Marking your HiPo Harmonic Damper

[NC TRACKRAT]

We took 1467 to a local Cars & Coffee this past week-end and, on the way back home, a few lifters seemed a little too noisy so I decided to check/adjust the valve lash. Fortunate that I did!  Found a couple of nuts that were loose, probably from old age.  I had some spare nuts and had been meaning to install lock-nuts anyway, so this was a good time to do it all.  For some stupid reason, I had never marked the damper at 90 deg. intervals to make adjustments easy with only two complete revolutions of the damper. Because it's hard to access, I came up with a way to do it and thought I'd share it.  With a spare damper, I measured the diameter as 6-15/32" or 6.468" X 3.1416 makes the circumference 20.323". Divide by 4=5.08".  Take some blue painter's tape or masking tape and measure out a length of 20.323 as close as you can. 20-5/16" is close.  Mark the 5.08" (5-1/16" is close) intervals to show 4 equal parts.  Start one end of your tape on the installed damper at TDC and slowly turn it as you carefully apply the tape.  You should end up back at TDC. Then transfer your marks on the tape to the damper by scribing or paint daubs. 

[Drew Pojedinec]

Or set via EOIC (my preference, as it is foolproof)
Or get some timing tape, would be a little more accurate as your method allows for stacking of imperfect measurements.

[NC TRACKRAT]

I can certainly see the benefit of high-resolution accuracy if I were building a race engine but I'm just an old "Shade tree mechanic". My goal was to just mark the other 90 degree quadrants in addition to the TDC mark already there with what I had.  Timing tape would be great if a) I had some handy and b) it were available for 360 degrees (Haven't seen any like that). In any event, the valve lash adjustment went just fine.

[6s1802]

I second EOIC that's how I was taught and my turd still runs.

[Drew Pojedinec]

I second EOIC that's how I was taught and my turd still runs.

It works so well because it assures the cam being on the base of the lobe. With a performance cam, TDC method is imperfect.
The only time I use TDC is when a fresh engine needs a basic valve setting prior to cam break in. In that scenario, perfect setting is less important than keeping the break in lube from wiping off.
After cam break in, reset via EOIC.

Either way, I applaud your creativity. Good luck, and thanks for sharing.

[NC TRACKRAT]

I'm old but I'm always willing to learn.  Please explain why EOIC is better than adjusting when both E and I are fully closed at TDC.

[CharlesTurner]

The way I was taught:

Watching rocker arms while turning the crank by hand:

-When an exhaust rocker starts down, set the intake
-When an intake rocker goes all the way down and starts back up, set the exhaust

[Drew Pojedinec]

I'm old but I'm always willing to learn.  Please explain why EOIC is better than adjusting when both E and I are fully closed at TDC.

Look at this diagram:
https://images.app.goo.gl/ZBgzqPABU2vHypLMA

You are trying to set via tdc when the lifters are between the lobes. This is fine for a very mild stock engine. With performance cam separation angle, overlap, and more duration make it to where the lifter edge can reduce clearance for either valve at tdc.
By setting via EOIC you are setting on he base circle instead of the other end, thus assuring lifter is fully down.
Sure it is harder to rotate the engine so many times, but doing one valve in order makes it very hard to miss one.

[NC TRACKRAT]

Thanks for the explanation. Can understand the preference for a highly-tuned performance engine. My method, while perhaps not as precise, allows me to check all 16 valves in only two revolutions of the crankshaft.  Also found this article: https://www.onallcylinders.com/2012/02/28/lashing-out-how-to-adjust-valve-lash/. 

[SFM6S087]

Okay, I'll admit I'm a simple minded guy. But just looking at this thing mechanically it appears that around half the camshaft lobe is comprised of the low spot where you want the lifter to be resting when you set the valve. That means there's a roughly 180 degree target area. (Maybe 140 degrees on some cams.) I see that area labeled in some diagrams as the "base circle" or the "heel" of the lobe.

Although the middle of that area is probably optimum, does it really matter as long as the lifter is resting somewhere in that target area when you set that valve? i.e. not touching the raised portion of the lobe?

If that's correct, there's a heck of a lot of room for error in positioning the cam for each valve. And since the crank turns 2 degrees for every 1 degree of the cam, that means even more latitude in the crank position. But that would seem to conflict with some of the precision advice offered in this thread. Someone please tell me where I'm going wrong.

Or was Charlie Chan right when he said, "Any powder that kills flea is good powder." (Pardon me for the old C.C. quote. I love those old movies.)

Thanks,
Steve

[shelbydoug]

Okay, I'll admit I'm a simple minded guy. But just looking at this thing mechanically it appears that around half the camshaft lobe is comprised of the low spot where you want the lifter to be resting when you set the valve. That means there's a roughly 180 degree target area. (Maybe 140 degrees on some cams.) I see that area labeled in some diagrams as the "base circle" or the "heel" of the lobe.

Although the middle of that area is probably optimum, does it really matter as long as the lifter is resting somewhere in that target area when you set that valve? i.e. not touching the raised portion of the lobe?

If that's correct, there's a heck of a lot of room for error in positioning the cam for each valve. And since the crank turns 2 degrees for every 1 degree of the cam, that means even more latitude in the crank position. But that would seem to conflict with some of the precision advice offered in this thread. Someone please tell me where I'm going wrong.

Or was Charlie Chan right when he said, "Any powder that kills flea is good powder." (Pardon me for the old C.C. quote. I love those old movies.)

Thanks,
Steve

Your presumption is correct and accurate.

The Ford Shop Manual clearly desalinates the procedure used by Ford. The stock hipo camshaft is a VERY mild profile. Almost embarisingly mild.

It doesn't have a radical cam lobe profile like something like a mechanical roller lifter camshaft might have?

The size of the base lobe is huge and difficult to miss.


This discussion reminds me a lot of recommendations of aligning the suspension on a computer guided laser machine to the accuracy of .001 degrees. The alignment specs are an approximation to begin with so what's the big deal?

At some point you need to take charge and make your own decisions. This is called applying your education.

[kjspeed]

I'd like to stir the pot a bit more if that's okay. Hot or cold?

Most, if not all, cam cards specify the lash when the engine is hot. In the case of an FE engine in a Shelby or Mustang, it's a project to remove the valve covers and a major project to remove all 8 plugs (to allow the engine to turn more freely). If one was to set the lash on an FE in a Shelby by removing all but a couple valve cover bolts, warming the engine to operating temperature, then removing the valve covers and plugs, the engine would have cooled off considerably. Not to mention that removing the plugs on a hot engine would be a nightmare. Of course you could do it with the spark plugs in place but it would require more effort to turn the crank by hand. Several times around for the EOIC method.

An alternative would be to set the lash on a cold engine, however the lash settings would have to be opened up a few thousandths to allow for thermal expansion. Is this possible to do with any degree of accuracy? Or is this a cardinal sin? Obviously the lash needs to be set cold on a fresh rebuild before the engine is first run, but maybe all that's required in that case is to be in the ballpark and then, once warmed and broke in they get reset.

[Drew Pojedinec]

I always set cold for the reasons you mention.
At work I regularly do valve adjustments on 16 cylinder two stroke industrial engines, it would be impossible to have all of them evenly warm as it often takes several hours. Many engines do not have hot settings due to this.

I was not telling the original poster he was wrong, simply providing an alternative method that I think is better.
As far as precision, professional methods yield professional results.

[shelbydoug]

You determine a point of zero clearance by tightening the adjusting nut, with the feeler gauge in place, until you just can't turn it any more. That's zero clearance. That is not possible when the engine is hot.

You need to do that with your finger tips and quite simply you will burn your fingers. You compensate on a cold engine @ 70F, by closing down the hot clearance recommended with aluminum heads, .006" and on iron heads you add .002".

I would have to add that in this current atmosphere where yes might mean no, but not positively, where the video tape shows you did something but you say it wasn't you, hot absolutely does not mean hot. It means that you use a procedure cold that will result in a specific measurement hot.

So when you see with your own eyes the play at home plate and you are sitting on the third base side, the runner is clearly out, then you see the camera view from behind home and that's not what you saw, then you see the first base view and the runner is clearly safe, you need to rationalize the entire scenario. In any case, "who you gonna' believe, me, or your lying eyes?" (Groucho Marx).

Pick one. 

[kjspeed]

So you SUBTRACT .006" for aluminum heads and ADD .002" for cast iron to the cam card "hot" lash settings?