Yet another Cam Follower Data Point

[Little_Red_Fast]

Just replaced my cam follower after roughly 20k miles with the APR fuel pump. Prior to installing the pump, the follower looked brand new. I drive pretty aggresive in the summer months, but in the winter I am a granny, just to give you an idea of my driving style.

Pics (new on the right, old on the left of course), all the coating is worn off, but its a pretty nice pattern. I will start checking it at 10k miles from now on.

This one focused on the towel, but I used F/18+ to get decent depth of field, which didn't work too well with such a close up...but I will post it anyway:

Cam Surface (not the best I have seen, but still looks good to me):

 

[junker]

Is it worn off the entire bottom surface or just the center? Did you use break-in lube with MoS2 when you installed it last time?

At 27K mostly stock with easy driving and 5k oil changes mine just lost the DLC at the center up to the drain holes. I'm going to swap mine every 20-25k.

P.S.: I didn't know you had an APR pump?!?!:headbang:

 

[Little_Red_Fast]

Its worn off the entire surface. I didnt use any lube the first time, but this time I did in order to reduce initial wear/tear.

I was doing 10k oil changes still...so now I am going down to 5k oil changes. I think I am gonna change from the Castrol Syntec to Amsoil European Blend too.

Heck yeah I have the APR pump! :biggrin: I need more power still though, the itch keeps coming back everytime I upgrade...

 

[itisagoodname]

Can you put a straight edge across it and see if there is a concave shape to it or if its perfectly flat?

 

[Little_Red_Fast]

I can do that to the follower tomorrow morning..too tired right now...

 

[SoNgMaN]

is it fair to assume this aftermarket HPFPs use a slightly longer piston to provide slightly more operation of the fuel pump? thus inflicting this slightly increase of wear on the follower?

 

[Little_Red_Fast]

A long piston wouldnt make sense since the cam lobe and the follower are still the same as stock. This means that they are only allowed to travel so far based on the turning of the cam (as far as the stock HPFP).

A longer stroke would be worthless since neither the cam lobe nor the follower have changed.

If the bore changed though, more fluid would be allowed into the pump per stroke. Even if the pressure of the fluid remains the same (which in the end we know it is not because the tuners, APR REVO etc, have made a special tune that requests higher pressure), this larger bore would produce more force on the follower (Force = Pressure x Area), which in turn is probably the reason that we are seeing faster wear rates (faster because stock pumps still wear out the follower, there is a TSB out for this).

 

[Little_Red_Fast]

Can you put a straight edge across it and see if there is a concave shape to it or if its perfectly flat?

Didnt get a pic of it, but it is so very close to perfectly flat, maybe only 0.1mm or so higher in the middle.

 

[GTIzzle07]

can someone please shoot me a link to instructions on how to check the cam follower, cant find it

 

[andeep]

can someone please shoot me a link to instructions on how to check the cam follower, cant find it

http://forums.vwvortex.com/zerothread?id=3750088

 

[GTIzzle07]

http://forums.vwvortex.com/zerothread?id=3750088

thankyouu

 

[Little_Red_Fast]

I just used this:

http://www.goapr.com/VW/support/fsi_fuelpump_installation.pdf

And checked the cam follower. As for torque specs:

 

[mose6161]

next time check it at 15,000 miles.

you don't want metal to rub on metal, ever. the DLC is meant to wear away, the metal is not.

 

[Little_Red_Fast]

Yeah, took a few mechanical component design classes when I got my degree in engineering...figured that one out...lol

But I will change it more often now, and I am going to start doing oil changes every 5k.

 

[doctorgonzo]

is it fair to assume this aftermarket HPFPs use a slightly longer piston to provide slightly more operation of the fuel pump? thus inflicting this slightly increase of wear on the follower?

No sir. The piston is larger in diameter, so that it pumps more volume with each stroke. The stroke of the piston is exactly the same as stock, because you're not changing the cam lobe profile. The piston diameter is larger so the piston surface area is also larger. If the fuel pressure stays the same, more square inches (SI) of piston surface area equates to higher pressure (pounds per square inch) on the cam lobe, and follower.