The Ford Barn

Bob Johnson · 06-16-2017, 12:25 AM

I have a camshaft that I removed from an engine that was too bad to rebuild. This camshaft has a grind that is so severe that there was 0.030" removed from the side opposite the lobe. Below is a picture of the camshaft. I wondered what the lift profile would be for this camshaft, It appeared to have a very high lift. So I thought it would have a short duration. I have included a graph which shows the lift profile for a stock B camshaft and the profile for this re-ground camshaft. It has a little better lift than the B and the duration is same except for just at the beginning and end. Note that the area under the curve is a good representation of the "performance" of the camshaft. I would say that this re-ground camshaft would perform similar to a new B camshaft. It looks like it has both the lift and duration of a stock B camshaft. The only issues this camshaft would have is that all of the hardening has be removed and the points on the lobes are very sharp. This could result in a camshaft that would wear very fast.

Bob

Terry, NJ · 06-16-2017, 07:22 AM

Bob , I'm experiencing a similar scenario with a cam of mine. Assuming that the numbers at the left are heights in thousandths, my blue line would fall somewhere just above the .250 point (.265).
Terry

Bob Johnson · 06-16-2017, 09:43 AM

Terry,

The left axis is inches. I have seen many re-gound cams with a lift around 0.25" to 0.27". What is unusual about this cam is that it has a lift greater than a stock B cam without reducing the duration.

Bob

Dick Steinkamp · 06-16-2017, 10:28 AM

Quote:

Originally Posted by Bob Johnson

Terry,

What is unusual about this cam is that it has a lift greater than a stock B cam without reducing the duration.

Bob

Not unusual at all. Any and all cam grinders do it. They reduce the base circle which allows them to increase both the lift and duration on the lobe. You make up the difference in overall lobe diameter with valve (lifter) adjustment.

Since the lobes of a Model A cam just barely fit through the journals in the block, even a brand new Model A cam with more than stock lift has to have a reduced base circle to fit in the block.

Fullraceflathead · 06-16-2017, 10:33 AM

The Magic is to make the cam journals larger in the block and run a insert that is larger to allow a decent lift on the camshaft.

Jim Brierley · 06-16-2017, 10:37 AM

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What Dick says is true but usually a re-ground cam to B specs hardly, if at all, goes down into the base circle. I don't grind any cams that have a smaller than 1.556" center bearing diameter, I suggest you measure that and id OK, go ahead and use that cam.

PC/SR · 06-16-2017, 10:55 AM

Nice graph. The cost of the regrind was to take some of the ramp off the base circle/heal. Might want to reduce the valve/lifter gap a touch to reduce the shock of valve train engagement and pick up a few degrees of duration. Could get valve bounce on seating at higher rpm.

Bob Johnson · 06-16-2017, 12:06 PM

The bearing diameter is 1.5576". My concern is how it will wear. All of the hardening has been ground off and it does not appear to have been re-hardened.

Bob

Fullraceflathead · 06-16-2017, 01:13 PM

The base circle it lightly loaded as the spring pressure is off just the lifter weight.
The beginning of the opening ramp is slowly loaded as the lash is taken up and valve spring pressure is gradually increasing. You could get it hardened.

PC/SR · 06-16-2017, 04:59 PM

There is spring pressure even when the valve is closed and the lifter is on the heel of the cam. As I recall, stock Model A closed spring pressure is around 38-40 lbs. It would be a bit less with a reground cam because some of the base circle/heel material has been removed.

=====
Do not know how to delete this. This is wrong and fullraceflathead is correct. The danger of, as my mother used to put it, talking when you should be listening. Thinking of something else.

Terry, NJ · 06-16-2017, 05:28 PM

I would just like to know if I can use my cam without suffering a loss of power? As someone said, a performance cam should have a higher lift, not lower. Yet there's a conflict here too. Bill Stipe's chart show a .287 lift, What's that do?
Terry

Fullraceflathead · 06-16-2017, 09:13 PM

There is so much technology it what appears to be so simple.

Kahuna · 06-16-2017, 09:53 PM

"The Magic is to make the cam journals larger in the block and run a insert that is larger to allow a decent lift on the camshaft".
This has been done on Flathead V8's, with great success.
I wonder if anyone has tried this on a Model A/B block?

Jim Brierley · 06-17-2017, 10:42 AM

Terry, If your engine is all, or mostly stock, go ahead and use that cam as it is hardly any different than a stock cam. Don't worry about hardness either, most re-grinds don't get any hardening treatment, some nothing, some a coating called 'parkerizing' which is mainly for break-in.

06-16-2017, 12:25 AM	#1
Bob Johnson Senior Member Join Date: May 2010 Location: California Posts: 979	Interesting cam grind I have a camshaft that I removed from an engine that was too bad to rebuild. This camshaft has a grind that is so severe that there was 0.030" removed from the side opposite the lobe. Below is a picture of the camshaft. I wondered what the lift profile would be for this camshaft, It appeared to have a very high lift. So I thought it would have a short duration. I have included a graph which shows the lift profile for a stock B camshaft and the profile for this re-ground camshaft. It has a little better lift than the B and the duration is same except for just at the beginning and end. Note that the area under the curve is a good representation of the "performance" of the camshaft. I would say that this re-ground camshaft would perform similar to a new B camshaft. It looks like it has both the lift and duration of a stock B camshaft. The only issues this camshaft would have is that all of the hardening has be removed and the points on the lobes are very sharp. This could result in a camshaft that would wear very fast. Bob

06-16-2017, 07:22 AM	#2
Terry, NJ Senior Member Join Date: May 2010 Location: Bucks Co, Pa Posts: 3,740	Re: Interesting cam grind Bob , I'm experiencing a similar scenario with a cam of mine. Assuming that the numbers at the left are heights in thousandths, my blue line would fall somewhere just above the .250 point (.265). Terry

06-16-2017, 09:43 AM	#3
Bob Johnson Senior Member Join Date: May 2010 Location: California Posts: 979	Re: Interesting cam grind Terry, The left axis is inches. I have seen many re-gound cams with a lift around 0.25" to 0.27". What is unusual about this cam is that it has a lift greater than a stock B cam without reducing the duration. Bob

06-16-2017, 10:33 AM	#5
Fullraceflathead Senior Member Join Date: May 2012 Location: Chillicothe, Missouri Posts: 1,175	Re: Interesting cam grind The Magic is to make the cam journals larger in the block and run a insert that is larger to allow a decent lift on the camshaft. __________________ "If I asked people what they wanted they would have said faster horses." -Henry Ford "Primitive technology is not a design flaw" 1928 Ford Model A Roadster Pickup 1930 Gordon Smith Air Compressor 1941 Willy's Pickup 1960 Thunderbird-For Sale 1964 Buick Riviera 2x4 425 1965 Pontiac GTO, 455 Super Duty 2004 Dodge Ram SRT-10, V-10 Viper 1977 Charger Jet Boat,460 Ford,Jacuzzi Jet Front Engine Nostalgia Dragster,Supercharged 296 "Fullrace Flathead" Ford Engine Build up on DVD ask

06-16-2017, 10:37 AM	#6
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,087	Re: Interesting cam grind Sponsored Links (Register now to hide all advertisements) What Dick says is true but usually a re-ground cam to B specs hardly, if at all, goes down into the base circle. I don't grind any cams that have a smaller than 1.556" center bearing diameter, I suggest you measure that and id OK, go ahead and use that cam.

06-16-2017, 10:55 AM	#7
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,279	Re: Interesting cam grind Nice graph. The cost of the regrind was to take some of the ramp off the base circle/heal. Might want to reduce the valve/lifter gap a touch to reduce the shock of valve train engagement and pick up a few degrees of duration. Could get valve bounce on seating at higher rpm.

06-16-2017, 12:06 PM	#8
Bob Johnson Senior Member Join Date: May 2010 Location: California Posts: 979	Re: Interesting cam grind The bearing diameter is 1.5576". My concern is how it will wear. All of the hardening has been ground off and it does not appear to have been re-hardened. Bob

06-16-2017, 01:13 PM	#9
Fullraceflathead Senior Member Join Date: May 2012 Location: Chillicothe, Missouri Posts: 1,175	Re: Interesting cam grind The base circle it lightly loaded as the spring pressure is off just the lifter weight. The beginning of the opening ramp is slowly loaded as the lash is taken up and valve spring pressure is gradually increasing. You could get it hardened. __________________ "If I asked people what they wanted they would have said faster horses." -Henry Ford "Primitive technology is not a design flaw" 1928 Ford Model A Roadster Pickup 1930 Gordon Smith Air Compressor 1941 Willy's Pickup 1960 Thunderbird-For Sale 1964 Buick Riviera 2x4 425 1965 Pontiac GTO, 455 Super Duty 2004 Dodge Ram SRT-10, V-10 Viper 1977 Charger Jet Boat,460 Ford,Jacuzzi Jet Front Engine Nostalgia Dragster,Supercharged 296 "Fullrace Flathead" Ford Engine Build up on DVD ask

06-16-2017, 04:59 PM	#10
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,279	Re: Interesting cam grind There is spring pressure even when the valve is closed and the lifter is on the heel of the cam. As I recall, stock Model A closed spring pressure is around 38-40 lbs. It would be a bit less with a reground cam because some of the base circle/heel material has been removed. ===== Do not know how to delete this. This is wrong and fullraceflathead is correct. The danger of, as my mother used to put it, talking when you should be listening. Thinking of something else. Last edited by PC/SR; 06-16-2017 at 08:16 PM. Reason: Error

06-16-2017, 05:28 PM	#11
Terry, NJ Senior Member Join Date: May 2010 Location: Bucks Co, Pa Posts: 3,740	Re: Interesting cam grind I would just like to know if I can use my cam without suffering a loss of power? As someone said, a performance cam should have a higher lift, not lower. Yet there's a conflict here too. Bill Stipe's chart show a .287 lift, What's that do? Terry

06-16-2017, 09:13 PM	#12
Fullraceflathead Senior Member Join Date: May 2012 Location: Chillicothe, Missouri Posts: 1,175	Re: Interesting cam grind There is so much technology it what appears to be so simple. __________________ "If I asked people what they wanted they would have said faster horses." -Henry Ford "Primitive technology is not a design flaw" 1928 Ford Model A Roadster Pickup 1930 Gordon Smith Air Compressor 1941 Willy's Pickup 1960 Thunderbird-For Sale 1964 Buick Riviera 2x4 425 1965 Pontiac GTO, 455 Super Duty 2004 Dodge Ram SRT-10, V-10 Viper 1977 Charger Jet Boat,460 Ford,Jacuzzi Jet Front Engine Nostalgia Dragster,Supercharged 296 "Fullrace Flathead" Ford Engine Build up on DVD ask

06-16-2017, 09:53 PM	#13
Kahuna Senior Member Join Date: May 2010 Location: NorCal Posts: 2,617	Re: Interesting cam grind "The Magic is to make the cam journals larger in the block and run a insert that is larger to allow a decent lift on the camshaft". This has been done on Flathead V8's, with great success. I wonder if anyone has tried this on a Model A/B block?

06-17-2017, 10:42 AM	#14
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,087	Re: Interesting cam grind Terry, If your engine is all, or mostly stock, go ahead and use that cam as it is hardly any different than a stock cam. Don't worry about hardness either, most re-grinds don't get any hardening treatment, some nothing, some a coating called 'parkerizing' which is mainly for break-in.