cast iron cam - surface treatments other than nitriding?

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ChargerST
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cast iron cam - surface treatments other than nitriding?

Post by ChargerST »

My first post (I've been a lurker so far on this great forum - lots of great advice!)..

Besides nitriding Comp Cams offers several surface treatments for their camshafts such as micropolishing, xtreme surface finish enhancement and MSE (which is relatively new as it was first offered at the end of last year). Is any of these surface treatments beneficial for cast iron cores? Apparently MSE is only offered on LS roller cams and the description for the xtreme surface treatment talks about steel cams - that would potentially only leave micropolishing for cast cams.

Which cam companies/grinders offer similar surface treatments? BBM solid flat tappet cam btw.

thanks
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Re: cast iron cam - surface treatments other than nitriding?

Post by modok »

For old fashoned iron flat tappet cams and lifters polishing to a fine finish is not necessarily a good idea, because they do have to wear-in.

Cryo & temper may do some good.
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Re: cast iron cam - surface treatments other than nitriding?

Post by PackardV8 »

modok wrote: Fri Apr 20, 2018 8:52 pm For old fashoned iron flat tappet cams and lifters polishing to a fine finish is not necessarily a good idea, because they do have to wear-in.
Glen, you must have a reason and experience with this. Wearing in knocks off the high spots. Polishing is wearing in ahead of installation. Can you elaborate?
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Re: cast iron cam - surface treatments other than nitriding?

Post by modok »

You yourself being a bit of a historian :wink: You know how many different combinations have been tried by factories and aftermarket. the different companies keep re-discovering the same stuff. :lol:
I think of other iron on iron interfaces such as machine ways, or piston rings, or gears, or iron in iron plain bearings. The recommended surface finish in most cases is NOT polished, rather ground or machined as TRUE as possible but with an even distribution of both high plateaus as well as an even distribution of low valleys. Old vocabulary would be "you want the pores open" or "don't make too much heat and work hardened it" "a good surface holds oil"
I don't know if it's scientifically correct, but what is meant it more or less makes sense IMO.

Phosphating one or both usually works well. That is.....somewhat the opposite of polishing.
I guess we need to know what polishing is, especially considering iron is a very grainy material.
I think of it as going towards burnishing or forming an oxide layer. Making a glaze. So....why are we always de-glazing cylinders?? It's all the same.
You don't want glazed lifters. They are to form their own glaze as they mate. Rust IS a polishing compound, so avoid that. There is some evidence that the temperatures generated are important but it has a lot to do with the lube involved and oxides being formed. Chase it too far you might find some relationship between lube VS surface finish VS heat (force*speed), but that's getting complex. I have wondered if peening or micro-peening would be good....because that would hold oil and maybe relieve any stresses in the surface from grinding, but on the other hand with the abrasives and coolants being better than ever it's probably better to focus on just grinding it really clean, which you have no control over after the fact.....but makes you value a WELL ground cam all the more.
So what surface condition is most suited to wearing and forming a glaze?? I think we've known all along. But...lemme know if something new is discovered.
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Re: cast iron cam - surface treatments other than nitriding?

Post by kirkwoodken »

Here is some info from CMC. As CamKing says, they provide cores and MAY be able to provide some information on your core. "CMC" may be cast in your core. "CWC" may ALSO be cast in your core but is different company.

http://camshaftmachine.com/wp-content/u ... -01-30.pdf

Just another source of info for the camshaft curious. You will notice some of the duration numbers listed look very familiar. This is where a lot of boxed cams come from. They do not sell to individuals.

"CWC" info here:

http://www.cwctextron.com/history.html
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Re: cast iron cam - surface treatments other than nitriding?

Post by Charliesauto »

ChargerST wrote: Fri Apr 20, 2018 1:30 pm My first post (I've been a lurker so far on this great forum - lots of great advice!)..

Besides nitriding Comp Cams offers several surface treatments for their camshafts such as micropolishing, xtreme surface finish enhancement and MSE (which is relatively new as it was first offered at the end of last year). Is any of these surface treatments beneficial for cast iron cores? Apparently MSE is only offered on LS roller cams and the description for the xtreme surface treatment talks about steel cams - that would potentially only leave micropolishing for cast cams.

Which cam companies/grinders offer similar surface treatments? BBM solid flat tappet cam btw.

thanks
We have built hundreds of flat tappet SBC and SBF race engines and have tried every combination we are aware of.

Nitriding cast iron cams did not work well for us.

If you are moderate spring pressure, < 360 LB open, then standard parkerizing and a decent lifter like a Johnson Hy Lift will serve you well.

If you are over that pressure, up to 400 lb open then having the cast cam micro polished and using a tool steel lifter from Precision Products or Trend will give you satisfactory service.

If going much over 400 lb open, spend the money for a steel core and DLC lifters.

The above pressure recommendations are for SBC cams with standard (1.868") bearing journals. If you go larger bearing and therefore larger base circle , you can get away with more pressure than I stated above.

Also there are variables such as nose radius that come into play. For instance a COMP GRI lobe will not tolerate as much pressure as a profile with a less aggressive nose. Unfortunately, the more aggressive stuff generally needs more pressure.
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Re: cast iron cam - surface treatments other than nitriding?

Post by ChargerST »

Thanks for the input! I don't want to nitride my cam as I don't like the fact that the core becomes softer due to the nitriding process. I thought that tool steel lifters and cast cores don't work well together as the hardness is quite close - micropolishing wouldn't change the hardness.

As for lifters I want to use Howards direct lube AMC lifters (91718)

Thanks!
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Re: cast iron cam - surface treatments other than nitriding?

Post by Dave Koehler »

I was dabbling with coatings a while back. I had a seasoned chrysler customer that was experiencing early cam failures using a factory performance cam in different engines. I think rodders call it the purple stick due to some paint on it.
It had no treatment at all from the factory.
Anyway, we decided to try a Techline coating on it. Problem went away.
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Re: cast iron cam - surface treatments other than nitriding?

Post by Krooser »

Dave...what coating did you use and at what cost?
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Re: cast iron cam - surface treatments other than nitriding?

Post by cknight »

Dave Koehler wrote: Mon Apr 23, 2018 8:25 am I was dabbling with coatings a while back. I had a seasoned chrysler customer that was experiencing early cam failures using a factory performance cam in different engines. I think rodders call it the purple stick due to some paint on it.
It had no treatment at all from the factory.
Anyway, we decided to try a Techline coating on it. Problem went away.
Chrysler opted to not process their factory camshafts with a phosphate type treatment, but instead applied it to the faces of their lifters. Regards, Chase
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Re: cast iron cam - surface treatments other than nitriding?

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Induction hardening.
There is no S on the end of RPM.
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Re: cast iron cam - surface treatments other than nitriding?

Post by modok »

In most cases the camshaft cores are already hardened and pre-ground when the cam grinder guy buys them.

Usually it is best to phosphate the cam but not necessarily the lifter.
But sometimes they do the opposite. Cummins does that, and the flat tappets are truly FLAT, and the cam is slightly crowned and made of ductile iron.
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Re: cast iron cam - surface treatments other than nitriding?

Post by novadude »

Does CMC provide cores to most of the "popular" cam grinding companies, or are there multiple sources for SBC flat tappet cores?
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Re: cast iron cam - surface treatments other than nitriding?

Post by CamKing »

novadude wrote: Mon Apr 23, 2018 9:12 pm Does CMC provide cores to most of the "popular" cam grinding companies, or are there multiple sources for SBC flat tappet cores?
CMC and EPC provide over 99% of the cast iron flat tappet cores to the industry.
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Re: cast iron cam - surface treatments other than nitriding?

Post by ChargerST »

I have a pint of Techline's ceramic coating in the workshop. Might try to coat the lifter bottoms. I assume the coating will eventually wear off but it should get me through break-in.

About the cores: I doubt that CWC has different cast iron cores. From a production standpoint I just doesn't make sense in my opinion meaning that I think all of the cast cores are Proferall ++
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