following the step by step valve geometry i've got a few possible issues? when no shims used and exhaust and intake geometry is set the swivel feet are almost bottomed out (almost no adjustment left). so next it was shimmed with .025, the geo/swivel tightness got better (not so close to bottoming against swivel) when shimmed with .040 shims i have more space to adjust up left before swivel contacts rocker (3/4 to 1 turn).

bottom line it seems to work out better with .040 shims. with no shims it has wider range of measurements between each valve -and- closer swivel foot to rocker arms.

1] is .040 shim o.k.?

2] if o.k. is 3/4 to 1 turn until swivel foot hits the bottom of the (modified) rocker acceptable? yes they are o.e.m. swivels from a 2.7

3] if not o.k. can i remove .030 or ? more from rocker arm

4] if none of the above is good what am i needing to do to correct this?

mike

"3] if not o.k. can i remove .030 or ? more from rocker arm"

Did you already grind off the required .060" off the rocker arm? If not, that may solve your problem. Do a search here for some rocker arm before and after pics.

, yeah you gotta grind about .060 off the stock rocker arms. Were you using an adjustable pushrod? There are photos somewhere around here. I run more shims , but that's just me

I helped Mike with the geo last sat.

The rockers where decked .060
We did have an adjustable p/r

The p/r length numbers where very close accross the board, within 1.5 mm.

I didn't feel comfy using more shims and thought he sould post here to get more input.

BTW- Mike is using heads built by Len at LN eng.

they are awsome!

Keith

I have .045 shims on my 2270 assembled at Jake's and beat on his dyno.

Dave

I have read that guy's hae used up to .060 for shims. I used .040 shims and decked the rockers .100

This is Mikes engine so I wanted him to get more info.

Keith

keith spent alot of time was a big help getting these right on the money.

from hearing .040 is no big deal i think that the best route is the shims and an average cut on the exhaust pushrods (4) and an average cut on the intake pushrods (4)... MAYBE another .020 off the rockers. thats the most ify one, again)

whats the census out there?

mike

the quote is from jake

were you able to get satisfactory settings before you added shims? if so why shim? just to allow more adjustability? are you setting these at zero lash? what push rods?

I read that quote also.


We where not able to get a satisfactory reading on the geo @ 1/2 lift without shims.

The geo would be close but not perfect. Also the swivel foot was 1/2 turn away from the rocker.

Even with the .040 shim there is only 3/4 of a turn from the rocker

Yes, it was set at 0 lash

They are the manton p/r's that Jake sells and uses and where provided by him wht the purchase of the valvetrain kit.

The question is, WITH a .040 shim, the swivel foot is ONLY 3/4 of a turn from bottoming out aginst the rocker.

I felt this is too close, Mike does too, BUT we are not sure.

That means you have 3/4 of 1mm of valve adjustment allowable.. If your valves stretch that far they'll snapp off.

Should we add more shim, take more off the rocker or both?

jake, with no shims we measered .440 INT. lift, and .419 EX. lift. Perfect valve train geometry at half lift had a bigger difference in lengths between intake and exhaust pushrods without a shim, but they were closer with .040 shims.

(1)- i am not clear if .040 is advised or not needed?

(2)-with no shims, having approx. half turn at most, will i have problems with swivil foot/rocker-arm interference?

(3)-is it better to have a more equall exhaust and intake total lift that adding a .040 shim?

mike what cam are you using?

in the valve train article jake says exhaust pushrods are generally 1 mm shorter on his cams

what are you getting as your pushrod lengths? intake? exhaust?

Mike is using Jakes 9550 cam.

In the earlier postsI stated there is only about a 1.5mm delta between all 8 p/r's.

The cam and p/r length is really not of concern. The concern is the swivel foot clearance in relation to the rocker and what to do about it, as posted ealier.

I spent 11hrs with Mike making sure his geo was right. We where not able to get a satifactory geo ( at half lift ) w/o .040 shims.

Keith

This is good stuff.

so... the feedback i'm getting is:

although the swivels are close to the rockers with no shims (3/8 to 1/2 turn from interferance), it isn't an issue. this is better than .040 shims

no??

mike

I think it's the other way around. With the swivel feet being so close to the rocker, if the valve stretches, you will run out of adjustment, not good.

If I understand it right, what Jake is saying, 3/4 of a mm is NOT good

We definitly need the shim. shims are not a bad thing (escpecially if they are nesacarry), we just need to know weather or not to add more.

if i understand jake correctly, he was saying 3/4 of 1 mm is PLENTY because if the valve ever stretches that much, it'll snapp off long before you bottom out your adjustment ...
Andy

Why would it be bad to deck the arm a little more instead of adding more shim? Is shimming just easier then decking? I can't see how a .070 deck would provide less structure then a .060 deck.

But I am a noob, and am watching this thread like a hawk (cause I am going to need to do it soon).

Zach

Thank's Andy, you're right! was I thinking! sorry Mike, my bad!.

you can deck the rocker a bit and add more shim if it's necassary.

In this case, we just wanted to be sure 3/4 of a turn was enough clearance, and it looks like it is.

10/4... thats what i pulled from jakes post also, but need to confirm... is 3/8 to 1/2 turn (no shims) aceptable (plenty) and perferred???... jake???



i guess unless we hear negatives on the .040 shims, that this is the prefered setting. even though these heads were L.N. prepared (and beautiful masterpeice at that) , i would think that the possibility of the seats recessing over time could be a factor to go .040 shims???

mike

by the way andy i think i should confirm that these rockers i got from you were .060 cut? or were they done before you?... they look consistant and professionally cut so i'm not doughting just confirming.

mike

Run it.

Worrying and fighting issues like this will breed mistakes...

Just deck a tad more off the rocker if you are worried about the clearance, or you can do that after you stretch the valves 30 thou and need the adjustment.

The valves in my 912E engine haven't moved more than .005 in 140K miles and it has been purposely abused, neglected and was built with marginal parts 6 years ago.

Thank's Jake, that 912engine cracks me up! You should start a " when is it going to die" pool .

Mike I will take anothe .010 off the rockers, make the shims and cut the p/r's and drop them in the mail.

Keith

i didn't build the motor, so i can't say for sure ...
Andy

thanks guys for the direction. much closer

mike