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I'm still building my SBO stroker engine with ProComp heads and I'm having pushrod and rocker arm geometry problems. I have assembled the rocker arms and pushrods, but the rockers seem to be cockeyed. Some look true i.e parallel to the valves cover rail, but most seem to lean to one side or the other. Is this normal for roller rockers? The roller tips of the rockers seem to be centered on valve stems, but the pushrods are not all parallel to each other. Some are slightly angled and not centered in the push rod holes in the heads either. Is this a casting issue with ProComp heads? Could the valve locations be inconsistent within the the chambers causing these alignment issues? This is my first build using aluminum heads and roller rockers; I think all the pushrods where parallel to each other when I rebuilt iron headed Olds engines in the past.
Here are some pics:
Last edited by cdrod; February 5th, 2016 at 11:34 AM.
Reason: bad grammer
I'm using the Isky adjustable guideplates. They were recommended to use with 5/16" pushrods and 7/16" studs. I needed the 5/16" pushrods to clear the holes in the heads. the 3/8" pushrods were running up inside the push rod holes in the heads. It as a real pain getting the guideplates to center the rocker arms on the valves stems because they always moved a little when I torqued the studs down (50 ft-lbs). I had to anticipate how much they would move before tightening then assemble the rockers to see how well they were centered on the valves.
Or if he's locating the straight edge on the VC rail and its not straight.......
The rockers seem to be misaligned with each other, the valve cover rail surface wouldn't cause the relative misalignment between individual rockers.
The rockers came with the heads which I purchased 2nd hand from guy who bought them from Bernard Mondello. I think they are Scorpion brand. I'm not using the poly locks that came with the rockers. Could the poly locks affect the alignment? I think I'll take everything back apart tomorrow and check few things, like if the studs are perpendicular to the head surface, if the valves are evenly spaced.
I've disassembled a few of the rocker arms looking for an explanation to the alignment problem. One thing that I noticed was a some play between the stud and the rocker arm trunion. The diameter of the stud measures .433" and the diameter of the trunion is .438" - so there is .005" of clearance here. Does that seem excessive?
No not really
Take two pieces of threaded rod and screw them into the stud holes, no rockers. Then check for parallel alignment that way along with a carpenters square just get an idea of where the misalignment is.
No not really
Take two pieces of threaded rod and screw them into the stud holes, no rockers. Then check for parallel alignment that way along with a carpenters square just get an idea of where the misalignment is.
Mark,
I didn't think the clearance was too much. I will get some threaded rod as you suggest and check for squareness. I may also try some different guide plates. The Isky adjustable ones I have now are hard to keep aligned properly, they slide and twist out of position as you tighten them down.
The rockers seem to be misaligned with each other, the valve cover rail surface wouldn't cause the relative misalignment between individual rockers.
The rockers came with the heads which I purchased 2nd hand from guy who bought them from Bernard Mondello. I think they are Scorpion brand. I'm not using the poly locks that came with the rockers. Could the poly locks affect the alignment? I think I'll take everything back apart tomorrow and check few things, like if the studs are perpendicular to the head surface, if the valves are evenly spaced.
Why is EVERYTHING associated with Mondello screwed up? Just a question. They never seem to work out of the box as advertised. Always a problem somewhere, somehow.
That is correct! These heads came from Bernard Mondello not Mondello Perfromance in Paso Robles, California. Bernard milled them down to 70cc chambers, my local machinist took another .018" off to get to my desired compression ratio. I don't think the additional milling would caused the rocker issues I'm chasing.
That is correct! These heads came from Bernard Mondello not Mondello Perfromance in Paso Robles, California. Bernard milled them down to 70cc chambers, my local machinist took another .018" off to get to my desired compression ratio. I don't think the additional milling would caused the rocker issues I'm chasing.
I can't see how the milling for compression ratio would cause a rocker problem. Subscribing to find out what caused the issue. Looked like what Mark cutlassefi suggested with the threaded long studs and check alignment was a good place to start.
Have you tried using the polylocks that came with rockers? I know some guys on Chevy forum had issues with different brand polylocks where thick upper part of poly lock hit rocker body before making contact with rocker trunion.
I don't have the original poly locks that came with the rockers. I had another set of roller rockers from CompCams that had shorter 1" tall poly locks. In a "bonehead" move I sold the original poly locks (which were 1.2" tall) with the Comp rockers set only to discover later on that the shorter poly locks wouldn't clear the rocker arms when they pivot. The original locks had a 6-pt hex head on them which contacted the rocker when it pivoited; so I bought a set of no-name poly locks that have a 12-pt head (which you can see in my pics). These allow full travel of the rocker without interference. I'm going to take Mark (CustlassEFI's) advice and pick up some threaded rod material to screw into the stud holes and check perpendicular with a small combination square.
This is a little out there, but I've made this mistake with my build. Caught it quick though. I'm not familiar with the Scorpion rockers - this is from my Harland Sharp rockers.
The trunion may be machined to fit the polylock on only one side. That is, one side of the trunion has a machined flat face, while the other side is rounded. If the rounded side is up and that's what it rides on against the polylock, then the rocker may not locate correctly.
This is a little out there, but I've made this mistake with my build. Caught it quick though. I'm not familiar with the Scorpion rockers - this is from my Harland Sharp rockers.
The trunion may be machined to fit the polylock on only one side. That is, one side of the trunion has a machined flat face, while the other side is rounded. If the rounded side is up and that's what it rides on against the polylock, then the rocker may not locate correctly.
Well yeah that can happen if you put one on upside down on a Harlan Sharp rocker.
Oddball:
That is a great suggestion! These trunions do have a flat side and a round side, but I've already checked this and they are install with the flat side up, facing the poly lock. I'm starting to think that the adjustable guide plates made be the part of the problem. They moved around quite a bit when I tightened the rocker studs, and the pushrods are all at different angles as well making me think that the guide plates are not be holding the pushrods in correct alignment with the valves. Too much angle on the puhsrods would put a side load on the rocker arms, could cause this alignment problem. I'll have some time this weekend to double check the stud alignment and play with the guide plates some more.
Oddball:
That is a great suggestion! These trunions do have a flat side and a round side, but I've already checked this and they are install with the flat side up, facing the poly lock. I'm starting to think that the adjustable guide plates made be the part of the problem. They moved around quite a bit when I tightened the rocker studs, and the pushrods are all at different angles as well making me think that the guide plates are not be holding the pushrods in correct alignment with the valves. Too much angle on the puhsrods would put a side load on the rocker arms, could cause this alignment problem. I'll have some time this weekend to double check the stud alignment and play with the guide plates some more.
Push rods don't touch the guide plate.Mine don't anyway but i am using Harland Sharp.
I had rocker arms that where not dead even and the rockers where slightly cocked side to side but not on an angle vertically speaking. Ran em for years with no issues. Im still running them slightly off even after adjusting them becasue i dont feel like pulling the guide plates out to open up the bolt holes a bit.
One way to get around the guide plates moving around is to tig them together with the rocker studs lightly snugged down. Remove them and weld them fully then put them back and torque them down.
A pushrod moving side to side should only cause the rocker to shift sideways - along the plane parallel with the valve cover surface since Olds valves don't have much angle to them - NOT along a vertical plane like you're seeing.
The rocker only sits on the trunion face on the polylock, the top of the valve and the top of the pushrod. The pushrod is rounded, so you're not going to have much effect for this type of shift. Try wiggling a rocker side to side when the valve is closed but the preload is set. It'll move along the plane parallel with the valve cover surface - not rock the way you're seeing.
I think you're down to just a few easy problems:
1) mangled rocker studs. I have a history of bending the Comp 5/16"x3/8" conversion studs (tiny six point face + 12 point deep socket = bad times), but 7/16" studs should be far more resilient
2) mangled polylocks, but this would be readily apparent on visual inspection
And really, really hard problems:
3) mangled rockers
4) out of alignment stud holes
These can be check by just swapping rockers. Does the alignment problem stick with the rocker, the stud, or totally unpredictable?
A pushrod moving side to side should only cause the rocker to shift sideways - along the plane parallel with the valve cover surface since Olds valves don't have much angle to them - NOT along a vertical plane like you're seeing.
The rocker only sits on the trunion face on the polylock, the top of the valve and the top of the pushrod. The pushrod is rounded, so you're not going to have much effect for this type of shift. Try wiggling a rocker side to side when the valve is closed but the preload is set. It'll move along the plane parallel with the valve cover surface - not rock the way you're seeing.
I think you're down to just a few easy problems:
1) mangled rocker studs. I have a history of bending the Comp 5/16"x3/8" conversion studs (tiny six point face + 12 point deep socket = bad times), but 7/16" studs should be far more resilient
2) mangled polylocks, but this would be readily apparent on visual inspection
And really, really hard problems:
3) mangled rockers
4) out of alignment stud holes
These can be check by just swapping rockers. Does the alignment problem stick with the rocker, the stud, or totally unpredictable?
I'm almost dead sertain that it is #4. How was the treads in the heads cut? By hand?
I'm almost dead sertain that it is #4. How was the treads in the heads cut? By hand?
Oldwlf:
I didn't drill or tap the stud holes in the heads, they came to me with the studs already loosely installed. The studs screwed into the heads easily enough so I don't think the threads were damaged in some way. I will check the alignment this afternoon and report back my findings.
Weird thing about my 455. I am running Ford, yes Ford, rocker arms. Any input to that? I was shown by my builder how they matched the valvetrain movement exactly. The aftermarket rockers I WAS using had the wrong geometry. Anyone heard of this? He is dead and gone and I can't question his genius.
I think I've found the solution to my crooked rocker arms, but have other obstacles that need to be corrected before I can be certain. The whole valvetrane/rocker arm problem started when my original 3/8 pushrods were rubbing against the head in the pushrod holes. I tried clearancing the holes a little on one head (without going too far) but the 3/8 pushrods were still rubbing. I ordered a new set of 5/16" pushrods, but couldn't find any 5/16" guide plates with 7/16" studs holes. That's when I tried the Isky adjustable ones - but they move all over the place when you tighten them down. Some suggested tack welding them together before tightening them, but the stud holes in the guide plates are really large, they still move around when you tighten them
So I ordered set of cheap 5/16" guide plates and drilled out the stud holes to fit my 7/16" studs. These don't move around nearly as much as the Isky adjustable ones and seem to hold the rocker arms in better alignment to the valve stems without canting sideways (as shown in my first post). But I'm still having interference issues with the pushrods rubbing against the holes in the heads. I need to pull the heads and open up the pushrod holes a little more so they won't rub, then I'll assemble one head with the modified guide plates and snap a few pictures for comparison. I'm hoping to have some garage time on Wednesday evening.
....But I'm still having interference issues with the pushrods rubbing against the holes in the heads. I need to pull the heads and open up the pushrod holes a little more so they won't rub, then I'll assemble one head with the modified guide plates and snap a few pictures for comparison. I'm hoping to have some garage time on Wednesday evening.
This seems very strange. I'm thinking you may have the wrong rockers on the heads.
Do you have any part number for the rockers you have?
Midrange:
I agree that something is not right here, but I have never used roller rockers before so I really don't know what's typical. I don't have any paperwork on the rockers arms because I bought the heads and rockers 2nd hand, but unused, from I guy who never built his engine. I do know they are from Howard's Cams and stamped 1.6F, which I believe is a Ford part. The pushrods clear the top of the holes fine, but at the bottom of the head (closest to the lifter valley) they are very near the top edge of the hole. It's almost seems like the pushrod holes in the heads are drilled at the wrong angle, or possibly the lifters are too tall. The lifters do stick up out of the holes about 3/8" when on the base circle of the cam,b ut I don't know if that's normal. It's a roller cam spec'd by Mark (cutlassefi) but this is my first roller cam so I don't have any experience here.
Midrange:
The lifters do stick up out of the holes about 3/8" when on the base circle of the cam, but I don't know if that's normal. It's a roller cam spec'd by Mark (cutlassefi) but this is my first roller cam so I don't have any experience here.
Rodney
Yes the lifters should stick up about that far. With the right rocker you should need a pushrod about 8.00" long.
For the record never had a problem with the pushrod holes on these heads. Working with my 6th set of Procomps now. But maybe they were drilled wrong, might be why the guy got rid of them.
I know that a certain model of Ford rocker will work with an Olds.
Could it be possible that these rockers while marked 1.6F, are for the other Ford engines that are not compatible with Olds?
Maybe you can look into that as a possibility, although without a part number, you may have to research the dimensions.
I'm not seeing how the pushrod hole is to blame, especially with a 5/16 pushrod. Exactly how does the pushrod change the rockers angle like that? The rocker shouldn't deflect that much.
Mark:
The pushrods are 7.95" long so I should be in the ballpark on the length.
Trip:
The pushrod clearance is a separate issue but one that led to using the Isky adjustable guide plates. Here's a pic of the pushrod holes with the 3/8" pushrods. They are touching the the edge of the hole and when I turn the engine over by hand, the pushrods rub against the hole. Here's a pic.
I understand the picture and have to say that is a common place to rub with a 3/8th pushrod.
Why that is cocking the rocker to one side is what I don't understand? I don't see how that is possible at least to that extreme.
Mark:
The pushrods are 7.95" long so I should be in the ballpark on the length.
Trip:
The pushrod clearance is a separate issue but one that led to using the Isky adjustable guide plates. Here's a pic of the pushrod holes with the 3/8" pushrods. They are touching the the edge of the hole and when I turn the engine over by hand, the pushrods rub against the hole. Here's a pic.
The obvious reason for tilting the rockerarms like the first picture is out of 90 degree angle of the studs. Why dont you check that?
Take two long 7/16 bolt or 7/16 treaded rod. put them in two of the stud holes, drive them down as far as possible. Measure the distance at the bottom (head) and at the top. The two measures should be equal for correct rocker arm alignment.
Check cylinder by cylinder.
February 5th, 2016, 11:31 AM
