URGENT: pushrod help

[ShiftTheDrift]

I ran into some problems today trying to get the right pushrod length..

First off, the block is stock and the heads are stock from TrickFlow.

I purchased a pushrod length checker form TrickFlow and for some reason, I'm getting different lengths for different valves. I know what you're thinking. But the lifters are all the way down. I honestly don't know if I'm doing the process correctly or maybe my lifters are bad?!?!

Basically, I'm installing the adjustable pushrod between the lifter and the 1.7 rockers. Then, I'm making sure the adjustable pushrod is closed all the way. Then, I install a rocker on a head stud and begin screwing the adjustable pushrod until there's no play up and down. I then get under the car and turn the crank a few times.

I've done this for three different valves and only two ended up with the same measurement. I've noticed TrickFlow says to use 6.750 rods and my rod measurements fall below 6.700?

Does increasing the rocker ratio from 1.6 to 1.7 warrant a shorter pushrod?

I've looked at Comp Cams, Crane Cams and others with no idiots guide for doing this and knowing it's been done right. Anyway, it's getting late here in California and I was hoping somebody might help me out with this. Please help if you can guys! -Bill

 

[TrueBlue95GT]

You know that you have to be on the base circle of the cam right?

 

[RIO5.0]

I may be wrong, but I thought you need to use a "solid" lifter when using a checker for lenght??? this way your assured your at the pumped up height...

 

[ShiftTheDrift]

I am sure that I am on the base circle because the lifter is fully depressed.

It would appear that both 6.70 and 6.75" rods yield the same result. Doesn't the longer push rod just cause the adjustable rocker arm assembly to be located further out on the stud? How important is push rod length for any other reason than the location of the fulcrum to the base of the mounting stud? It would seem that the closer the rocker is to the base of the stud the less potential there is for bending of the stud.

 

[ShiftTheDrift]

Is setting preload on a lifter the same thing as preloading the rocker?

I just don't see how you can have two separate preloads on both parts connected to each other.

 

[WHITE94COBRA]

Are the pedestal mount or stud mounted rockers? Pedestal mount rockers are more tempermental to pushrod length, stud mount you have the ability to adjust them to pushrod length, (to an extent of course). If there tw heads i'm assuming there stud mount, the locking nut on the rocker is the adjustment. Sombody correct me but i'm pretty sure they adjust about 10- 15mm up or down??

 

[ShiftTheDrift]

They are TrickFlow's Twisted Wedge heads with 3/8 studs.

Would you say they're the same then? lifter preload vs. rocker preload?

 

[WHITE94COBRA]

Go to the ED C. website there is a detailed write up on this subject. www.flowtechinduction.com I just checked the site and its not there anymore i'll look around and find it for ya.

 

[1slow95]

I followed this article when I checked my pushrod length. http://carcraft.com/techarticles/116_0401_push/

You really should use a solid lifter. You can convert a stocker to solid if you have one.

 

[WHITE94COBRA]

Heres one from comp cams. http://www.compcams.com/Technical/Instructions/Files/250.pdf

 

[tmoss]

An easy way to convert a stock lifter is to take a cut-off wheel and cit a groove through the lifter body and into the plunger on the flat where the lifter guide lays. Run a bead in there and grind down to the flat surface agin - walla, solid lifter at the exact right "pumped up" height.

 

[RIO5.0]

Go to the ED C. website there is a detailed write up on this subject. www.flowtechinduction.com I just checked the site and its not there anymore i'll look around and find it for ya.

I stashed that one for future use....

This is how I do it (tech article provided by Ed Curtis of FlowTech Induction )


HYDRAULIC LIFTER/VALVE ADJUSTMENT PROCEDURE


--------------------------------------------------------------------------------

1. Remove the valve covers, and pick a cylinder you are going to set the pre-load on. Only do one cylinder at a time.

2. Rotate the engine in its normal direction of rotation (clockwise) and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder's intake rocker arm.

3. To adjust, back off the intake rocker arm adjusting nut and remove any tension from the push rod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the push rod seat up against the retaining lock, if you give it time to do so.

4. Twist the intake push rod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning of the push rod, you are at "Zero Lash". Turn the adjusting nut down one half to three-quarters of a turn from that point for street applications. Use 1/8 to 1/4 turn for race applications. Lock the adjuster into position. The intake is now adjusted properly.

5. Continue to turn the engine, watching that same intake valve/rocker you just set. It will go to full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.

6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.

There may be some initial valvetrain noise when the engine is first fired up but once oil pressure has stabilized and the engine heats up, it should quiet right down to a normal level.

Remember that some racier camshafts will have a mechanical sound to them and will not be a silent as factory units.

 

[ShiftTheDrift]

So, preloading the lifters and rockers are the same thing?

 

[tmoss]

Yes

 

[nmcgrawj]

you are right on with 6.7 and 6.75 on the lengths. Thats what those heads usually run. The reason u see them as the same is because .05 isnt enough to show a difference. I think you need .1 to see a difference. Mike Curcio told me this when he walked me through it over the phone

 

[ShiftTheDrift]

You guys came through in fine style. I got the pushrods ordered yesterday.

Thanks again!

 

[ShiftTheDrift]

Turn the adjusting nut down one half to three-quarters of a turn from that point for street applications. Use 1/8 to 1/4 turn for race applications. Lock the adjuster into position...

What is the difference between using one half to three-quarters vs. 1/8 to 1/4 for race applications?

I tried using 1/4 turn and it sure seems awfully loose. Any ideas?

 

[RIO5.0]

What is the difference between using one half to three-quarters vs. 1/8 to 1/4 for race applications?

I tried using 1/4 turn and it sure seems awfully loose. Any ideas?

For your application, according to Mr Ed... a 1/4 turn should be loose....run the other method....1/2-3/4 turn and check it out...

 

[ShiftTheDrift]

Yeah, I'll try that tomorrow. Why would you want them that loose?

 

[RIO5.0]

Yeah, I'll try that tomorrow. Why would you want them that loose?

Thats a good ????? Must have something to do with clearances at high RPM...figure those guys are running some hardcore valvetrain sets for the 7500K and up they run...
Good luck with it....