What is a "steel offset ground crank with Chevy Journals" ?

[Mike Gaines]

After all the input, he is just going to remove the "steel offset ground" crank and replace it with a new aftermarket steel crank with the 3.915 stroke, either from 440 Source another Supplier to get rid of any concerns about that steel offset ground crank. Thanks for the input from all of you guys.

 

[1 Wild R/T]

Then he'll ned different rods... The Manley's won't fit unless he narrows them....

 

[Mike Gaines]

Then he'll ned different rods... The Manley's won't fit unless he narrows them....

Thanks

 

[1 Wild R/T]

Thanks

Tell him to use all the trick stuff like the Jessel belt drive & T&D rockers but build another short block, the cost will be close to the same & he can probably fine a buyer for that short block... Or keep it as a back up...

 

[dvw]

The rod width difference is 1.017" Mopar, .995" Chev. The sides can be trimmed with a surface grinder to the needed spec. The material can be taken off the crank radius side and still retain clearance to the crank fillet.
Doug

 

[Brewzer67]

I ran this combination for a number of years back based on an article by Tony Defeo. This was even before Muscle Motors started building their welded stroker 496's. I was running a true 550 hp with it as bore out by my timeslips. I can share that I beat the crap out of that motor for 5 years and it just kept coming back for more. As a matter of fact, it is still in my stable as my emergency shortblock I use when I hurt something and have to get it fixed. It is probably the best combo I have ever had in the car from a durability standpoint. I had well over a 1000 runs and 20k miles on it when I pulled it. Unless you are going to go beyond that you should be fine. The biggest thing is to make sure the crank is ground with a nice radius and use bearings with a nice matching filet and you are fine. You will not regret it if it was built well.

 

[POMONAMISSEL]

smaller bearing , less heat . stays stronger longer , the deal to reduce chrysler bearing sizes , even to 2.1 on b motors on stock crankshafts . well sprint car motors use a 1.88 bearing with a thousand hp's at 6500 or better rpm , thats the honda bearing size , nascar uses that as well , 800 hp's at 9000 plus rpm .

 

[PROSTOCKTOM]

FYI: A NHRA Pro Stocker makes close to 1500 HP and spins the engines 10,700 rpms (Yes I know they have a 10,500 rpm rev limiter, but the engine will spin 10,700 rpms trust me). It too also uses a 1.88" Honda rod journal, but NONE of the engines your making reference to use a very long stroke and all have very high quality lightweight crankshafts, high quality rods and very light pistons, so I can’t see the relevance in your comparison because they are entirely different World's.

To the original poster, Offset ground crankshafts have been used in engines since the first hot rodder to race one probably started making them in late 1910's early 1920's. Just because there were no magazine articles to profess it as the, "HOT TICKET" doesn't mean offset grinding wasn't done over a hundred ago. Fast forward to the Chrysler 440 steel crankshaft and offset grinding to a Chevy journal. Now think about this for a minute!!! How is it that millions and millions of Chevy 454 engines have lived with a 2.200" crank pin and a factory 4.00" stroke for the last 50 years? Why all the negativity of using an offset steel Mopar crank at 3.900" stroke with a 2.200" crank pin journal? Do you suppose that means if you put the offset ground Mopar crank into a Chevy block that it would fail? If you think about it that steel crank doesn’t really know what brand it is. There is nothing wrong with that combination and will still serve many more years without issue. You mention all the trick parts that engine already has, well that crankshaft was also as trick at the time that combination was assembled. Yes, you can buy a 4340 crank from China now $750 just like most do today, however that OEM steel crank will probably last just as long. It's easy for the arm chair racers to tell you it's no good, but 35 years ago this was cutting edge, it worked fine then and still works fine now. The only difference now is you can get on the internet and buy one 24/7 anywhere in the World. Now people read magazine articles (that by the way get their revenue from advertisers aka: parts sellers) will tell you using an offset cranks is not the way to go. How would their advertisers make money if you’re using an offset OEM junkyard crank? The only real difference now is the cost to have an OEM steel crank reworked to fit into a B block vs buying an off the shelf readymade crank is probably getting close to the same, so why would you do it today. However your friend already has a complete assembly and I would tell him to just keep on using it.

Tom

 

[Curiousyellow71]

IMHO...I don't think the offset grinding has any effect on a cranks ability to survive big hp. Rod journal size is not that critical. If you turn some rpm's at big hp in a b stroker w oem steel crank its going to stress a main journal if the crank main in ground down for the b. Early 90's a friend had a 452 crank last one season...440 crank in a 400, B1 heads, Mains ground to b size. I think it was dynoed at 730hp. It ran a 9.85 ... 70 Cuda, we bought the car the following season. Lucky the crack was caught on the inspection after the season was over. We still have the aluminum rods and cam that was run that season. It was a Ray Barton build, he later oversized the block mains instead of grinding the crank I saw in a magazine. My guess Bartons probably went w aftermarket cranks on their builds like everyone else. I don't think their is quite enough material on a factory steel crank to get as nice of radius on the main journal as a aftermarket crank. Maybe after its ground you could get it nitrited, or hardened and help prevent the crank, but then with all the work your back to a aftermarket crank price.

 

[66Satellite47]

My 451 & 452 400 block builds cut the 440 mains down to B size. Both experienced cracks in the cranks. However IIRC the cracks were all in the rod journals with the undercut radius. I'm convinced this was from my high(7,000+) RPM's. Fortunately for me they stayed together until post season teardown. Not sure if the offset grind corrects the undercut on the stock crank.

 

[Curiousyellow71]

My 451 & 452 400 block builds cut the 440 mains down to B size. Both experienced cracks in the cranks. However IIRC the cracks were all in the rod journals with the undercut radius. I'm convinced this was from my high(7,000+) RPM's. Fortunately for me they stayed together until post season teardown. Not sure if the offset grind corrects the undercut on the stock crank.

That's interesting that you cracked it where its undercut, Stress cracks always start in places like that, but I figured most gave up in the mains. It's possible offset grinding could change it....but, Its hard to believe it would be better. The only aspect I think would be better is more cubes would move the rpm band down. I dont know how long the second crank lasted, the b1 engine like yours was being shifted well past 7000. If I am recalling it was shifted at 7600. It got moved from our cuda to a stretched wheelbase 93 Daytona and steel h beams were put in it, and I lost track of the car. The first time it cracked the engine had aluminum hemi rods and 1.24 ch arias pistons.

 

[Budnicks]

It was the deal, back years ago
I had quite a few old offset grinds, in a few different combo/cars
edited;
most of the racecar/street-er combo's were checked for structure
no cracks, no porosity in forgings, re-hardened (surfaced)
nitrite'd afterwards & re-balanced too

they did it a lot in spint-cars engine combos too, SBC & SBM combos

I had a buddy that did a BB 400 3.38" crank (real bastard combo)
to 0.200" offset grind 3.58" stroke, in a god awefugly 73 RR
going off memory, IIRC was 0.030" over 4.370" low-deck 429cid,
short stock length big bolt BBC rods resized, also internally balanced
(don't remember the bearings)
pistons were custom units/like $700 back in the mid-late 80's,
to my shock it was a real beast, but he didn't need a bunch of RPM,
it was mostly just a cam'd up bumpty bump cruiser/daily driver really,
he won quite a few street races too, he had that combo for a decade or more too

I never had a crank failure on an offset grinding
albeit; I had a lot of aluminum rod combos too
Pisano Bros lightweight Childs & Albert rods, lightweight Venolia pistons
far less rotating mass

500cid modern Pro-stocks are
high compression huge bore & short stroke
high rev combos, radical camshafts, short lived high pressure valves-springs etc.
most all now are depending on specific combos de-stroked if anything,
or more like custom/specific strokes/grinds/billets,
some of the bigger High $$$ teams, even
are in house machining now for their own custom combo
generally:
NHRA P/S a min. of a 4.60" to 4.750 bore "usually"
& 3.50" strokes for the bigger bores to
& 3.75" strokes for the lessor bores, not many of them
they are nothing like these combo, we are discussing here
not unless they are mountain motor IHRA huge cid etc.,
really still nothing like what is being contemplated here

NHRA style builds, even in Nitro, they don't have big throw cranks,
they have larger bores, shorter strokes to make 500cid
P/S
they make power in high rpms, serious #'s high flow heads
not down lower, like big throw cranks/strokers
It's truly an apples to oranges comparison
especially with usually far smaller bores 4.375"-4.5"-ish
like most these street/strip combos here
& again unless it's a 600-900+ cid mountain motor combos

they are 2 completely different styles of builds
P/S they are making 1400+ naturally aspirated HP, with short strokes

or "allegedly" 12,000hp in nitro & 14:71 Blowers at 50% overdriven
adding serious volumes of cubic air/boosts