Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 04-01-2017, 12:29 PM   #1
Ian in Mississauga
Senior Member
 
Join Date: May 2010
Posts: 116
Default Measuring camshaft lift

If I measure the diameter from heal to nose and then at a right angle to the first measurement ( the narrowest) will the difference be the lift?
Ian in Mississauga is offline   Reply With Quote
Old 04-01-2017, 12:36 PM   #2
MikeK
Senior Member
 
MikeK's Avatar
 
Join Date: May 2010
Location: Windy City
Posts: 2,821
Default Re: Measuring camshaft lift

No. You will be measuring across the acceleration and deceleration ramps.
__________________
Mechanical engineering 101: If you put an adjustment knob, screw, bolt, or tolerance specs on something, some people will immediately fiddle with it. If you mark it DO NOT TOUCH everyone will mess with it.
MikeK is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 04-01-2017, 12:47 PM   #3
redmodelt
Senior Member
 
redmodelt's Avatar
 
Join Date: May 2010
Location: Portland OR
Posts: 4,658
Default Re: Measuring camshaft lift

http://www.mtfca.com/discus/messages...tml?1491059157
__________________
I know the voices aren't real but damn they have some good ideas!
redmodelt is offline   Reply With Quote
Old 04-01-2017, 06:10 PM   #4
BILL WILLIAMSON
Senior Member
 
BILL WILLIAMSON's Avatar
 
Join Date: Dec 2010
Location: FRESNO, CA
Posts: 12,558
Default Re: Measuring camshaft lift

I'd say, measure from the center of the cam to the highest point of the lobe, then measure from the center of the cam to the center of the heel.
Subtract the LITTLE number from the BIG number, and that's the LIFT!
There's probably a FORMULA, but I don't know it????---A dial indicator would work, also.
Bill Slightlystupid
__________________
"THE ASSISTANT GURU OF STUFF"
BILL WILLIAMSON is offline   Reply With Quote
Old 04-01-2017, 06:22 PM   #5
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,520
Default Re: Measuring camshaft lift

Quote:
Originally Posted by Ian in Mississauga View Post
If I measure the diameter from heal to nose and then at a right angle to the first measurement ( the narrowest) will the difference be the lift?
YES, in the case of a model A Ford original cam.
They were of the 3 arc design so the base circle is concentric.
There are no clearance ramps.
Pete is offline   Reply With Quote
Old 04-01-2017, 06:31 PM   #6
Mikeinnj
Senior Member
 
Mikeinnj's Avatar
 
Join Date: May 2010
Location: Northern New Jersey
Posts: 1,224
Default Re: Measuring camshaft lift

#2 says No

#5 says YES

???????
Mikeinnj is offline   Reply With Quote
Old 04-01-2017, 06:59 PM   #7
Mitch//pa
BANNED
 
Join Date: May 2010
Location: Bucks County, PA
Posts: 11,454
Default Re: Measuring camshaft lift

Quote:
Originally Posted by Mikeinnj View Post
#2 says No

#5 says YES

???????
Go with #4. Dad knows his shit

Last edited by Mitch//pa; 04-01-2017 at 07:11 PM.
Mitch//pa is offline   Reply With Quote
Old 04-01-2017, 07:05 PM   #8
BillLee/Chandler, TX
Senior Member
 
BillLee/Chandler, TX's Avatar
 
Join Date: May 2010
Location: The sticks of east Texas
Posts: 451
Default Re: Measuring camshaft lift

Just a week ago I mounted an A-grind cam between centers in my lathe and used a dial indicator to measure (accurately!) the lift.It was the same as when measured as the OP described.

Did the same with a B-grind and the difference in lift was OTOO .050", the same as using the OP's method.
__________________
Bill Lee
http://www.CedarCreekAs.org

Last edited by BillLee/Chandler, TX; 04-01-2017 at 07:12 PM.
BillLee/Chandler, TX is offline   Reply With Quote
Old 04-01-2017, 08:06 PM   #9
MikeK
Senior Member
 
MikeK's Avatar
 
Join Date: May 2010
Location: Windy City
Posts: 2,821
Default Re: Measuring camshaft lift

Quote:
Originally Posted by Mikeinnj View Post
#2 says No

#5 says YES

???????
Pete is correct. It will work with the relatively primitive cam geometries. If it is a later profile, either new or regrind, at 90 degrees you may already be on a clearance ramp designed to take the inherent 'clack' out of a solid lifter cam. Then all bets are off. If it is an unknown cam use vee blocks and a height gauge or dial indicator.
__________________
Mechanical engineering 101: If you put an adjustment knob, screw, bolt, or tolerance specs on something, some people will immediately fiddle with it. If you mark it DO NOT TOUCH everyone will mess with it.
MikeK is offline   Reply With Quote
Old 04-01-2017, 11:40 PM   #10
hardtimes
Senior Member
 
hardtimes's Avatar
 
Join Date: May 2010
Location: South California
Posts: 5,785
Default Re: Measuring camshaft lift

Quote:
Originally Posted by Mikeinnj View Post
#2 says No

#5 says YES

???????
Hey Mike,
If you do not know Pete, then I understand your question.
Your answer is....Pete is a 50 some years of experience as...... CAM MAKER !

Pete builds and races cars and engines also.

There may be another here on this board, besides Jim B, who knows cams, but I would not question Pete's credentials where cam knowledge is concerned.
hardtimes is offline   Reply With Quote
Old 04-01-2017, 11:58 PM   #11
Fullraceflathead
Senior Member
 
Fullraceflathead's Avatar
 
Join Date: May 2012
Location: Riverside, Ca
Posts: 920
Default Re: Measuring camshaft lift

I was able to just catch the edge of a valve with my one inch travel indicator thru the spark plug hole. With the spark plugs out and car in high gear you can slowly move the engine. Zero out the indicator with the valve closed then push car slowly and you will see the rise and fall of the valve and lift. Mine was .287 lift which is correct for a stock cam with proper lashed valves.
__________________
"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
Fullraceflathead is offline   Reply With Quote
Old 04-02-2017, 12:59 AM   #12
Chuck Sea/Tac
Senior Member
 
Chuck Sea/Tac's Avatar
 
Join Date: May 2010
Location: Between Seattle & Tacoma
Posts: 1,778
Default Re: Measuring camshaft lift

Question: if your lift is , say 305, then is that the lift before the lash is subtracted or the total of the lift and lash.?
Chuck Sea/Tac is offline   Reply With Quote
Old 04-02-2017, 02:56 AM   #13
Mike V. Florida
Senior Member
 
Mike V. Florida's Avatar
 
Join Date: May 2010
Location: South Florida
Posts: 14,013
Send a message via AIM to Mike V. Florida
Default Re: Measuring camshaft lift

Quote:
Originally Posted by Pete View Post
YES, in the case of a model A Ford original cam.
They were of the 3 arc design so the base circle is concentric.
There are no clearance ramps.
I like pictures,



http://www.lunatipower.com/Tech/Cams/CamSpecTerms.aspx
__________________
What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II
Mike V. Florida is offline   Reply With Quote
Old 04-02-2017, 07:30 AM   #14
MikeK
Senior Member
 
MikeK's Avatar
 
Join Date: May 2010
Location: Windy City
Posts: 2,821
Default Re: Measuring camshaft lift

I like pictures too.
Here is a drawing showing clearance ramp locations that will clearly interfere with attempts at measuring the base circle 90 degrees to the lift.

__________________
Mechanical engineering 101: If you put an adjustment knob, screw, bolt, or tolerance specs on something, some people will immediately fiddle with it. If you mark it DO NOT TOUCH everyone will mess with it.
MikeK is offline   Reply With Quote
Old 04-02-2017, 09:41 AM   #15
BILL WILLIAMSON
Senior Member
 
BILL WILLIAMSON's Avatar
 
Join Date: Dec 2010
Location: FRESNO, CA
Posts: 12,558
Default Re: Measuring camshaft lift

I "think" I once read that CLEARANCE RAMPS had something to do with using HYDRAULIC LIFTERS????---"Maybe" I'm just confused????
Bill W.
__________________
"THE ASSISTANT GURU OF STUFF"
BILL WILLIAMSON is offline   Reply With Quote
Old 04-02-2017, 02:39 PM   #16
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,520
Default Re: Measuring camshaft lift

Checking on the master cams for 3 of the most popular street/touring grinds for the model A/B, there is no difference in lift as measured with micrometers or a dial indicator.
In other words, the clearance ramps start above or at the center line.
However, as the grind becomes more radical as in a drag race or circle track grind, this does not hold true. this is primarily because the base circle becomes smaller.
The readings can vary as much as .002 to .005.

For Bill W, the base circle on a hydraulic lifter cam is concentric.
Pete is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 08:59 AM.