Camshaft Choice

I am *sure* Bob knows how cast iron is welded.

Anyway, you first heat it slowly and then weld (and hammer), while it's hot, then let it cool VERY slow on a bed of straws or something (You will need to bring heat into it again, like you did when you first heated it up)

The process with parts as big as a cylinder head would take the best part of the day. The welding part of it would be like 10 minutes.

Jan

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Dear Tom,

Although commonly called 'cast iron' your Jeep's cylinder head is actually made of what is called 'demi-cast STEEL.'

VW cams are made of high-density grey cast iron; break a few and look at the grain structure. It can be brazed but it can NOT be fusion-welded.

Metal-spray is sometimes used to build up a worn cast iron surface but the cost makes it impractical to do so in the case of after-market cam re-grinds, most of which wholesale for twelve to fifteen dollars (ie, the cost of the grinding alone).

This particular thread wound its way down to the fact most re-ground cams do NOT have hardened surfaces and wear at an accelerated rate compared to the good stuff. The reason most re-grinders do not nitride the surface is because they don't bother to remove the cam gear, which is a magnesium alloy (if stock) and which would MELT if subjected to the usual nitriding temps. And yes, the base diameter is normally reduced in the regrinding process. (You can prove this for yourself by simply MEASURING a reground cam.)

But I guess things are done differently in Finland :-)

-Bob Hoover

Stock cams are poor candidates for any high performance re-grinds. Better to start with a cam that has as much "meat" in the right places as possible to start with. The less welding it needs, the better. This means you buy an aftermarket high lift/duration cam as your starting point. At which point the cam gear is bolted on, instead of riveted on.

Add to this the usual benefit of altering cam timing by way of installing an adjustable cam gear, and the stock cam along with it's stock, riveted cam gear, become a poor alternative for a core.

The base circle only needs to be reduced if you are after more lift and don't want to weld material at the tip of the cam lobe. (It would probably wear fast there). Again choosing a high lift aftermarket cam to grind, will help here.

Now, I have not been standing next to a cam when it is being reground, so I cannot tell absolute truths regarding the process. Our race cams are reground by a pro who really doesn't want anyone in his shop noseying around.

My experience stems from a certain low budget race type, where cams have

*wild* durations and lift. (exact details are a well kept secret, more or less) And the durabuility is not high priority. I have used one such race cam on the street for one summer, but I swapped it out again for the next season. It showed no signs of excess wear. It had already been used in a race engine prior to that. (The design was outdated and the cam was shelved, in favor of a new profile design... )

I wouldn't recommend a *welded* and reground cam for an engine where long, troublefree life is required. Then again, anyone even cosidering a cam of that grade should realize he is not building an engine that by nature would last anywhere as long as stock. :D

Just plain reground cam will work ok, and live along life if done right. (as discussed above.. nitrated etc.. ) If the base circle gets very small, the lifter bores will wear faster than normal too. The lifters would come out further from their bores at zero lift, and the sideways load on them from the cam lobes would try to push them back in their bores at an angle, angle greater than stock.

Summa summarum: I think we can conclude that factory made performance cams with large base circles and no grinding would bring most miles and best reliability. A well made regrind works in a pinch, if you stay relatively mild.

For the wildest, special design cams, there is no choice but to regrind, maybe weld. Since nobody "makes" them.

I just can't see why anyone would regrind a cam, to arrive at an exact copy of a commercially available cam. Makes no sense to me. BUY one. Much better. Order one from

if you don't have a local source. Yes they deliver to other countries.

Oh almost forgot: Get new, matching lifters too for the cam. If I'm not mistaken, ac.net cams don't have as good a guarantee if old lifters are used. (accelerated wear very likely, which cannot be helped)

Jan