Pedestal mount rocker arms

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Pedestal mount rocker arms

Post  BennyX on September 4th 2015, 1:32 pm

I have a 460 in a jet boat. It is the carbureted 1988 marine/RV engine. Long story short, the rockers that it originally came with, had an oil deflector at the top and a number "7" stamped in them. The only stock rocker replacement I can find it a Sealed Power R855. They don't have an oil deflector and they seize and bend the pushrods. Comp cams has a listing for the correct rockers that can withstand jetboat operation:
Part number 1232-1

But I ordered those and when they arrived they were the same as the Sealed Power R855


Does anyone know where I can get the compcams 1232-1 style? I'm open to used as well. Spent some time at the local junkyard and couldn't find anything.

Thanks

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Re: Pedestal mount rocker arms

Post  rmcomprandy on September 4th 2015, 3:07 pm

BennyX wrote:I have a 460 in a jet boat. It is the carbureted 1988 marine/RV engine. Long story short, the rockers that it originally came with, had an oil deflector at the top and a number "7" stamped in them. The only stock rocker replacement I can find it a Sealed Power R855. They don't have an oil deflector and they seize and bend the pushrods. Comp cams has a listing for the correct rockers that can withstand jetboat operation:
Part number 1232-1

But I ordered those and when they arrived they were the same as the Sealed Power R855


Does anyone know where I can get the compcams 1232-1 style? I'm open to used as well. Spent some time at the local junkyard and couldn't find anything.

Thanks

Those two rocker arm numbers ARE the same and ARE replacements for a "pedestal mount" 351M/400, 351 Cleveland and 460 engines.

Something is not right here so, have you got a photo of the valve train area of the cylinder head...?

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Re: Pedestal mount rocker arms

Post  dfree383 on September 4th 2015, 3:57 pm

How long did the stock ones last? What did you change in the engine?
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Re: Pedestal mount rocker arms

Post  BennyX on September 4th 2015, 4:55 pm

New to the forum so all kinds of f*^#ing restrictions. Can't post links, can't post pictures.

Clarification: the stock rockers are the ones with the oil deflector above the oil hole and the number "7" stamped into them. They have been great and none of them have failed due to seizure. I didn't install the intake manifold correctly, got water into the cylinders on one side of the engine, bent push rods, valves and broke rockers. I replaced the valves and pushrods and replaced the rockers that had broken with the Sealed Power R855. If you look closely, they have a smaller oil hole, no deflector, and no hole on the bottom half of the rocker. I explored the possibility of something else being bent by switching the R855's that break with one of the original rockers. The R855's fail so consistently that I can predict the point on the river that they will break. The rockers with the 7 stamped in them have never failed (other than than the hydro lock), regardless of which valves I switch them to.

Thanks in advance for your help.

Ben

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Re: Pedestal mount rocker arms

Post  BennyX on September 4th 2015, 5:00 pm

I just googled the two part numbers to see what you were seeing, and the JEGS link for compcams 1232-1 incorrectly shows the identical R855 style. If you select the Amazon link for compcams 1232-1 or the compcams link, the differences should be apparent.

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Re: Pedestal mount rocker arms

Post  rmcomprandy on September 4th 2015, 5:18 pm

BennyX wrote:I just googled the two part numbers to see what you were seeing, and the JEGS link for compcams 1232-1 incorrectly shows the identical R855 style. If you select the Amazon link for compcams 1232-1 or the compcams link, the differences should be apparent.

The JEG'S link shows a CHEVROLET rocker arm which is a stud mount not a pedestal mount.

The Amazon link for the R855 Sealed Power rocker arm, (Summit, also), shows a later Ford rocker arm with NO oil deflector.  Those later rockers used a sheet metal deflector under the bolt when the deflector was not part of the valve cover.

Though the Summit photos look more like 302/351 Windsor rocker arms.

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Re: Pedestal mount rocker arms

Post  BennyX on September 4th 2015, 5:53 pm

Google: Sealed Power R855
Click on the summit racing link. These have no oil deflector and they are failing.

Google: compcams 1232-1
Click on the comp cams link. They are the style with the deflector that doesn't fail

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Re: Pedestal mount rocker arms

Post  BennyX on September 4th 2015, 5:56 pm

I am aware of the deflector that sits under the bolt. I found some deflectors on an old Lincoln and added them to the R855 style rockers. They definitely last longer with the deflector, but they still fail.

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Re: Pedestal mount rocker arms

Post  supervel45 on September 4th 2015, 6:01 pm

How much preload are you running on the lifters?

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Re: Pedestal mount rocker arms

Post  BennyX on September 4th 2015, 6:04 pm

They are non-adjustable so I am following torque spec which I believe is 28ft-lbs.

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Preload

Post  DanE on September 4th 2015, 6:52 pm

Do a search on what "preload" means.

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Re: Pedestal mount rocker arms

Post  supervel45 on September 4th 2015, 6:57 pm

I know they are torque to spec. but they make shim kits for them, to adjust preload. You have changed rocker arms push rods and maybe other tolerances when the valves were replaced, that may have changed the preload, is why I was asking.

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Re: Pedestal mount rocker arms

Post  supervel45 on September 4th 2015, 7:42 pm


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Re: Pedestal mount rocker arms

Post  rmcomprandy on September 4th 2015, 10:40 pm

BennyX wrote:They are non-adjustable so I am following torque spec which I believe is 28ft-lbs.

18 - 20 foot pounds is correct for that 5/16-18 bolt ... are your new pushrods the same length as the other ones...?

There is a dimension in your valve train which is probably not correct.
I have NEVER had any trouble with breakage of those rocker arms with using over .600" valve lift and 350 pounds of open valve spring force.
I have conservatively used a 1,000 of those rocker arms.

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Re: Pedestal mount rocker arms

Post  dfree383 on September 4th 2015, 11:41 pm

Are you floating or loosing control of the valves?

That will wreck things too.

Springs old?
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Re: Pedestal mount rocker arms

Post  DaveMcLain on September 5th 2015, 7:56 am

I have a jet boat customer who's running those stock rockers with a hydraulic roller that has about .600 lift, double springs, 140/330lbs with no problems and that engine has been running for years with no failures. What are your rockers doing when they fail?


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Re: Pedestal mount rocker arms

Post  BennyX on September 18th 2015, 5:10 am

Know what would be cool? If this fucking POS forum let me post pics above 0MB

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Re: Pedestal mount rocker arms

Post  maverick on September 18th 2015, 8:35 am

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^And that, friends, is how a newb can endear himself to the moderators. Laughing
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Re: Pedestal mount rocker arms

Post  supervel45 on September 18th 2015, 9:08 am

He's might have gotten used to YB? Wink It would be nice, Photo Bucket is a pain. I don't care either way I don't attempt to load photos much anyway. Rolling Eyes

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