Model A cam ground to "B" profile

M

mcgarrett

Well-known member
What will this modification provide? What kind of power difference can I expect? The engine I'm putting it in has all new stainless valves, springs, new hard seats, new adjustable lifters. Anything I need to be aware of before installing it?
 
You can expect mediocre performance from an antique cam grind.
There are lots of modern grinds that are easier on the valve train and give better performance.
 
Pete,
Thanks for your reply. I thought it might give a little bump in performance, but never had any firsthand experience myself.
 
I have two A engines with B cams in them.They both have Brumfield heads too.They go nicely.When I was doing some work on the pickup one year I loaned the engine to a friend while he was doing his engine over.He stuck his Stipe cam in my engine,what a difference.Makes you want to use the B cam for a tent peg after that.Of course he swapped them back when he finished his engine and returned mine,but it was a first hand education.
 
Keith,
I forgot to mention that I am also using a Brumfield head. I'm sure the combination of head and cam will be a noticeable improvement over my current stock setup!
 
I am happy with my Burtz cam. A touring cam is a good choice too. Unless you are going racing and have lots of other modifications to your engine to support it, a racing cam is not a good idea.
 
nkaminar said:
I am happy with my Burtz cam. A touring cam is a good choice too. Unless you are going racing and have lots of other modifications to your engine to support it, a racing cam is not a good idea.
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Neil, do you (-or anyone for that matter) know what the specifications of a 'touring cam' truly are?

In my thoughts, Bill's IB330 cam is what comes to mind simply because it is a torque-style cam. I think most regrinds are just the opposite of what a 'tour' camshaft should be because they increase the lift at the expense of duration which means the engine must be operated at a higher RPM to obtain the same torque reading. We always hear we have a touring engine however I don't really know what the specifications are?
 
Ruth said:
Can you even get a Stipe cam anymore? Or anything else. Their website doesn't even open?
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Your point is definitely valid. Bill & I talk from time to time and in one of our conversations he said he needed to redo some of his fixturing which has him on hold. I guess for the time being, a Burtz camshaft might be another good option.
 
Appreciate all the comments and recommendations, but I'm going to run the B grind cam that came with the engine. No plans to spend more money since I'm on a budget.
 
The Burtz cam is a copy of the Stipe 340. They are good but not cheap @ $400. Too hot of a grind in an otherwise stock engine can actually hurt performance. 'B' cams came in 3 different profiles, the most common one had .302" of lobe lift, next came one with the same duration but had .315" these were followed by one with a little more duration, about 5 degrees, and .339" lobe lift, these are somewhat rare, but make a nice touring cam.
 
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Jim Brierley said:
The Burtz cam is a copy of the Stipe 340. They are good but not cheap @ $400. Too hot of a grind in an otherwise stock engine can actually hurt performance. 'B' cams came in 3 different profiles, the most common one had .302" of lobe lift, next came one with the same duration but had .315" these were followed by one with a little more duration, about 5 degrees, and .339" lobe lift, these are somewhat rare, but make a nice touring cam.
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Thanks for the info, Jim. Where does your cam(s) fit into all of that?
 
Brent, All things about cams can be found here: https://www.tildentechnologies.com/index.html.

A touring cam is one that is designed to have more torque at the lower rpms. The lift will be greater and the duration set for the higher torque at the lower rpms. The picture below is what I mean. These are not Model A cams but the idea is the same.

I am not found of regrinds, for the reasons you gave, and because sometimes the quality is not there.
 

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nkaminar said:
Brent, All things about cams can be found here: https://www.tildentechnologies.com/index.html.

A touring cam is one that is designed to have more torque at the lower rpms. The lift will be greater and the duration set for the higher torque at the lower rpms. The picture below is what I mean. These are not Model A cams but the idea is the same.

I am not found of regrinds, for the reasons you gave, and because sometimes the quality is not there.
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Yeah, what I highlighted in red is the misconception.

About 15-20 years ago we had a discussion here regarding reground camshafts. The issue was when a Model-A/B cam was re-ground, the duration was changed which effectively moved the torque band UP the RPM range, -and not in lower RPM range. For awhile, I was modifying an aluminum timing gear to advance the cam by about 7° to counter this by trying to increase low-end. It might have helped a little but when Bill started his cam program, he changed the centerline and increased duration along with lift which made advancing reground cams obsolete. So again, most reground camshafts that are advertised as Touring cams really aren't IMHO.

And FWIW, I do think that guys like Bill, Jim, Pete, and maybe a couple others can regrind original camshafts with pretty decent quality. You just gotta have the right 'someone' to do it if a regrind is what you want.
 
Touring cam. A cam with a personality that desires to be around other engines with touring cams.
RV cam. (Recreational vehicle) All cams in street driven antique vehicles are recreational.
3/4 cam. One that goes 3/4 of a mile before the engine blows.
Semi cam. One that is only half finished.
Stump puller cam. Obvious.

All terms generally associated with a cam regrind to mean more low rpm range torque (Off idle to 2500 rpm) and better fuel mileage.

To get slightly technical, this is accomplished by:
1 - Increasing lift velocity. (Most important)
2 - Slightly increasing lift.
3 - Decreasing duration.
4 - Decreasing overlap.

There are several other parameters involved also and all of them interact so cam design gets VERY complicated and is usually left to people with pointed hats that stir big iron cauldron's at midnight.
 
Years ago working with VW and Porsche motors I took a VW cam and removed a single lobe
I then refinished and moly coated it
I put it on display as a 3/4 cam with a price tag of about $100

You would not believe how many not in the know tried to purchase it

Truth in advertising it had 3 of 4 lobes

J
 
johnneilson said:
Years ago working with VW and Porsche motors I took a VW cam and removed a single lobe
I then refinished and moly coated it
I put it on display as a 3/4 cam with a price tag of about $100

You would not believe how many not in the know tried to purchase it

Truth in advertising it had 3 of 4 lobes

J
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Giggle.
 
Ruth said:
Thanks for the info, Jim. Where does your cam(s) fit into all of that?
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I have many grinds to choose from. My 'C' grind is a copy of the latest B grind with a few thou taken off the nose (the pointy end) to attain longer lobe life. It makes a really good touring cam, smooth idle and power where you want it with an overdrive, etc. My next step up is a mild Winfield grind, a copy of his SU1R, designed for short-track racing. It has a little lope at idle but pulls really good up to about 3500 RPM. With this cam, stock size valves, mild smoothing of the ports, a single Stromberg 97 and one of my 7:1 heads, it produced 102 HP @ 3600 RPM.

The two fastest and easiest way to get power out of am A/B engine is to raise HP and install a bigger carb.
 
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