L24 - Does Anyone Know What Cam & Rocker Configuration? F30 Cam ?

[moritz55]

Hello .. I am in the middle of adjusting my Valve Lash and as I removed the Valve cover I noticed my rockers' lock nut and Adjusting nut are not Stock.  This leads me to believe my Cam is not also.. so before I go to far on adjusting I'd like help on getting some questions answered.  Engine was rebuilt about 25k miles ago and runs absolutely great.   Last valve lash adjustment was done about 20K miles by the prior owner and he does not know the specifics of the rebuild other than is was "enhanced" and has a 9.5 : 1 compression ratio as a result of new valves & seats, pistons, stock block bore & hone.   Any insight or help is appreciated.    

 

1) My L24 cam has F30 stamped on it (see photo), is this stock or not?

 

2) My adjusting nut is 17mm (vs 14mm stock) and lock nut is 24mm(vs 17mm stock).   Should I adjust the Valve lash to FSM L24 spec?

 

Cold Intake Gap:   .008"

Cold Exhaust Gap:  .010"

 

3) If the F30 Cam is not stock, what should I adjust my valve lash too or doesn't it matter? 

 

 

Many thanks... I am new at this and would like to do it right .

 

Mark

Edited March 21, 2015 by moritz55

[zKars]

Sorry, I think you are confused about which hex items are the adjusters and the lock nuts. The 24mm hex at the base on the head surface are NOT something you undo. The 17mm lock nut is above that, and the 14mm hex that you rotate to adjust height, are on the top of the balls that seat in the end of the rocker arms. They are just hiding under the end of the rocker arms. Take a closer look, I see them in picture 4.

As far as correct lash specs, using stock specs is perfectly safe. All your sacrificing (maybe) is some performance. Just make sure you have SOME lash and you can't hurt anything.

Edited March 21, 2015 by zKars

[moritz55]

Ah ... thank you ...   My error.  As you can tell I am new at this....

 

Great help here... will let you know how it turns out.

 

Many thanks....

Mark

Edited March 21, 2015 by moritz55

[240260280z]

Just a thought:

We set "valve clearance" but we actually set cam-to-rocker clearance. The real valve clearance is ~ 1.5X greater.

No worries, I checked the FSM and the EM picture shows measurement at the rocker... not the lash pad (where it is more accurate)

[Diseazd]

BTW......The cam doesn't look like a regrind (looks stock). If it has been re ground, the cam grinder usually etches the profile on the back end of the camshaft (you would probably need a mirror to see it in the car), but yours looks bone stock.

[siteunseen]

BTW......The cam doesn't look like a regrind (looks stock). If it has been re ground, the cam grinder usually etches the profile on the back end of the camshaft (you would probably need a mirror to see it in the car), but yours looks bone stock.

Well I'll be damned. You are absolutely right. Cam numbers and lobe separation are engraved on the sprocket end of mine. Learned something today.

[moritz55]

Thanks everybody for all the posts.  

I finished up the Valve Lash adjustments and am glad I did. Also I re-torqued head-bolt #1 & #2 to correct a very minor oil leak.  FSM Torque spec :  47 - 61 ft-lbs.

 

Headbolt #1 - when I backed it off 1/4 turn .. I used my torque wrench and noted 50 ft-lb to break it free.  I figure this was low since I had to overcome static friction.  I then torqued #1 bolt to 60 ft-lbs.  The re-torque added about ~1/2 turn.

 

Headbolt #2 - when I backed it off 1/4 turn ... was noted at ~63 ft-lbs.  Re-torqueing was just over 1/4 turn at 60Ft-lbs.  

 

Note:  I had a very slight oil leak between cylinder #3 & #4 on the passenger side near Head bolt #1.  This seemed to fix the very slight leak... no signs of oil when I started and ran it for a while after the valve adjustments.  I will watch for this long term.

 

Now .. I'd like some feedback on my valve readings.  All were taken "Cold".  The car had 20k miles on these and I think they should have been adjusted 10k miles ago.  Maybe they were initially set up to tight from the rebuild?  These seemed extremely low.

 

Intake (Cold Gaps):   .004"  (lowest) .. most ran .005"

Exhaust (Cold Gaps):  .006" (lowest) .. most ran .007"

 

I adjusted all the Valve gaps to their FSM Cold settings.

Intake:  .008"

Exhuast:  .010" 

 

When I finished up, the car started great and warmed it up.  Ran it total a good 20-25mins up to 3500 RPM smoothly and smooth on decelerations.  Checked the timing and idle when all was done and everything remained stable and no adjustments were needed.  I have a Mallory Breaker-less Disty, don't know if this makes any difference.   Only I believe slightly more valve tapping - but it may be just me expecting with the wider gaps to spec., but not loud and bad.

 

Anyway - thank you all for the help...

I welcome feedback on the Cold, valve readings before & after adjustment.

 

Many thanks, Mark.

Edited March 22, 2015 by moritz55

[240260280z]

yes you will hear more tap by opening the lash.

FYI the oil passage to the head from the block is between 3 and 4 on the passenger side

[moritz55]

Any insight on the Cold Valves being .003" - .004" under spec.   For 20k miles since the last check and 25k since the rebuild, I wouldn't expect them to be that closer to spec but have no experience on this.  My other thought is the valve gaps were set incorrectly at rebuild.

 

Maybe others could weigh in.

 

Many thanks....

[240260280z]

They could have been set tighter before you measured or the valves could have seated more (worn in) and risen the difference from nominal. Nothing to worry about.

You can do a compression test to see how well they are seating.