Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 10-18-2019, 11:53 AM   #1
fordwife
Senior Member
 
Join Date: Dec 2015
Posts: 182
Default Mercury crank

How do you identify the difference between a 049-53 ford crank and a mercury 'crank? I've forgotten, its been too long.
fordwife is offline   Reply With Quote
Old 10-18-2019, 12:09 PM   #2
RalphM
Senior Member
 
RalphM's Avatar
 
Join Date: Nov 2015
Location: North Pole, Alaska
Posts: 2,114
Default Re: Mercury crank

Clean out plug on the front will be five eights inch diameter, is the best way
RalphM is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 10-18-2019, 12:19 PM   #3
Tim Ayers
Senior Member
 
Join Date: May 2010
Location: NJ
Posts: 2,994
Default Re: Mercury crank

The counter weight width as well. I forgot the measurement, but if I recall correctly, the Merc crank counter weight is approx. .500" wider than a Ford crank. Something like 6" in total width at the widest part for a Merc crank seems to ring a bell.

Last edited by Tim Ayers; 10-18-2019 at 01:27 PM.
Tim Ayers is offline   Reply With Quote
Old 10-18-2019, 01:13 PM   #4
bbrocksr
Senior Member
 
Join Date: May 2010
Location: Yakima Washington
Posts: 586
Default Re: Mercury crank

A Merc crank is 12" longer than a Ford crank. REALLY?

A merc counterweight is 6" wide, a Ford counterweight is 5 3/4 wide is what I think he meant.

Bill
bbrocksr is offline   Reply With Quote
Old 10-18-2019, 01:25 PM   #5
Tim Ayers
Senior Member
 
Join Date: May 2010
Location: NJ
Posts: 2,994
Default Re: Mercury crank

Quote:
Originally Posted by bbrocksr View Post
A Merc crank is 12" longer than a Ford crank. REALLY?

A merc counterweight is 6" wide, a Ford counterweight is 5 3/4 wide is what I think he meant.

Bill
Haha. I meant to say the width of the counter weight is 1/2" wider. I'll correct it. It's been a long day.
Tim Ayers is offline   Reply With Quote
Old 10-18-2019, 01:27 PM   #6
Tim Ayers
Senior Member
 
Join Date: May 2010
Location: NJ
Posts: 2,994
Default Re: Mercury crank

Quote:
Originally Posted by bbrocksr View Post
A Merc crank is 12" longer than a Ford crank. REALLY?

A merc counterweight is 6" wide, a Ford counterweight is 5 3/4 wide is what I think he meant.

Bill
Yes, thanks Bill.
Tim Ayers is offline   Reply With Quote
Old 10-18-2019, 01:51 PM   #7
GOSFAST
Senior Member
 
GOSFAST's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 919
Default Re: Mercury crank

I have about 10 Flathead Ford/Merc cranks here at the moment. All are 8BA style, later pieces!

They both measure about 7.000" across the front c/weights, if there is any difference it is immeasurable with a conventional ruler.

The plugs are another story, the Merc is .625" (5/8") like mentioned above. These actually lend themselves very well with this size to drill & tap fpr a 3/8" NPT pipe plug, requires no add'l drilling. We do these all the time!

Thanks, Gary in N.Y.

P.S. Here's a shot of a Merc on one of our balancers now getting balanced. On the left I wrote the dimension (7.000") in "chalk" to show the span of the c'weight, on the right that single line shows the pressed-in oil plug, it measures 5/8". I can supply a shot of the front c'weight on the 239" Ford also if necessary?
Attached Images
File Type: jpg Flathead Merc Crank Front View-7.000.jpg (81.5 KB, 160 views)
File Type: jpg Flathead Merc Crank-Pressed In Plugs.jpg (85.5 KB, 152 views)
GOSFAST is online now   Reply With Quote
Old 10-18-2019, 02:14 PM   #8
Tim Ayers
Senior Member
 
Join Date: May 2010
Location: NJ
Posts: 2,994
Default Re: Mercury crank

Quote:
Originally Posted by GOSFAST View Post
I have about 10 Flathead Ford/Merc cranks here at the moment. All are 8BA style, later pieces!

They both measure about 7.000" across the front c/weights, if there is any difference it is immeasurable with a conventional ruler.

The plugs are another story, the Merc is .625" (5/8") like mentioned above. These actually lend themselves very well with this size to drill & tap fpr a 3/8" NPT pipe plug, requires no add'l drilling. We do these all the time!

Thanks, Gary in N.Y.

P.S. Here's a shot of a Merc on one of our balancers now getting balanced. On the left I wrote the dimension (7.000") in "chalk" to show the span of the c'weight, on the right that single line shows the pressed-in oil plug, it measures 5/8". I can supply a shot of the front c'weight on the 239" Ford also if necessary?

Gary: Check the width of the 2nd counter weight in from the one with the chalk line. Is there a difference between the two widths of this weight? That's the one I've always checked.

Last edited by Tim Ayers; 10-18-2019 at 02:31 PM.
Tim Ayers is offline   Reply With Quote
Old 10-18-2019, 02:18 PM   #9
r_reed
Senior Member
 
r_reed's Avatar
 
Join Date: May 2010
Location: east glenville NY
Posts: 131
Default Re: Mercury crank

i built a simple v shaped rack, rotated the crank and measured the stroke. since the difference is a 1/4" it is not hard to tell.
__________________
1949 F-1 Flatrod II (flat paint, flat motor)
Keeping one more flathead alive
It smoked, but gave it up 7/26/2013
East Glenville NY
r_reed is offline   Reply With Quote
Old 10-18-2019, 02:19 PM   #10
bbrocksr
Senior Member
 
Join Date: May 2010
Location: Yakima Washington
Posts: 586
Default Re: Mercury crank

That's where the difference is, the second counterweight the thick one.

Bill
bbrocksr is offline   Reply With Quote
Old 10-18-2019, 03:33 PM   #11
Ronnieroadster
Senior Member
 
Ronnieroadster's Avatar
 
Join Date: Dec 2010
Location: East Coast in CT
Posts: 566
Default Re: Mercury crank

Quote:
Originally Posted by Tim Ayers View Post
Gary: Check the width of the 2nd counter weight in from the one with the chalk line. Is there a difference between the two widths of this weight? That's the one I've always checked.



Well anyone who has spent time building lots of Flathead s should know the second counterweight is wider on the Merc crank than the Ford! Heck the difference is plenty enough to see without measuring if you build enough of them. Not to mention the cranks are not the same weight just saying. Another detail to mention not all Merc crankshafts have 5/8" oil plugs I have seen 1/4" on a few also.
Ronnieroadster
__________________
I use the F word a lot no not that word these words Flathead , Focus and Finish.
"Life Member of the Bonneville 200 MPH Club using a Ford Flathead block"
Owner , Builder and Driver of the First Ford Flathead bodied roadster to run 200 MPH Record run July 13, 2018 LTA timing association 200.921 from a standing start in one and a half miles burning gasoline.

Last edited by Ronnieroadster; 10-18-2019 at 03:42 PM.
Ronnieroadster is offline   Reply With Quote
Old 10-18-2019, 04:27 PM   #12
Tim Ayers
Senior Member
 
Join Date: May 2010
Location: NJ
Posts: 2,994
Default Re: Mercury crank

Quote:
Originally Posted by Ronnieroadster View Post
Well anyone who has spent time building lots of Flathead s should know the second counterweight is wider on the Merc crank than the Ford! Heck the difference is plenty enough to see without measuring if you build enough of them. Not to mention the cranks are not the same weight just saying. Another detail to mention not all Merc crankshafts have 5/8" oil plugs I have seen 1/4" on a few also.
Ronnieroadster
Ron,

Have you found that the extra weight impacts fuel economy in any way?

Last edited by Tim Ayers; 10-18-2019 at 05:08 PM.
Tim Ayers is offline   Reply With Quote
Old 10-18-2019, 05:19 PM   #13
GOSFAST
Senior Member
 
GOSFAST's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 919
Default Re: Mercury crank

Quote:
Originally Posted by Tim Ayers View Post
Gary: Check the width of the 2nd counter weight in from the one with the chalk line. Is there a difference between the two widths of this weight? That's the one I've always checked.
Hi Tim, the "span" across the second c/weight (where I have the 7.000" number in my photo) measures 5.750" on the 239" 8BA's, the 255" Merc (on the balancer) measures 6.000". Now, the "thickness" of the c/weight is the same on both, nominally speaking it is just above 2.000", probably 2.050" or so?

Quote:
Originally Posted by Ronnieroadster View Post
Well anyone who has spent time building lots of Flathead s should know the second counterweight is wider on the Merc crank than the Ford! Heck the difference is plenty enough to see without measuring if you build enough of them. Not to mention the cranks are not the same weight just saying. Another detail to mention not all Merc crankshafts have 5/8" oil plugs I have seen 1/4" on a few also.
Ronnieroadster
Hi Ronnie, in ALL my years of building/dynoing these Flatties, I can't even really recall ever doing an OEM 239", so yes, we are very limited with our knowledge about that particular shaft. I have a bunch here now that we've taken in on "trades" (at least a 1/2 dozen or more just recently) but not sure tonight I ever built a single one, there was never a market around here for that size.

To add to that, other than that OEM Merc shaft you see on the balancer tonight in my photo, the last time I recall building an OEM 255" Merc was back probably about 15 or 20 years ago, somewhere in that time frame anyway! It was our first build using the OEM shaft but with the Eagle H-beam rods (conventional rod journals, not the 2.000" ones) and learned on that build that their rods were absolutely no good to us. Haven't used a single one since then!

Hope this clears some of the questions up??

Thanks, Gary in N.Y.

P.S. Back in the late '80's and into the early '90's were doing the ALL the machining on an average of 10/15 blocks per year. At that time I was tied in with a close friend who did nothing but Flatheads, he also did nothing but the Merc's. We did do a bunch of 4.125" stroker cranks for him, but all were on the OEM Merc shafts! Grinding the 255" cranks for this stroke was very popular back then, today we use everything new (Eagle cranks/Scat rods/Ross pistons). I just learned today Eagle supposedly only has 8 (4.250") shafts in inventory, we are considering taking all 8??

Last edited by GOSFAST; 10-18-2019 at 05:21 PM. Reason: C
GOSFAST is online now   Reply With Quote
Old 10-18-2019, 06:51 PM   #14
Ronnieroadster
Senior Member
 
Ronnieroadster's Avatar
 
Join Date: Dec 2010
Location: East Coast in CT
Posts: 566
Default Re: Mercury crank

Quote:
Originally Posted by Tim Ayers View Post
Ron,

Have you found that the extra weight impacts fuel economy in any way?


Fuel economy will be affected by the weight difference but I have found a faster speed caused by this additional weight gets you to the gas pump faster
__________________
I use the F word a lot no not that word these words Flathead , Focus and Finish.
"Life Member of the Bonneville 200 MPH Club using a Ford Flathead block"
Owner , Builder and Driver of the First Ford Flathead bodied roadster to run 200 MPH Record run July 13, 2018 LTA timing association 200.921 from a standing start in one and a half miles burning gasoline.
Ronnieroadster is offline   Reply With Quote
Old 10-18-2019, 07:00 PM   #15
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,502
Default Re: Mercury crank

Besides all of that, I discovered in the mid 50's that some Merc cranks are cast steel and most are cast iron. The steel ones were obviously the better choice for welded strokers.
Pete is offline   Reply With Quote
Old 10-18-2019, 08:49 PM   #16
Ol' Ron
Senior Member
 
Ol' Ron's Avatar
 
Join Date: May 2010
Location: Chester Vt
Posts: 7,053
Default Re: Mercury crank

I think the Canadian Nerc cranks had a 3/8 oil plug.
Ol' Ron is offline   Reply With Quote
Old 10-19-2019, 04:01 AM   #17
Mart
Senior Member
 
Mart's Avatar
 
Join Date: May 2010
Location: Solihull, England.
Posts: 5,833
Default Re: Mercury crank

Quote:
Originally Posted by Ronnieroadster View Post
Fuel economy will be affected by the weight difference but I have found a faster speed caused by this additional weight gets you to the gas pump faster
Where's then "like" button?
Mart is offline   Reply With Quote
Old 10-19-2019, 07:26 AM   #18
glennpm
Senior Member
 
glennpm's Avatar
 
Join Date: Sep 2014
Location: Wiscasset, Maine
Posts: 712
Default Re: Mercury crank

Here's a good article by Bill Boomer I came across a few years ago about the Merc crank identification.


http://myflatheadford.com/identify-4...ry-crankshaft/
glennpm is offline   Reply With Quote
Old 10-25-2019, 09:33 PM   #19
Desoto291Hemi
Member
 
Join Date: Oct 2019
Location: Carthage , Tennessee
Posts: 34
Default Re: Mercury crank

Hey Gary,
Do you recommend to tap the front weight for a pipe plug instead of a press in plug?

Tommy
Desoto291Hemi is offline   Reply With Quote
Old 10-26-2019, 06:06 AM   #20
GOSFAST
Senior Member
 
GOSFAST's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 919
Default Re: Mercury crank

Quote:
Originally Posted by Desoto291Hemi View Post
Hey Gary,
Do you recommend to tap the front weight for a pipe plug instead of a press in plug?

Tommy
Hi Tom, without a doubt, have all 4 tapped. The nice part about the Merc's starting with the 5/8" plugs is they don't need drilling, they're already the correct size to just tap for the 3/8" NPT thread!

Thanks, Gary in N.Y.

P.S. In all my time doing these builds we've literally done hundreds of those crank holes, more than 90% were Merc's, we did some Ford's way back in time.
GOSFAST is online now   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 02:18 AM.