The Ford Barn

TomT/Williamsburg · 08-01-2018, 08:11 AM

I have a '40 59ab that needs a new main belt. I have a Napa belt in my trunk that I put in there as a spare, Napa number 25-20544. It's a 5/8" width belt.

When I look up what I need I see a number 27666 belt is what is needed. Are they one in the same?

The present belt has probably stretched but here is an issue I have. I am running a "Y" 2-deuce progressive intake that the generator hits the bottom of the front carb leaving the belt somewhat loose as I cannot tighten it enough. Is there a slightly shorter belt I can use to take up that slack? I am running the newer sealed bearing water pumps ...

Thanks for any help you can give ...

PS - I think the 27666 belt is for the front mount fan I have - it's 37"

The Napa belt 2520544 is 54.73" long and that should be the main belt replacement BUT is there one slightly smaller?

markdtn · 08-01-2018, 09:31 AM

Gates B52 is a 55” belt. B50 and B51 are 53” and 54”.

TomT/Williamsburg · 08-01-2018, 09:34 AM

Thanks!

BUBBAS IGNITION · 08-01-2018, 01:31 PM

Quote:

Originally Posted by TomT/Williamsburg

I have a '40 59ab that needs a new main belt. I have a Napa belt in my trunk that I put in there as a spare, Napa number 25-20544. It's a 5/8" width belt.

When I look up what I need I see a number 27666 belt is what is needed. Are they one in the same?

The present belt has probably stretched but here is an issue I have. I am running a "Y" 2-deuce progressive intake that the generator hits the bottom of the front carb leaving the belt somewhat loose as I cannot tighten it enough. Is there a slightly shorter belt I can use to take up that slack? I am running the newer sealed bearing water pumps ...

Thanks for any help you can give ...

PS - I think the 27666 belt is for the front mount fan I have - it's 37"

The Napa belt 2520544 is 54.73" long and that should be the main belt replacement BUT is there one slightly smaller?

Tom , The napa store has a chart for that belt , i just went thru it on my flathead engine,i think mine was a 252055 (55 inch) for a late flathead with alternator..

rotorwrench · 08-01-2018, 01:45 PM

I think the old Ford belts were nearer 11/16" wide originally. Most of the new stuff is based on new part standards. They have gone to metrics pretty much.

deuce lover · 08-02-2018, 08:11 AM

Sponsored Links (Register now to hide all advertisements)

Took a pic of a chart I have originally posted by 35tn.Print it out -worth having in the drawer of the tool box.

Kahuna · 08-02-2018, 09:05 AM

Tom
On both my 39 & 32 Fords, I run Machine belts from the Hardware store.
On the 32, I used the original motor mounts, and by using a machine belt,
I didn't have to grind the mounts, as the belt fits into the pulleys deeper.
Machine belts are also available in incremental lengths.
I think Rotorwrench is correct in that Ford belts are 11/16 & the hardware
store belts are 5/8's..
Now, some say these belts won't work well or last long. The 39 has had one
for 26 years & the 32 for about 7 or eight. Should one fail, you're only an
ACE Hardware store away. Cheap too.
Jim

flatheadmurre · 08-02-2018, 09:27 AM

I´ve been running B52 or B53 depending on size of generator pulley for years...no issues with them wearing out fast.
Fan belt for newer trucks is B35.

08-01-2018, 08:11 AM	#1
TomT/Williamsburg Senior Member Join Date: May 2010 Location: Williamsburg, Virginia Posts: 2,654	V-Belt Cross Ref I have a '40 59ab that needs a new main belt. I have a Napa belt in my trunk that I put in there as a spare, Napa number 25-20544. It's a 5/8" width belt. When I look up what I need I see a number 27666 belt is what is needed. Are they one in the same? The present belt has probably stretched but here is an issue I have. I am running a "Y" 2-deuce progressive intake that the generator hits the bottom of the front carb leaving the belt somewhat loose as I cannot tighten it enough. Is there a slightly shorter belt I can use to take up that slack? I am running the newer sealed bearing water pumps ... Thanks for any help you can give ... PS - I think the 27666 belt is for the front mount fan I have - it's 37" The Napa belt 2520544 is 54.73" long and that should be the main belt replacement BUT is there one slightly smaller? __________________ Run to the LA Roadster Show - 2016 My Run to Bonneville - 2013 My 32 5-Window Build My Run to the LSRU Last edited by TomT/Williamsburg; 08-01-2018 at 08:34 AM.

08-01-2018, 09:31 AM	#2
markdtn Senior Member Join Date: Jun 2016 Location: Chattanooga, TN Posts: 139	Re: V-Belt Cross Ref Gates B52 is a 55” belt. B50 and B51 are 53” and 54”.

08-01-2018, 09:34 AM	#3
TomT/Williamsburg Senior Member Join Date: May 2010 Location: Williamsburg, Virginia Posts: 2,654	Re: V-Belt Cross Ref Thanks! __________________ Run to the LA Roadster Show - 2016 My Run to Bonneville - 2013 My 32 5-Window Build My Run to the LSRU

08-01-2018, 01:45 PM	#5
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,426	Re: V-Belt Cross Ref I think the old Ford belts were nearer 11/16" wide originally. Most of the new stuff is based on new part standards. They have gone to metrics pretty much.

08-02-2018, 09:05 AM	#7
Kahuna Senior Member Join Date: May 2010 Location: NorCal Posts: 2,617	Re: V-Belt Cross Ref Tom On both my 39 & 32 Fords, I run Machine belts from the Hardware store. On the 32, I used the original motor mounts, and by using a machine belt, I didn't have to grind the mounts, as the belt fits into the pulleys deeper. Machine belts are also available in incremental lengths. I think Rotorwrench is correct in that Ford belts are 11/16 & the hardware store belts are 5/8's.. Now, some say these belts won't work well or last long. The 39 has had one for 26 years & the 32 for about 7 or eight. Should one fail, you're only an ACE Hardware store away. Cheap too. Jim

08-02-2018, 09:27 AM	#8
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: V-Belt Cross Ref I´ve been running B52 or B53 depending on size of generator pulley for years...no issues with them wearing out fast. Fan belt for newer trucks is B35.