finished stroker crank pics

EP

Member
Here are the pics of a finished 7 1/8 inch M crank. I posted some pics at the start of the project if you want to look back at the archives. Search stroker crank pics. I have it counterweighted and balanced. Thanks to Jim Benjamin for all the advice
 
Sorry, the pics don't seem to want to upload from phone.
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I guess it's an illusion, but those rod journals look small and fragile. This baby adds 1 7/8ths to the stroke and will go right in and clear everything, right? Hmmmmm.
 
Rod journals are 2.375,/ same as big block Chrysler + bigger than big block Chevy. Those engines put out way more HP per cubic inch than a tractor engine. With a nice set of 4140 steel rods everything will be plenty strong. Minimal clearance work had to be done because of the profiled rods. Not much other way to do it if you want a high power engine
 
Rod journals of 2.000" are not uncommon stroker cranks. NASCAR engines producing over 800hp survive with 1 7/8" rod journals (I believe they use a modified Acura rod bearing).
 

ep, I enjoy when people share pics and ideas for next year's tractors. What cubic in. are you going for and what rpm range do you intend to run?
 
Dukester, Rod journals of 2.000" are not uncommon stroker cranks. NASCAR engines producing over 800hp survive with 1 7/8" rod journals (I believe they use a modified Acura rod bearing).
 
The ingenuity and craftsmanship used to build these old tractor engines is unique and in some ways quite surprising. Coming from circle track racing and building those engines for the past 30 yrs, when I started my first tractor engine, as I told people “how hard can this be”, 2,000 RPM’s vs 8,000 RPM’s. The past couple of years have been an eye opener and if I had just built something on my own without consulting people with experience, I would have for sure had my "A" handed to me, which could easily still happen. There’s a lot more going on inside these old tractor engines than I would have supposed…and it’s been going on for quite awhile. As far as comparing automotive type crankshafts to those for a long stroke, heavy rod tractor engine, it’s a little like apples and oranges. Crankshaft stresses are not a simple crank pin diameter to HP/cylinder ratio because of the extremely high recipicating stresses (inertia) for the heavy crank/rod/piston LONG stroke combinations used in a tractor. Also, we’re looking at low carbon steel weld buildup vs forged low alloy steel with grain orientation designed for high stress. There are many of us that have used “previously raced” parts from Hendricks or Childress racing for Saturday night engines. The small journal rods, 1.850 IRL dia, or 1.880 Honda, have all been tried, including the small 5/16” Carr bolts ($800/set) only torqued to 33 ft-lb, 3 times and throw away. Most of the light weight pieces are no longer available since NASCAR took the qualifying engines from the teams. Now that they must use the same engine for the weekend, everything is heavier. The typical crank is now 2.000 or 2.100 pin dia, crankshafts no longer weight 34-37 lb, but in the mid 40’s near 50lb. Also, the big bore 4.185, short stroke, 3.25 combinations are vanishing. So, back to the tractor combinations where cubic inches are king, small rod dia journals, short stroke, and light weight parts from automotive engines just wouldn’t hold up. Below is a picture showing the relative difference of tractor components beside NASCAR sized pieces. As an example of weight comparison, look at your tractor wrist pins, the NASCAR pin in the picture is .826 dia x 2” long x .080 wall, hard coated, $950/set. As an engine builder, I hate rules, but as a competitor buying parts,[b:17704dddb3]the stock appearing on the outside rule [/b:17704dddb3]can be very expensive, not hard to spend $5,000 per cylinder.
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It will be 453 cu.in, relatively small these days. Rpm range will be up to about 2600. Have a new LP head, good cam and carburetor. Should make pretty good power
 
I have worked on some of those light
cranks for the dirt track guys. You don't
need to use the hoist to get them in the
grinder because they are so light, the
rings are paper thin on the pistons also.
I agree that this wouldn't work well in
these low rpm pulling engines, but who
knows
 
Previously mentioned was a mechanized crankshaft welding machine you were putting into operation, was it up and running for this crankshaft?
 
Yes I do have it up and running
I don't think that I could have built this crank using it. It works great for journal repair and a small amount of stroke, with very little distortion
 
Mostly because it is a straight bore, no moving the center line. I would have liked to go 4 7/8 but it would have required more issues than I wanted to deal with, including Welding up the water ports in the head so the head gasket would have a sealing area.
 
(quoted from post at 18:41:04 11/13/14) Mostly because it is a straight bore, no moving the center line. I would have liked to go 4 7/8 but it would have required more issues than I wanted to deal with, including Welding up the water ports in the head so the head gasket would have a sealing area.

Just an FYI- Do as you wish but a 4.5" bore can be more hassle in longevity than it is worth. At 4-3/8" the original bores are left in the block to support the deck from moving.
 
(quoted from post at 18:41:04 11/13/14) Mostly because it is a straight bore, no moving the center line. I would have liked to go 4 7/8 but it would have required more issues than I wanted to deal with, including Welding up the water ports in the head so the head gasket would have a sealing area.
Don't let welding the water port be the deciding factor if you really want an optimum combination. 4 years ago, I wanted to use the Chevrolet Bowtie Vortec head for our circle track engines, raised narrow runner and better combustion chamber. But, the water port lies right beyond the combustion chamber and wouldn't let the head be angle milled (rolled over) to get the comp ratio up beyond about 11:1. So, I had the water port milled out, approx. 3/8" wide, heads sent to Indy for gas welding and we haven't had any problems. Except for some very slight porosity at the ends of the weld, there was no hardness or color variation from the original cast iron base metal. The last set probably has well over 1,500 laps, no leaks or cracks. I would imagine a pulling tractor would never see that much time, so it should work OK. The Sharpie outline on the head in the picture is the location of the original water port. Original comb chamber was 64cc now 50cc. My 2 cyl putt putt is a flat head, no welding required.
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My sleeves have a nice counter bore on
them so they will lock everything in place
plus I made a 3/8 steel plate in place of
the tin water jacket plate. Don't think
the deck of this block will move. This
will be stronger than the smaller bore
that the walls are starting to get thin
 
(quoted from post at 18:49:10 11/14/14) My sleeves have a nice counter bore on
them so they will lock everything in place
plus I made a 3/8 steel plate in place of
the tin water jacket plate. Don't think
the deck of this block will move. This
will be stronger than the smaller bore
that the walls are starting to get thin

I'm not trying to tell you how to do your engine, but good luck with that. Maybe talk to Baker and he can give you some insight also.
 
thanks, I was also using a 281 block that had a crack going up the block, eliminated crack and put sleeve in. I actually sent my cam to him for the grind. Had a friend of mine that had an m block bored to 4.5 with no flange on top and it lifted the deck. he pinned it and it never bothered again
 

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