Input on welding a crank.
Thread Starter
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Input on welding a crank.
Have a 383 crank (3.75) that has about 500 miles on it but has gone through a couple bearing failures and now is just a touch under spec. Seems I have heard that with a cast crank you can weld the journal and regrind to spec. Anyone have experience with this?
Melting Slicks
Joined: Jun 2002
Posts: 2,844
Likes: 99
From: Orrtanna Pa.
Re: Input on welding a crank. (Fevre)
Get a firm price on the work before you commit.I was going to have a 350 crank turned and found I could get a new one for about $50.00 more.
Much better off getting a new crank if performance is what you have in mind.
Much better off getting a new crank if performance is what you have in mind.
Melting Slicks
Joined: Aug 2001
Posts: 3,047
Likes: 124
From: Wichita KS
Re: Input on welding a crank. (Fevre)
Have a 383 crank (3.75) that has about 500 miles on it but has gone through a couple bearing failures and now is just a touch under spec. Seems I have heard that with a cast crank you can weld the journal and regrind to spec. Anyone have experience with this?
Thread Starter
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Input on welding a crank. (mapman)
Seems I paid about $100 to have it reground the first time but I neglected to check the rods. The rod is out of round and needs resizing. I have a new 383 forged crank but wanted to put together the old parts I have and put that motor in my Formula. I want a lower the comp ratio than the pistons I have are rated at, 10/1, so I can build a supercharged 383 with the forged crank. I also have to take into consideration having a new crank balanced with the old parts which with ext balancing adds a few more $'s to the equation.
Le Mans Master
Joined: Nov 1999
Posts: 5,768
Likes: 3
From: San Diego CA
Re: Input on welding a crank. (Fevre)
If material is welded onto the old crank and then ground to spec, what makes you think the balance is still good? buy a cast Scat or prowler crank for $180-$200 if you need a reliable new crank for fair price.
Unless you are trying to build a real screamer, a static balance of matching the weights of each rod assembly will work. it certainly isnt the preferred method, but is done all the time. In fact since your reciprocating componants are already balanced the crank balance may not be as big an issue.
The last crank I had this done too was over 15 years ago and even if I could remember what I paid it wouldnt apply now anyway. BTW that was for an odd-fire buick V6 that had rod knock for over a month before I diagnosed it correctly - rebuilt over one weekend with reground crank and new bearings.
Unless you are trying to build a real screamer, a static balance of matching the weights of each rod assembly will work. it certainly isnt the preferred method, but is done all the time. In fact since your reciprocating componants are already balanced the crank balance may not be as big an issue.
The last crank I had this done too was over 15 years ago and even if I could remember what I paid it wouldnt apply now anyway. BTW that was for an odd-fire buick V6 that had rod knock for over a month before I diagnosed it correctly - rebuilt over one weekend with reground crank and new bearings.
Thread Starter
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Input on welding a crank. (fauxrs)
If material is welded onto the old crank and then ground to spec, what makes you think the balance is still good? buy a cast Scat or prowler crank for $180-$200 if you need a reliable new crank for fair price.
Melting Slicks
Joined: Oct 2001
Posts: 2,064
Likes: 1,382
From: Halifax, Nova Scotia, Canada
Re: Input on welding a crank. (Fevre)
Why not have the the crank polished.
That combined with an already loose fit should allow you to use a .001 or .002 oversize bearing which should put you back in spec...
That combined with an already loose fit should allow you to use a .001 or .002 oversize bearing which should put you back in spec...
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Re: Input on welding a crank. (Barry's70LT1)
Not an expert on this ( or anything else for that matter ) but I think you can get the journals chromed or something like that to build them up, maybe someone else knows a little more about this.
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Thread Starter
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Input on welding a crank. (vette_c5c6)
Was reading a rebuild manual and found that you can go .040 under on the journals so looks like I got one more regrind left in it. :thumbs:
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Re: Input on welding a crank. (Fevre)
I checked this morning with a very knowledgable Professor that specializes in this type of thing and he is very sceptacle. He doesn't recommend a cast crank and unless put on just right flacks off or if put on too aggressively affects the fatigue of the crank.
I would go for another crank.
I would go for another crank.
Burning Brakes
Joined: Mar 2001
Posts: 1,211
Likes: 5
From: Nashville TN
Re: Input on welding a crank. (Fevre)
Call DS Engines in Clawson - Ask for Mike. 248 583 9240
Top notch machine shop - they do a ton of hi po stuff, would be able to help you out.
http://www.dsengine.com/
Top notch machine shop - they do a ton of hi po stuff, would be able to help you out.
http://www.dsengine.com/
Thread Starter
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Input on welding a crank. (norvalwilhelm)
Thanks Norval, figured it would be optimal for performace, hoping to get one more regrind out of it.
Derrick
I'll check em out, :thumbs: .
Derrick
I'll check em out, :thumbs: .
