° @ 0.001" and let's say the lobes are on a 115° LCA (big cams/big engines get big LCAs) and for simplicity, the cam is installed straight up, so the intake centerline is 115° ATDC and the exhaust's is 115° BTDC.

The center of the intake's base circle will be one revolution after its max. lift point, at 115° ATDC-compression (65° BBDC) and it will be 720 -380 = 340° long. From the exhaust lobe's 368° advertised duration and 115° ECL, the exhaust valve's actual opening point is 119° BBDC. Therefore, the 'perfect' set point for the intake lash will be 119 -65 or 54° after the exhaust valve clears its seat. BUT, given that the intake's base circle extends 170° either direction from this point, positioning the cam at anywhere from first movement to full lift of the exhaust valve will leave 50 or more degrees of position 'insurance' for intake lashing.

Similarly, the exhaust lobe's base circle is centered at 115° BTDC-compression, Vs. the intake valve's actual closing point of 109° ABDC or 71° BTDC-compression. Thus the perfect set point for the exhaust is 115 -71 or 44° before the intake closes. Again, the tolerance is great, +/- 170° in this example, so lashing the exhaust anywhere between the intake starting to close and touching down on its seat will give ample leeway.

The cam in this example is probably longer duration than 99.9% of SpeedTalkers will ever encounter, so real-world examples will have even more elbow room.

[Boz-Race Engines]

so there you have it. Amen to that, thanks Bill

[CamKing]

The biggest lobe in the ~ 8 year old Comp catalog at hand is a Pro Mod exhaust at 368° advertised. My guess (CK or someone may have a better number) is that we can add 30° to find the first thous. of ramp. Lets call it 400° duration @ 0.001".

I did a quick check of my profiles, and besides the PS exhaust lobes, the longest duration I found(294@.050"/.465" lobe lift)
from max lift to the very end of the clearence ramp was 115.5 cam degrees.
So if you used that exhaust on a cam with an LSA of 110, as soon as you moved 6 cam degrees past max lift on the intake valve, the exhaust would be on the base circle, and it would stay on the base circle for 129 cam degrees.