Valve stem damage?

[JDSfastGN]

I am in the process of diagnosing my engines issues. After doing a leakdown and finding a hurt number 1 cylinder and a few iffy cylinders I am pulling the motor. But in the process of the leak down I found two damaged valve stems. What would cause this? I run Kmotion K750s at 1.75 installed height with stock rockers on a solid shaft. Could worn rockers cause this? Worn valve guides? I realize the stock rocker assembly isn't ideal for a roller cam with heavy springs but I didn't realize it would cause this. Thanks for the help.

 

[Radke]

By one of the good stems the wear area of the rocker seems extremely close to the edge of the stem. I'd say you need roller tipper rockers and perhaps the rocker geometry checked to ensure a more central valve stem contact

 

[fastblackracing]

What brand valves are those and what type of oil do you use? How many miles on that set-up?

 

[JDSfastGN]

What brand valves are those and what type of oil do you use? How many miles on that set-up?

I'm pretty sure they are Ferrera 1.77/1.50 but they could be Manleys. My dad has 3 Buicks so sometimes its hard to remember what has what haha. Ive had the heads setup this way since 2004 and probably 60-70k. I'm running 5w40 Shell Rotella T6. I have been running this roller cam since 2008-9. I didn't notice any wear when I did valve springs back in September of 13.

 

[JDSfastGN]

By one of the good stems the wear area of the rocker seems extremely close to the edge of the stem. I'd say you need roller tipper rockers and perhaps the rocker geometry checked to ensure a more central valve stem contact

Ill try and take some pictures of the other good valves to show their wear pattern a bit better.

 

[Jerryl]

That sucks. I am sure you'll figure it out as you always do.
Post pics of the rocker contact.
Are you using any additives with the oil?

 

[Nick Micale]

........ Could worn rockers cause this? Worn valve guides? I realize the stock rocker assembly isn't ideal for a roller cam with heavy springs but I didn't realize it would cause this......................

Good questions!

My guess would be both stock rockers and worn guides are issues.

Even on stock heads with stock spring pressure we see lots of guide wear, and usually we have to install bronze guides, always if it is a performance build.

I would also "assume" you are NOT using a light-weight oil with that spring pressure at your RPM which is way above the stock level?

 

[JDSfastGN]

That sucks. I am sure you'll figure it out as you always do.
Post pics of the rocker contact.
Are you using any additives with the oil?

Thanks Jerryl, no additives. Ill post some more pictures when I get home this evening.

Good questions!

My guess would be both stock rockers and worn guides are issues.

Even on stock heads with stock spring pressure we see lots of guide wear, and usually we have to install bronze guides, always if it is a performance build.

I would also "assume" you are NOT using a light-weight oil with that spring pressure at your RPM which is way above the stock level?

These do have bronze guides but obviously 5 years with no refreshing on an engine that only goes out to get run hard might be hard on components haha. I don't consider the Rotella T6 a light weight oil at a 5w40 but I did switch from a 15w40 to the lighter 5w40 a couple years ago. Thanks for the help guys.

 

[PSID6]

I would like to see the rockers. If the case hardness is worn through a metal object it will chew it up. Like Nick said I would have to guess the valve to guide clearance is excessive.

 

[m233roller]

Your valve geometry looks pretty far off to me. That one beat up stem looks like metal fatigue either the rocker or the stem. Who's heads are they and do they have real valve guides in them or just have liners? Knurled liners are notorious for going to hell quick. If they were my heads I'd throw those adjustable push rods away. Just saying !!

 

[Nick Micale]

........... I don't consider the Rotella T6 a light weight oil at a 5w40 but I did switch from a 15w40 to the lighter 5w40 a couple years ago. .......

Rotella is ok for break-in oil, but since it has much more detergent than oil for gasoline, we would never use that in a performance built engine.

My diesel was normally between 2000-2800 RPM, and we are capable of over twice that range and diesel oil does not contain nearly as much anti-foam additive which is also not good, as air will not lubricate as well as oil.

 

[GNTIM]

Stock rockers with a roller cam=fail.

 

[fastblackracing]

With that amount of miles on it Id say you did pretty good running the stock rockers with that kind of spring pressure.

 

[JDSfastGN]

Rotella is ok for break-in oil, but since it has much more detergent than oil for gasoline, we would never use that in a performance built engine.

My diesel was normally between 2000-2800 RPM, and we are capable of over twice that range and diesel oil does not contain nearly as much anti-foam additive which is also not good, as air will not lubricate as well as oil.

Hmmm well I will look into it. All the testing and information I found on Bobistheoilguy forums and LS forums showed it would do well under other conditions than diesels.

Anyway here are some pictures of the rockers. Nothing obvious other than a couple light scuffs.

 

[pacecarta]

you might want to look at the lower rocker in the pic of the two rocker again

that rocker is beat to hell ,those scrapes didnt happen inside an engine , looks like it was used to scrape high spots off a cinder block

 

[JDSfastGN]

you might want to look at the lower rocker in the pic of the two rocker again

that rocker is beat to hell ,those scrapes didnt happen inside an engine , looks like it was used to scrape high spots off a cinder block

I'm not sure how it happened. It looks worse in the picture than it feels. I can barely catch my fingernail on the scratch and to me it doesn't seem like It could have caused the damage, especially considering other valves also show some wear. But I am remembering when I did valve springs I had a broken plastic keeper and I'm pretty sure it was that one. I did not see any wear on the valves though when I did the springs.

 

[pacecarta]

they look real bad zoomed up in the pic and those gouges would have displaced the metal and had high spots at the both edges