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Cam Metallurgy - Before You Weld

new 10/05/02

Well, I went and visited the QC guys today and we analyzed the camshaft assembly components. We used the Metallurgist Pro Analyzer. Results were varied initially so we did approx. 15 sample runs per component until we achieved satisfactory repetitive readings. 100% accuracy would entail taking it to the lab, and Mike Frey would not appreciate me handing his assembly over to them. They would probably hand it back to me in a bottle as a liquid solution, and a comprehensive report of course.

Mat'l analysis of the V8 Composite Camshaft as follows;

Camshaft: Tool L6 - Special Purpose Low Alloy Tool Steel

Sprocket: SAE 3145 - Med-High Carbon Alloy Tool Steel

Cam Lobes: Unable to nail it down with enough confidence to state. It is high chrome, high carbon and fairly hard. The SAE number's provided didn't quite add up.

In a nutshell,

It would be advised to use Stainless 308, 309 or Iconel 308, 309 Wire/Filler for this application. Using regular 7018, 6010 or whatever will draw out most of the carbon from around the weld. This will cause the surrounding area to become unduly brittle. Heat is also crucial, use MIG if possible and let cool to touch between passes. TIG is more than OK but it induces a higher degree of heat at a quicker rate, allow the area to cool to the touch. Follow proper sequence going opposite sides to negate heat build up and pulling. As MIG is "dirtier" ensure critical components are protected from splatter. Done properly, both would be OK IMO. The two critical factors are extracting the carbon in the immediate weld zone and tempering the surrounding area. Some people on this list will already be familiar with this condition if ever they have had an extension tool made. (hex key, tap, drill, etc) Weld any of those onto the end of an extension bar and it will just snap at the first use without the proper media being used as filler.

As I said, this was presented in a nutshell as it can and does go much more specific. I did a reverse confirmation of the specs supplied by cross-referencing with the data of reference data I have on hand. It correlated properly. I hope this helps to address this issue and prompt list input.

A big thanks is owed to Mike Frey by everyone for his display of genuine SHO Trust. Kudo's to him for sending his Cam up to someone he's never even met.

John Hamilton (Hammy)
Ptbo, ON, CAN.

97 ES 105k km 91 Mocha/Mocha 150k km
Turbos Stock
Yoko db's

Many thanks Hammy, Canadians kick butt.



Many thanks for this info! Your timing couldn't have been better. The welder who is going to do my cams was asking about all of this info.

One of the concerns the welder mentioned was the presence of oil in the immediate area of the weld. He was concerned that the carbon content of the oil could contaminate the weld. Do any of you know if this has been a problem? Would a low temp flame as from a propane torch used to heat the weld area to "evaporate" or burn off the oil be advisable?

Also, in regard to the amount of heat, the mechanic was concerned about the sprocket "seals". He worries that the heat will kill them. Any comments about this? I wonder what FPS does to avoid the problem but still ends up with good welds?

Up in the hills in Placerville, CA

I used a non-residue contact cleaner to blow the oil out of the sprocket/cam area when we Loctited the cams.

Paul Nimz
'97 TR

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