GM MUSCLE

Hi Guys,
I have a question. I recently removed my intake manifold to check the lifters, due to a ticking sound. I was told that the engine had been gone through before I purchased it 4 years ago. It is really clean inside, but due to my negligence I failed to add the zinc additive I found out I should have been using. I read without this additive it will cause rapid and severe damaged to your cam and lifters. So after three oil changes I developed this tick sound.I think I shot myself in the foot for this mistake. I found all the lifters like brand new except for number three cylinder exhaust lifter had wore out and mushroomed and the cam lobe has a burr on it. Should I replace the cam as well? Then I proceeded to remove the heads seeing I went this far and found the umbrella type valve seals were up on most of the valve stems, not sitting on the head itself. So I started removing the valves starting with number three and It looks like the guides were redone but at the top of the guide it is broken up. I will try to post pictures so you can see what I'm talking about. I hope I remember how to upload the pics..Do I need to send them out for repair? Or just install new seals over them. If the seals did not move upward on the stem, I never would have even seen this. I read on a different thread that this might be normal due to pounding out old valves that are hard to remove and sometimes this happens??? I do not know..I need your advice.....Please help, I'm dying to drive my car after four years of working on it....

MDchanic

Looks to me like that cam is shot, though you caught it fairly early.

Low ZDDP levels could have contributed to that, but if this is a low-mile cam, poor break-in was probably the main culprit.

Those valve guides look like they've been sleeved and re-sleeved - it's actually kind of weird. Usually there are just new guides, either bronze or iron, but these look like they are multiple layers.
Regardless, they look stable to me, and I think they're okay to leave the way they are. In fact, they may have been repaired in the past specifically because of those chips.
I'm interested in hearing what others think of this.

As for the umbrella seals - that's what they do. They sit up a bit high on the stems.

- Eric

GM MUSCLE

Thank you for your input..I appreciate it. So new cam as well huh? OK...

Augie

Magna86

Not sure what would case the guides to break like that but it shouldn't be that way. Yes you want to replace all the lifters and swap that cam out as well. Take the heads to get checked out by a shop and mayeb they will only have to replace those guides.

edzolz

They break like that because the rebuilder had too much interference fit betwen the steel guide and the cast guide in the head. In other words the hole was too small for the part and when they were pressed together, something had to give. This time it was the weaker cast iron. I don't think there would be any problem with the heads.

GM MUSCLE

Thanks for the input..So what do you think? New seals and assemble? It's not like the guides were dropping or anything. Of course new lifters and camshaft are in order.

Augie

67 Cutlass Freak

As others have stated, you should replace the cam and lifters. I had a set of heads come through my shop about a month ago that were doing exactly the same thing. When the new guides were installed, there was too little of material left at the top to be stable. This is why I prefer the stepped full bronze guides. We fixed them with a tool that Summit sells, that cuts the flaking cast iron off. You can still use the umbrella type seals, and they will ride up on the valve. I was worried more chunks would break off and go down into the engine. You should check the valve to guide clearance before you go too far.
Good luck, hope you get to enjoy her soon, Dave - The Freak

GM MUSCLE

Thanks Dave, I appreciate your input, believe me.....

Augie