Cam shaft, Lifts

[Terry, NJ]

Now I'd like it to take a place where we seldom go here on FB. Camshafts! I know very little about cams and it seems to be an art form which not too many master. I bought a reground Mod.A cam (center journal 1.559") at Hershey last year, tis a thing of beauty! But I decided to mike it one day and unless my math was wrong, the lift is only around .265". It was sold to me as a 3/4 race grind. How can that be? I can check it again. I realize that the dwell may have been lengthened with the lower lobe, but it doesn't seem likely. So what have I got? I'm thinking it will run like a lawnmower engine with this shiny hunk of steel.
Terry

[Patrick L.]

What is the diameter of each cam journal [ not bearing journal] ?. Then measure perpendicular.

[ursus]

It might actually be only 0.265 lift! Some Model A and B engines built by aftermarket firms for industrial use have been found with cams ground more for torque than for RPM's. Over the years I have acquired a few Model B engines that had been lightly used in industrial applications, and by lightly used I mean that the bores and crank journals had not been bored or ground beyond STD. The cams had lifts of either 0.307 or 0.315 and appeared to have come that way. This is quite a bit less than the 0.339 that was stock for cams placed in 1932-34 Model B engines placed in motor vehicles by Ford.

[Kurt in NJ]

You can't make a worn cam into an unworn cam by regrinding, to get duration you loose lift

you really need to set it up and use a degree wheel and dial indicater to see what you have

When I ordered a Optima from Summit I saw a degree wheel on sale, summit brand, it also came with adapters to mount on snout of crankshaft that fit A& V8---it was under 25$ and with the battery I got free shipping

Here is a link to marcos site with specs---
http://www.fordgarage.com/pages/camshaftspecs.htm

[Dick Steinkamp]

Originally Posted by Kurt in NJ

You can't make a worn cam into an unworn cam by regrinding, to get duration you loose lift

This seems intuitive, but it is a common misconception. Lift is determined by subtracting the base circle from the high point of the lobe. To get even more lift on a regrind, leave the highest tip of the lobe and make the base circle smaller. The smaller base is taken up by the valve lash adjustment. To get the same lift as stock, you only need to take a little more off the base circle than you take off the high point of the lobe. Adding both lift and duration to a regrind is not only possible, but is often done.

[Big hammer]

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Originally Posted by Terry, NJ

Now I'd like it to take a place where we seldom go here on FB. Camshafts! I know very little about cams and it seems to be an art form which not too many master. I bought a reground Mod.A cam (center journal 1.559") at Hershey last year, tis a thing of beauty! But I decided to mike it one day and unless my math was wrong, the lift is only around .265". It was sold to me as a 3/4 race grind. How can that be? I can check it again. I realize that the dwell may have been lengthened with the lower lobe, but it doesn't seem likely. So what have I got? I'm thinking it will run like a lawnmower engine with this shiny hunk of steel.
Terry

I think a better way to measure would be with a dial indicator. Set the cam in V blocks, adjust indicator to O on the base circle, rotate to lobe high spot and read the lift ! Most like the lobe rising a valve!

[Terry, NJ]

another question, who else besides Bill Stipe copper coats their cams? This thing is copper coated/plated. I've been researching cams and I notice that Bill Stipe copper treats/plates his cams. Also, I was looking closely and I notice that here and there, there are little black spots that look like the bottom of a rust pit. I'm thinking this might be a rusted out stipe with a good center journal, that they decided to clean up on the cam grinder and sell to an unsuspecting person (ME!) Caveat emptor and I forgot to caveat. Next, What are the dimensions/ profile of a real 3/4 race cam and what is meant by "Touring Grind"?
Terry

[Tom Wesenberg]

3/4 race cam is a meaningless term to say you have a cam different from stock.
You really need to know the specs to compare with any other cam.

[Dick Steinkamp]

Originally Posted by Tom Wesenberg

3/4 race cam is a meaningless term to say you have a cam different from stock.
You really need to know the specs to compare with any other cam.

...and the same with the term "Touring Grind".

Here's the specs for some of Stipe's cams...

http://www.fordgarage.com/pages/stipecamshaftspecs.htm

On his web site...

http://www.specialtymotorcams.com/pages/camshafts.html

...he calls both the 330 and 340 "Touring Grinds" (although it looks like his cam nomenclature has changed since the Ford Garage page was published). Other grinders will probably have different specs for what they call Touring and 3/4 grinds.

Note also that since valve lift = overall cam height - base circle diameter - valve clearance, that reducing the valve clearance from .015 to .012 (as Stipe recommends) increases the lift .003. A 20% increase. An old hot rodder trick you can do with your stock cam.

[Bob Johnson]

Dick,
Your statement " A 20% increase." is correct but somewhat misleading. The reduction of the lift due to the valve clearance is increased by 20% (0.003 is 20% of 0.015). But the increase of the overall lift is about 1%.

Bob

[Dick Steinkamp]

Originally Posted by Bob Johnson

Dick,
Your statement " A 20% increase." is correct but somewhat misleading. The reduction of the lift due to the valve clearance is increased by 20% (0.003 is 20% of 0.015). But the increase of the overall lift is about 1%.

Bob

My bad. Thanks for the correction, Bob.

[Jim Brierley]

A touring or performance cam should have more, not less, lift than a stock cam. Most stock B cams had .302" cam lift, later ones had .315" or .339". Not too many of the .339" cams were made. The exception on lift might be for an OHV conversion, they gain valve lift via the rocker-arms.

[Dan McEachern]

To answer the copper plating question- its part of the heat treating process for a cam that is carburized rather than through hardened. The cam blank is copper plated prior to carburizing, the cam lobes and bearing surfaces are roughed in, removing the plating in these areas and then the cam is carburized, hardened and drawn to final hardness. The copper plating acts as a block-off or barrier to the migration of carbon into the surface of the cam during carburizing, thus keeping these areas relatively soft, but allowing the lobes and bearing surfaces to be much harder. Hope this helps.
Dan

[hardtimes]

Originally Posted by Dan McEachern

To answer the copper plating question- its part of the heat treating process for a cam that is carburized rather than through hardened. The cam blank is copper plated prior to carburizing, the cam lobes and bearing surfaces are roughed in, removing the plating in these areas and then the cam is carburized, hardened and drawn to final hardness. The copper plating acts as a block-off or barrier to the migration of carbon into the surface of the cam during carburizing, thus keeping these areas relatively soft, but allowing the lobes and bearing surfaces to be much harder. Hope this helps.
Dan

Hey Dan,
Thanks for this explanation/information !

I've had nos Ford B cams that were copper plated as you describe. Did Ford commonly use this copper process , and if so, did it start in '32 or so ?

[30 Tudor]

Originally Posted by Dan McEachern

To answer the copper plating question- its part of the heat treating process for a cam that is carburized rather than through hardened. The cam blank is copper plated prior to carburizing, the cam lobes and bearing surfaces are roughed in, removing the plating in these areas and then the cam is carburized, hardened and drawn to final hardness. The copper plating acts as a block-off or barrier to the migration of carbon into the surface of the cam during carburizing, thus keeping these areas relatively soft, but allowing the lobes and bearing surfaces to be much harder. Hope this helps.
Dan

Thanks,,
Would that also apply to the two tooth copper plated worm gears?

[johnneilson]

Maybe not so funny, but with all the technological changes these days, making a parts doesn't change. When making new cams from billet stock, I have the blanks copper coated, carburized and then finish ground.
Part of the process is the penetration depth of the hardness and it can be costly to have more than about 1/32".
I am trying out full tool steel as an option, not plating necessary and less steps to take. The jury is still out on this, have looked at a couple broken ones from Top Fuel motors.

J

[Terry, NJ]

Yes Dan, Thanks for the explanation! I thought it might be one manufacturer's signature surface treatment. Now I know it's prevalent throughout the cam making business.
Terry

Originally Posted by Dan McEachern

To answer the copper plating question- its part of the heat treating process for a cam that is carburized rather than through hardened. The cam blank is copper plated prior to carburizing, the cam lobes and bearing surfaces are roughed in, removing the plating in these areas and then the cam is carburized, hardened and drawn to final hardness. The copper plating acts as a block-off or barrier to the migration of carbon into the surface of the cam during carburizing, thus keeping these areas relatively soft, but allowing the lobes and bearing surfaces to be much harder. Hope this helps.
Dan

[updraught]

>>What are the dimensions/ profile of a real 3/4 race cam

http://www.tildentechnologies.com/Cams/Take_34Race.html

[Chuck Sea/Tac]

So when a lift is said to be .330", is that the actual lift the valve gets moved? Minus the lash clearance of course. In other word a cam on a v block with a dial indicator. I ask , ecause none of the cams I've checked this way we're full lift.

[Tom Wesenberg]

Originally Posted by Chuck Sea/Tac

So when a lift is said to be .330", is that the actual lift the valve gets moved? Minus the lash clearance of course. In other word a cam on a v block with a dial indicator. I ask , ecause none of the cams I've checked this way we're full lift.

That should be the actual lift, but I would imagine the sharp pointed tip wears a fair amount on any used cams.
I have an NOS cam that I will remove the cosmoline and check before I install it some day.