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Need a hand with lifter preload

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macdude443 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote macdude443 Quote  Post ReplyReply Direct Link To This Post Topic: Need a hand with lifter preload
    Posted: Jan/22/2017 at 9:54pm
I'm almost done my first engine rebuild. I have an '82 258 for my Eagle and I want be sure I'm setting up my lifter preload correctly.

I have a block from one 258 and a head from another. Both were 1982 motors. The machine shop found a crack in the first block after the machining process, so they redid another block. Since the head was already done, I used it with the second block. The second motor was once rebuilt so the head surface may have been shaved. There are some unknowns.

Anyway, I want to be sure I have my procedure correct. I am using a Comp Camshaft, one grade above stock. New rockers, pivots and bridges. I put each cylinder on the compression stroke, both valves fully seated. I torqued the rockers to 19ft-lbs. I then placed a dial indicator on the pushrod end of the rocker and zero'd the needle. I then carefully backed off the rocker bolts, alternating one then the other, just until the needle stopped moving (pushrod under no more tension). This should be my preload, correct?

Here are the numbers I recorded:

Preload measurements:

Valve 1: .054
Valve 2: .042
Valve 3: .053
Valve 4: .053
Valve 5: .046
Valve 6: .062
Valve 7: .062
Valve 8: .056
Valve 9: .052
Valve 10: .065
Valve 11: .051
Valve 12: .060

From what I read, my goal is .020-.060". I'm a little beyond that. I take it if I order pushrods that are .020-.030" shorter I should be right in the sweet spot. However, I'm not sure how that will effect the valve side of the equation. If my valve stem contact point/sweep is off, I'm not sure what to do about it.

Thoughts?
1982 Eagle SX/4
1986 Eagle Wagon
1985 Jeep Grand Wagoneer
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uncljohn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote uncljohn Quote  Post ReplyReply Direct Link To This Post Posted: Jan/23/2017 at 5:59am
There is no preload spec. that I am aware of on the AMC engine, the lifters are installed as follows using a 1980 TSM as a reference one of 4 or 5 TSM's I have.
Page 1b-41
Step 2 install Tappets (Hydraulic lifters)
Step 3 install cylinder head and gasket tighten screws
Step 4 install push rods
Step 5 Install rocker arms, bridge and pivot assembly's and tighten

This is not exact words, but abbreviated. The point? NO LIFTER PRELOAD SPEC!

THE BOTTOM LINE?

The rule of thumb I have used with an AMC engine is simply if valve lift at the valve is under .5 inches than the cam can be installed as if FACTORY OEM which is bolt It in and not worry about it.

If it is greater than .500 Inches that is when I go to the CAM Catalog for instructions as what to do next and what parts I need to purchase and modify.

So if the cam you have chosen is under .500 lift at the valve open your TSM for your engine and bolt it together according to the instructions given
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SC397 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SC397 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/23/2017 at 7:09am
All hydraulic lifters have a pre-load spec and your range is correct for a normal hydraulic lifter.
Anything over .060" is a little too much. You might get away with it but why take the chance.
You can change it two ways. If it were me, I would shim the rocker arm pedistals by .020". PM your address to me and I can ship a set to you.
The second way is to measure your push rods and buy some replacements at '020" shorter.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 6PakBee Quote  Post ReplyReply Direct Link To This Post Posted: Jan/23/2017 at 7:09am
I have never personally checked preload the way you are but your procedure sounds appropriate.  For a stock rebuild 0.060" is fine.  If you are going to twist it's tail I like 0.030".  I think you are good to go.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote macdude443 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/23/2017 at 10:29am
Originally posted by SC397 SC397 wrote:

All hydraulic lifters have a pre-load spec and your range is correct for a normal hydraulic lifter.
Anything over .060" is a little too much. You might get away with it but why take the chance.
You can change it two ways. If it were me, I would shim the rocker arm pedistals by .020". PM your address to me and I can ship a set to you.
The second way is to measure your push rods and buy some replacements at '020" shorter.


Sounds like the way to go.  The second set of push rods I have (from the second block) look to be 1/8" longer than the ones I'm using.  That would have really caused me grief if I hadn't checked them out.  There was a problem with push rod length in '82 or '82 IIRC which is another reason I checked.  Cam lift is .433/.433 (Comp Cams CCA-CL68-200-4), so that shouldn't be an issue.  I just want to be thorough is all.  Even a stock rebuild isn't a budget-friendly endeavor these days.

I don't have a very accurate way of measuring a push rod, so it makes more sense to shim.  Hopefully that doesn't mess up the valve stem tip contact, but we'll see.

Thanks for the assistance!


Edited by macdude443 - Jan/23/2017 at 10:32am
1982 Eagle SX/4
1986 Eagle Wagon
1985 Jeep Grand Wagoneer
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macdude443 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote macdude443 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/23/2017 at 11:17am
Also, is there any reason to suspect this rocker arm kit wouldn't work on a 1982 block?  I see they say 1983-2006.  Seems the 1981-1982 blocks don't get mentioned in a lot of fitment guides.  These rockers look identical to my originals.  Any input on that?

http://www.quadratec.com/products/51103_0222.htm
1982 Eagle SX/4
1986 Eagle Wagon
1985 Jeep Grand Wagoneer
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macdude443 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote macdude443 Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2017 at 12:37pm
Just to follow up on this.  I was convinced the Quadratec brand rocker arm kits were causing some trouble.  Looks like I may have been correct.  I returned them and bought (6) Sealed Power R905 kits.  Here are the numbers now.  I only used one .010" shim on one valve to bring it into spec.  The contact pattern is nice and centered now too.  It's a little wider then I'd like, but I'm satisfied.  The cheapo rocker arms were hanging off the edge of the valve stem according to the mark.  Here's to using quality parts the FIRST time...

#1 .052
#2 .037
#3 .040
#4 .038
#5 .037
#6 .045
#7 .048
#8 .042
#9 .037
#10 .046 (used .010 shim, was .062 prior)
#11 .034
#12 .044






1982 Eagle SX/4
1986 Eagle Wagon
1985 Jeep Grand Wagoneer
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amcenthusiast View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amcenthusiast Quote  Post ReplyReply Direct Link To This Post Posted: Mar/23/2017 at 4:06am
Nothing wrong with doing the best you can do but that's the beauty of hydraulic lifters; they're self adjusting & that's why the stock rocker arm system is non-adjustable (no need to shim, just tighten them down and you're good to go... but with the steel strap type bridged rocker, one needs to pay attention to making sure the rockers are aligned 'straight' because the strap tends to flex when torquing down the mounting bolts ...even with the 'Oldsmobile type' aluminum bridges, but to a lesser degree)

Hence, for about 90% of all AMC inline six applications, the only rocker arm issue a person might become obsessed about is rocker arm alignment instead.

(none of these full production 'fast built' AMC engines came from the factory with carefully assembled 'slow built' valve train assemblies; all the valve spring install heights, seat depths, chamber volumes etc. will be 'in the ballpark' only = they simply didn't take the time to build a precision valve train in that high speed assembly line environment; that would be cost prohibitive -so the invention of the self adjusting hydraulic lifter was an evolutionary break through for mass production to get a 'perfect' lifter adjustment every time regardless of precision (or lack thereof) or 'loose tolerances')

Basically, none of the US automakers did (AMC was doing the same thing; trying to make the 'best' car for the lowest price ...so everybody could own a car (and live like a king -the good ol' American Dream))

One may read a well written story of Johnson Hylift/Sealed Power hydraulic lifters here:

http://hylift-johnson.com/our-company/

Prior to self adjusting hydraulic lifters, cars from the factory would often come to the dealerships in dire need to adjust their solid lifter valvetrains since the assembly line did not make time to fully adjust them to precise specifications (Prior to the invention of hydraulic lifters, my non-mechanically inclined Dad took a job delivering 'cars that just came off the boat' when he was a young man from Houston Ship Channel to dealerships and he says 'those cars ran and drove very poorly' with a big invisible question mark on his forehead)

In the racing world, where a hydraulic lifter pump up might be a problem somewhere around 6000+ rpm (many variables) there are engine builders who'd say to completely bottom out all hydraulic lifters by using longer pushrods and adjustable rocker arms which essentially converts them into running like solid lifters. In such a case, then, they would obsess with adjusting the otherwise self adjusting hydraulic lifter.

More than a simple 'anti pump up' high performance hyd lifter, there are 'race type' hydraulic lifters that do call for a pre-load spec such as Sealed Power HT-2011R or SBI VL112RH -these demand a careful preload adjustment (and certain Rhoads lifters) and their instructions say 'must use adjustable rockers'. (to obtain a precise pre-load setting) ...but they cost as much or more than a solid lifter system so they fall out of favor for cost effectiveness (arguably less bang for the buck; money might be better spent on reducing valve actuation assembly weights such as tool steel or titanium valve spring retainers etc)

Race engine builders more often decide to run solid lifters anyway so they can 'tune' a higher rpm rated cam with an adjustable valve train, using the lash clearances to slightly adjust duration and lift... but no, the greater majority of hydraulic lifters are specifically made to be self adjusting and there is no need to obsess over lifter preload/plunger depth settings.

Since you obviously display a good mechanical aptitude, I think you'd enjoy owning your own copy of AMC's high performance modifications book named "Performance American Style" -the book describes race application needs better than I do here.


Edited by amcenthusiast - Mar/23/2017 at 5:30am
443 XRV8 Gremlin YouTube video: https://www.youtube.com/watch?reload=9&v=2DmFOKRuzUc
XRV8 Race Parts website: http://amcramblermarlin.1colony.com/
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macdude443 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote macdude443 Quote  Post ReplyReply Direct Link To This Post Posted: Mar/27/2017 at 1:36pm
Thanks for the kind words.  I'll check out the book.  As far as the rocker arms being straight, these SP bridges seem substantially more robust than the bridges in the cheaper kit.  If I do tweak one as I torque them down, is it ok to carefully bend it back?  I had to do this once when I bent one changing a valve cover gasket.  The job had to get done and it was a tight squeeze under the AC hose.
1982 Eagle SX/4
1986 Eagle Wagon
1985 Jeep Grand Wagoneer
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