Prefer tuftrided, cross-drilled crank like was in Special High Performance 396/427 engines originally. Prefer std/std, but turned 0.010/0.010 m/r journals ok.
Thanks,
John
Thanks,
John
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- Thread starter L78fanatic
- Start date
I see these at swaps for around $200 as cores. If it's turned, the tufriding goes away, it's a very thin treatment. So, unless it's a virgin crank, which you'll pay dearly for, it's not even a factor. I do believe they're all cross drilled. Also, I think I read there is a difference in the 366 long throw truck cranks, and they never were tuffrided from factory, so do a little research on that.
The exact wording in my book, “Chevrolet by the numbers” states the following: All tuffrided (i.e. tuftrided) cranks have been cross-drilled, but not all cross-drilled cranks have been tuffrided.
A recent contact from a machine shop seller on ebay told me this: Most of the Chevy 366 and 427 truck cranks were tuftrided but not cross drilled. In fact I don't think any of the truck cranks were cross drilled.
I need to research the tuftriding process, which was done for all SHP engines, but I believe tuftriding leaves a darker color on the entire crank, so simply turning the journals would have no effect, except for the first time turned at the factory. Anyone, please correct me if I am wrong on this. Tuftriding is all about "strength", nothing else. This is why truck cranks were always/usually tuftrided.If I can find a suitable crank that is cross-drilled, but not tuftrided, I may go for it, since these days and the way I'll drive the car won't be for racing so it may not matter.
I was under the impression tuftriding was a surface hardening treatment. Might have to look it up in the BBC bible I guess.
www.themotorbookstore.com
How to Hotrod Big-Block Chevys: 396, 402, 427, 454
This book covers all big-block Chevy engines, 1965 and later, including the 396, 402, 427 and 454 ci. HPBooks 42.
www.themotorbookstore.com
Thanks for looking! Isn't that the truth! If only my Dad had held onto all of my wheels & tires, and original L78 cast iron exhaust manifolds after I sold my '67 Chevelle SS L78 before going into the Army! That stuff would be worth a whole lot these days!
My wife gets mad at me for holding onto everything now! LOL!
I have that book, but this one also:I was under the impression tuftriding was a surface hardening treatment. Might have to look it up in the BBC bible I guess.
How to Hotrod Big-Block Chevys: 396, 402, 427, 454
This book covers all big-block Chevy engines, 1965 and later, including the 396, 402, 427 and 454 ci. HPBooks 42.
Amazon.com
www.amazon.com
On page 77 it speaks of tuftriding;
High output big-blocks with forged, Tuftrided cranks have to be treated specially after machining......You can recognize a Tuftrided crankshaft by its dull-gray finish,. When the journals are ground, this hard surface is removed. However, if your crank is in good shape, all you have to do is polish the journals, there is no need to re Tuftride. [Cranks can be re-Tuftrided but it's expensive!]. Tuftriding is a chemical heat-treating process that applies a very thin hard surface to the bearing journals.
I think Jim might have something you might like
I didnt know there was a difference, Ops
I'm like Rick...I had no clue. Just figured the stamping on the crank was abbreviated. What is full dress? Cross-drilled? I am watching a nice NOS crank on ebay and the guy wants too much for it ($1,600)....too much for me anyway. It sure is purdy though! I suppose I could offer him less, but he'd likely still want too much. His crank has the full part number stamped in one of the weights.
kmakar
Janitor
Make an offer of the max you're willing to spend.... if he doesn't accept the offer, no loss, but later down the road he may if no one buys it. I've had guys come back weeks later and offer what I wanted for the price I offered and I snatched it up. Can't hurt to try.
Found some good info here :
Either process does not make the Crankshaft any stronger and in fact, (as already mentioned) can make them weaker. It gives added wear resistance to the Crank Journals so it can usually go longer between grinds.
EN16T isn't tuftrided but the T mans it's 'tempered'. The 12G1505A isn't Tuftrided as supplied.
It only takes to the machined surfaces of the part being treated and can random effect on the raw unmachined 'skin' of the part.
Nitriding is only very shallow, typically 0.005" to 0.010" deep. Truftriding goes in deeper. Most steels, including EN40 can be Tuftrided with varying effects, however, few can be Ni
Tufrided cranks can go to 0.020" grind before re-treatment is needed. Nitrided Cranks need to be after 0.010".
As both processes involve heat treatment they relax the stresses in the Crank from Forging and this part of the process can increase Crank Life and can be done without Nitriding or Tuftriding, however, with this relaxation, the crank will also change shape, it will only likely be a few thousands, but you can be sure it won't be true and needs to be bent back.
Personally, I wouldn't bother with either process, it can bring about headaches.
www.theminiforum.co.uk
Either process does not make the Crankshaft any stronger and in fact, (as already mentioned) can make them weaker. It gives added wear resistance to the Crank Journals so it can usually go longer between grinds.
EN16T isn't tuftrided but the T mans it's 'tempered'. The 12G1505A isn't Tuftrided as supplied.
It only takes to the machined surfaces of the part being treated and can random effect on the raw unmachined 'skin' of the part.
Nitriding is only very shallow, typically 0.005" to 0.010" deep. Truftriding goes in deeper. Most steels, including EN40 can be Tuftrided with varying effects, however, few can be Ni
Tufrided cranks can go to 0.020" grind before re-treatment is needed. Nitrided Cranks need to be after 0.010".
As both processes involve heat treatment they relax the stresses in the Crank from Forging and this part of the process can increase Crank Life and can be done without Nitriding or Tuftriding, however, with this relaxation, the crank will also change shape, it will only likely be a few thousands, but you can be sure it won't be true and needs to be bent back.
Personally, I wouldn't bother with either process, it can bring about headaches.
Nitriding Vs Tuftriding - Crankshaft And Conrods - Problems, Questions and Technical
Page 1 of 4 - Nitriding Vs Tuftriding - Crankshaft And Conrods - posted in Problems, Questions and Technical: I have 12G1505A crankshaft and apparently this is 1275cc - Non-S, EN16T with 1.75 dia. big ends. It is already -0,020 and I will need to go to -0,040 for my engine. I plan to take...
Kinda what I thought too. Full dress I guess you can call it what you want but yea cross drilled & tuftrided & maybe you could include numbers matching.
I looked it up on Mortec, didn't give much info but the 6223 looked like a generic steel crank for 3.76 stroke.
I posted a detailed post on Team Chevelle (today, 2-2-22) regarding the difference between "6223" and "3856223" Cranks. If I'm right, the "6223" is the one I want! Please pm me about your 6223 crank hanging in your shop! I'm still looking...very frustrated!
John
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What would be wrong going with this Scat crankshaft if anything?
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