This is why I did my cam swap *pics*

[SHOman24v]

Take a look at these lobes! yeah they are really bad. These are the exhaust cams from the rear of the motor. Does anyone know why the rear cam is the first to go? I have seen many Junk yard sho's with just a bad exhaust cam... Anyways, I swapped in 4 cams with not pitting at all in my car. Its so much better, here are the pics.

this is what happends when you dont do a valve lash job for 122k mi

 

[Dr. Tweak]

password 530 not accepted...

 

[SHOman24v]

works now

 

[Ishodu]

They don't look good at all. Nice work!

 

[yamahaSHO]

Yeah, you have pitting... but that part of the lobe doesn't really touch anything.... You could have left them in.

 

[somedude_001]

yeah but who wants damaged internals?

 

[SHOman24v]

Yeah, you have pitting... but that part of the lobe doesn't really touch anything.... You could have left them in.

What??? I hope you mean something else, that pitting is what the shim touched for the last like billion times.....

Before i swapped in my cams i flipped my shims, all were good still and had the numbers on them. except the shims that touched those cam lobes.. those were f***ed up....

 

[yamahaSHO]

What??? I hope you mean something else, that pitting is what the shim touched for the last like billion times.....

That is part of the "base circle"... it should not come in contact with the shim if gapped correctly.

 

[SHOman24v]

All i care about is what touches the shim, and i know you wouldnt want that cam in your car... that cam is bad no matter what. the top of the lobe is suppose to touch the shim, and if its pitted, the bearing surface is rough and therefor needs to be replaced

 

[yamahaSHO]

All i care about is what touches the shim, and i know you wouldnt want that cam in your car... that cam is bad no matter what

What I am saying, is that part of the cam(spot where the pitting is) should not touch the shim. That is just they way the thing was made... It may have even been installed looking like that.

 

[SHOman24v]

huh...how did you shim your car? the shims are suppose to come in contact with about 1/4" down from each side of the lobe, as the valve turns it slowly starts to push the valve, then it will reach full lift (at the top of the lobe) then after time the bearing surface on the shim wears causing the top of the lobe to wear out. the base part of the lobe (the larger diameter of the cam), never ever should come in contact with the shim, if it does you are out of spec and will need a smaller shim to get to your specified gap (0.25 - 0.35 exhaust 0.15 - 0.25 intake)

 

[yamahaSHO]

the base part of the lobe (the larger diameter of the cam), never ever should come in contact with the shim, if it does you are out of spec and will need a smaller shim to get to your specified gap (0.25 - 0.35 exhaust 0.15 - 0.25 intake)

Correct... your pitting is on the base circle

 

[SHOman24v]

You do know that is the top of the lobe right??? not the part that doesnt touch the shim ever

 

[yamahaSHO]

When you measure the base circle, you measure the diameter 90 degrees(where your pitting is; 1.3" for stock) from the top and bottom of the lobe. The bottom is what you are refering to. The top is the where you get your lift(the lobe).

If I were at my home computer, I would have some pics to post.

 

[Dr. Tweak]

Um, that part that is pitted is the lobe.

 

[yamahaSHO]

Um, that part that is pitted is the lobe.

In the pic, only one cam shows to be barely pitting where the lobe starts. The top pic is completely on the "base circle" and the bottom is mostly on the "base circle".

 

[SHOman24v]

Um, that part that is pitted is the lobe.

WTF am i posting this wrong, that is the LOBE

 

[yamahaSHO]

Do you know what the base circle is?

 

[Dr. Tweak]

Jason, what are you talking about? Look at the pic. The LOBE, aka the part that touches the shims which opens with valve, that part right there, is pitted. The TIP of the LOBE is PITTED.

 

[yamahaSHO]

Now that I look at it again.... I can see the lobe is pointing straight up... You should have taken the picture at an angle. It almost looks like the base cirlce. My computer screen is dark, I could not see the bottom portion, it almost looks like the lobe was at the bottom.