Diagnosis for scored cam lobe

[LAllison20]

This is the second time I have had issues with my valve train. The first time I has a lash adjuster collapse, thrown follower and destroyed BBR stage 1 regrind.

A couple of weeks ago I noticed a ticking noise coming from somewhere, but I couldnt pinpoint where. It was more noticeable with the hood closed, from underneath the car. Today Greg and I pulled the valve covers because I was going to to a VC swap anyways and I found the same lobe on the stock cam scored up shown in the picture. The scratch is smooth to the touch with skin, but with a fingernail you can feel the scratches. The scratches do not cover the whole circumference of the lobe. We cranked the engine manually and the roller spun freely. We pulled the cam caps and check the roller on the follower. It rolled freely. Im not sure how to tell if the lash adjuster is bad, but it was consistent with the other lash adjusters. So my question is, how or where can this damage come from, and would this cause the tick that I have been hearing? Any input would be appreciated.

 

[BruceH]

If you can feel it with a fingernail it's at least .003" in depth. I hope you figure out what is causing it. Lack of lubrication would be the first thought. The valvetrain gets oil last at start up.

 

[LAllison20]

Is the cam FUBAR?

 

[white05gt]

I wouldn't run it.

 

[JEWC_Motorsports]

A good machine shop can clean it up.

 

[Greg Hazlett]

Hmmm....guess we need to see if anyone local has a passenger side camshaft.

Would taking emory cloth to it hurt it/clean it up without hurting the lobe?

 

[Ampire]

Hmmm....guess we need to see if anyone local has a passenger side camshaft.

Would taking emory cloth to it hurt it/clean it up without hurting the lobe?

Depends how deep it is, don't see how it could make it any worse than it is.

 

[JeremyH]

Thats propable the best/cheapest option replace the that side stock cam, im sure someone in the 757 has one, also probably a good idea to replace the the lash adjuster and follower to rule that out.

 

[Greg Hazlett]

Luke bought new lash adjusters/followers so we will see how that does....but....I don't understand something; Luke uses 5W-20 oil, when we had the lash adjusters out they were tight/tough to move by hand; if it was that hard to move by hand with the 5w-20 oil how hard would it be to move with heavier weight oil since some people say to use heavier oil with a turbo and to quiet the valvetrain?

 

[BruceH]

Luke bought new lash adjusters/followers so we will see how that does....but....I don't understand something; Luke uses 5W-20 oil, when we had the lash adjusters out they were tight/tough to move by hand; if it was that hard to move by hand with the 5w-20 oil how hard would it be to move with heavier weight oil since some people say to use heavier oil with a turbo and to quiet the valvetrain?

The lash adjusters are fairly stiff when first pulled out. After a little oil gets pushed out they loosen up pretty quick.

Edit: What springs are being used?

 

[Greg Hazlett]

Stock springs.

 

[vinnybarber]

Seat pressure

 

[Greg Hazlett]

^^ elaborate please?

 

[vinnybarber]

I had this little gremlin that kept breaking followers. Not enough seat pressure

 

[Greg Hazlett]

What caused that and what can be done to fix it?

 

[Bobby]

stiffer springs.

 

[rcm90]

A spring that dosent have enough seat pressure. Install springs with a higher seat pressure..

stiffer springs.

beat me too it

 

[Greg Hazlett]

I don't understand why stock cams would need stiffer springs.....?

 

[white05gt]

I don't understand why stock cams would need stiffer springs.....?

For starters, how many miles are on this engine? Springs get weaker over time.

 

[Greg Hazlett]

I think around 70-75K; had the BBR stage 1 regrinds in it and were removed when a follower was seized/destroyed that wiped a lobe on the passenger side cam.