Ratchet nut
 

Rather than pay a small fortune (exchange, shipping, duty, etc) for a ratchet nut wrench that the vendors sell, I bought a 1-3/8" combination wrench with the intention of heating and bending it to fit. I test fit in on a spare engine and found it to be a very loose fit, although it will just catch and turn. I measured the nut to be 1.315" (just over 1-5/16"). I can't reach the nut in my car to compare it and don't want to bend the wrench until the size is confirmed. Is this normal or were the ratchet nuts made in different sizes? Maybe the wrench is just poorly made oversize? The block in my car is 1928 but the spare is 1930.

Re: Ratchet nut
 

I think the originals were 1 3/8" but I've seen 1 5/16" also.

Re: Ratchet nut
 

Do you or someone you know have a 1-5/16" or 1-3/8" socket to try? I have bent several wrenches for this purpose, just about every one being 1-3/8"

https://live.staticflickr.com/65535/...7dde30a6_z.jpg

Re: Ratchet nut
 

1 3/8"

Re: Ratchet nut
 

The ratchet nut on my '31 is 1-1/4".
As suggested in post #3, use sockets to check the size.

FWIW, in case you don't know it, "The Old Car Centre" in Langley carry Model A parts.

Re: Ratchet nut
 

This ratchet nut on my spare engine (block dated 3/28) is 1-5/16”.
No idea if it’s a replacement or not. The nut on my ‘31 is 1-3/8.

Re: Ratchet nut
 

A 1 3/8" socket with a long breaker bar works fine.

Re: Ratchet nut
 

I found the tolerance of my wrench to be at the upper limit per ASTM , accounting for some of the looseness, so returned it to the tool store and exchanged for a 1-5/16 wrench which fits the spare nut perfectly. Still not sure what is on the car so plan A. Grabbed some play-doh from my grandkids toy box and packed it around the nut. Made a nice impression but too soft to measure within 1/16" and now someone's going to be in trouble for getting grease on her play-doh. On to plan B. I have a 35 mm socket but it woudn't fit over the nut so I had to remove the spring clamp to get it on. Removed the nut and confirmed it is 1 -3/8. So now it's back to the store to exchange for the 1-3/8 wrench. Also just read in Les Andrews book that some aftermarket nuts are 1-1/8 1-1/4 or 1-5/16. I guess thats why some people have complained that the vendor's wrenches don't fit. Too bad they don't mention this in their catalogues.

Re: Ratchet nut
 

13/8" is the A size .The smaller nut is B and later.

Re: Ratchet nut
 

Loosen your generator, remove the timing belt, get a cheap long nail puller similar to this "WORKPRO 2-Piece Nail Puller Set".


my nail puller slipped right into the pulley of the engine and i was able to get it to top dead center to adjust my timing. no damage to anything on my engine and it worked all the same.


on that: adjusting distributor timing.
i didnt use a fancy wrench, i slipped a piece of rubber hose over the cam, slowly tightened a locking wrench, and was able to unscrew and adjust as needed.

Re: Ratchet nut
 

Here is a safety tip.

Re: Ratchet nut
 

Original ratchet nuts are 1 3/8”. An original KR Wilson wrench is 1 7/16” across the flats which fits the original nut.

Re: Ratchet nut
 

OK, y'all confused me. If an original ratchet nut is 1 ⅜” and a KR Wilson wrench is 1 7/16” across flats, how does that fit an original ratchet nut?

Re: Ratchet nut
 

The 1 7/16" KRW 6-point wrench will probably work but it would be loose, just like my 1 3/8" 12 point wrench will turn the 1 5/16" nut but is a loose fit.
I also found a ratchet nut from an old '48 flathead block that I had planned to use - it measures 1-1/8", but the hole is too small for a Model A hand crank so would not likely be found on a rebuilt Model A engine. Happy to report that my new wrench fits and works well.