crank short and long nose

3

3W Hank

Well-known member
The cranks pre 38 or is it 39 has a short nose and a smaller diameter.
The later 59AB has the long nose or equal as the Merc 4" 49-53.
Is it a benefit to use the longer ?
I think about stroke a crank 1/8" and I think short nose is also with both big main and the bigger rod journal, or is it just the big mains and always the 2" rod journal.
I had one before but I think it was the smaller mains ( will not fit a 41 block if not thicker bearings ) or are they aviable ?

But I'm not shore, maybe I go with the std stroke 3.75.
If so is a crank better of long nose than the short nose ?
 
You're better off with the long-nose crankshaft - as you can much more easily find pulleys and all aftermarket parts are designed for it. You can even get a harmonic balancer (though you obviously won't use one in a period build).

You can take a 59x crankshaft, offset grind it for an 1/8" increased stroke and then run either 21A or 91A rods an full-floater bearings for a "baby stroker".

You can get Ross to make the pistons with the pin location where you need it. I always measure the crank and rod/pin in the actual prepped block to determine the true compression height needed to achieve the squish/quench that I need.
 
Ok, I guess best way is to use the 59AB crank then, then see if I stroke it or not but 1/8” stroke sounds hotrod ’cool’ pre 49.
On the rods, who is prefered the 21 or 91 ( is both for 2” ) and this rods weaker then the 49-53 Merc rods ?
 
In most of the world the short cranks have the smaller diameter rod journals and cannot be stroked.
I have not heard of any strength differences between 91A, 21A, or later rods. The 49-53 Mercury rods are the same as 49-53 Ford rods. If you stick with a 3.75" stroke the simplest engine assembly is an 8BA crankshaft and rods using normal individual rod bearings. If you go 59A or stroker crank you must use floating rod bearings. Bored&Stroked has an exceptional engine build documented on the HAMB and he has a short video on Youtube showing proper floating rod bearing fitting.
 
It all comes down to whether or not you want to create a Pre-49 1/8" stroker by offset grinding a 59X 3 3/4" crankshaft. As 38Coupe noted, if you are NOT going to offset grind the journals to 1.999" and are going to use a large journal crank, then you might as well go with a 49-53 Ford crankshaft (large journal) with 49-53 rods and insert bearings. This is by far the easiest to setup. Or go with the Merc crank and you'll get the extra 1/4" of stroke.

If you're going to build a Pre-49 stroker, then you'll need to run the full-floating bearings and 91A or 21A rods and take the time to "tune" the bearings and clearances so everything floats as it should.

Important! Very few machine shops know how to setup these bearings (you can't just drop in a set) - so consider it something you must do yourself. Also, full-floating 1.999" bearings are expensive - especially if you need anything other than STD. The bearings I prefer to run (but are hard to find) are the ones labeled Cadmium-Silver . . . for heavy duty truck and bus applications. They are a softer bearing and are better for the crank on a stroker. These are kind of like the Vandervell bearings we used to run in high-end blown BBC applications - a bit softer than other bearings.

To me, if I was going to go to the expense of an offset stroked crank, I'd use the later Merc crank, stroke it to 4 1/8" and run the 1.999 full-floater rods. You also have the option of modern H-Beams rods and insert bearings if you have a crankshaft with 2 rod-journal oil holes (49-53 Ford or Merc). It will cost as much to buy/setup 21A rods and full-floater bearings as new H-Beam rods and insert bearings (just a fact of life these days!).

In the end, nobody knows what is inside the engine but you . . . and very few would even be able to discuss/understand what I just wrote up above . . .
 
The 21 studs and 24 studs had an overlap of manufacturing where both were still in manufacture for a short period in that time frame. The standard cars got the 21 and the deluxes got the 24 stud.
 
1938 was when Ford was producing both 21 stud and 24 stud engines. I am not aware of any effort Ford made to pick standard or deluxe vehicles to install either type of engine in. The later in the year a vehicle was made the more likely a 24 stud motor was used. My 38 Phaeton is a 21 stud engine car and my late year 38 standard coupe is a 24 stud engine car. As described in the engine identification thread and pdf the 24 stud 1938 engines had the smaller main bearings and shorter crankshafts. 1939 production got the bigger mains and longer crankshafts.
 
Bore&Stroked, and others.

I has zero machine experiance on the FH, but it's a 'motor', so a rod can be grinded/honed to size, then add in a bearing and check diameter, then crank get checked or if new grinded to the Babbits rule 0.001" per inch or say 0.002" clearance or whatever this engines like vs oil and oilpump/pressuare.

Question.
Is it possible get another brand of bearing that has 2" inside or under clearnce but the same housing as the Ford 21A rods ( if the std For undercut is hard to get or Very expensive at 010 020, 030.

Another question.
The 59AB cranks is long nose and big main and big rod jornal, but I heard the 1939 cranks has thinner counterweights.
I also heard this cranks haso sometimes big main/small rod and some has bigmain/big rod.
-Is that correct, so how can one see that from a later 59AB crank ? ( thin counterweight ) vs partnumber etc.
 
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I did found mains for 59A today ( crank/block ) in std or 010 to 030.
They had not the thicker wall if go a 37 crank in a 59A block ( hard to find now by guess )
On the 2" they had NOS 21A rods and bearing was in std and 010 to 030.

I'm seraching for weight on a 37 crank short nose vs a 59A crank and the Merc 4" crank.
Has someone allot of cranks and time over ?

I dont think the 1939 cranks are less weight than a 1940 etc.

If the 37 crank has less weight I really could go 3.75" stroke aswell.
But issue is mainbearings but inserts might can be done. But not a a real nice idea..
 
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