[Richiehd]

Im thinking I need a hair shorter pushrod on my 355. I have enclosed a picture for review. Also haveing a little trouble getting guide plates adjusted so the rocker is square on top of the valve, something I'm missing?

[oldbogie]

Originally Posted by Richiehd

Im thinking I need a hair shorter pushrod on my 355. I have enclosed a picture for review. Also haveing a little trouble getting guide plates adjusted so the rocker is square on top of the valve, something I'm missing?

Sometimes guide plates have to be cut apart and rewelded to adequately position the push rod so the rocker is held square to the valve stem. Isky makes some, though not the stepped kind, in two pieces with a tongue and slot specifically for this.

The root cause is tolerance build up between the lifter location, the rocker stud and that of the valve. One of the problems of roller tip rockers is that this shows up causing worry. While people argue the merits of centering the sweep and whether mid-lift rockers are superior to others to squeak out a couple tenth's of a percent of lift, this kind of crap is running in the background. Oh-well!

Bogie

[ezobens]

It's not so much that the guide plate that is off but the valves are moved out and are not parallel with the rocker studs / pushrods.
I see this on a lot of aftermarket (and even GMPP) heads. In order to get better flow they move the valves out slightly and you get the ****-eyed looking rockers.
For a street application, as long as wear is still centered on the valve stem, the fact that it's not square isn't of huge concern.
Elm

[snydski]

I don't know how that problem is caused by but could you tell me if your running 1.5 rocker arms and are those the type of heads , the ones that need guide plates or are you using them for extra precautions . I'm doing some what the same scenario soon . I also was told by the people that sold me my roller rockers that, I should sure them up with girdles. I didn't really want to but maybe I should . One more question has this motor been run for a while or was this noticed during this assembly . It looks like the roller doesn't travel very much as I would expect the way comp cams showed in their push rod checker instructions. They show it moving across the top alot more . sorry I can"t be more help but I would sure like to know how this turns out . P.S. from what I see your motor looks killer.

[Richiehd]

Originally Posted by snydski

I don't know how that problem is caused by but could you tell me if your running 1.5 rocker arms and are those the type of heads , the ones that need guide plates or are you using them for extra precautions . I'm doing some what the same scenario soon . I also was told by the people that sold me my roller rockers that, I should sure them up with girdles. I didn't really want to but maybe I should . One more question has this motor been run for a while or was this noticed during this assembly . It looks like the roller doesn't travel very much as I would expect the way comp cams showed in their push rod checker instructions. They show it moving across the top alot more . sorry I can"t be more help but I would sure like to know how this turns out . P.S. from what I see your motor looks killer.

This is a brand new build. 355 World heads and Scorpion 1.6 rockers. Mike Jones cam W/.500 lift, 280 duration

[cdminter59]

World products lists many heads, what is your Part# or intake runner size? I don't like world heads I purchased a set of the Motown 220's for a 383 I built years ago. I like the price until I started installing the valve train. I had bought Harlan sharp rollers but they wouldn't fit. Had to use Crane Gold series which was double the money.

[Richiehd]

Originally Posted by cdminter59

World products lists many heads, what is your Part# or intake runner size? .

I have the Sportsman II angle plug heads. 200CC runners.

[larrywalk]

As far as pushrod length is concerned, the pattern looks fine to me. Changing the length will move the pattern either inward or outward.

To get the rocker tips centered on the valve stems, move the guide plate in the opposite direction. If the rocker tip misalignment is equal but opposite on the two valve stems, it is an indication that the guide plate is either too narrow or too wide, or that the heads have a wider valve spacing than stock. There are some other plates which have larger or smaller widths, but you'll need to look, or simply use the adjustable guide plates and tack weld them when you've got it right.

If the misalignment of the rocker tips is just a little off, consider using lash caps for the wider surface for the rocker tip to run on.

[vexzer]

Originally Posted by oldbogie

Sometimes guide plates ... position the push rod so the rocker is held square to the valve stem. Bogie

I thought guide plates were just for safety -just in case the pushrod tried to jump. Maybe I misunderstand your advice but surely you are not suggesting to use the guide plate to "position" the pushrod. If all goes as planned the pushrod should never touch anything other than the lifter and rocker. The roller-rocker tip not contacting the valve tip squarely is another issue that possibly could be caused by a wrong guide plate, but cannot be "corrected" by a guide plate. There are no wear surfaces on a guide plate.

[Richiehd]

I have a set of World guide plates ordered, the part number they recommend. For some reason CP sent me different guide plates, Im thinking this may be the problem. Will post findings ASAP.

[oldbogie]

Originally Posted by vexzer

I thought guide plates were just for safety -just in case the pushrod tried to jump. Maybe I misunderstand your advice but surely you are not suggesting to use the guide plate to "position" the pushrod. If all goes as planned the pushrod should never touch anything other than the lifter and rocker. The roller-rocker tip not contacting the valve tip squarely is another issue that possibly could be caused by a wrong guide plate, but cannot be "corrected" by a guide plate. There are no wear surfaces on a guide plate.

Oh no, the guides are performing a several very important functions. With out them the stud mounted rocker would be quite free to move away from contact with the push rod and valve stem. With roller trunnions the rocker can swivel away loosing contact with the valve stem and then push rod. With the ball and socket, they can add flopping over on their side(s) as well.

Your choice of a stepped guide is an excellent one in that it minimizes push rod out of plane movements at a location closer to the rocker. The end result of this is that what "strange" movement there is amounts to less disturbance of the rocker's position. The bad part is if the total tolerance build up in the engine parts forces an out of plane position onto the rocker, it is more rigidly enforced by the stepped guide than a flat guide or the original guide cast into the head. The rocker that guides on the valve stem is also more flexible in this regard, but I rather think that the valve stem has enough to do without aiming the rocker so I avoid using this set up for performance engines.

The guide, any and all, will be touched by the push rod this is why hardened push rods are required when using guides. Guides themselves provide a problem as they need to be hardened but sometimes with high lift cams the slot's depth binds the push rod so the slot needs to be deepened, care must be taken when doing this that the sides of the guide slot are not touched by the grinding tool except for the zone where the lengthening of the slot occurs as the surface hardening will be removed from the side of the guide slot.

Frankly for a street engine the alignment you show is plenty adequate. Unless there is a need to chase every fraction of a horsepower, trying to get all of these parts in a straight line gets to be a lot like a dog chasing its tail. A lot of work for no reward.

Remember you have to use hardened push rods with a set up using guide plates whether they are cast-in the head or are separate pieces. The only time a non-hardened push rod can be used is with self-guiding rocker arms. When using self guiding rocker arms do not use guide plates as this risks binding the push rod, one or the other guiding type not both. A similar thing goes with heads using cast-in guides, if you convert to guide plates with these heads the cast-in guide needs to be machined out. Clearance is aways an issue to be checked where the push rod passes through access holes in the head and through guides. Every location for every valve needs to be inspected by rotating the crank (cam) to observe the motion of the valve train for clearance with adjacent hard parts.

Bogie

[lmsport]

Isky makes two piece guideplates for aligning the rockers.
Try them and you will only use the two piece ones in the future.

[Caballerokid]

I don't have World heads, I'm just running the 882's but something to keep in mind, when I went to the 1.6:1 full roller rocker arms I had to make sure that the opening in the heads for the pushrod was big enough so that it would rub or wear against the head when operating. This was the case for me. I opened the holes up to allow the clearance needed and used self-aligning "SA" roller rocker arms instead of the guide plates.