Valvetrain help...?

Topic: Valvetrain help...? (Read 1883 times) previous topic - next topic

Lash adjustment ? with pedestal rockers

Reply #15 – July 04, 2007, 09:13:25 PM

Quote from: JAMEZILLA;158591

Now one more thing, that you will not need if you are using all of the original parts, or the stock length pushrods, THERE ARE shim kits available that raise the seat of your fulcrums ( what your rockers sit on) particularly with roller rockers. These can be used in addition to or instead of different length pushrods. Good luck, and just be certain you are at TDC on the intake stroke #1 ( and 1 revolution out- hence check where your distributor's rotor is pointing! better be the #1! ) If you're running the H.O. firing order let me know and I'll getcha the torquing order for it. LATER!

The torque order for the HO would be cool. I just have trouble understanding why the torque order and spec would be necessary on a non-adjustable pedestal rocker? Does the number of turns required to get to the torque spec have any affect on the rocker?
I've had people say it does but how does it affect the sled/fulcrum?
The shims would increase the valve lash. correct?

Thanks,
Mike

Valvetrain help...?

Reply #16 – July 05, 2007, 05:56:12 PM

Quote from: t.birdsc;158596

The torque order for the HO would be cool. I just have trouble understanding why the torque order and spec would be necessary on a non-adjustable pedestal rocker? Does the number of turns required to get to the torque spec have any affect on the rocker?
I've had people say it does but how does it affect the sled/fulcrum?
The shims would increase the valve lash. correct?

Thanks,
Mike

ON bolt down pedestal rockers, 25ft lbs is 25ft lbs... Makes no difference where the cam is in it's rotation... If any thing was changed in the VT then yes it's a good idea to check lifter preload... If nothing changed, bolt it back together and don't worry about it...

It's obvious you guys never worked on anything with shaft mounted rockers(Ford FEs, Y blocks, Chrysler engines, etc). On those you are bolting down all eight rockers at once, so the non adj type(99%), are going to open some of the valves as you bolt them down... It ain't a big deal...

Tom

US guys?

Reply #17 – July 06, 2007, 03:32:07 PM

Well I'm a professional machinist / engine builder and what's obvious to me is that attention to detail EVERY TIME on EVERY part makes long lasting consistent engines that don't leave you standing there looking at it wondering what you halfassed that's causing the problem. Lifters stick more often than people may realize especially used ones at ambient temperature vs operating temp where they will free up. The torque spec. ( 25 ft/lbs) puts the max clamp load on the rocker that the threads in the head will produce, if you're not completely bottomed out you might not be getting that clamp force. Better to " over think" once than to do the job over again after scattering some top end parts. If you're in a hurry... don't do the job 'til you have time to do it right.

Valvetrain help...?

Reply #18 – July 07, 2007, 10:09:49 AM

Quote from: JAMEZILLA;158984

Well I'm a professional machinist / engine builder and what's obvious to me is that attention to detail EVERY TIME on EVERY part makes long lasting consistent engines that don't leave you standing there looking at it wondering what you halfassed that's causing the problem. .

well, time to eat your words,, its half assed to install old lifters...........................They are too cheap to be sitting there looking at them and not replace them.

so that obviously being the case here, you need to metnion that cause thats the first thing i noticed.

so................
with new lifters, you will not need to tdc every hole on pedistal type rockers, its a waste of time and shop labor/customer dollars especially when the shop manual does nto require or call for it unless you are checking heads and lash upon troubleshooting valve train noice or compression problems prior to dissassembly preceeded by a leakdown test as well.

So.,,,,,,,, being at the reassembly stage,, just bolt them on cause thats what you need to do.

as for shims,, its a good idea but in his case shimming the bottom spring cup is the only option especially if the valve seats are recut or freshend with compound.

the reason you dont worry about cam position is because each lifter( mini oil pump) has a spring that gives wayyy more than you can imagine. Even out of the box new lifters dont compare evenly when you push down on the lifter cup with a push rod. Get em pumped up full of oil and it takes pretty much all the ass you got to compress them. When you first put new ones in, the engine will tap but eventually they will pump up. Some say to soak them over night in oil or tranny fluid or even thin oil like PAG or PEG oil ,even mineral oil. Whatever you do, just dont reuse old ones unless for the rare instance your cam / lifters are a matched set.

Answer to your quesiton,,,,,,,,
just what cougarse already said as well as others.,,yes pedistal type rockers are that easy. Overthining is good for many things, this just happens to be one part you dont need to. If this were adjustable rockers,,,, You are dead on the the money and everything you've been "hearing" applies. Trust me,, i over think a lot cause im always wanting the best quality possible.

Listen to the wrench , not those who sit on the bench.

Valvetrain help...?

Reply #19 – July 07, 2007, 10:42:50 AM

Quote from: 88XR7;157359

How am I suppose to get an accurate torque reading when bolting on the rockers if they have to press down the spring(opening the valve)?

I don't know if you know what I am referring to...

Since the cams position would have the valve open if it was all together, the pushrod would be out further pushing onto the rocker and opening the valve.
So when I bolt on the rocker I would have to fight the spring.

Unless, I am overthinking this and the spring wouldn't change my torque readings...

correct,, that is exactly what is going to happen especially with lifters that are already pumped or primed. the same thing happens when you shut off your engine,,, some valves remain open while others are closed. Your just duplicating that situation with your torque wrench.

For that matter,, your springs nor the lifters exceed that benchmark of 25ft/lbs so your not "getting a torque reading" but rather you are reaching a "torque limit" that will only occure when you hear the CLICK. In the area near 25ft/lbs, your springs nor your lifters will have an effect on the final torque applied no matter the cam position.,,,,unless you have a defective or binding lifter which wont compress completely.

you need new ones.

Valvetrain help...?

Reply #20 – July 07, 2007, 01:10:49 PM

I just don't see how the pressure from the valve spring WILL NOT affect the torque reading.

The OE lifters are being used as well as the pushrods and cam.

Good news, I just got my heads back yesterday, they should be going on soon, most likely in the next few days.
I can't wait to get a sound clip of her and load her up.

Valvetrain help...?

Reply #21 – July 07, 2007, 04:41:20 PM

Quote from: jcassity;159157

well, time to eat your words,, its half assed to install old lifters...........................They are too cheap to be sitting there looking at them and not replace them.
.

There is absolutely no need to replace roller lifters unless it has collapsed...you can change cams every other week and still use the same set of roller lifters...if you are referring to flat tappet lifters, then yes, they should be replaced.