depth of camshaft clearancing

[Northof49]

Any idea to what depth I will need to notch an Engle cam to clear I beam rods on an 82mm crank? What's the maximum safe amount I can notch it? It would be a lot less work to simply mark where to notch it, then notch it to the safe maximum then check for ample clearance.
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1958 Karmann Ghia owner

[bugguy1967]

Just mocked up a client's 82 SCAT with VW journal SCAT rods. I only need to remove about 1mm off the four spots on the cam, but will remove about 2mm to be safe. It really depends on what parts you're using. To be safe, you can copy a cast in clearanced cam's depth.
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"A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine"

[vwracerdave]

You need to mock it up and measure. You need at least .040" clearance.
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2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK

[Northof49]

[Northof49]

[chrisflstf]

[Quokka42]

[bugguy1967]

H Beam. Just measured a pre-clearanced casted in cam, and the narrow areas are 4mm smaller than the non-clearanced, so if you didn't have the parts to mock-up, 2mm per relief would be adequate.

The measurements were approx 23mms on the non-clearanced areas, and 19mms on the clearanced areas.

The best way is to mock up though, and remove only what is needed
_________________
"A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine"

[Northof49]

So the pre-clearanced cams have the reliefs cast in ,not machined? Why don't thet make them all on preclearanced blanks then?

I am considering offsetting it in the lathe by the desired clearance and cutting the reliefs that way. That way it's only cut on one side.
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1958 Karmann Ghia owner

[vwracerdave]

[Northof49]

Aha, well said.
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1958 Karmann Ghia owner

[bugguy1967]

Mmm, maybe not. I don't see how it'd cost more for the pre-clearanced blanks. They're less material, and all blanks come from one, or a couple of places. I think companies charge more for them because they can. They COULD be exactly the same price, and the old casting could be eliminated.
_________________
"A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine"

[bugguy1967]

I'll be milling a camshaft possibly this week, because I think my machine shop grinds the cam, which is kind of scary to me because of the heat.

A 3/4" end mill for cutting steel with rounded ends is what I'll use. I have a SCAT cam to use as reference. The oil pump drive lines up with two of the spots that need clearancing. I'ma go reeeeal slow and use a bunch of coolant.
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"A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine"

[neil68]

I've clearanced an Engle FK8 trying to remove as little material as possible. It took several mock-ups...to complete the work.

Since then I've always purchased notched or turned cams. I currently use a Raptor cam that was nicely turned (with proper edge radius) by JPM. Here's a good thread on the subject:

http://ultimateaircooled.com/engines/8629-clearancing-cam.html
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Neil.

Der Kleiner Rennwagens
68 Beetle 2332 cc, 204 WHP
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[jfats808]

I mark the cam areas that need clearancing and hit it with an acorn steel carbide bit. Ive had to remove quite a bit on the last 2110 I did. Even in the back side of the cam collar. My first k8 cam on the 2276 had no clearancing required on the cam. With the web 86c 8 had to do crank and cam. Wait till you have no choice and have to grind the crank c/w throws! That kinda sucks. Even if you have web or another shop preclearance a cam for you and then nitride it, doesnt mean everythings going to fit. Sucks but its the name of the game. Gotta look see.
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2017 48 Trijet DRLA's W125

[mark tucker]

diferent rods and journol sizes and stroke will dictate the amount needed to be removed if any.pauter said it's better to remove it by turning the cam down,it might be I dont realy know,Ive done it both ways.my hyd roller is on a preclearanced blank but will probably need more clearancing for the 3/8 rods&86 stroke. Ill do what it needs. and remember the rod needs to be in the correct location when it is done, not just dangling.

[bugguy1967]

[Northof49]

I took some measurements of my engle cam, and it is between .890 and .910 in diameter between the lobes. According to Don Pauter, minimum turned diameter is 0.800

There isn't a lot of interference between my rod (caps) and the cam on this 82mm crank, but until I remove material and can gain clearance, I have no measurable parameter.
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1958 Karmann Ghia owner

[mark tucker]

my thinking is thicker is stronger....but a flat can easyer to bend than a round...but..Ive never tested it on a clamshaft.

[AlteWagen]