Pushrod Problems?

[pishta]

RAU sells 3 part numbers for a 225: PL33, PL33S and PL33H(Hydraulic). The PL33 is the same across the mechanical lifter line. The S is for 75-80 225's (cast crank and its bearings, what else changed?) but I don't know what the diff would be rocker arm wise. @slantsixdan

 

[Charrlie_S]

RAU sells 3 part numbers for a 225: PL33, PL33S and PL33H(Hydraulic). The PL33 is the same across the mechanical lifter line. The S is for 75-80 225's (cast crank and its bearings, what else changed?) but I don't know what the diff would be rocker arm wise. @slantsixdan

It's possible the arms are the same (they should be) but the difference being the rear mounting hole in the shaft. That hole did change somewhere around that time frame (not sure of the exact year).

 

[Gramps1]

Just wanted to know if you were anywhere near someone (maybe me) versed in slant sixes.
170 pushrods are ball and cup, but there is no way they could work on a 198/225 engine.
You said the original rocker setup, had the same issue (adjusters way down in)?
Do you know if any valve work has been done to the head?
There are only a few things that could cause the problem you have.
1) wrong push rods (possible, but not the 170 units)
2) Cam base circle too small (again possible, but not likely to cause that big an error)
3) Incorrect valve stem heights, due to incorrect valve job. (very possible)
4) Rocker shaft/arms not in the correct height in relation to the cam (usually problem is in the other direction, due to head milling)
5) since the rockers were rebuilt possible problem there (in your case not likely, as you stated problem also with original rockers.
I'm leaning toward number 1, or 3

Here is a couple of pictures if it helps
I know nothing about this engine other than it was a running engine.
Nothing had been done to it recently as far as the head goes.
I thank you for your time.

 

[Gramps1]

FYI, stock length OE 225 pushrods (mechanical cam) measure 9.954" (over-all length).
Jus sayin............

Thats very helpful .
I should have just asked that to start with.This is what we have.
Thanks

 

[Charrlie_S]

What nuts are you talking about? I don't see any nuts.
From the pictures I don't see anything wrong.
PS: when you install the shaft, make sure it is installed correctly. The oil holes should point down and towards the valve spring.

 

[Gramps1]

What nuts are you talking about? I don't see any nuts.
From the pictures I don't see anything wrong.
PS: when you install the shaft, make sure it is installed correctly. The oil holes should point down and towards the valve spring.

We took the lock nuts off the "new"rockers.
I guess if the oe isn't supposed to have lock nuts maybe we don't have a problem.
We can get the lash we need its just the adjuster looks way down in the rocker.
Thank you

 

[Charrlie_S]

The factory does not use lock nuts. Just make sure the adjusters are fairly tight, so they don't move on their own. The adjusters are supposed to be an interference fit.

 

[KosmicKuda]

The factory does not use lock nuts. Just make sure the adjusters are fairly tight, so they don't move on their own. The adjusters are supposed to be an interference fit.

Charlie is the man here so I'll defer to him. But isn't 3-4 threads showing below the rocker about normal?
The pushrods appear to be about the right length.
Try it again without the locknuts.

The Chrysler stamped rocker arms were somewhat of an engineering marvel when introduced. The adjusters are an interference fit when everything is right. It is probably not possible that your new rockers are brand new reproductions but rather "renanufactured" originals. Cleaned and reground pads. (Another variation contributing to clearance stack up by the way). So maybe the rocker vendor is covering their butt by providing locknuts to make up for a worn out interference fit. Leave the nuts off for now and check for torque resistance.

With so many unknowns in that engine, you may need a custom pushrod length afterall.

 

[circlepilot]

Yes same push rods different rockers.
We got the rockers from Rocker Arms Unlimited, they look the same as the original.
This was a running engine when we started..The adjusters on the original were adjusted about the same as far as no lock nuts and the adjuster deep in the rocker.
Like I said it was running,but if its a deal where we need different pushrods now is the time.
I'm just not sure they are the problem.
Thanks

You mention locknuts, my 225 (1965) solid lifter engine, has no "lock nuts" on the rocker arms. The adjusters are held in place by friction. Were there rocker arms manufactured with locknuts? I haven't been able to find an example of one.
Norm

 

[Charrlie_S]

Were there rocker arms manufactured with locknuts?

No

 

[Gramps1]

I want to thank everyone for their input.
After hearing all the good advice I've decided it's operator error.
Thanks again

 

[Charrlie_S]

Just remember, no one knows everything (except me ) we all keep learning. Lots of help here. Don't be afraid to ask for help, if in doubt.

 

[RustyRatRod]

Are the pushrods visibility different lengths?
We are looking at a goog 1/2 in of length.
Thanks

I think what you are experiencing is that you have nuts on the adjusters. You're going to need to measure how much tall the nuts are and add that much length to a new sec of custom pushrods, if you're going to keep the nuts. You're probably going to have to, because if those came from Gary at Rocker Arms Unlimited,like you say, the self locking feature on the threads has been removed, so it sounds like you will indeed need longer pushrods.

 

[RustyRatRod]

We took the lock nuts off the "new"rockers.
I guess if the oe isn't supposed to have lock nuts maybe we don't have a problem.
We can get the lash we need its just the adjuster looks way down in the rocker.
Thank you

Careful! Don't "just remove" the locknuts and assume all is well. Normally, when Gary makes that, mod he runs a tap through the rocker and runs the adjusters through a die and removes any self locking function of those threads, so all you have is the locknut that holds the adjusters tight. So inspect that very carefully. If that's the case, you will need longer pushrods. They will need to be longer by however tall those locknuts are. Without the locknuts, those adjusters should be pretty tight. I've never put a torque wrench on them, but I suspect it would take 10-15 LB FT to overcome the self locking feature and turn the adjuster. If they are "much looser" than that, I would get longer pushrods and run the locknuts. IMO, if you're building any kind of performance engine, the locknuts are a good idea anyway.

 

[Gramps1]

Careful! Don't "just remove" the locknuts and assume all is well. Normally, when Gary makes that, mod he runs a tap through the rocker and runs the adjusters through a die and removes any self locking function of those threads, so all you have is the locknut that holds the adjusters tight. So inspect that very carefully. If that's the case, you will need longer pushrods. They will need to be longer by however tall those locknuts are. Without the locknuts, those adjusters should be pretty tight. I've never put a torque wrench on them, but I suspect it would take 10-15 LB FT to overcome the self locking feature and turn the adjuster. If they are "much looser" than that, I would get longer pushrods and run the locknuts. IMO, if you're building any kind of performance engine, the locknuts are a good idea anyway.

I'm just not familiar with a rocker with out a lock nut.
These did come from Rocker Arms Unlimited so thats what the deal is.
On to new push rods.
Thanks for your knowledge and time.

 

[my68barracuda]

Smith Brothers is a reputable shop for custom length pushrods. There are other sellers also
To do it right, you will need a ‘push rod length checker’ basically push rod approximately the correct length with a threaded section in the center for changing the length by screwing it in or out. They are available pre made or if you are handy with a tap, pretty easy to make using one of your existing push rods, use a fine thread bolt.
Where are you in Indiana? I am in Indy.

 

[RustyRatRod]

I'm just not familiar with a rocker with out a lock nut.
These did come from Rocker Arms Unlimited so thats what the deal is.
On to new push rods.
Thanks for your knowledge and time.

I'm not knocking John's suggestion at all. It's a good one, but IMO you don't really need a checking pushrod. I would simply mic one of the locknuts, measure the total length of one of the 225 pushrods and add the lucknut thickness to it.That will get pushrods that will be just right and you'll be using what you have, instead of buying something extra. Make sure to tell whomever you deal with that you are using the TOTAL length and not measuring down into the pushrod cup. That way you'll be on the same page and use the same measurement.

 

[Gramps1]

Smith Brothers is a reputable shop for custom length pushrods. There are other sellers also
To do it right, you will need a ‘push rod length checker’ basically push rod approximately the correct length with a threaded section in the center for changing the length by screwing it in or out. They are available pre made or if you are handy with a tap, pretty easy to make using one of your existing push rods, use a fine thread bolt.
Where are you in Indiana? I am in Indy.

Thanks
We have gotten pushrods from Smith Brothers before.
We are in Anderson,or at least what's left of it.

 

[Gramps1]

I'm not knocking John's suggestion at all. It's a good one, but IMO you don't really need a checking pushrod. I would simply mic one of the locknuts, measure the total length of one of the 225 pushrods and add the lucknut thickness to it.That will get pushrods that will be just right and you'll be using what you have, instead of buying something extra. Make sure to tell whomever you deal with that you are using the TOTAL length and not measuring down into the pushrod cup. That way you'll be on the same page and use the same measurement.

Thats a good idea.
We will get this engine together yet!
Thanks