How does one know if pushrod guide plates are required on a paticular engine combo?

world product sportsman II heads
harland sharp roller rockers
comp cams retro hydraulic roller lifters
.502/.510 lift cam


thx

jeff

 

jjlabinski,

I was told that you either need guideplates or self aligning rocker arms.
One of the two to keep your valvetrain geometery inline.

Did the heads come with guideplates? Are your rocker arms self aligning?


Rabi C>

 

rockers are not self aligning and the guide plates I have now make excessive noise due to the pushrods rubbing against them.
Any ideas?

thx

jeff

 

Guideplates prevent pushrod deflection at high rpms. It's insurance for an aftermarket setup.

 

What?

No, you need to align the pushrods one of 3 ways;

1) slotted holes for the pushrods to go through on cylinder heads. This is common on most factory heads before the '90s. If your pushrods go through "slots" that are barely .015" wider than the pushrod itself, you have this. If the heads have giant (1/2") round holes, then you don't have this.

2) Self aligning rockers - these have little "saddles" where the pushrod hits the back bottom of the rockers, little rails if you will. Rather than the "cup" style part.

3) guide plates.

You need 1, and only one of these. I'd bet those heads you have DO NOT use the slot method. So i'm going to go out on a limb and say you need guide plates.

Your guide plates may need adjustment, if they are sloppy fitting. I wouldn't guess that your pushrods are making noise from hitting the guideplates, that isn't a place that could cause a sound, since they'd be rubbing, and would rub away the material before you could even really take note of the sound. Mis-adjusted rockers, (lash is off perhaps?) or a loose rocker stud or something..

 

no, they are rubbing. and I proved it by putting stp on them then starting engine. oil does not get on them as they are behind where the pushrod discharges oil.

thx

jeff

 

They're oiled by splash flung around by the rockers. They don't need much lubrication since the guide plates don't apply much pressure to the pushrod.

If you installed them dry and the noise went away when you finally oiled them like the should have been, then I wouldn't worry about it.

 

If you run guide plates, make sure you have hardened pushrods. The plates will eventualy rub the non-hardened pushrod to failure. Is there noticable wear on the current pushrods?

 

I don't buy that, in stock form pushrods are... (probably lightly case hardened?), and are aligned via the slot in the heads, which does the same job as guide plates. Hence the typical visual wear on stock pushrods, the colored area.

 

Most of the aftermarket pushrods are hardened. Stock pushrods on self-aligning configurations might not be.

 

Sonix, I just meant if you have a guide plate installed you will have to run a hardened pushrod. Stock heads usualy dont have guide plates so there is no need for a hardened pushrod.

 

In my factory cast heads there was plenty of clearance between the rods and the slots in the castings. Using guide plates, when the roller of the rocker is as close to the center of the valve stem as possible pushrods touch the side of the plates even when the engine is not running. There is very little side to side adjustment for the plates just that allowed by the mounting hole diameter with respect to the stud diameter. I centered everything as best possible with the adjustment clearances provided.

Has anyone else experienced this condition?


thx

jeff

 

That's not that unusual. What would be worrisome would be if the pushrods touched the head and the guide plate, or both sides of the guide plate, and were binding.

 

Yea, I know what you mean. I just meant if you had slotted heads on the motor you were tearing down, the factory pushrods would be hardened, and ok to use with guide plates. My 416 heads on my 305 had this, so I re-used them again on my 350. (albeit still with 416 heads and slots in the heads..)

 

I see what you mean. You got me wondering now, I ordered a set of hardened pushrods from Comp cams for my build. How can I tell what my previous pushrods were? I didnt realy see a part number or anything. I hope I didnt order the new set for nothing. Sorry,I didnt mean to Hi-jack the thread.

 

if you have the heads that are supposed to be used with guideplates, i.e. not the small holes, not with guided rocker tips, then the pushrods are supposed to touch the guideplates. and as mentioned, if you have the correct hardened ones, it's not an issue at all.