I'm rebuilding my motor (putting it back together tomorrow.

Anyways, I plan to adjust the valves cold while assembling,
but I need to know how to measure zero lash without the
car running (excuse my stupidity, but I've never done it
cold before).
Would I be better off adjusting with the car running?

Also, what torque should I put the screw in studs on my new
sportsman II heads to?

Thanks,
Jack

 

OK, I'll take a whack at this.

On the head studs. Make sure the threads in the block are clean. Run a tap into them to make sure. Coat the threads of the stid that go into the block with Permatex No. 2A. Screw them in just finger tight. Lay down your gasket. Guide your head(s) onto the studs. Put washers on all of them and run the nuts down to just about finger tight. Tighten them IN SEQUENCE to 65 ft. lbs in 3 steps--35 ft. lb, 55 ft. lb., 65 ft. lb., or similar.

"Zero Lash" when it comes to hydraulic or hydraulic roller lifters is easy. Tighten the adjusting nut slowly while turning the pushrod between two fingers of your other hand. The instant you feel any resistance in the pushrod, you are at zero lash. Tighten the adjusting nut down 1/2 turn farther (Or whatever your lifter manufacturer recommends). That's it, unless you're using roller lifters with poly locks. In that case, just go to zero lash, hold the adjusting nut with your 9/16" wrench and use an allen key to snug up the set screw.

Your valves should be re-adjusted when the engine is warm, however. Consider that Job One after break-in.

 

Hey Dude... you forgot to say that the Zero lash point is when the valves are closed. So you can only do certain ones and then turn the engine to adjust more valves. The sequence for this is in a few manuals and it IS easy, you just have to know which valves are closed.

 

I move the push rod up and down feeling for zero lash. I think when you rotate the push rod you can go past zero lash and get a valve too tight. The hydraulic lifter has a small plunger spring loaded and with turning the push rod you can't really feel when it is a zero lash. There are charts telling which valve to do when the motor is at TDC then BDC etc. If you need this chart I can type it out. I don't have a scanner.

 

Jack,
The Crane Cam website describes this in detail.

I see you bought better than just replacement heads! What else did you do?

 

Quote: "Also, what torque should I put the screw in studs on my new
sportsman II heads to?"

I see you got a response that assumed you were talking about head bolt studs, but when I look at your question, I'm not sure. Is that what you were asking, or were you asking about the screw in rocker arm studs?

 

norval has it right... if you rely on the "twist the pushrod" method, you can easily put a lifter plunger beyond its zero lash position and when you start the engine, drive a valve through the top of a piston. I build engines professionally, and I never rely on the "twisty" method... it's too dangerous.

The reason why so many people use it (with varying degrees of success & catastrophy) is because they read it in a manual somewhere. The same text usually also makes it clear that the objective is "zero lash" plus x turns... so if you go past zero lash way into the forbidden zone... it's your own fault... not theirs. This eliminates any liability on their part.

When I first heard someone suggest this method, knowing it was a krap shoot, I tried something..

I installed a new set of lifters in an engine I had on a stand and proceeded to use the "twisty" method. In 50% of the lifters, they ended up "out of range". This is a result of several factors, the most important being the amount of oil and/or pre-pressure built up in each lifter, and significant variance in the internal spring pressure of each lifter. The ones that were "pumped" up (or had slightly stiffer internal springs), went to zero lash correctly. The ones that were a little shy in the back pressure department, went past zero lash into the forbidden zone.

I have been called to the scene of such accidents many times, and the "twisty" method" always ended up being the culprit.

Not flaming anyone... just setting the record straight as a professional engine builder.

Norval knows his stuff.

Tom

PS- The torque figure on the screw in rocker studs depends on thread size and whether you are using alumimum heads.

 

I, too, use the "jiggle it up and down" method on hydraulic lifters. Why I suggested the "twisty" method is because it was easier to describe and a quick, serviceable way to get his engine fired up for initial break-in. And yes, the valves need to be adjusted in sequence, too. I was trying to give the guy a serviceable answer without writing a manual. The assumption is that, if he has the engine that far apart, he probably has a manual kicking around someplace that goes into specifics of the procdure.

Screw-in studs in cylinder heads? Dart recommends 45 ft. lb. for the Comp Cams studs and guideplates that come packaged with--or pre-installed on--aluminum Pro-1s. Other head manufacturers probably provide specific information on the literature that accompanies the product. If there is no literature with his heads, I'd suggest that 45 ft. lb. on the screw-in studs might be a reasonable place to start. That's not to say there aren't people on the Forum who would suggest--and have perfectly valid reasons for--torquing screw-in studs to 40 ft. lb., for example. Or maybe 50 ft. lb. Or using a lathe to turn the threads completely off the bottoms of the studs and installing them with an adhesive like JB Weld or something. (Mixed, of course, at a precise at a 45:55 ratio of steel to hardener and only while the ambient air temperature is precisely 73.4 degrees Fahrenheit, the humidity is between 43 and 61 percent and the barometric pressure is between 29.31 and 29.43 and applied only with a flat toothpick manufactured from spruce instead of pine.)


[Modified by The Dude, 10:00 AM 2/1/2002]

 

I'm not sure, so don't quote me on this, but doesn't the Service Manual suggest the "twisty" method? I believe they also suggest squirting motor oil down the rod hole after you remove the rod to keep the lifter pumped up. Again, I'm not sure, so don't go flaming me on this one, but I thought that's what it said.

 

The Hydraulic lifter is one of the most highly precision -engineered parts made with the individual components sized to 35 millionths of an inch

Never pre oil hydraulic lifter-preload cannot be set!

Proffesional builders set the lifter on the "heel" of the cam of each lobe to set the lifter to not more than .035 preload.Not turns of a wrench.

Zero clearance is just that,Zero clearance.Preload must be set Does not mean Zero lash

That old way of setting 3 or 4 lifters at a time does not cut it when upto a 8 degree LCA difference in cams over stock is used.The difference in the base circle diameter of the cam can become an issue as well when one tries this method as well.

A hydraulic cammed motor will always run best when "preload" is set at a minimum of .005 but will rattle a little during cold start

Hope this helps clear a few things up

 

I know Tom and Lars disagree on this somewhat, but here is a full step-by-step:
http://vettefinders.com/index.cfm/fu...tory/ID/17.htm

 

The Dude cracks me up. :) Good one.
-terry

 

Cracks me up too! I liked this one:

((Mixed, of course, at a precise at a 45:55 ratio of steel to hardener and only while the ambient air temperature is precisely 73.4 degrees Fahrenheit, the humidity is between 43 and 61 percent and the barometric pressure is between 29.31 and 29.43 and applied only with a flat toothpick manufactured from spruce instead of pine.)

 

I would like to clear up a few things about hydraulic lifters.

1. The springs in a hydraulic lifter have nothing to do with the pre-load, etc. The reason some lifters are easier to compress than others is the amount of oil in the lifter, and the amount of air in the lifter. Ideally, the lifter would be completely full of oil, and the oil would have no air in it. If this were true, the oil would be completely incompressible. However, all oil has some amount of air in it. The more air, the more the lifter compresses-this is bad. Also, when your lifters are shipped to you, they are no doubt partially empty. This is due to shipping and handling pf the lifter, and also the fact that the factory may not have filled the lifter all the way.

2. You can not hurt the lifter by pre-oiling it. GM tops off lifters at just about all of its assembly plants.

3. The best way to adjust the valves is as follows: first make sure the valve you are working on is on the base circle of the cam. Then, without the intake on, watch the lifter as you tighten the nut. Rotate the nut back and forth watching the lifter, to determine exactly when the lifter piston begins to move. Knowing that the lifter piston has about 2mm of travel, you want to move the piston between 0.5-1.0mm. Tighten the set screw and move on to the next valve. However, you probably will have the intake on. I strongly suggest the up-down method with valves. Spinning the pushrod depends on too many things, like how well lubed the pushrod ends are.

If you want to know where this comes from, I work for a supplier of valvetrain components. I work with hydraulic lifters everyday. My idea here is not to flame anyone, just inform. The engine builders that responded know what they're doing, I am just trying to explain some of the details of hydraulic lifters. Hopefully, the more you understand about how lifters work, the easier adjusting them is.

 

By pre oil another definition would be to soak the lifter overnite and work the plunger.No air is in the lifter at that time therein lays a mistake.

Quote:
"2. You can not hurt the lifter by pre-oiling it. GM tops off lifters at just about all of its assembly plants."

They probably do this after lifter adjustment.Certainly it won't "hurt " a lifter.Just will not be able to set the preload as easy w/dial indicator.An Oldsmobile or AMC engine without adjustable rockers for example with milled heads and a performance cam with a altered from stock base circle must be measured.At least the ones that run hard get this done by the builder.




[Modified by mountainmotor, 6:14 PM 2/1/2002]

 

I'll have to disagree with this one part...

"The springs in a hydraulic lifter have nothing to do with the pre-load, etc."

I have equipment capable of measuring spring rate very accurately. There is a lot of variance in the springs inside the lifters. When a lifter has no oil in it, these springs are the ONLY thing that determine how much pressure is exerted upward when the pushrod is being "twisted". If a mechanic is trying to adjust a set of lifters with little or no oil in them, he will end up taking some of them too far down based on little or no backpressure before they "bind". Combined with a different amount of pre-lube (oil) in each lifter, each lifter will exhibit a different amount of "back pressure" while you are twisting the pushrod. This means that as a mechanic rotates the pushrod, the exact point where "resistance" is "felt" will be different for each lifter. The mechanic, trying to adjust each lifter identically, will end up pre-setting the lifters at different depths due to the variance in perceived backpressure.

This is all based on 36 years of "field" experience... no books... no arm-chair speculation. I have demonstrated this to customers, other mechanics,and engineers many, many times over the years. The test is conclusive. There is no room for debate. Anyone who would like a demo is free to come to my shop and I will gladly do a show & tell. In fact, I have a local C3 club coming over next Sunday for a tech session and I will make it a point to show them. This is something that being a "reader" or a "designer" will not teach you.... it must be learned in the field.

The service manuals do not just say use the "twisty method". The service manuals all say... adjust to zero lash & then x turns down (not all valve systems require the same number of turns on the nut). They are relying on a good mechanic to know that some lifters will be "hard" and some will be "soft" going in to the task.... and to make the proper judgement call on each lifter. The "twisty method" relies on all lifters to be exerting exactly the same amount of backpressure during initial adjustment... this simply is not so.... at least not in the thousands of engines that I have put together.

I have read all of the recommended service procedures on hydraulic lifter pre-adjustment. The bottom line is that you need to achieve "zero" lash, and then adjust the lifter into its operating range. You cannot judge zero lash effectively by rotating the pushrod since the lifters do not all react the same to a given amount of pushrod pressure. This is especially true of used or worn lifters. You must adjust the rocker until there is no clearance, and then down x number of turns to achieve about .030 pre-load (this also varies).

When I do a valve job, I always remove, dis-assemble, and manually clean hydraulic lifters. Upon re-assembly, I do not fill them with oil. I only provide a light coat of oil to facilitate assembly. When I push the plunger down to re-install the spring clip, some will be extremely easy to depress, some will be medium, some will be harder.... this is all with NO oil in the lifter.

I have never had to remove a valve cover to re-adjust hydraulic lifters on any engine that I have built. My engines all start instantly, and after the oil system equalizes, the lifters quiet down and work as designed, requiring no further adjustment.

"Zero clearance is just that,Zero clearance.Preload must be set Does not mean Zero lash" .... mountainmotor is absolutely correct... and I use the two terms interchangeably myself (my bad)... they are not the same thing.


[Modified by Tom454, 7:21 AM 2/2/2002]

 

My next cam will be a solid :yesnod:
While true for new cars, it is a MYTH that H cams require less hassle on old cars like ours.
When you factor in wasted time with H lifter adjustments(and the occasional noisy ticking lifter), there is no time saved. This adjustment controversy makes my point quite nicely :lol:
Plus Solid cams wind higher, and often make more power.
Comp Cams makes solid versions of the XEH's, we are all dummies for not buying it, or another brand of S (me included)
(i am also an up and down guy, no twisty)

 

True statement. When adjusted properly (while hot, hardened correct gage) the adjustment stays in for a fairly long time. Being the seasoned old fart that I am, I started building engines when there was no such thing as a hydraulic cam (at least, not in my circle of acquaintances). Everything was solid lifters. If the oil was changed regularly to keep wear minimized, a solid cam will stay adjusted for years. Of course, most people were either too cheap or too lazy to change their oil regularly... so I was fed a steady diet of cams/lifters to adjust. My own engines (in my own cars) stayed adjusted for up to 3 years at a time. I remember one Ford 292 Y-Block V8 that stayed in range for over 5 years. Things that make ya go Hmmmm...

 

The valve spring rate,lobe intensity that depicts the lash setting".022" on a mild lobe design verses ".030" for a high lift rate lobe and the general application or rather use comes to play as well as valve train weight,quality of parts ect and how many times the motor is grossly overrevved as in missed shifts :eek: all are factors.Most all the older springs and lobes were mild in comparison of todays parts.Remember the Plymouth Slant 6? A very small percentage of them ever recieved a lifter adjustment.Yet ran 100k +

 

funny you should mention the slant 6.
i ran the stock cam, put springs from a 340 on it and i shifted at 7000. once the pedal stuck to the floor mid-1/4 and it went to 8600, and bent 1 pushrod! (turbo 22psi boost)
for my stick 61 i would invest in a rev-limiter with a solid cam, might be iffy with the shift light i use now....on my TH400 72 i would just recalibrate the governor so it would NEVER over-rev.
I wonder what my 72 would sound like at 70mph in 1st gear? ....Judge, i couln't been speeding, it was in 1st :lol:


[Modified by drives61, 2:25 PM 2/3/2002]