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Discussion Starter · #1 ·
A friend bought old chevy drag truck with 355. Man the rocker arms are loud at idle. He be-leaves there's hdy roller lifters in the motor. I adjusted the valves 3 times. O lash to 1/2 to 3/4 turns the valves are still loud. So I pulled the rocker arms and found - Rocker arms rubbing on the retaining rings and springs. The springs are single to, are not double or triple springs like on my motors. Push rod size 7.200. "O" I change the oil there was shavings in the oil. I don't when the motor was built. "O" to when the motor is running along with the rocker arms being loud I could here tap in the motor. What you guys think would cause this.
 

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Some insight to the block and cam?

The rockers do hit the retainers, that is something of an odd event with beehive springs.

The rockers appear to be not self guiding which drags me back to what is block and cam in that is it a factory roller block or not?

How are the rockers being guided if not self guiding then is it using push rod guides and if so whose?

Push rods at 7.2 inches are usually for factory roller cams, aftermarket may be that or something else. In the end the pushrod length is determined by where the roller is contacting the valve stem. In correcting this you might discover the rocker studs are too short, consider that if a longer push rod pushes the nut too high that your running out of thread length than you’ll need to shop for longer studs.

Check the stud bosses for cracks that allow the studs to wander. Head’s that use push rod guides need the longer base screw length on the stud which is .73 to .75 inch not the more typical .5 inch long base thread.

The springs appear to be Howard’s electro polished beehives. The retainer fit these with the standard Chevy 11/32 stem needs to be the Comp 787-16, a common mistake is to run retainers for 8mm stems with beehives which don’t fit on the 11/32 stem and locks properly.

If using push rod guides the push rods must be hardened otherwise with self guiding rockers that or non hardened are fine.

Racing hydraulics, if that’s what’s in there, tend to tick but that doesn’t grind metal off anything as the rockers show.

Bogie
 

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Discussion Starter · #4 · (Edited)
The heads are world DJO 1-37, Rocker arms 1.6 PBM. the push rods has on them 1915 7.200 080 wall. The cam no specs but sound like at 50 duration in the 240's nice thump to it. The motor don't no much about but my friend said it should be a chevy 355 Block info passenger side 14088548 driver side 71, 5 L O, 3 next to a bellhousing bolt , C F D,
 

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A friend bought old chevy drag truck with 355. Man the rocker arms are loud at idle. He be-leaves there's hdy roller lifters in the motor. I adjusted the valves 3 times. O lash to 1/2 to 3/4 turns the valves are still loud. So I pulled the rocker arms and found - Rocker arms rubbing on the retaining rings and springs. The springs are single to, are not double or triple springs like on my motors. Push rod size 7.200. "O" I change the oil there was shavings in the oil. I don't when the motor was built. "O" to when the motor is running along with the rocker arms being loud I could here tap in the motor. What you guys think would cause this.
Can your see the rockers actually contacting or getting very close to the springs? Maybe it was a previous set of bigger springs that did the damage and not these Beehives.
 

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Discussion Starter · #7 ·
Incorrect pushrod length is a definite possibility.
You'd have to do a geometry check to verify pushrod length.

Guideplate alignment could be part of it also.
I have order the push checker can't find the that would fit this motor.
Question base on what I'm seeing some good motor parts. Motor builder would have install the right push rods.
 

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I have order the push checker can't find the that would fit this motor.
Question base on what I'm seeing some good motor parts. Motor builder would have install the right push rods.
The plastic things are trash and I’m glad you trust people so much they wouldn’t make a mistake aside from the mistake your working on trying to figure out.
 

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The plastic checker is really made for sliding shoe rockers which are less particular than rollers. To do roller rockers your into a process of addressing where an instant contact point is sweeping the stem tip. Typically with roller rockers we set up at a thing called mid-lift. Here’s a link to a decent vid on the process:

Bogie
 

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Discussion Starter · #11 ·
Hey thinks, Question the last time I did this was the intake off and and pair if soft springs and blue fake rocker arm. This was about 8 years ago solid roller cam motor. What would be the way do to this with the intake still on the motor. Or do have to pull the intake.
 

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Process is the same, just put the DI on the push rod.
Removing the intake would be easier for sure. It's doable though.
Before you get lost in the weeds, mark the stem with a sharpie and roll it over with the parts you have so you know where your starting from. Check clearances all around while your at it. Then you'll have a better idea of direction you need to go in. Basics first...
 

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Discussion Starter · #13 ·
Some insight to the block and cam?

The rockers do hit the retainers, that is something of an odd event with beehive springs.

The rockers appear to be not self guiding which drags me back to what is block and cam in that is it a factory roller block or not?

How are the rockers being guided if not self guiding then is it using push rod guides and if so whose?

Push rods at 7.2 inches are usually for factory roller cams, aftermarket may be that or something else. In the end the pushrod length is determined by where the roller is contacting the valve stem. In correcting this you might discover the rocker studs are too short, consider that if a longer push rod pushes the nut too high that your running out of thread length than you’ll need to shop for longer studs.

Check the stud bosses for cracks that allow the studs to wander. Head’s that use push rod guides need the longer base screw length on the stud which is .73 to .75 inch not the more typical .5 inch long base thread.

The springs appear to be Howard’s electro polished beehives. The retainer fit these with the standard Chevy 11/32 stem needs to be the Comp 787-16, a common mistake is to run retainers for 8mm stems with beehives which don’t fit on the 11/32 stem and locks properly.

If using push rod guides the push rods must be hardened otherwise with self guiding rockers that or non hardened are fine.

Racing hydraulics, if that’s what’s in there, tend to tick but that doesn’t grind metal off anything as the rockers show.

Bogie
Thanks for the info.
 

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Discussion Starter · #14 ·
Process is the same, just put the DI on the push rod.
Removing the intake would be easier for sure. It's doable though.
Before you get lost in the weeds, mark the stem with a sharpie and roll it over with the parts you have so you know where your starting from. Check clearances all around while your at it. Then you'll have a better idea of direction you need to go in. Basics first...
Funny I am lost in the weeds. thanks again
 

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Lets think about this. The rocker arm travels in an arc. From the midpoint of the arc which theoretically should be in the center of the valve or maybe slightly past center with the valve height at midpoint we have the top arch (short pushrod ) and the bottom arc (long pushrod) and both can put the rocker roller in the same position.

The way I find the best way to solve or understand a problem is to exaggerate the situation and use a sketch. Lets start with a pushrod that is too short (top arc). The roller would be on the very inside (rocker stud side) or completely off the valve. As we slowly increase the pushrod length the rocker roller moves toward the center of the valve and the roller contact area becomes smaller. Very straight forward and the way it should be done.

Now lets assume the pushrod is to long and we are on the other side of the arc (bottom arc) of the rocker arm. Lets assume the pushrod is very long again an exaggeration. The rocker roller will again be on the inside (stud side) of the valve and by shortening the push rod the roller will again move to the center of the valve just as it did when the short rod length was increased. This is the problem.

If we used too long of a pushrod to start with to center the roller and we are on the bottom of the arc the rocker arm will contact the retainer or spring. In this case the rocker arm is close to the valve retainer and as the valve opens it moves closer and cause interference. This is what I think is happening in this case. What we need is a side view of the rocker installed with your pushrod and we may be able to see this.

I speak from experience. If a sketch is wanted I can make one! This is something I have never seen discussed but can be a common mistake. My suggestion is install checking springs and an adjustable pushrod and adjust the pushrod to be very short. Increase the length to stay on the top of the arc to obtain the correct contact patch on the valve.
 
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