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Discussion Starter · #1 ·
Hardened pushrods are required when using guideplates but what about hardened guideplates when using hardened push rods? While running the valves on the 302 240Z, which has less than 100 miles and (10) 1/8 mile passes, I noticed some rocker arms seemed to have excessive side to side movement and the roller tips could almost be positioned to ride the retainer instead of the valve tip. Turns out the pushrods were wearing into the guideplates. The heads I installed came with these CAT brand guideplates.CAT doesn't have a good quality reputation and now I can see why.
 

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geeeez, it looks like they're made of butter, sorry to hear that...
 

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That's not necessarily a problem with the guide plate hardness. That's a problem with your valvetrain geometry. Often this happens when you use a rail type roller rocker on a system that's using guideplates. Another thing that can cause this is lifter bores that aren't spaced correctly, wider than stock valve spacing, etc etc. Whatever the issue with your heads, it looks to me like you need some adjustable guideplates. They're relatively inexpensive, and allow you to center your guideplates on your pushrods, so there is no binding and/or rubbing which as you can see, is a problem. Comp makes them, Isky, and most other reputable cam/valvetrain companies.

Good luck!

Cris
 

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Discussion Starter · #6 ·
I can see where running rail type rockers with guideplates might be a problem but the motor doesn't have rail rockers.The pushrods show no wear marks or scuffing which indicates to me the guideplates were too soft.I'll check out the alignment closer though.

I'm glad 1bad6t posted the pics of the Manley guideplates.I just bought a set of Ford Racing guide plates from PAW,the other type they had in stock were Manley.Good thing PAW is open on Sunday.

http://store.summitracing.com/partdetail.asp?part=FMS%2DM%2D6566%2DD311&N=700+400070+4294925232+4294778626+4294867013+115&autoview=sku
 

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I had the same thing happen years ago on my 302 with Manleys IIRC..I never did figure out what happened.I replaced the pushrod and the guide plates and never had anymore problems.

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<font size=-1>[ This Message was edited by: frdnut on 11/13/06 4:47am ]</font>
 

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The idea is that you want to guideplate to go away, not the pushrod, hence non-hardened plates and hardened rods.

I'd check your valve tip geometry, make sure you have no coil bind at full lift, and if nothing suggests a broken or misaligned part, throw a new guideplate on it.
 

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Well thats enough to keep you up at night. I havnet fired mine yet.
I had alignment issues when i was building my engine. One set of plates(no name chinas Prob) skewed the rollers outward, the other set (Ford motorsports) Skewed them inward.

SIGH!!
So I bought the iskys

They are a pain the arse though.
They move around when you tighten the stud. And they need to be welded when you get them set, per instructions. I used a shielded wire to weld them. Worked but man what a splattering mess. Should be TIG'ed. Sigh so now ive got to wonder about my possiblities of wear after all that work

Anyways just sharing my issues with you. Hope ive helped in a round-about way.
I hope to see you at Irwindale some day!! Although you'll prob smoke me! LOL


_________________
71 Pinto Sedan

5.0 block,B303,1.7 Rockers,beehives,'68 ported heads,Coated custom Must II headers,Edlb Airgap,Holley570,Msd Billet,Crane HI 6,Milodon 8 quart Deep Pan,2.5" 40 Flowmasters.

<font size=-1>[ This Message was edited by: 71hotrodpinto on 11/13/06 10:24am ]</font>
 

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Discussion Starter · #11 ·
On 2006-11-12 17:23, thekingofazle wrote:
The idea is that you want to guideplate to go away, not the pushrod, hence non-hardened plates and hardened rods.
I was being sarcastic when I titled the post "Hardened Guide Plates Required".Of course they should be hardened. I really don't believe the guideplates or pushrods should wear or "go away". Both should be hardened to function properly.I checked the alignment again and didn't see any signs of coil bind or anything else out of the ordinary.

71HotrodPinto: Those Isky guideplates sound like quite an ordeal.Good luck. I might go out to Irwindale at the end of the month.Should have the guideplates and other stuff fixed way before then.
 

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If I have to sacrifice one or the other I am glad the guide plates are softer - they are a lot cheaper than push rods!

What happens when you wear through a push rod?

Paul
 

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Discussion Starter · #13 ·
It's hard to believe that the guideplate is designed to be sacrifical like a bronze distributor gear used with a steel roller cam.If the push rod wears to the point of bending or breaking then the valve won't open. If the guideplate wears to the point that the rocker is allowed to ride on the retainer not the valve tip then there is a chance a valve will drop causing untold damage. Seems like a hardened push rod and hardened guideplate would wear at similar rates.

I'm thinking the CAT guideplates were stamped out of sheet steel and then just black oxide coated missing the heat treatment hardening process. Normally, after stamping, parts are heat treated then the finish is added if required. Hardening costs more.
 

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No, you're right, neither is supposed to dissapear... something is up.

But by the same token, wouldn't a non-hardened pushrod and guideplate wear at the same rate too? Why do you always have to run hardened pushrods with guideplates?

I always zip over the edges on the guideplate with a sanding roll and a die grinder, just to knock the sharp edges off where the pushrod will ride.

How's the Z doing? I think you posted the track times, but I can't remember how it did.
 

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Discussion Starter · #15 ·
I installed Ford Motorsport guideplates like '71hotrodpinto posted a pic of. All of the CAT guideplates showed some form of wear, some worse than others.Sure didn't take long for the wear to occur.

The Datsun is still getting dialed in . Best run is a 7.86/85+MPH in the 1/8 (12.35 1/4).I'm yanking out the B&M Pro Stick shifter because it's too hard to operate.A B&M Pro Ratchet hopefully will be easier.
 

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Could the problem be caused by bowing pushrods due to high valve spring pressures? In effect, the bowing hardened pushrod pushes up against the guideplate increasing the wear? Maybe stronger pushrods would reduce the problem. I have heard that if you could see your valvetrain in slow motion, the amount of flex would be surprising.

I've gone to probes 1.7 shaft rockers for my rebuild. Woddy1 got me a great price on them.

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'65 FB Mustang 331, 282S cam, ported 351W heads. T5z, 3.50 9" posi.
346 [email protected] on a warm spring day (335 RWHP SAE corr.)


<font size=-1>[ This Message was edited by: blkfrd on 11/15/06 12:31am ]</font>
 

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Both guideplates and pushrods should be hardened. You can test the hardness by using a corner of a file on the edge of the guideplate. The file should not significantly scratch it... and should NOT dig into it like it would mild steel.

Bad geometry, guides that are not installed straight, rocker studs that are not threaded straight, etc. can also cause those problems.

The rocker tip needs to be centered pretty well on the valve stem. If it is off to the side, it will cause the rocker to tilt and try to run off the side. That constant 'sawing' pressure WILL cause problems. To get it centered, guideplates can be modified. If BOTH are off to one side, a stone in a die grinder can be used to oval out the holes where the rocker studs mount through. This will allow the plate to be moved over to center both rockers. Simply flipping the plate over or swapping with other plates can also make things better.

This doesn't affect the pushrod to plate condition, but the pushrod length also needs to be adjusted to provide less than 0.080" sweep from front to rear, or the guides will wear out prematurely.

Good Luck!
 
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