The Ford Barn

Waorani · 05-09-2023, 02:51 PM

The cam lobes in my '31 are pitted and I need to replace. I can find reground cams but the idea of a new cam is appealing. Snyder's/etc list new cams and I'm on waiting lists but they haven't been in stock for at least a couple of years now. I notice the new Burtz cam is available but I'm new to Model As so wondering what the thoughts are on using one of those?

Pete · 05-09-2023, 03:26 PM

Depending on how bad the pitting is and the journal wear, you might be able to just have yours reground.

jgriffin · 05-09-2023, 03:39 PM

I am new as well but can someone explain a "reground camshaft"? I am assuming to get proper lift that there has to be some welding or adding of material, then it gets ground down to desired specifications...

Y-Blockhead · 05-09-2023, 04:10 PM

Jim Brierley (on Ford Barn) sells cams.

Big hammer · 05-09-2023, 04:26 PM

Quote:

Originally Posted by jgriffin

I am new as well but can someone explain a "reground camshaft"? I am assuming to get proper lift that there has to be some welding or adding of material, then it gets ground down to desired specifications...

The cam can be ground to give original lift, basically they grind the base circle and the lobe so the total lift can stay the same

Werner · 05-09-2023, 04:59 PM

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The overall diameter is a few hundredths smaller, but the control times and angles remain the same.

Waorani · 05-09-2023, 06:23 PM

I understand the basics of cam lobes and the basics of regrinding to maintain relative geometry. And they've been regrinding cams for just about as long as they've been making them so obviously it works. But I also struggle with idea that you are removing material so I don't see how you can possibly get the same lift or clearance with solid lifters/non-adjustable valve train as on the Model A. So either I'm overthinking, it doesn't matter, or I'm missing something fundamental.

My original cam lobes don't meet minimum specs listed by Snyder for regrind. I've got another cam out of an engine I recently picked up that is in spec so I can have it reground. As I said though, I like the idea of a new cam if of quality and available. I only plan to go into this engine once and want to put the best in it. Realistically however, it probably won't get but a couple thousand miles on it during my lifetime so maybe I need to get out of that mindset with the Model A stuff.

J Franklin · 05-09-2023, 06:45 PM

A good machine shop could make you a cam. The why the reground cam works is that they don't diminish the bearings and the valves are adjustable.

Waorani · 05-09-2023, 07:04 PM

Quote:

Originally Posted by Y-Blockhead

Jim Brierley (on Ford Barn) sells cams.

Thanks, I'll try to get up with him.

johnneilson · 05-09-2023, 07:09 PM

Quote:

Originally Posted by Waorani

I understand the basics of cam lobes and the basics of regrinding to maintain relative geometry. And they've been regrinding cams for just about as long as they've been making them so obviously it works. But I also struggle with idea that you are removing material so I don't see how you can possibly get the same lift or clearance with solid lifters/non-adjustable valve train as on the Model A. So either I'm overthinking, it doesn't matter, or I'm missing something fundamental.

My original cam lobes don't meet minimum specs listed by Snyder for regrind. I've got another cam out of an engine I recently picked up that is in spec so I can have it reground. As I said though, I like the idea of a new cam if of quality and available. I only plan to go into this engine once and want to put the best in it. Realistically however, it probably won't get but a couple thousand miles on it during my lifetime so maybe I need to get out of that mindset with the Model A stuff.

Your assumption is correct, to a certain point.
Typically, you would regrind or replace the cam and the lifters as a set.
The lifters could be replaced with adjustable ones, so that makes up the amount of material ground off of a regrind.

Typically a reground cam is done to increase duration/lift and performance.

New camshafts are expensive compared to just a regrind.
The Burtz cams are Cast material and heat treated, I hear that they respond very well to a regrind.
New billet ones are expensive, Stipe made some, a good value if not looking for full racing cam. (Larger bearings and much longer duration)

The center main bearing wears and causes issues and this is the specification folks use for judging cores.

John

BRENT in 10-uh-C · 05-10-2023, 05:43 AM

Quote:

Originally Posted by johnneilson

Your assumption is correct, to a certain point.

Typically a reground cam is done to increase duration/lift and performance.

John

One thing that was a hot discussion here about 20-25 years ago was that during a re-grind, you either get more valve lift however you lost valve duration time, -or visa-versa. The base circle must be reduced on the cam to increase the lift during a re-grind however at the expense of losing the time the valve is actually open. With a siamesed port, the velocity and reversion is affected, ...especially with the firing order of the Model-A/B engine where #2 and #3 cylinders are following #1 and #4.

As I recall from the discussions back then, what the various dyno results were showing was the torque band was pushed higher in the engine's RPM range when the base circle was ground smaller in diameter. Depending on your driving style and/or your vehicle's gearing ratios, having the torque band moved upward was a detriment since with overdrive transmissions and lower rear end gear ratios were being used in so-called 'Touring' engines that need power at a lower RPM to be able to pull the vehicle along without constant downshifting. In other words, it was more engine torque that was needed rather than higher-RPM horsepower when touring with overdrives and low gear ratios. This in a nutshell was why Bill came up with the new IB330 camshaft and why it became so popular over the less expensive regrinds. Again, it is all in what you want I suppose.

nkaminar · 05-10-2023, 07:18 AM

I have the Burtz camshaft and I am happy with it. It pulls good from low rpm and still pulls good at the higher rpm. A race cam is not a good idea for Model A's unless you are building a full race engine with all the extra stuff and modifications that implies. I touring cam is the right cam for most Model A's. I am not found of regrinds because you cannot get both the duration and lift you want.

Phil Brown · 05-10-2023, 10:26 AM

As far as your original question about using a Burtz cam I would not be afraid to try one given the overall good reports about their parts.
Also never heard about anyone not being happy with one of Jims cam's

Jim Brierley · 05-10-2023, 12:01 PM

An original cam can easily be ground to almost any spec. To do so the cam is mounted in a special machine using the center-line of the cam to hold the cam. (note the small hole in each end of a stock cam) A cam grinding machine is similar to a crank grinding machine but the eccentricity is controlled by a 'master cam'. Most of the grinding is done on the base of the cam, so picture this; you grind off the base (not the nose witch is the fully open part of the lobe), you then adjust the lifter to make it longer and to the proper clearance. Now because the nose has not been ground, the lift is greater by the amount that you extended the lifter. The master lobe usually has greater lift and duration than stock. The only downside is the cam becomes weaker, not a problem in mild cams like touring grinds, in performance cams the racer often adds supports between the original bearings, making it a 5 bearing cam. I have run performance, reground, cams with over 300 degrees of duration and with a lobe lift of .430". A stock A cam has about 240 degrees and .302" of lobe lift. Stock valve spring pressure is 40 lbs., racing cams often have 140 lbs. or more, and when multiplied by the rocker arm ratio on an OHV engine, that is a lot of pressure, but is needed to attain 6,000 or 7,000 RPMs in racing.

Jim Brierley · 05-10-2023, 12:03 PM

I have reground a few Burtz cams, and they are of good material, suitable for either a flathead or OHV engine.

Quote:

Originally Posted by Waorani

The cam lobes in my '31 are pitted and I need to replace. I can find reground cams but the idea of a new cam is appealing. Snyder's/etc list new cams and I'm on waiting lists but they haven't been in stock for at least a couple of years now. I notice the new Burtz cam is available but I'm new to Model As so wondering what the thoughts are on using one of those?

Waorani · 05-10-2023, 02:22 PM

Thanks Jim for your explanation and response to my PM. I think I'm going to go with the Burtz cam.

And thanks all for the responses. I've learned a lot!

Pete · 05-10-2023, 04:47 PM

As with previous discussions on camshaft grinding, there is still some marginal information floating around. This nothing new. I noted it when I first got in the cam grinding and design business 71 years ago.

I recommend, for a basically stock "touring" engine, a 77B. It will idle SMOOTH at 400 rpm and still give improved low end "off idle" torque with NO other mods.
Find someone who has one and drive the car. That is the still best way to evaluate ANY cam.

Another thing no one has mentioned. With ANY new or REGROUND cam, it is imperative that new or refaced lifters be installed. In the case of a regrind, the lifters will have to be adjustable or the valve stems welded up for adjustment.

Waorani · 05-10-2023, 06:33 PM

Quote:

Originally Posted by Pete

Another thing no one has mentioned. With ANY new or REGROUND cam, it is imperative that new or refaced lifters be installed. In the case of a regrind, the lifters will have to be adjustable or the valve stems welded up for adjustment.

That makes sense and gets to my basic mental block with the idea of regrinding a cam to "stock."

I've ordered a Burtz cam so my OCD can take a break!

johnneilson · 05-10-2023, 09:12 PM

Quote:

Originally Posted by BRENT in 10-uh-C

One thing that was a hot discussion here about 20-25 years ago was that during a re-grind, you either get more valve lift however you lost valve duration time, -or visa-versa. The base circle must be reduced on the cam to increase the lift during a re-grind however at the expense of losing the time the valve is actually open. With a siamesed port, the velocity and reversion is affected, ...especially with the firing order of the Model-A/B engine where #2 and #3 cylinders are following #1 and #4.

As I recall from the discussions back then, what the various dyno results were showing was the torque band was pushed higher in the engine's RPM range when the base circle was ground smaller in diameter. Depending on your driving style and/or your vehicle's gearing ratios, having the torque band moved upward was a detriment since with overdrive transmissions and lower rear end gear ratios were being used in so-called 'Touring' engines that need power at a lower RPM to be able to pull the vehicle along without constant downshifting. In other words, it was more engine torque that was needed rather than higher-RPM horsepower when touring with overdrives and low gear ratios. This in a nutshell was why Bill came up with the new IB330 camshaft and why it became so popular over the less expensive regrinds. Again, it is all in what you want I suppose.

Brent,
I agree, it is all in what the owner wants, from cost to usage.
You have to agree that just adding a cam to a stock engine really does not make much difference. It is the combination of cam, carb, compression and exhaust that makes up the performance increase.
In reference to the regrinding of cams and specifically the base circles, is only partially true. If the cam profile is the same as a stock cam, you will not lose duration. The Winfield profiles did increase the lift by taking the base circle smaller but also increased the duration marginally. The profile of the lobe and specifically the open/close ramps will make more of a difference in performance than anything else. (valve open time under the curve)
I was looking at the stock Model "A" cam drawing today while setting up the gear cutter to do the drive on some blanks, it would take a lot of welding on a stock cam to get the profile up to a performance piece.

I will not even go into the Siamese port problems, only to say that by changing the crankshaft to 360 deg between 1&2 will address it.

The truth is in the eye of the beholder, if satisfied, who can argue?

John

BTW, Bill set a very high bar for others to follow, much respect from here.

Pete · 05-10-2023, 09:41 PM

And still another thing many people fail to address is the cam journal bores are almost ALWAYS worn beyond specs for a stock replacement cam.
The easiest fix for this is order a replacement cam with custom size journals and have the block align bored to fit.
The next step up would be to sleeve the journal bores back to standard and use a standard cam.
The next step up would be to bore the cam journal holes for insert bearings like modern blocks.
The next step up would be for racing and has been discussed elsewhere.

While checking various things in the block, be sure to check the cam LIFTER bores for wear. These are very important to a proper running rebuild.

05-09-2023, 04:59 PM	#6
Werner Senior Member Join Date: Jan 2019 Location: Germany, near Aachen Posts: 1,153	Re: Thoughts on new camshaft? Sponsored Links (Register now to hide all advertisements) The overall diameter is a few hundredths smaller, but the control times and angles remain the same. __________________ Beste Gruesse aus Deutschland, Werner Ford Model A, Roadster, 1928 Citroen 11 CV, 1947 Hercules W 2000, 1976; (with NSU-Wankel Rotary Engine), Canadian version

05-09-2023, 06:23 PM	#7
Waorani Member Join Date: May 2023 Location: Opelika, AL Posts: 43	Re: Thoughts on new camshaft? I understand the basics of cam lobes and the basics of regrinding to maintain relative geometry. And they've been regrinding cams for just about as long as they've been making them so obviously it works. But I also struggle with idea that you are removing material so I don't see how you can possibly get the same lift or clearance with solid lifters/non-adjustable valve train as on the Model A. So either I'm overthinking, it doesn't matter, or I'm missing something fundamental. My original cam lobes don't meet minimum specs listed by Snyder for regrind. I've got another cam out of an engine I recently picked up that is in spec so I can have it reground. As I said though, I like the idea of a new cam if of quality and available. I only plan to go into this engine once and want to put the best in it. Realistically however, it probably won't get but a couple thousand miles on it during my lifetime so maybe I need to get out of that mindset with the Model A stuff.

05-09-2023, 06:45 PM	#8
J Franklin Senior Member Join Date: May 2010 Location: Oregon Posts: 5,959	Re: Thoughts on new camshaft? A good machine shop could make you a cam. The why the reground cam works is that they don't diminish the bearings and the valves are adjustable.

05-10-2023, 07:18 AM	#12
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,899	Re: Thoughts on new camshaft? I have the Burtz camshaft and I am happy with it. It pulls good from low rpm and still pulls good at the higher rpm. A race cam is not a good idea for Model A's unless you are building a full race engine with all the extra stuff and modifications that implies. I touring cam is the right cam for most Model A's. I am not found of regrinds because you cannot get both the duration and lift you want. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

05-10-2023, 10:26 AM	#13
Phil Brown Senior Member Join Date: May 2010 Location: Santee Calif. Posts: 507	Re: Thoughts on new camshaft? As far as your original question about using a Burtz cam I would not be afraid to try one given the overall good reports about their parts. Also never heard about anyone not being happy with one of Jims cam's

05-09-2023, 02:51 PM	#1
Waorani Member Join Date: May 2023 Location: Opelika, AL Posts: 43	Thoughts on new camshaft? The cam lobes in my '31 are pitted and I need to replace. I can find reground cams but the idea of a new cam is appealing. Snyder's/etc list new cams and I'm on waiting lists but they haven't been in stock for at least a couple of years now. I notice the new Burtz cam is available but I'm new to Model As so wondering what the thoughts are on using one of those?

05-09-2023, 03:26 PM	#2
Pete Senior Member Join Date: May 2010 Location: Wa. Posts: 5,407	Re: Thoughts on new camshaft? Depending on how bad the pitting is and the journal wear, you might be able to just have yours reground.

05-09-2023, 03:39 PM	#3
jgriffin Junior Member Join Date: Jan 2023 Location: North Idaho Posts: 28	Re: Thoughts on new camshaft? I am new as well but can someone explain a "reground camshaft"? I am assuming to get proper lift that there has to be some welding or adding of material, then it gets ground down to desired specifications...

05-09-2023, 04:10 PM	#4
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 5,848	Re: Thoughts on new camshaft? Jim Brierley (on Ford Barn) sells cams.

05-10-2023, 12:01 PM	#14
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,085	Re: Thoughts on new camshaft? An original cam can easily be ground to almost any spec. To do so the cam is mounted in a special machine using the center-line of the cam to hold the cam. (note the small hole in each end of a stock cam) A cam grinding machine is similar to a crank grinding machine but the eccentricity is controlled by a 'master cam'. Most of the grinding is done on the base of the cam, so picture this; you grind off the base (not the nose witch is the fully open part of the lobe), you then adjust the lifter to make it longer and to the proper clearance. Now because the nose has not been ground, the lift is greater by the amount that you extended the lifter. The master lobe usually has greater lift and duration than stock. The only downside is the cam becomes weaker, not a problem in mild cams like touring grinds, in performance cams the racer often adds supports between the original bearings, making it a 5 bearing cam. I have run performance, reground, cams with over 300 degrees of duration and with a lobe lift of .430". A stock A cam has about 240 degrees and .302" of lobe lift. Stock valve spring pressure is 40 lbs., racing cams often have 140 lbs. or more, and when multiplied by the rocker arm ratio on an OHV engine, that is a lot of pressure, but is needed to attain 6,000 or 7,000 RPMs in racing.

05-10-2023, 02:22 PM	#16
Waorani Member Join Date: May 2023 Location: Opelika, AL Posts: 43	Re: Thoughts on new camshaft? Thanks Jim for your explanation and response to my PM. I think I'm going to go with the Burtz cam. And thanks all for the responses. I've learned a lot!

05-10-2023, 04:47 PM	#17
Pete Senior Member Join Date: May 2010 Location: Wa. Posts: 5,407	Re: Thoughts on new camshaft? As with previous discussions on camshaft grinding, there is still some marginal information floating around. This nothing new. I noted it when I first got in the cam grinding and design business 71 years ago. I recommend, for a basically stock "touring" engine, a 77B. It will idle SMOOTH at 400 rpm and still give improved low end "off idle" torque with NO other mods. Find someone who has one and drive the car. That is the still best way to evaluate ANY cam. Another thing no one has mentioned. With ANY new or REGROUND cam, it is imperative that new or refaced lifters be installed. In the case of a regrind, the lifters will have to be adjustable or the valve stems welded up for adjustment.

05-10-2023, 09:41 PM	#20
Pete Senior Member Join Date: May 2010 Location: Wa. Posts: 5,407	Re: Thoughts on new camshaft? And still another thing many people fail to address is the cam journal bores are almost ALWAYS worn beyond specs for a stock replacement cam. The easiest fix for this is order a replacement cam with custom size journals and have the block align bored to fit. The next step up would be to sleeve the journal bores back to standard and use a standard cam. The next step up would be to bore the cam journal holes for insert bearings like modern blocks. The next step up would be for racing and has been discussed elsewhere. While checking various things in the block, be sure to check the cam LIFTER bores for wear. These are very important to a proper running rebuild.