Camgrinder

I can tell those cams were not done by me.

Tell me you didnt put the 225k mile old lifters on the new set of cams?

2V4V

Nope,

They weren't done by you.

Greg

fst951

Dave A,

There are very few forged camshafts! All your Porsche camshafts are castings. That is why they are so brittle and can break if they are dropped. Which camshafts do you think are forged? I would love to see a forged Porsche camshaft. I only know of to tractor camshafts that are forged, but I really can't think of a late model car camshaft that is forged.

Let me know I am curious

"it would fold the quarter panel if I gave it full throttle!"

Camgrinder

Austin Healy, MGA, MGB , Bmc A series, Jaguar, Alfa Romeo, some Ferrari, Model T and A/B Fords are all steel camshafts. Some of these (Jaguar, Alfa Romeo) you can easily identify by a wide forging line on the shaft.
Porsche cams are chill-cast cast iron.
It would have been nice to have steel cams for the 928 4V and 944 4V, The timing sprockets might hold up better.

SharkSkin

My bad... I should have said cast. Sorry about the brain fart. My point was that as manufactured, cams have a very consistent internal structure to the metal, whether cast or machined billet. Welding really louses that up, creating potential weak spots. But you already knew that, right?

fst951

So my question still stands Camgrinder. What recent cars might have I seen with forged camshafts. The only engines I can think of are a couple that I have seen out of John Deere tractors. I have seen many Jaguar cams out of V-12 XJS adn XJ-6 cars and I am pretty darn sure they are cast. I know about forging and how it works and that it gives wider material convergence lines. The line you talk about is actually called a "parting line" in industry. It tends to be narrow in cast materials and wider in forged units. In nicely done materials often it is ground off completely to eliminate potential stress risers.

Do any current production vehicles use forged cams? I have never seen a Porsche with a forged camshaft, but maybe some of there race products did. I would like to know, so if you get a chance drop a line and aside from the British cars you listed, fill us in on others.

Thanks!

Camgrinder

The Jags are absolutely forged. As are the Alfa cams.
Forging camshafts is way too expensive these days. Most domestic hydraulic roller cams are steel. Some are forged, most are castings. The honda VTEC cams are some type of steel.
My guess is the only forged cams made today would be for motorcyles and snowmobiles , small engine stuff.
I have seen some early racing 906 cams that were steel. The type with the fine thread nut in front. I also remember a set of 908 cams that might have been steel.
Have you seen any of the Ford modular V8 cams? Very interesting.

fst951

I have a 2003 Cobra SVT in here right now that blew a oil squirt in the cam gasket on top of the engine. The camshafts appear to be a cast iron. I think that maybe the early V-12 engines were possibly forged, but are you talking about 1989 vintage V-12 XJS as still being forged? I did a few of them and there were no fat parting lines on the camshafts, only narrow.

Yes forging is expensive and it doesn't take surface heat treats as easily as higher carbon castings, but it sure does last in many applications. But now we are talking about dollars and anyone that has looked at a new Porsche must know that they are cutting all sorts of quality corners.

I was told that Ferrari used forged cams up until the mid 1990's. Not having serviced the cylinder heads I cannot confirm this. I am amazed that you even see Alfa cams. I would figure when they need a camshaft, they might as well go to the junk pile!

So do you know about the Ferrari camshafts.

The different metal in the Honda camshafts on the V-Tec engines are a powdered metal substance. Almost as cheap as a casting and almost as strong as a forging. This the the way of the future for quality control, strength, and cost savings for high performance camshafts according to Honda.

Thanks!

Camgrinder

The Jaguar cams are a very nicely done forging. They dont have the big ugly parting line. I did a set last week that needed the barrel of the camshaft undercut. It was awful, no carbide tool would touch it, had to set up and grind it undersize. As for holding up, I have never seen a worn out Jag cam. And I have probably ground a few hundred in the past 13 years.

The Cobra cams have pressed on cam lobes, Ford makes each lobe, heat treats it and slides it onto the shaft. Then a big ball is wedged thru the shaft inducing a press fit. Then the cam is finished ground. (Less than .004" stock removal) Actually I believe Timkin came up with the process for Ford originally. The lobes are hard all the way thru, so regrinding them is easy.


Yes we do Ferrari cams, and Lambos too.

Fastest928

Having been one of the early adapters of welded 928 camshafts, of which TWO sets failed, the second causing me to lose an engine, and was the motivating force into getting me into the 928 marketplace...offering RELIABLE products that work!

Once this happened, I hired a metalurgist to study the welding failure...and after review, they made some comments. Basically, this alloy of German chill cast iron that is used in these camshafts was unweldable/unhardfacable reliably.

I sucked up close to 30K in engine parts, mechanics bills and then realized that no 928 supplier knew how to make high hp engines other than Bob DeVore and Lucky Ekman....DEVEK. They already offered 16v factory fresh camshafts, they knew form first hand experience the issues of welding the two vavle cams. BTW, we have about 5 sets remaining....I should have called them first, but relied on others 928 experts who "confirmed" +100 hp from cam and chip!

BTW, the gain was less than 10 rwhp!

From this experience came our stroker engines and head work....until I understood more about the 928 cams and engines, the best thing to do was increase displacement and match valve airflow through the head. so began our stroker kits and head development efforts....

Heed this warning, if you have a 928 with welded cams, 2 or 4 valve, it is just a matter of time before they fail.

BTW, racing is EASIER on cams then a street car idling! Nose pressures....

I feel for ya Greg!

Regards,
Marc
DEVEK

2V4V

Thanks Marc. One of those stoopid things I've done when I knew better. I was not really surprised that they failed, though the rapidity of the failure was - just over 35K miles. At least it would appear the oil filter and the magnets got the chunks. I haven't been cutting open my oil filters, guess I should go back to that...

I have had the "no dude, racing is sooo much harder" discussion more times than I can count, probably because I argue that much of the time, and for many of the parts, racing is NOT harder - at least not harder than doing 40K miles on the street. So many more variables on the street with much longer abuse times/thermal cycling/maint intervals....

Oh well, picked up a clean set of Euro cams last night from QuickCarl - no more experimenting with stuff that I know will fail.

Thanks to all. I'll post when I contact the purveyor of this stuff later today.

Greg

Camgrinder

Id like to hear the reasoning behind this statement.

Mark Anderson

Just for the record I have a set of Elgin Cams in my race cars which I have been using for over 7 years. Every time I pull the valve covers off they still look like new. Over the years we have done a few sets for others and have never had a set fail but I have heard of a few poeple that did have problems.

Fastest928

Street cams are EXPECTED to last 200,000 plus miles without any perfromance degrading wear......find me a race cam that can offer that level of durability! Testing is done to confirm the durability of the cams, material, heat treating, etc....rarely is any durability testing done on ANY race cams offered by most cam grinders....right? They are "racing parts", with no warranties

I really am not intersted into getting cam grinders into pissing matches.....but, I am willing to dive in to the pool of successful street "welded cam" 928 owners...BUT, only if you/anyone is willing to offer full engine warranties on welded cams for street applications, I am in.

But wait, how many welded street cam folks have 40-60K miles on their welded cams?

My first failure was at around 31,000 miles and the second was more rapid, at around 20K miles. The second failure destroyed my engine.

Who is next?

Marc
DEVEK

Camgrinder

I am not trying to start a pissing match either...
I just think the statement needs to be backed up.

Yes, Racing parts get zero warranty. Some are experimental, some are proven, some are even proven to wear out. Unless someone pays the big bucks and has castings made, (500 sets) we are going to weld.