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 02-01-2020, 07:14 PM   #1
Vanspeed
Senior Member
 
Vanspeed's Avatar
 
Join Date: May 2010
Location: Waterford, Mich.
Posts: 3,083
Default 2 bolt crab on a 21 stud question

Hi guys. I ordered a rebuilt 2 bolt crab distributor from Bubba. I have a 3 bolt cover and a 2 bolt cover. Can I just bolt the 2 bolt cover on and be good? My cam has a fiber pressed on gear. Just want to know what all I need to make the swap.
__________________
Respecting and Resurrecting Ford Model A's.
Vanspeed is offline   Reply With Quote
Old 02-01-2020, 07:24 PM   #2
Kube
Senior Member
 
Kube's Avatar
 
Join Date: May 2010
Location: Wisconsin, USA
Posts: 5,656
Default Re: 2 bolt crab on a 21 stud question

Quote:
Originally Posted by Vanspeed View Post
Hi guys. I ordered a rebuilt 2 bolt crab distributor from Bubba. I have a 3 bolt cover and a 2 bolt cover. Can I just bolt the 2 bolt cover on and be good? My cam has a fiber pressed on gear. Just want to know what all I need to make the swap.
Nope, you can't just bolt it on. The distributor housing is "deeper" on the crab than on the authentic helmet style and as such the crab must be spaced outward to accommodate this.
__________________
"I can explain it for you. However, I can't understand it for you".
Kube is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 02-01-2020, 07:36 PM   #3
cas3
Senior Member
 
Join Date: Jan 2011
Location: sw minnesota
Posts: 2,066
Default Re: 2 bolt crab on a 21 stud question

speedway has the spacer. most, mine and others i have heard of, require a little trimming around the vacuum port. not a big deal, a few swipes with a file. i cant remember, but i think it hits a timing cover bolt or something. check the fit when you get it.
cas3 is offline   Reply With Quote
Old 02-01-2020, 08:51 PM   #4
V8COOPMAN
Senior Member
 
V8COOPMAN's Avatar
 
Join Date: May 2010
Location: East Shore of LAKE HOUSTON
Posts: 5,971
Default Re: 2 bolt crab on a 21 stud question

Here's the 2-bolt spacer at Speedway. Click the link below! DD


https://www.speedwaymotors.com/Flath...cer,25074.html


__________________
T5 W/TORQUE TUBE


It's one thing to be ignorant! It's a whole 'nother story when you're proud of it!




V8COOPMAN is offline   Reply With Quote
Old 02-01-2020, 09:00 PM   #5
Vanspeed
Senior Member
 
Vanspeed's Avatar
 
Join Date: May 2010
Location: Waterford, Mich.
Posts: 3,083
Default Re: 2 bolt crab on a 21 stud question

Ok cool that is not a bad price at all to make it all work.
__________________
Respecting and Resurrecting Ford Model A's.
Vanspeed is offline   Reply With Quote
Old 02-01-2020, 11:59 PM   #6
JM 35 Sedan
Senior Member
 
JM 35 Sedan's Avatar
 
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 9,972
Default Re: 2 bolt crab on a 21 stud question

You also have the option to stay with the original, to that 21 stud engine, three bolt cam gear cover, and go with the spacer that bolts to the three bolt cover, and accepts a two bolt distributor. When going this way you could initially go with the two bolt crab style distributor, but quickly change back to a three bolt style distributor if you ever wanted to go back to your original distributor. This is the option I prefer to use on my '35, 21 stud engine so I can run my two bolt Harmon Collins distributor with the 3 to 2 bolt adapter, or quickly switch back to the stock 3 bolt distributor, if/when I ever care to do so, without the need to change the timing gear cover. Its mostly about flexibility for me on long distance touring.

Here's a picture of the late, great Dick Spadaro's reproduction offering of a three bolt to two bolt adapter for mounting a crab style two bolt distributor on an original three bolt timing gear cover used from '32 to '41.
Attached Images
File Type: jpg MVC-002S.JPG (35.9 KB, 67 views)
__________________
John

"Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein

Last edited by JM 35 Sedan; 02-02-2020 at 11:25 PM.
JM 35 Sedan is offline   Reply With Quote
Old 02-02-2020, 10:34 AM   #7
Mart
Senior Member
 
Mart's Avatar
 
Join Date: May 2010
Location: Solihull, England.
Posts: 6,260
Default Re: 2 bolt crab on a 21 stud question

I run a crab distributor on a 3 to 2 bolt adaptor on the 21 stud Pilot motor in my 33 coupe.
Mart is offline   Reply With Quote
Old 02-02-2020, 09:40 PM   #8
Tinker
Senior Member
 
Tinker's Avatar
 
Join Date: May 2010
Location: MN/FL
Posts: 5,397
Default Re: 2 bolt crab on a 21 stud question

https://www.jalopyjournal.com/forum/...dapter.217554/
Tinker is offline   Reply With Quote
Old 02-13-2020, 09:24 AM   #9
Ol' Ron
Senior Member
 
Ol' Ron's Avatar
 
Join Date: May 2010
Location: Chester Vt
Posts: 7,266
Default Re: 2 bolt crab on a 21 stud question

You can also run a late style 49/53 dist with a gear drive adapter and the late front cover. However your cam protrudes out from the cam and the adapter must be clearanced or the cam ground down.. Not an easy project. and the crab distributor is a good one.
Ol' Ron is offline   Reply With Quote
Old 02-25-2020, 06:49 PM   #10
Vanspeed
Senior Member
 
Vanspeed's Avatar
 
Join Date: May 2010
Location: Waterford, Mich.
Posts: 3,083
Default Re: 2 bolt crab on a 21 stud question

Hey guys if I am going for optimal clearance, meaning distributor as close to the cover which one do I use? I have both a 3 and 2 bolt cover. I think the 2 bolt cover and spacer will get me closer to the engine. Reason I ask is because I am running a ‘46 crank gear, fan with hub and generator. I don’t want the crab pushed out to far to interfere with the fan belt.
__________________
Respecting and Resurrecting Ford Model A's.
Vanspeed is offline   Reply With Quote
Old 02-25-2020, 07:12 PM   #11
Mart
Senior Member
 
Mart's Avatar
 
Join Date: May 2010
Location: Solihull, England.
Posts: 6,260
Default Re: 2 bolt crab on a 21 stud question

Vanspeed: What cam do you have in it? If the 46 type cam then the 2 bolt cover and the crab dist. will bolt right on. No spacer required.
Mart is offline   Reply With Quote
Old 02-25-2020, 07:20 PM   #12
JM 35 Sedan
Senior Member
 
JM 35 Sedan's Avatar
 
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 9,972
Default Re: 2 bolt crab on a 21 stud question

So you're running a '46 front crankshaft gear on....which year crank shaft?? So...which cam and camshaft timing gear are you actually using in your 21 stud engine?? There are what's known as long and short cams, and depending on which one you have, will determine if you need a distributor spacer or not. Your first post says... press on fibre timing gear, which usually/normally means you have the long style camshaft, but let's make sure before we attempt to answer your last posted question....
__________________
John

"Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein
JM 35 Sedan is offline   Reply With Quote
Old 02-25-2020, 07:20 PM   #13
Vanspeed
Senior Member
 
Vanspeed's Avatar
 
Join Date: May 2010
Location: Waterford, Mich.
Posts: 3,083
Default Re: 2 bolt crab on a 21 stud question

Just looked and it is the press on type fiber cam gear.

Quote:
Originally Posted by Mart View Post
Vanspeed: What cam do you have in it? If the 46 type cam then the 2 bolt cover and the crab dist. will bolt right on. No spacer required.
__________________
Respecting and Resurrecting Ford Model A's.
Vanspeed is offline   Reply With Quote
Old 02-25-2020, 07:23 PM   #14
Vanspeed
Senior Member
 
Vanspeed's Avatar
 
Join Date: May 2010
Location: Waterford, Mich.
Posts: 3,083
Default Re: 2 bolt crab on a 21 stud question

Yeah I know you are thinking why a Ď46 crank pulley and fan? I am fitting a 36 LB engine into my Ď29 A coupe and I needed a mechanical fan that was in the center of my radiator.

Quote:
Originally Posted by JM 35 Sedan View Post
So you're running a '46 front crankshaft gear on....which year crank shaft?? So...which cam and camshaft timing gear are you actually using in your 21 stud engine?? There are what's known as long and short cams, and depending on which one you have, will determine if you need a distributor spacer or not. Your first post says... Press on fibre timing gear, this usually means you have the long style camshaft, but let's make sure before we attempt to answer your last posted question....
Attached Images
File Type: jpeg 28275A4B-5064-47B5-BBD1-196B2DC19743.jpeg (29.5 KB, 26 views)
File Type: jpeg 40A34164-24B3-4778-9B62-43D8935338B9.jpeg (26.8 KB, 22 views)
__________________
Respecting and Resurrecting Ford Model A's.
Vanspeed is offline   Reply With Quote
Old 02-25-2020, 07:26 PM   #15
Mart
Senior Member
 
Mart's Avatar
 
Join Date: May 2010
Location: Solihull, England.
Posts: 6,260
Default Re: 2 bolt crab on a 21 stud question

In that case the two bolt cover with the spacer or the three bolt cover with the three to two bolt adaptor will both give the same result. They are both designed to mate a crab distributor to a long nose (as in 21 stud with a pressed on fibre gear) cam.
Mart is offline   Reply With Quote
Old 02-25-2020, 07:37 PM   #16
Vanspeed
Senior Member
 
Vanspeed's Avatar
 
Join Date: May 2010
Location: Waterford, Mich.
Posts: 3,083
Default Re: 2 bolt crab on a 21 stud question

So they both then must push the dizzy out 3/8 of an inch then correct? To me the 2 bolt to 2 bolt spacer is better looking than the 3 bolt to 2 bolt spacer. I didn’t know they both push the distributor out the same amount.
__________________
Respecting and Resurrecting Ford Model A's.
Vanspeed is offline   Reply With Quote
Old 02-25-2020, 07:39 PM   #17
JM 35 Sedan
Senior Member
 
JM 35 Sedan's Avatar
 
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 9,972
Default Re: 2 bolt crab on a 21 stud question

Vanspeed, you said '46 crank gear....so I'm guessing you really meant '46 crankshaft pulley?? Or am I confused??

"Correction, I thought you were looking for max fan to distributor space for using a crab vs. helmet type distributors.

I believe the crab style distributor with spacer would give you the most space between fan and distributor, with your present engine construction.

So, if you're only talking crab distributor and long cam, the best you can be is whatever space you have using the crab and one of the two spacers, with the appropriate timing gear cover.

To get the maximum space, you would need to go with the short cam, bolt on camshaft timing gear, and two bolt timing gear cover, as I believe Mart has already said.
__________________
John

"Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein

Last edited by JM 35 Sedan; 02-25-2020 at 08:47 PM.
JM 35 Sedan is offline   Reply With Quote
Old 02-25-2020, 07:44 PM   #18
Mart
Senior Member
 
Mart's Avatar
 
Join Date: May 2010
Location: Solihull, England.
Posts: 6,260
Default Re: 2 bolt crab on a 21 stud question

The distributor will only correctly engage with the cam at one spacing. Both setups should give you this spacing.

The ideal scenario would be to swap the cam and go direct two bolt and no spacer.
Mart is offline   Reply With Quote
Old 02-25-2020, 08:35 PM   #19
JM 35 Sedan
Senior Member
 
JM 35 Sedan's Avatar
 
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 9,972
Default Re: 2 bolt crab on a 21 stud question

Quote:
Originally Posted by Vanspeed View Post
So they both then must push the dizzy out 3/8 of an inch then correct? To me the 2 bolt to 2 bolt spacer is better looking than the 3 bolt to 2 bolt spacer. I didnít know they both push the distributor out the same amount.
The only advantage that I can think of at the moment, with the 2 to 3 bolt spacer, 3 bolt timing gear cover is...if your ever wanted to quickly go back to a 3 bolt helmet distributor. Which is the best way for me, since I carry both 2 and 3 bolt distributors when I'm on long distance, possibly cross-country, tours.
__________________
John

"Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein
JM 35 Sedan is offline   Reply With Quote
Old 02-25-2020, 08:56 PM   #20
Vanspeed
Senior Member
 
Vanspeed's Avatar
 
Join Date: May 2010
Location: Waterford, Mich.
Posts: 3,083
Default Re: 2 bolt crab on a 21 stud question

I donít think I could ever get a stock helmet back on because of the Ď46 fan setup.

Quote:
Originally Posted by JM 35 Sedan View Post
The only advantage that I can think of at the moment, with the 2 to 3 bolt spacer, 3 bolt timing gear cover is...if your ever wanted to quickly go back to a 3 bolt helmet distributor. Which is the best way for me, since I carry both 2 and 3 bolt distributors when I'm on long distance, possibly cross-country, tours.
__________________
Respecting and Resurrecting Ford Model A's.
Vanspeed 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 12:11 PM.