[Richard/SIA]

Trying to complete an essentially stock SBC 350 truck engine.
Plain old stamped rockers, original pushrods, Summit heads.
Most of the rockers appear well centered at the valve stem but a few are clearly off-center, No, 8 intake visibly moves sideways.
Some do not seem to retain adjustment.
Adjusted carefully, spin engine over, rockers are loose at TDC.
Adjusted them three times and decided I need to figure out the issue.
New cam so need to run it in before trying any sort of running adjustment, which I despise anyway as it's a hot oil mess.
My El Camino 327 will get solid lifters but this is a truck and real PITA to get at once installed so has to be hydraulic.

I used a drill and priming tool before attempting adjustment.
Left bank gets lots of oil out of the rockers but right bank sees very little.
If I have to pull the intake again now is better than later.

Suggestions please.

 

[77 cruiser]

Do the heads have the factory style pushrod guide slots? Or did you use guide plates?

 

[Richard/SIA]

Do the heads have the factory style pushrod guide slots? Or did you use guide plates?

Factory style cast slots so room for correction.

 

[BillK]

Richard,
You say that the heads have factory cast slots but there is room for correction ??? With the factory cast slots there is no room for adjustment. Are you sure your heads do not need guide plates ? Cannot say I have ever seen an aftermarket head that did not need to have guide plates. Either that or the self aligning rockers.

 

[shovelrick]

I was just reading about the SUM-152123 heads, if those are your heads, and it says they need extra machining for guide plates, that would make me think they're OK to run W/O guide plates but I would listen to BillK

 

[BillK]

Its easy to tell. If the pushrod "hole" in the head is round then you need guide plates. If it is a enlongated "slot" that keeps the pushrod from moving then you do not need guideplates.

 

[Richard/SIA]

Just realized there is no post edit button here.
I meant to type, Factory type slots so NO room for correction!
Let me guess, I need different rockers?
It would seem to me that "Self aligning" rockers would force the pushrods against the slot for more friction and heat, correct but unavoidable?

 

[77 cruiser]

If you used self guiding rockers you would have to open the slots so the pushrods wouldn't bind.

 

[BillK]

Richard,
If you have the factory type slots then you are correct, you do not need the self aligning rockers. I just wonder why yours are not aligning properly ?

By the way if you look at the top right of each reply where it says "new" there are three dots. If you click on them you will see the "edit" option

 

[Richard/SIA]

These look like what I replaced as they had cracks starting at the valve contact area.
They were stock with the original heads.
I now have the SUM-152123 heads. Summit cast iron heads.

Least expensive and no chance of roller failure.

For a little more I can get these.

PRW Sportsman rollers.
I do not know what they use for the bearing and this is for a truck so not looking for extra power at the cost of reliability.

Another $50.00 gets these.

Comp Cams Magnum roller.

So what would you use for a one-ton truck engine?
Being a one-ton obviously there is no racing involved, just rebuilding to regain lost stock performance and some hoped for boost in mileage.
It will be my Support Truck for more interesting vehicles including the crazy 327 powered '68 El Camino.

I need to post faster, others answered while I was composing my reply.
Sounds like I may have to pull the heads, that would Stink.

 

[BillK]

If it is just a stock rebuild with a stock camshaft I would stick with the stock type rockers. Only thing is to make sure and get something decent. Some of the "white box" stuff is questionable. I would expect to pay around $65 - $70 for a decent set.

 

[Richard/SIA]

Richard,
If you have the factory type slots then you are correct, you do not need the self aligning rockers. I just wonder why yours are not aligning properly ?

No. 7 Intake is the worst of all. It slides sideways and appears to roll as well.
Cannot be good for valve life and will not hold adjustment.

 

[77 cruiser]

Post some pics of it if you can.

 

[Billdini]

I am glad you mentioned these Summit Heads. Yes they do look like DxxT heads and now on sale for $318 each I picked up two. My wifes 71 Camaro SS needed a valve job and my machinist told me to buy some Darts and not waste my money on 71 heads. I will keep the original for future sale since its a number matching engine but these should put some more HP back in that smog motor.

 

[David Ray]

A lot of misalignment problems ocur on the set guide hole heads when a shop installs screw in rocker studs, and does not bet them installed in the center of the stud holes, or, offset, tilted on the boss, etc. In those cases, the ONLY fix is to find a good head shop and redo the holes and studs, with guide plates under the studs. A good machinist will bet things realigned properly.

 

[Richard/SIA]

Just took another look with fresh eyes.
Most of the rockers are clearly off-center.
Screw in studs came with the heads so should not be the issue.
New rockers and I see nothing to indicate they are off-set in any way for intake/exhaust.
All are marked alike.
I have another set of rockers from my 327 I think I will try a couple of and see if they make any difference.
Correct me if I am wrong, but I thought the rockers were all the same?
I may try moving some around but really do not expect that to be the answer.
May pull the intake so that I may see the whole length of the valve-train, but again I don't expect to find anything major to explain this.
Hoping for a simple answer as I really do not want to pull the heads for modification to use self-aligning rockers.

 

[Rmchevelle]

I wonder if something was cast or machined off center, such as, the pushrod holes. This problem has been seen before with some aftermarket heads.

 

[Richard/SIA]

Solved!
Embarrassing, but solved.
O'Reilly sold me the wrong rockers, too long, BBC?

Once I set one of my old rockers on the head the error was obvious.
First thing next year I'm getting new glasses, should have seen this sooner.

So I could use the 327 rockers as they do not have much wear,
But the pockets are not worn to these push-rods.
New valves probably deserve new rockers too.
So another couple of days delay waiting for the correct parts.

 

[Richard/SIA]

I find this odd.
Summit Roller Tip rockers for $98.00, less than the price of standard stamped parts.
Summit roller rockers.
Just need to verify that they will clear my springs.
Melling or Sealed Power plain stamped are $128.00 and not in stock locally.
I'm only looking at in stock, this build has taken too long already.

Re-use the old push-rods, another $80.00 I just really do not have right now.
This engine was actually pretty low mileage and the ball ends look new.

 

[Ericnova72]

Roller tip in a stock ball pivot style rocker are a waste of time.....the real place rollers need to be is in the pivot....just look at the current rockers on the LS engines and the last 4.3 V6 Chevrolet put out there. Needle bearing pivot with a walking shoe/pad tip.
On a non-full race valvetrain common to what a stock ball pivot rocker can survive in, a roller tip just adds weight and increases the chance of valve float in a mild spring application..
They roller tip is just eye candy to seperate you from more $$$.

You can get full sets of stock rockers from Summit in several brands, all under $80 a set and Summit house brand under $50 a set/16.

If the tips are in good shape, you can re-use the stock pushrods without a problem. Just use a moly assembly lube on the tip going into the new rocker pivot. Moly on the rocker ball pivots also.