Hydraulic lifter preload...who really checks this?

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Kern Dog

Kern Dog

Build your car to handle.
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Somehow, I'm the guy that has stumbled through this hobby sometimes not doing things the way that I am supposed to be doing.
I've never checked or compensated for installed height with valve springs. I've never experienced valve float or kissed a valve with a piston.
I've never checked or adjusted end play in a crankshaft, I've never measured piston to wall clearance either.
I've adjusted valve lash with solid lifters but never gone the other way with a hydraulic lifter. With small block Chevys, it was customary to tighten the rocker arms to zero lash then turn the nut 1/2 to 3/4 turn more.
Here we are as Mopar guys and we have rocker shafts that are non adjustable. I've rebuilt several engines, had milled heads, decked blocks, different head gasket thicknesses and have not seen any adverse effects from the lifter preload not being checked and/or blueprinted to spec.
This topic comes up for me because I'm doing a Hydraulic roller cam swap in a big block and Dwayne Porter told me about what the spec is for lifter preload with the Comp Cams Evolution lifters.
I have a 1990 360 that I'm also working on and it came with a Hughes 1.6 rocker arm set. I'd be okay with just settling with a decent set of stock rocker arms but now I'm wondering if I should be concerned with lifter preload on the 360. How do you adjust that with a stock shaft mounted rocker arm setup? Do you perform a mock up with an adjustable length pushrod and determine the preload with a dial indicator?
 
1) you have not lived unless you kiss a valve to a piston on a missed shift.
2) hydraulic preload -I loosely check but on Mopar’s I feel it is not as critical. Just me maybe.
3) custom length push rods is how you adjust - make at home units. With stock rockers. They have a lot of play brand new.
 
Basically what you're saying is you've never properly built an engine. The few engines I've built are in the opposite end. I've scrutinized every detail.

Hughes has instructions on how to set all this stuff up the right way. It involves setting the proper wiping path across the valve face using shims, and setting the rocker adjuster balls to the proper amount of extension beyond the rocker body. Its a tedious job but worth it as you'll ensure proper geometry. Be warned those rockers often require clearancing around the valve springs.
 
When you twist engines to the peak of their RPM range, you better have checked everything at least twice. I haven't destroyed any engines due to over revving them, but I have seen evidence of slight eyebrow marking on pistons, not to mention some "slightly" bent pushrods.
 
Engines can be very forgiving when run under normal circumstances. I’ve taken apart engines before that had been previously put together with some questionable decisions. However, the further you deviate from stock and the harder you push an engine, as demon racer pointed out, the more everything has to be done correctly.
 
I checked the 340 I just built as the heads had been totally redone. The preloads were fine.
 
You saying you’ve only checked bearing clearances in all the stuff you’ve pit together? You have gotten lucky when assembling, if you’ve never checked any of the other things.

My UPS driver has a 55 Belair Gasser with a 502 ZZ with 704 HP from a now defunk shop from AZ. The motor kept eating the #7 lifter. After the 3rd time he changed it out, I told him the motor has to be torn down to find out the issue. That issue is cus shitty rocker geometry and spring was all fucked off. And come to find out JE made the Pistons for Chevy performance, and the piston to wall clearance was too tight once the motor got warm thus causing the 502ZZ‘s to run hot and overheat.
 
Kern Dog said:
I have a 1990 360 that I'm also working on and it came with a Hughes 1.6 rocker arm set. I'd be okay with just settling with a decent set of stock rocker arms but now I'm wondering if I should be concerned with lifter preload on the 360. How do you adjust that with a stock shaft mounted rocker arm setup? Do you perform a mock up with an adjustable length pushrod and determine the preload with a dial indicator?
Click to expand...
If you're considering swapping the hughes rockers for stock stamped rockers, I'd do just as you say measure with an adjustable pushrod tool. I'd check all four corners intake and exhaust. Also check that the tops of all valve stems are level or close to it. Any variation will impact pushrod length for a given amount of lifter preload. Be sure to account for head gasket thickness if the heads aren't final bolted down. I'd lengthen the pushrod tool until there is zero lash, then take it out and measure. Then just add whatever preload amount the lifters need.

You're probably aware already, but with a stock stamped shaft rocker setup, lifter preload cannot be adjusted. You simply need to purchase a set of pushrods that provide the appropriate amount of lifter preload. Once you start decking the block, heads, vary head gasket thickness, shimming rocker shafts, etc., stock pushrods may not cut it. But then again, the lifter preload spec may be wide enough to cover any of those differences in the build. Heck, if you're revertting back to stock shaft rockers on your roller LA motor, I'd imagine stock length pushrods for a roller LA motor would be pretty close to what you need. It's best practice to verify though.

Disclaimer: This is just my hobbiest-level understanding and how I've done it in the past. I'm certainly no expert.
 
Direct connect used to offer adjustable pushrods to make up the lifter preload on high lift hydraulic cams when running the stamped rocker arms.
 
You can buy an inexpensive adjustable pushrod length checker. Some of them come in varying length ranges.
ps I have an extra set of Mancini rocker shaft shims if you have too much preload :)
 
Mean416 said:
Basically what you're saying is you've never properly built an engine. The few engines I've built are in the opposite end. I've scrutinized every detail.
Click to expand...
No.
First off, I never said anything, I wrote some things.
Secondly, I never built a race oriented small block where issues such as these would seem to be more crucial. Nice try at an underhanded insult. It didn't slip right by me at all.
I've built a few engines but never anything with the intention of drag racing. I run my stuff on the street for occasional fun or for daily driving. It would seem that measuring preload on a fairly stock engine is a matter of splitting hairs on whether or not it will make a difference. Stock head gaskets were often .020 steel, replacements are often double that but when a surface cleanup head milling and block decking are done, you often end up close to where the deck clearance was originally.
I've built a few big blocks and have gone into greater detail with assembly and adjustments. That wasn't the point here. I'm told that the Mopar lifters had a greater amount of preload than some other brands but I was curious as to how crucial that was since I hadn't seen any adverse effects to date.
 
Kern Dog said:
No.
First off, I never said anything, I wrote some things.
Secondly, I never built a race oriented small block where issues such as these would seem to be more crucial. Nice try at an underhanded insult. It didn't slip right by me at all.
I've built a few engines but never anything with the intention of drag racing. I run my stuff on the street for occasional fun or for daily driving. It would seem that measuring preload on a fairly stock engine is a matter of splitting hairs on whether or not it will make a difference. Stock head gaskets were often .020 steel, replacements are often double that but when a surface cleanup head milling and block decking are done, you often end up close to where the deck clearance was originally.
I've built a few big blocks and have gone into greater detail with assembly and adjustments. That wasn't the point here. I'm told that the Mopar lifters had a greater amount of preload than some other brands but I was curious as to how crucial that was since I hadn't seen any adverse effects to date.
Click to expand...

If you aren’t checking preload one issue that crops up fairly often (not as much as it used to for the reason I’m about to say) is you have too much preload.

This happens with old heads that have had 3,4,5 valve jobs and the machinist didn’t correct stem height by not knowing to do it or not giving a ****.

The extra stem height raises the valve side of the rocker and that in turn lowers the pushrod side of the rocker.

That adds more preload. Those same heads will have been milled several times too. That lowers the head, lowers the rocker and increases preload.

Now what happens if the block has been deck a couple of times? It effectively lowers the head which lowers the rocker which increases the preload.

At some point you get the place where the lifter holds the valve open. Maybe not enough to miss but enough to keep the valve from dissipating heat through the seat because it’s hanging open a bit.

Next thing you know, you’ve got a burned valve.

Other **** happens too. Like a guy who has no clue about no adjustable shaft rocker systems and he throws a .100 long valve in there.

You can’t grind the stem down .100 to correct it or you ruin the valve. Now the geometry is whacked and you have too much preload and the calves don’t seat and you get a miss.

One last thing. I know guys get away with those cheap assed straight shims that just raise the shaft. Guys do it but they can break the stand and the kill geometry. Your better off not using them and living with the already bad geometry rather than using those shims and adding to the geometry issues.

I know damn good and well Dave Hughes knows this because we’ve talked about it. I didn’t care for his answer about why he uses them but he knows they are wrong. Our disagreement is I say it makes the geometry worse and he says it doesn’t make it THAT much worse.

If you need to shim the stands spend a bit more cash and get the proper shims from Mike at B3 racing engines.
 
At the risk of getting Big red-Xed again;
I'll tell you what I did on my engine;
ie the engine was built in 1999, and now has over 100,000 miles on it. and it went 93 in the Eighth with a 230/237/110 cam.
Now, this is on an 11/1, 360, pulling a manual trans. The KB107s were last set to .007 pop-up and I use the 039 gasket for a Squish of .032.
After checking the rocker arm sweep, I installed custom-fit pushrods under adjustable alloy rocker arms set to 1/4 turn preload.
After break-in, it was found to be a little noisy, so I reset it to 1/2 turn, and besides an occasional adjustment since 1999, that's where it has stayed.
You might ask, why so little preload?
Well, when I missed a shift once, I looked at the tach and saw the needle coming down across the face of 8000 rpm. the Hughes lifters that I am using have a plunger travel of .208 IIRC. Going thru 1.6 arms, that is a gross of .333 at the valve. which is greater than my piston to valve clearance. Had my lifters pumped up on that day, I'd had to rebuild my top end, at least.
As it was, I allowed the rpm to come down slowly, and it idled perfectly! surprise surprise.
Ok sure, I could have, during the build, cut my eyebrows deeper for more PV clearance, but why bother? I already have more than I need if the lifters don't pump up, so the simple solution was just to run less preload

The point is this, if you don't check things, you cannot know what will happen, when things go wrong.

BTW
I fixed my shifter and installed a rev-limiter, but, I haven't ever missed another shift since 2004. My rev limiter is a cheap dial-type. Most of the time, I use it for a cruise control. I just get the car up to speed, dial the limiter until the engine misses, then give back a hair. Badaboom. I have never received a speeding ticket with this system.
 
As AJ said, his lifters had over 0.200" of plunger travel. And post #12 gives the reasons why the manufacturer provides so much travel: for future maintenance [ valve jobs, heads milled, decking ] & factory tolerances. For your average performance engine, anywhere within the 0.200" range is ok. If the engine is to see high-er rpms, setting the prod cuphigh in the lifter risks pumping up the lifter & pushing the prod cup out. A stronger circlip here is the answer. As far as rocker geometry, there are different schools of thought.
 
My first Mopar build was a 1978 440 in 2001.
I followed the Mopar Muscle Q & A advice of "Dick Landy" and decked the block .010 and the heads .050. The pistons were stock, the heads were iron. I did use different valve springs but with stock rocker arms and pushrods.
There was no checking or lifter preload with the MP 280/474 cam. I ran the dude pretty hard and and had no problems with it. I later put the engine in another car that I sold. I built another 440, this time bored .030 over with the MP 284/484 cam and Edelbrock heads. Again, no checking of lifter preload and stock rocker arms and pushrods and again, no issues.
That engine split a rod so I built a 440/493.
.030 over, 4.15 stroke crank, pistons .017 in the hole with HD repro stock stamped steel rocker arms and stock pushrods, MP 292/509 cam, new valve springs but once again, no attention to lifter preload and no bad results from it.
Am I just lucky or is there so much of a range of tolerance that I was going to be fine no matter what I did?
I switched to a solid lifter cam later and went with an adjustable valvetrain.
I'm not one to ignore good advice or practices on engine builds but if you don't know , AND if there have been no ill effects to it, the best that you can do is learn from it.
 
Kern Dog said:
My first Mopar build was a 1978 440 in 2001.
I followed the Mopar Muscle Q & A advice of "Dick Landy" and decked the block .010 and the heads .050. The pistons were stock, the heads were iron. I did use different valve springs but with stock rocker arms and pushrods.
There was no checking or lifter preload with the MP 280/474 cam. I ran the dude pretty hard and and had no problems with it. I later put the engine in another car that I sold. I built another 440, this time bored .030 over with the MP 284/484 cam and Edelbrock heads. Again, no checking of lifter preload and stock rocker arms and pushrods and again, no issues.
That engine split a rod so I built a 440/493.
.030 over, 4.15 stroke crank, pistons .017 in the hole with HD repro stock stamped steel rocker arms and stock pushrods, MP 292/509 cam, new valve springs but once again, no attention to lifter preload and no bad results from it.
Am I just lucky or is there so much of a range of tolerance that I was going to be fine no matter what I did?
I switched to a solid lifter cam later and went with an adjustable valvetrain.
I'm not one to ignore good advice or practices on engine builds but if you don't know , AND if there have been no ill effects to it, the best that you can do is learn from it.
Click to expand...
The factory designed these as reliable passenger car transportation. They weren't designed to have adjustable preload. The lifter successfully took up the differences in tolerances from one engine to the next.

Those same lifters are more than capable of doing the same thing with a bigger cam and a performance build. The factory rockers are much more stout than most people give credit for. But there's no way to adjust preload except with custom push-rods.

It really ultimately depends on what you're wanting to accomplish with the build and what your tolerance for risk is. Most of the time the factory stuff works with fairly mild cams. Sometimes it might not. Roll the dice and send it!
 
Illahe said:
Direct connect used to offer adjustable pushrods to make up the lifter preload on high lift hydraulic cams when running the stamped rocker arms.
Click to expand...
Those things are complete junk. I have a set, error I have some, because a bunch broke on the first dyno pull. J.Rob
 
RAMM said:
Those things are complete junk. I have a set, error I have some, because a bunch broke on the first dyno pull. J.Rob
Click to expand...
Yep, let's put a tiny threaded connection into a very high cyclical load application that's sure to work wonderfully. (Sarcasm)
 
RAMM said:
Those things are complete junk. I have a set, error I have some, because a bunch broke on the first dyno pull. J.Rob
Click to expand...
I ran them in the without issue in my 340 for years with J heads and 901 springs.
 
Kern Dog said:
Somehow, I'm the guy that has stumbled through this hobby sometimes not doing things the way that I am supposed to be doing.
I've never checked or compensated for installed height with valve springs. I've never experienced valve float or kissed a valve with a piston.
I've never checked or adjusted end play in a crankshaft, I've never measured piston to wall clearance either.
I've adjusted valve lash with solid lifters but never gone the other way with a hydraulic lifter. With small block Chevys, it was customary to tighten the rocker arms to zero lash then turn the nut 1/2 to 3/4 turn more.
Here we are as Mopar guys and we have rocker shafts that are non adjustable. I've rebuilt several engines, had milled heads, decked blocks, different head gasket thicknesses and have not seen any adverse effects from the lifter preload not being checked and/or blueprinted to spec.
This topic comes up for me because I'm doing a Hydraulic roller cam swap in a big block and Dwayne Porter told me about what the spec is for lifter preload with the Comp Cams Evolution lifters.
I have a 1990 360 that I'm also working on and it came with a Hughes 1.6 rocker arm set. I'd be okay with just settling with a decent set of stock rocker arms but now I'm wondering if I should be concerned with lifter preload on the 360. How do you adjust that with a stock shaft mounted rocker arm setup? Do you perform a mock up with an adjustable length pushrod and determine the preload with a dial indicator?
Click to expand...
Comp says evo's have about .125" of travel. Verify this. If you use an adjustable Hughes rocker 1.6 ratio. you can do the following. Start with the intake. If the valves are all at the same height you only need to check one on each head.

1. turn the motor in the direction of rotation until the exhaust lifter ( paired with the intake lifter you are checking) starts to rise or when the ex. valve would start to open.

2. Assemble rocker arms and push rod loosely until the push rod is at zero lash or slightly loose. If the shaft isn't bottomed out yet loosen the adjusters screw until you can. if you can't get the rocker shaft all the way down with the pushrod at zero lash or slightly loose then the pushrod is too long and you need a shorter or better yet an adjustable pushrod.

3. when you get to zero lash or slightly loose with the shaft snuged up lossen the adjuster until you can feel slight up and down movement then turn back in until movement is gone. This is zero lash.

4. I think Hughes uses a 7/16" x 20 tpi on their adjusters. Verify that. Turn the adjuster 1 1/4 turns in. this will be .0625" or at mid travel of the lifter.

5. Contact Hughes to find out what the accepted range is for positioning of the adjuster screw. When you find that range use the middle of the range. if your screw is already in that range you're good. If not while keeping track of how far you turn the adjuster, turn the adjuster to the center of the acceptable range.

6. (For a 7/16x20 tpi adjuster.) Multiply the number of turns times .050. Add that to the length of your pushrod if you had to loosen the screw. Subtract from the length if you had to tighten it. This should be the length of the pushrod you need.

If someone sees and error here please point it out.
 
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Kern Dog said:
……I'm wondering if I should be concerned with lifter preload on the 360.
Click to expand...

Yes. Make sure you have some preload, and make sure you’re not bottoming out the lifter plunger. Everything in-between is fine. This is what a hydraulic lifter is supposed too do.

Back when you could buy good hydraulic lifters, guys that were pushing the rpm limit would set the pre-load to zero and gained a few hundred rpm without concern of lifter pump up. I don’t think anyone is doing that with today’s hydraulic lifters.
 
BSB67 said:
Yes. Make sure you have some preload, and make sure you’re not bottoming out the lifter plunger. Everything in-between is fine. This is what a hydraulic lifter is supposed too do.

Back when you could buy good hydraulic lifters, guys that were pushing the rpm limit would set the pre-load to zero and gained a few hundred rpm without concern of lifter pump up. I don’t think anyone is doing that with today’s hydraulic lifters.
Click to expand...
Still being done. We do it on 602 crate motors all the time.
 
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