How smooth do cam lobes need to be?

[928]

Cut your losses- get some used cams and followers - this guy isn't doing you any favors, the cams will fail prematurly once the hardening is ground through, but they will probably last through the warranty period meanwhile putting metal through the engine.
To answer your original questio- how smooth do they need to be- they need to be as smooth as a crank

 

[Avery4]

Avery4, do you know what machine shop this guy uses? I would be surprised if a good machine shop would try to "clean" the rust off of those cams and then stand behind the work.

For all we know, this guy will dump the cams in a vat of EvapoRust or vinegar over the weekend and hope for the best.

Good luck - I hope this works out in your favor.

Andrew S.

I was thinking the same thing. I don't know the name of the machine shop he is supposedly taking these cams to. We will see how the cams look once I get them back, but even if they look good that doesn't necessarily mean they will work correctly.

 

[Gene K]

Pitting of cams will cause failure eventually. Search "Cummins ISX Camshaft Failures" if you want corroboration.

 

[ZeeOSix]

I have no way to know the maintenance history of this engine, but it does look very clean inside and the cam lobes that weren't rusted appeared to have no visible wear. I think if the engine ran with inadequate lubrication for whatever reason there would be damage to all the cam lobes and likely the cam journals also, at least that has been my experience.

Well, if some of the cam lobes have zero pitting then it's probably not a metallurgy wear issue and/or lack of lubrication issue that caused the pitting. And as you already mentioned, it looks like the cam lobes in perfect condition are the farthest away from where you said you though water could have been forced into the valve train when cleaning/power washed the engine.

 

[HowAboutThis]

Had a K20A3 with 2 lobes pitted at about 60k miles. If they're pitted, I'd replace, personally.

 

[DuckRyder]

Just put new cams in it.

There is nothing you can do to "clean" a cam (other than send it to a reputable place for a regrind).

 

[Cujet]

I hate to tell you this, but that those cams are scrap. Yes, they might hold up for some time, and in fact, could hold up for long enough to lead you to believe that they will be OK. Especially if you choose a more viscous oil. However, as they fail, the hard, ferrous wear particulates will be circulating in your engine, and can create a disaster. Replace those camshafts.

I also suggest you pull the oil pan and inspect carefully.

This is what happened to my rusted cam lobe, it should look exactly like the others:

 

[Yah-Tah-Hey]

What you have there is scrap.

 

[ABN_CBT_ENGR]

I was thinking the same thing. I don't know the name of the machine shop he is supposedly taking these cams to. We will see how the cams look once I get them back, but even if they look good that doesn't necessarily mean they will work correctly.

Just a recommendation, I wouldn't worry as much about how they look but what they ( and the follower/tappet/whatever) actually mic out to be at all critical dimensions. I would also ask for a hardness file to be touched over the face ( if that service is available) to see where that face is relative to design.

That's important because its normally not possible to re-treat hardened steel

 

[Avery4]

Just a recommendation, I wouldn't worry as much about how they look but what they ( and the follower/tappet/whatever) actually mic out to be at all critical dimensions. I would also ask for a hardness file to be touched over the face ( if that service is available) to see where that face is relative to design.

That's important because its normally not possible to re-treat hardened steel

Thank you. I am going to be picking up the cams from his shop tomorrow, I will post pictures of what they look like. I have my doubts about whether he actually took those cams to a machine shop because I would think having those cams reground would cost more than the $150 or less that a used set of cams would cost, but I never had cams reground so I don't know.

 

[ABN_CBT_ENGR]

I have my doubts too because whatever mass/dimension removed has to be compensated for and he aint gonna do that for free.

I think you might get a glass bead and a brushing from a belt sander or stiff wheel at best ( I'm not even seriously expecting that)

I recommend mic'ing them and testing the hardness if possible

 

[Avery4]

I have my doubts too because whatever mass/dimension removed has to be compensated for and he aint gonna do that for free.

I think you might get a glass bead and a brushing from a belt sander or stiff wheel at best ( I'm not even seriously expecting that)

I recommend mic'ing them and testing the hardness if possible

Either that or he may swap those cams for good ones from another engine he has, if any of his engines have good cams that is. I seriously can't believe how difficult he is being about this! If I were the owner of a successful JDM engine shop and a customer had this problem, I would gladly get them a usable set of cams. Even if someone doesn't care about ethics, it is seriously stupid to alienate a customer and risk a verifiable bad review over a $150 set of cams!

I think I will eventually get a satisfactory resolution though, and if I don't he will still lose more than me. If he gives me back unusable cams and refuses to provide usable cams or give me $150 back so I can buy a set of cams, I am going to post the name of his company here and bad reviews on the major review sites with pictures of the cams as well as a picture of the receipt as proof that I bought this engine from him so he can't respond to the review saying that he doesn't know who I am or that he has no record of doing business with me as he has done with a couple other reviews. I hope it doesn't come down to that, but if it does I think he will resolve this issue so he can respond to the review saying that the issue has been resolved since he seems to respond to every bad review.

 

[ABN_CBT_ENGR]

Either that or he may swap those cams for good ones from another engine he has,

I think I will eventually get a satisfactory resolution though, and if I don't he will still lose more than me. If he gives me back unusable cams and refuses to provide usable cams or give me $150 back so I can buy a set of cams, I am going to post the name of his company here and bad reviews on the major review sites with pictures of the cams as well as a picture of the receipt as proof that I bought this engine from him so he can't respond to the review saying that he doesn't know who I am or that he has no record of doing business with me as he has done with a couple other reviews. I hope it doesn't come down to that, but if it does I think he will resolve this issue so he can respond to the review saying that the issue has been resolved since he seems to respond to every bad review.

That would almost worry me more as you would now potentially have 2 different wear patterns.

Lets wait and see

 

[Silver]

I just want to say that if that engine was cranked looking like that it probably would have slowly eaten itself, if not suddenly. So you may have saved your sleazebag engine guy a whole engine warranty claim.

 

[Avery4]

I finally have an update. The cams were supposed to be done Monday, but they weren't actually done until today. It is obvious that he gave me used cams instead of having them cleaned by a machine shop as he said he did because every lobe has a visible wear pattern. If the cams were polished or reground my a machine shop, the wear pattern the lobes had would be gone. My guess is he took the cams out of another engine he has and put those junk cams in, but at least I have cams I can use now. Here is what they look like

 

[RadioMannnn]

I finally have an update. The cams were supposed to be done Monday, but they weren't actually done until today. It is obvious that he gave me used cams instead of having them cleaned by a machine shop as he said he did because every lobe has a visible wear pattern. If the cams were polished or reground my a machine shop, the wear pattern the lobes had would be gone. My guess is he took the cams out of another engine he has and put those junk cams in, but at least I have cams I can use now. Here is what they look like View attachment 27854

Well those look a whole lot better than the old ones.

The old one may have been driven through water in Japan. Maybe.

 

[Avery4]

Well those look a whole lot better than the old ones.

The old one may have been driven through water in Japan. Maybe.

I don't think it was in a flood because the oil doesn't have water in it and it has clearly been in the engine for a while. The cylinder walls also look very good, no signs of rust or unusual wear. The factory honing marks are still present and there are no scratches deep enough to be felt by my fingernail

 

[ABN_CBT_ENGR]

I finally have an update. The cams were supposed to be done Monday, but they weren't actually done until today. It is obvious that he gave me used cams instead of having them cleaned by a machine shop as he said he did because every lobe has a visible wear pattern. If the cams were polished or reground my a machine shop, the wear pattern the lobes had would be gone. My guess is he took the cams out of another engine he has and put those junk cams in, but at least I have cams I can use now. Here is what they look like

I do recommend mic'ing them and see. You cant really say a cam "looks" good

 

[spasm3]

If they just ground the cams down and polished them, they may not last. The surfaces may not have the hardening they had before.

 

[UncleDave]

You are already into the block why put it back together wondering if it will last? If it were my project I'd replace so I wouldnt have to worry about doing it twice.

Guessing you dont own a mic or you'd have mic'd them. If you dont own or it isnt easy to borrow a mic, just spend the money on sticks and move on.

Thanks for sharing with us, hope your project turns out well sir!

UD