valve adjustment

[sergeshishik]

Anyone have any advice on the "feel" of the .004 gage. It seems like my valves are tight the only way to get the gage into the gap is to loosen the valve. Then I have a hard time determining how tight to make the adjustment. Any advice would be appreciated, I don't want to screw something up.

Thanks

[jason2guy]

loosen it up and then put the feeler in. make sure the valve youre working on is closed and the cam lobe is opposite the rocker. then adjust kinda tight. the feeler will take a little pulling to get out. not a yank but little gusto. believe me, it took 4 or 5 times for me to finaly get a proper adjustment. usually your first couple times they end up loose, from being overly cautious

[sergeshishik]

Thanks Jason, your right I tend to keep them loose, any tips on tightening the retaining bolt. I also seem to f-up the adjustment when I tighten back down the bolt.

[john walker's workshop]

you need the gauge holder or you will not have any feel for tight or loose. counterhold the screw while you tighten the nut. in other words, keep just enough counter-clockwise pressure on the screw to keep it from being turned by the nut. the adjustment is right when the gauge can be removed and inserted with a couple of twists and it does not slip in or out. if it slips (slides), it's still a hair too loose. if the gauge gets damaged, it's too tight.

[sergeshishik]

thanks John

[BReyes]

Sergeshishik. Have you seen th set of gauge/holders sold by our host?

John has confidence you can do it.

Regards,

[Wil Ferch]

If you use the Porsche P213 tool..please remember to blue loctite the itsy teensy screws that hold the blade on.....

It'd be a "bad hair day" if the nuts come loose and fall into the nether regions of the engine....

Or get the island tool...

-Wil

[2.7RACER]

Much has been said about valve adjustment, special tools that hold the .004"(.10mm)shim, and the "feel" when things are proper.
I agree that you can develop a feel with the available tools and experience to accurately set the gap.
People do this every day and think nothing of it.
That said, there is some trepidation doing this for the first time. Particularly when you don't have a experienced mechanic looking over your shoulder.

So once you do all the adjusting, pushing and pulling, looking for the "feel": how do you really know you've got it right?

Once you have the gap at .004"(0.10mm), it is difficult to reinsert the shim. Almost at the risk of damaging the edge of the shim.

So you make a note of the screw position, loosen things up, reinsert the shim and reset everything until you feel confident the adjustment is OK.

Maybe you can get the shim back in between the foot and the valve, so you can recheck.

Unless the motor is out you find yourself in awkward positions, working by feel rather than actually seeing what is going on.

A simpler way to "check" the adjustment is to slip a .003" shim between the other side of the rocker and the back of the cam lobe.
If the .003" shim will not fit in between the gap is not over .004".

At least not enough to worry about. Why? When the foot to valve gap is at .004" the gap between the rocker and the back side of the cam works to .00285"
This is too close to allow a .003" shim in.
So now you have a "over guage" If the .003" shim fits your setting is loose.

Now you check the gap between the back of the cam and the rocker with a .002" shim.
If you are under .003" at the foot to valve gap, the .002" shim won't go. So now you have a "under guage"

So if three thou. won't go and two thou. goes relax your are very close.

Do this a few times to check yourself. Once you get the "feel" this may not be necessary.
If your anal like most of us, you'll check 'em all.

The nice thing about this check is the rocker and cam don't have sharp edges so the shim is guided into place. Much easier than reinserting under the "elephant foot"

Sounds like a lot of work. Try it, it works.

[sergeshishik]

Yes Bernard I have the gauge, and Will good tip I am about to make a blade change for I have buggered up the original. Doug good tips I'll see if I can figure that out.

Thanks everyone.

Serge

[sergeshishik]

Doug are yo refering to the .00285 gap located between point 18 and 19 on the picture?

[2.7RACER]

Serge,
Yes.
By the way, that is a very nice pic. Where did it come from?

[Wil Ferch]

Doug:
Excellent tip...BTW..that would be the point between 18 and 19 for the intakes...and between 18 and the mirror image piece below it...for the exhausts....

Doug... did you find this out by reverse-checking this area after you ( once) did it the common way? Meaning?...how did you determine 0.00285" etc.

Also...although the surfaces are smoother to engage a blade better with your method....can you actually get a blade in there?...maybe a longish piece...how long?

-Wil

[sergeshishik]

the pic came of the Pelican tech article on valve adjustments, but I suspect they got it from a Haynes manual. Doug I gotta tell you I have zero confidence that I am adjusting these valves accurately. I am half tempted to towing it in and spending the bucks, but I hate to give up.

Arrghh

[2.7RACER]

Wil,
The rocker arm ratio 1.40:1 or 1.45:1 depends on who you believe and how accurate you need to be, works out to between .00272" to .00285"
A difference of just over one ten-thousandth of an inch.
To prove this, I dialed in a intake rocker gap to .004" with a .025" indicator. That is one full revolution of the indicator is .025"
Satisfied that the foot to valve gap was truly .004", I then slipped a .002" feeler between the heel of the cam and the rocker. Of course it went in with room to spare. A .003" feeler wouldn't go, close but no cigar.
By calculation .003 X 1.4= .0042" Thus if the valve is two ten-thousands over .004" the .003" will slide in.
Of course if the true rocker ratio is say 1.45 then the number is .00435"
Or three and one half ten-thousands over.
As you can see the error rate is quite small.
If I had a .0025" shim and a .003" shim my over and under would be closer to the calculated numbers.
With this knowlege, I set my valves to a tight .003" at the heel of the cam. I don't even bother with the classic .004" at the foot and the valve. It is simply too much trouble.
Oh, I use a plain old feeler set, nothing special.
I'm sure someone else might have some exact rocker ratio numbers that might move my numbers a ten-thousandth or two. If so, I'd like to hear about it.
Ultimately, we need to take the mystery out of valve adjustment. I think for those not intimidated by milli-meters and thousandths of an inch will find my described procedure useful to double check their adjustments.
Serge, I'll look for the nice picture in the Pelican tech article.
Thanks,

[Wil Ferch]

Doug:
I'm bumping this because it is one of those "rare" jewels you come across every so often that are not appreciated by the masses until they work with it....( IMHO).... great find.

Look at this thread.... Oil leak from 6th cylinder?

Does every "port" look to be about *this* accessible?.... I haven't opened my engine in this area in a long time....

- Wil

[diy83sc]

Doug, excellent reply to this post! Wil, I took some pictures of the engine and can say that most, if not all, will have adequate clearance to slide the gauge between the rocker and cam by measuring the exhaust from the intake and intake from exhaust. I need to run out and get the .002 and .003 gauges to complete my work. I'd like to think that I am spot on but who knows. Thanks again for contributing this tip!

Adjusting valves is as easy as .004, .003, .002

View from intake. The highlight is where you'd check the exhaust rocker/cam clearance.


View from exhaust. The highlight is where you'd check the intake rocker/cam clearance.

[captainrb]

Originally posted by sergeshishik
Thanks Jason, your right I tend to keep them loose, any tips on tightening the retaining bolt. I also seem to f-up the adjustment when I tighten back down the bolt.

PRACTICE..PRACTICE.. Thats why Porsche tech's get the big bucks(LOL)

[sergeshishik]

It's ironic this thread bumped today, I took advantage of sun soaked salty roads and buzzed around with my car and my son for most of the morning, and everything ran strong and smooth. Thanks again for everyone's help.

[Wil Ferch]

diy83sc:

Thanks for the extra tips and photos...great tip....measuring gaps using Doug's (2.7racers's) method...but clearly from the "other" bank...top measured from bottom...bottom measured from top.... excellent !!

- Wil

[Todd Simpson]

Can't wait to try this...I've always erred on the loose side then been annoyed by ticking valves.