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can an 8BA crank be welded?

Discussion in 'The Hokey Ass Message Board' started by nitro29, Jul 3, 2009.

  1. nitro29
    Joined: May 26, 2005
    Posts: 66


    I have an 8BA crank that I was going to offset grind to 2'' and use 21A rods with full floating bearings. Then the possibility of make a4" stroke rather than a 3 7/8" stroke by welding or adding metal to the outside of the rod journal. I have read in the past of this happening but it had some problems. Because of the advance in the welding of various metals with new techniques I was wondering if anyone had any thoughts? Tahks.
  2. DE SOTO
    Joined: Jan 20, 2006
    Posts: 3,857


    How 'Bout just buying my Merc Crank That has been offset ground to 4 1/8 stroke & uses Small Journal Ford rods ? :D
  3. Fe26
    Joined: Dec 25, 2006
    Posts: 543


    Cost of welding, straightening, annealing and grinding would be high, much better to go with a Merc crank,if you need the extra H.P. that may bring.
  4. It will be cheaper, and result in a better crank, to just purchase a 4" Merc crank than to weld and grind a 3-3/4" Ford crank to 4".
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  5. kiwicowboy
    Joined: Nov 28, 2008
    Posts: 349

    from linwood nc

    It's cheeper to buy a merc crank
  6. Kevin Lee
    Joined: Nov 12, 2001
    Posts: 7,403

    Kevin Lee
    Super Moderator
    Staff Member

    Having the time and access to proper tools instead disposable cash could be one reason. Or just wanting to do something the way it used to be done. I get where he is coming from.

    That said, I asked this same question a while ago and did get some information. Stroking a FH crank w/offset grind still common? And in the end I decided to get a Merc crank - so I see what you are saying too.
  7. Screamin' Metal
    Joined: Feb 1, 2009
    Posts: 506

    Screamin' Metal
    from Oklahoma

    Yep, buying a crank is the way to go.....but if you wanna go 'old school'......weld her up! Back in the old days,(60's), a lot of the altereds and gasser cranks were welded up, offset ground......and even'll run across one every now and agian.

    The 392 and 426 Hemi's were the prime canadates! After'd look at the throws and go 'Holy Crap!', I can't run this! A properly welded crank would have some surface cracks on the journals.......but you knew they were good when you'd 'ring' them.

    Modern welding methods have improved on this stuff considerably! And still can and still is being done! :cool:
  8. RAY With
    Joined: Mar 15, 2009
    Posts: 3,133

    RAY With

    Cheaper and better to go with the merc and the complete scat stroker kit is 1,700 round figures. If money is tight the merc is still the cheapest deal
  9. Hotrod Lincoln
    Joined: Apr 8, 2009
    Posts: 55

    Hotrod Lincoln

    A 4" stroke 49-53 Merc crank can be offset-ground without welding to a stroke of 4 1/8" by using the 85 HP rods. My family ran bunches of them in 34 Ford coupes on the dirt track in the mid-1950's. We ran 3 7/16" bores, and 11.5:1 compression ratios with alcohol and hydrogen peroxide as fuel.
  10. 392_hemi
    Joined: Jun 16, 2004
    Posts: 1,737


    For what it'll take in time and money (machining costs, etc.) you can buy a brand new SCAT stroker crank with rolled fillets. It'll be way better than any stock unit, and ready to go out of the box.
  11. DE SOTO
    Joined: Jan 20, 2006
    Posts: 3,857


    I hear everyone saying "OLD SCHOOL"

    This is what i have, An "OLD SCHOOL" of set ground Merc Crank that use's the Small Journal Ford rods.

    How much more "OLD SCHOOL" can ya get ?

    You could buy My crank, Get some Ford rods & the major cost would be in Pistons... All this could be done for much less than $1700.00 for the SCAT stuff.

    SCAT stuff is nice & if you go that way you might as well go 4 1/4 & a great BIG bore even if ya have to sleeve the block.

    But then it all comes back to How Big & How Much Ya Wanna spend.

    I just offered mine cus it would be less $$$ to buy my "OLD SCHOOL" crank than weld up & grind a Ford Crank to 4"
  12. Pete1
    Joined: Aug 23, 2004
    Posts: 1,678

    from Wa.

    Some Merc cranks were cast steel..These are the prefered ones for welding.
    Welded strokers were common in the old days...4 1/2 inch being probably the most common..330 ci were common with these.

    Like the other guys said, a merc crank stroked 1/8 is the cheap way to go but it will limit
    you to just over 300 ci due to bore limitations.
  13. oldiron73
    Joined: May 26, 2009
    Posts: 396

    from WISCONSIN

    Get the Merc crank.
  14. Correct me if Im wrong, buyt were'nt the stock 3 3/4" cranks cast NOT forged?

    If so, welding up the cast iron crank's rod journals would be a lot different to welding up a forged steel crank which I understand is the preferred way to do it?

    Would'nt the cast crank need to be heated up a lot to enable a decent cast iron weld to be laid onto the journal?

    FWIW, Id prob go the aftermarket option, but you MUSTY check the main/rod journals for taper /ovality.

    Seen too many that have been out of round and needed work to be done right. That includes Scat AND Eagle etc....

  15. As Rat stated - the cast crank would have to -1. preheated, 2. welded, 3. post heated, to get rid of the stresses induced by welding.

    Fuck it - give it a go & let us know how it turns out. While you're at it, get it knife edged as well.
  16. friday I went to pick some cranks and they were welding a WRX crank to stroke and they were using a cold weld process and they use a soft and a hard wire,and they said that they did alot of welded strokers.they offset ground one of my cranks to stroke from 3,31 to 3.512
  17. No matter what the "add metal" process - metal spraying or welding, the total cost is far greater than just getting a Merc crank and going 4 1/8 with an offset rod grind. Then you can use the 21A or 91A rods - with full floater bearings, or buy the H-beam ones and run the Buick bearings.

    As noted, you can go larger with a new SCAT crank - and get your cubes in the 330 or so range - you'll just spend more money and you'll have more piston rock . . . but if you need cubes and have the money, go for it.

    About the only purpose I see in going over 296 cubes is if you're doing some serious racing where the cubes and additional HP will help you.

    Another way to get some good HP out of a flathead - and not having to go so large on the stroke/bore is a blower. Or you could build an injected motor on alky . . . ask Pete1, he'll show you some HP figures that will make your flathead spin!

    Or . . . what the hell . . . go large cubes and a blower . . . and bring a big bag of money to the engine builder!

    There are so many ways to build a flathead - which is one of the cool things about these engines. Have fun . . . no matter what you end up doing.
  18. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,683

    Bruce Lancaster
    Member Emeritus

    I think the issue here is location...everything triples in cost by the time it reaches the antipodes.
    From your question and your letter I assume you have a tame machinest on hand...
    Old tech before 1949...a 3 3/4 crank was done just like the 4 1/8 Merc procedure, resulting in a gain of 1/8" over 239 Ford...this was colstly and small enough that it made for immediate interest in the new Merc crank in '49, but it did work!
    Longer stroke then required either a billet $pecial, way out of sane reach, or welding, commonly done as metal spraying, which worked as long as the welder was good. All is doable if you have some control of the cost at the machine shop! I suspect some crank welding is common on expensive cranks, like ones from big tractors and such where cost of replacement is much higher than in automotive world...go find someone who rebuilds bulldozers and monstrous engines!
    Next--pistons for funny strokes are going to cost more than those for 4 or 4 1/8, unless you resort to primitive terroristic practices. Could your engine swallow a slight piston pop-up?? Maybe in your case stock pistons and a bit of redoming could be cheaper than special pistons...many people have done this, some claiming it as a speed secret and not just a kludge!
    All of this depends on who/how the work happens...I think it requires a real good relationship with the specialists to avoid becoming more expensive than just buying a bunch of high dollar parts! Look over your parts, your options, and who can do what at what cost.
    Remember that offset grinding requires a pretty good core, as resulting throw will have twice the undersize tghe original would have needed.
  19. OP is from Australia, so you're probably on the money with the location issue. Shipping stuff over there is ungodly expensive for some reason. Customs has to look at it and seal it back up right - and you have to pay a duty on it at that. And a crank I bet you'd want to crate up to ship, so it's going to be too heavy to send postal anyways. It may actually be cheaper to weld it up by the time you're done with all that.
  20. banjorear
    Joined: Jul 30, 2004
    Posts: 3,774


    Not sure if I'd say "way better". Still an imported part vs. the Ford part.
  21. Would love to know what costs you guys are seeing with a welded up stroker. When I've talked to machine shops that have the right equipment (specialized welders), it costs $100 - 150 a journal to do the welding, grinding, etc.. Also, I wonder if you still then need to hard chrome the journals - like they used to do? (That is expensive as well).

    It adds up quick - by the time you throw in the rest of the work, balancing, etc - you'll be north of $1000 in my estimation.

    What are you guys seeing on costs out there?
  22. 392_hemi
    Joined: Jun 16, 2004
    Posts: 1,737


    Current metalurgy and manufacturing methods are far superior to what was avail. 50-year ago. The fact that the cores are made overseas doesn't change that. In addition to the cost of welding and machining, there's always a risk of problems from welding a cast part.
  23. banjorear
    Joined: Jul 30, 2004
    Posts: 3,774


    Maybe we need to agree to disagree on this. If all things were equal, I would say your statement is indeed correct.

    Case in point: An imported $9.95 tie rod from Speedway is not of the same quality as a NOS Ford one. The Ford one is certainly made from better materials.

    Or off-shore made brake rotors for a '85 Jetta that can be bought from the big car parts stores are no where near the same or better quality than ones from Volkswagon.

    Both parts are certainly newer but not even close in quality.

    I think if things are spec'd and checked to ensure the spec was held to and required to be identical or of better quality than I'd agree with this, sadly this isn't always the case.

    From what I've heard, a good number of guys have had some issues with the quality of SCAT. Maybe this was early on and they've fixed the problem since. Don't know.

    I've been lucky to find real nice Merc. cranks for my stuff.

    My point is: Just because it's new doesn't mean it is superior to the original.
    Last edited: Jul 6, 2009
  24. Bettlejuice
    Joined: Apr 27, 2009
    Posts: 481

    from WV

    I've used a couple Scat cranks and seen alot more. They're much nicer than even later model factory Ford cranks and are way easier/cheaper to balance. Maybe I've always been lucky. My cast Merc crank ain't as nice, if I didn't have it I wouldn't waste any time looking for a good core.

    They're machined in the US. A Scat crank is a far cry from a $50 Autozone part. A crank cast overseas and machined in the US in modern days is gonna have WAY tighter manufacturing tolerances than a 60 year old part, the Scats are a good crank.
    Last edited: Jul 6, 2009
  25. fullhouse296
    Joined: Jan 30, 2009
    Posts: 378

    from Australia

    Stock Ford crank is nodular iron . They dont take hard chrome ,metal spray or wire weld very well. Yes , it comes out ok ,but when it gets finish ground , it comes away.Steel cast merc cranks are the ones to get , but zyglo for cracks where the journals meet the webs first . youde be surprised !
  26. 51 MERC-CT
    Joined: Apr 5, 2005
    Posts: 1,595

    51 MERC-CT

    Brings back some memories:)
  27. Kevin Lee
    Joined: Nov 12, 2001
    Posts: 7,403

    Kevin Lee
    Super Moderator
    Staff Member

    Where do you get a steel Merc crank?
  28. Doug Kennedy
    Joined: Nov 17, 2009
    Posts: 28

    Doug Kennedy

    Yes your 8BA crank can be welded. Now as far as doing a welded stroker it does get costly. I charge 150-200.00 per jornal. I use a submerged arc welding machine. I have 3 different wires I use for cranks. It depends on the type of crank and the hardness of the finished jornal that I want.

    I also use a semi finished crank for flatheads that I can furnish a new stroker for the flathead from 3.750-4.375 stroke cranks. When going to a 4.125-4.375 stroke you must use a 2.000 rod jornal. In that case I finish and sell a 4340 H-beam rod that is 7.000 long and uses a 2.000 buick rod bearing.

    Most of the welding of cranks that I do now are for just repairing a damange jornal or for welding strokers in a imposable to get crank.

    If you have any questions please feel free to contact me.

    Doug Kennedy
    Kennedy Machine
  29. Hell . . . just dig DEEP into your wallet and get Moldex to make you a billet one for $2500 or so. Put a SBC rear flange on it and a BBC snout on it and you're good to do. Then you can run a variety of flywheel/clutch combinations, standard blower drives/pulleys and you'll be off to the races.

    Yes . . . this is what I'd like to do . . . just can't afford to spend the $$$ at this time!
  30. can't run this! A properly welded crank would have some surface cracks on the journals.

    The above statement is absolutley NOT true.
    I worked several years in a shop with a submerged arc Peterson crank welder. the welder ran everyday doing automtive cranks and a lot of industrial work as well. In fact the local Electric motor place bought it after the shop owner retired and is still using it to build electric motor shafts.
    If the guy welding put enough on and ours did you can not tell ever it has been welded. There are no pockets nor rough edges, nothing . You can not see where the weld is. If there is any evidence it will be at the edge or the flillet but a good operator wil take that in account and make sure he puts enough there as well. Thrusts can also be repaired easily this way. (In fact the rank in my 426 MW has been welded on the thrust and repaired) A completey stroked carnk should be stress relieved but that is only about $100 dollars extra.
    Now for the rest of the story. Years ago I was at Cayauga(now TMP) I saw a gasser running and it had a sponsor from Midland Ontario. I went to see them in the pits and told them "my uncle is from Midland , Wally Daniells and he is a welder." They laughed and said "we know, he makes our stroker cranks. " So the next time I saw uncle Wally who was a gifted craftsman I asked him how to do it and he told me. Now uncle Wally did not use submerged arc , he stick welded them. He told me specifically what to do ,WHEN to do it and how so I did one myself successfully. It worked like he said. Instructions were very specific. I had three uncles who were welders all brothers . Another was also into cars and iis son Mark now crews for Gerg Biffle # 16 even though he is from Ontario Canada.
    Also Muscle Motors a mopar shop of some note began making their strokers by welding (mig process ) They work quite qwell and I would have no trouble making another if it was not avaialble. or if you want to build one "just because" that is ok too.
    Two cranks do not take well to welding because of molecular structure of the unusual metal they use. That is 500 Caddy and David Brown Tractor. Other wise we did hundreds littlerly with no trouble. In fact the 426 hemi I ran in the 70s still has the same welded crank in it I started with and has seen use with a blower and alky even. it is still in perfect condition and has given no problems in some 35+ years of racing. In fact that is how I was able to afford it. It hada severley damaged crank which we repaired in house going all the way.
    If you want to go a step beyond . After welding hard chrome it. Even when you die that crank will still be good even if it is 30 years from now. Cast cranks can and are welded but it isnt always pretty which may be what our friend is talking about. I have hand welded one of them too though for a close friend in a big jam.
    I am an amatuer welder of limited skill. If i can make it work then a pro which is a whole different kettle of fish as many are very gifted at their craft can make it perfecct. Weld is often stronger than original materil. BTW. I know , a thousand reasons why you cant do this or that are coming but this report is from the real world. been there done that. There is a lot that goes on behing the shop counter that few understand. Nowadays as mentioned you can buy cranks of almost any stroke you want. It wasnt always so. Back in the 90s even if we needed something for my favourite engines (BB Mopars) we had to make it or do without. Many of the current group of rodders and racer cant make anythng or wont. If it doesnt come in a box it cant be any good. Tis a shame because that was 90% of the fun. If it interests you find a spare and do it. Then you will have nothing to lose. It will I guarantee you be an intersting and most likely successful experience. It wont necesarily save you money but it will be fun.
    Last edited: Feb 10, 2010

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