Camshaft bearing surface shows dimples.

[4 im here again]

Hi.

My cam bearings on 4.0L SOHC V6 shows spots of sharp dimples. they are like grain of sands that took some bearing out. i feel them with fingernails. they catch. however there is no scoring marks. everything smooth with thumb going around. so surface adhesion to camshaft is working i think. but just want to know where these pecks came from. they are all over the first bearing on driver front. it looks like if the bearing was coated and the coat came off. One thing that interests me is it’s even on a surface that the camshaft didn’t sit on. on the first camshaft bearing, the pack of divot are all over the surface and it’s even on the area that the camshaft didn’t sit on.

where you see the scoring mark is where the camshaft ends so the area on the little bit of the left theres nothing that sits there and even in that area there’s a peck towards the top. This is more apparent on the driver side overall along the other three bearings, they all have some dimples like this. for the passenger side theres just one or two for each bearing or none at all, which is really nice

would like to know if this is a normal condition and if it’s OK to run, I try to sand it with 3000 grit just a little bit but it was hard to do because of sharp edges on the bearing. It would catch the sandpaper.

 

[GriffX]

Looks like pitting - metal to metal contact and ripping parts of the surface out. Oil quality, pressure, viscosity, temperature...... issue. Will get deeper over time, I would use 5w30 non-Ford-spec oil from now on.


5w30 for Ford is almost as thin as 5w20 when hot (hths) to optimize fuel economy.

 

[4 im here again]

what are non ford spec oil? this one uses 5w-30 and ive been using mobil1 full synt.

Should i get thicker oil?

 

[GriffX]

what are non ford spec oil? this one uses 5w-30 and ive been using mobil1 full synt.

Should i get thicker oil?

Normal 5w30 oil has higher HTHS (high temperature high shear) viscosity values compared to 5w30 with Ford approval.
Pitting occurs when the oil film cannot separate the two metal surfaces from each other.
Unfortunately not many oil manufactures gives you the hths values, my rule of thumb is not to get API SN plus oils or avoid ILSAC GF higher than 5. European spec would be A3/B4 (or Mercedes 229.5).

(I had to do a lot of research into this things because a 5w20 Ford approved oil wasn't available in Europe for my GT in 2008, so I had to buy a 5w30 oil for gasoline engines, which was also hard to find)

 

[4 im here again]

whats the reason behind not getting API SN PLUS? i thought they were the standard in motor oil and most of all oil companies have that mark on them as a certification.

 

[GriffX]

whats the reason behind not getting API SN PLUS? i thought they were the standard in motor oil and most of all oil companies have that mark on them as a certification.

SN plus again is optimized for fuel economy, therefore very thin when hot, in your case with already beginning damage I would not take the risk with low viscosity values. The new oils are not focused on wear protection anymore.
Oil is still a lot of alchemy. For my 22 year old Mercedes it is hard to get the right oil these days.

 

[MrBhp]

I would not give it a seconds thought, unless the camshaft is showing some kind of issue.

 

[4 im here again]

ok. ill try to look for thicker viscosity level oil. never seen anything like that before though. thank you all for the input. i hope to finish this build in a few weeks

 

[GriffX]

It is still a 5w30, but with A3/B4 spec, C3 is also ok