some of my TFS Rockers are heavily pitted on bottom

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some of my TFS Rockers are heavily pitted on bottom

Post  4604X4 on March 1st 2017, 10:11 am

I'm doing a cam swap so I have my engine apart, and I noticed some of the TFS roller rockers have a "sand blasted" appearance on the bottom. Not all the finish is gone, just a lot of pitting. And its only only on the rocker arms at #6, 7, and 8. The lifters are a couple of years old but not more than 500 miles.

Also one of the rocker trunnion snap rings had a broken tip (the hole for the snap ring pliers was gone). Other than that the rocker looks fine.

I'll try to get a picture and post it.

Has anyone seen this before.

This is a mild build, 9.5:1 466 with TFS 290 heads, Crane Hyd Roller Cam and Crane hyd roller lifters, Comp Cams (.080) 8.150" pushrods, and TFS 1.73 Roller Rockers.
With a little 150HP nitrous spray on occasion.
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Re: some of my TFS Rockers are heavily pitted on bottom

Post  SandHillsHillbilly on March 1st 2017, 11:29 am

You say pitted on the bottom. Where on the bottom, spring end, trunnion area, pushrod end?

Also have you located the end of the snap ring? Of 6, 7, or 8 which one was the snap ring end broken?

I can't think of anything that would break the end of a snap ring except that it might have been cracked when assembled.

Look inside the valve cover in the area over those rockers. Does it have a similar appearance?

My thoughts are that the end of the snap ring bounced around in the area of the rockers. Everytime it hit a spring it was shot somewhere. It would give the appearance of shot peening the area. I suspect that at times it may have hit the valve cover too.

If you can't find it I suspect it is stuck in one of the drain back holes or may be in the oil pan. I have seen rocker trunnion needle bearings stock in the opening and in the oil pan.
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Pictures of Rocker Arm pitting

Post  4604X4 on March 4th 2017, 5:08 pm

Here's some photos of what I'm talking about.

Top row from right bank, bottom row is left bank.


CLose up of rocker arm from right bank (Cyls 5- Cool


From the left bank (Cyls 1 -4)


Last edited by 4604X4 on March 8th 2017, 12:11 pm; edited 1 time in total (Reason for editing : To add descriptions to photos)
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Re: some of my TFS Rockers are heavily pitted on bottom

Post  69F100 on March 4th 2017, 5:24 pm

Looks like something was flying around from the looks of the rockers they should be signs of on the inside of the valve cover it might have been the ring off of the snap ring.
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Re: some of my TFS Rockers are heavily pitted on bottom

Post  4604X4 on March 5th 2017, 7:27 am

I didn't find anything in the valve cover or on the head when I removed the top end - but it would have been easy to miss.
Everything is cleaned up now. New rocker arm (since I couldn't buy/find the broken snap ring (not sure of size or hardness).

Putting new intake on. I asked on the other 460 forum if I should gasket match the intake to head, and it was suggested by someone who I trust and respect that it is not necessary (and may actually help increase torque to have the mismatch) for street driven. And just gasket match if higher rpm performance is the sole concern. However a second opinion is always nice.

Here's what it looks like.



Same gasket



Last edited by 4604X4 on March 5th 2017, 5:38 pm; edited 1 time in total (Reason for editing : typo)
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Re: some of my TFS Rockers are heavily pitted on bottom

Post  Scott Foxwell on March 5th 2017, 11:16 am

Those look like they could be Scorpions and if so, some time ago Scorpion was having problems with their anodizing. It looks similar to some of their other rockers I've seen where the anodizing was coming off.
Port matching would not be worth the time and effort.

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Re: some of my TFS Rockers are heavily pitted on bottom

Post  gt350hr on March 6th 2017, 12:16 pm

69F100 wrote:Looks like something was flying around from the looks of the rockers they should be signs of on the inside of the valve cover it might have been the ring off of the snap ring.


+1

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Re: some of my TFS Rockers are heavily pitted on bottom

Post  1EFF100 on March 8th 2017, 11:30 am

I worked at a plating shop for several years and from what it looks like in the pics from this side of my monitor, I'd say the anodizing is just flaking off.
Sometimes the parts don't get cleaned well enough prior to plating or maybe a problem with the electrical current during the plating process etc.

If there was a part flying around hitting the rockers hard enough to knock the anodizing off like that, you would think there would be little divots where the anodizing is missing.
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Re: some of my TFS Rockers are heavily pitted on bottom

Post  4604X4 on March 8th 2017, 12:08 pm

Thanks for looking.
Those rockers do have little divots where the marks are. It feels like 80 grit sand paper if you run your finger across the rockers.
Also, the rockers with the marks (divots) are all from the right bank. The left bank has no such marks (lower row in picture above), If it was a manufacturing defect it would be (statistically) odd that I only installed the defective rockers on one bank.

I think the cause was stated correctly earlier as it came from the "end of the snap ring" (that I found missing on one of the rockers) bouncing around. Although it's surprising that so many divots where created by such a small piece. I would have though it would have gone down the oil drain back hole long before making that much of a mess. I never did find that snap ring piece.
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Re: some of my TFS Rockers are heavily pitted on bottom

Post  Scott Foxwell on March 8th 2017, 2:05 pm

4604X4 wrote:Thanks for looking.
Those rockers do have little divots where the marks are. It feels like 80 grit sand paper if you run your finger across the rockers.
Also, the rockers with the marks (divots) are all from the right bank. The left bank has no such marks (lower row in picture above), If it was a manufacturing defect it would be (statistically) odd that I only installed the defective rockers on one bank.

I think the cause was stated correctly earlier as it came from the "end of the snap ring" (that I found missing on one of the rockers) bouncing around. Although it's surprising that so many divots where created by such a small piece. I would have though it would have gone down the oil drain back hole long before making that much of a mess. I never did find that snap ring piece.
There is no way that little teeny piece of a snap ring would continue to fly around inside that valve cover leaving thousands of identical marks on the tops and bottoms of all those different rockers. That doesn't even make sense.

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Re: some of my TFS Rockers are heavily pitted on bottom

Post  4604X4 on March 8th 2017, 2:10 pm

Okay - then I'm stumped. What do you think caused those marks?
- Well you said earlier "poor anodizing" may be the reason. But doesn't it seem odd that it only happened on the right bank?

Anyways, I have inspected and cleaned everything, and the valve covers are back on now.
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Re: some of my TFS Rockers are heavily pitted on bottom

Post  Scott Foxwell on March 8th 2017, 3:47 pm

4604X4 wrote:Okay - then I'm stumped. What do you think caused those marks?
- Well you said earlier "poor anodizing" may be the reason. But doesn't it seem odd that it only happened on the right bank?

Anyways, I have inspected and cleaned everything, and the valve covers are back on now.
I've seen this exact same thing on other Scorpion rockers, that's why I mentioned it. Why on one side and not the other? Can't answer that other than to say rockers are from different batches maybe?
Just notice that almost all the marks are little rectangles, and there are even patterns to some of them somewhat following the stresses or grain structure in the rocker.



I bet if you cut your filter open you'd find a bunch of little blue anno. flakes that didn't look "dented".

Here's a pic of others like yours, but worse.


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