offset ground cranks

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offset ground cranks

Post  colorado ford man on February 25th 2018, 12:31 am

I was wondering about offset grinding a 460 crank what rods/pistons for a 0.020" cut. I have quite the collection of un cut 460 cranks and access to a crank grinder, is this feasible to offset cut a 460 crank and use factory rods, seems like the math will put me at zero deck roughly being as I am starting at 0.030 down in the hole??

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Re: offset ground cranks

Post  rmcomprandy on February 25th 2018, 12:58 am

colorado ford man wrote:I was wondering about offset grinding a 460 crank what rods/pistons for a 0.020" cut. I have quite the collection of un cut 460 cranks and access to a crank grinder, is this feasible to offset cut a 460 crank and use factory rods, seems like the math will put me at zero deck roughly being as I am starting at 0.030 down in the hole??

I don't imagine that the extra .020" of stroke will be worth it for a whole lot of power except in an "all out" racing engine ... but, then you probably would not be using stock rods in that type engine. You would need to offset grind it .060" to gain .030" deck height. (If you offset grind a journal .020", you have only changed the journal center-line .010").

Offset grinding .120" and using a production 440 Mopar rod with the small end bushed, is done all the time.

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Re: offset ground cranks

Post  colorado ford man on February 25th 2018, 9:11 am

I don't why I wrote that, I ment to say "closer to zero deck" since yes, you get half to the centerline. I would say cut 0.020 or 0.030 and get rid of half of the deck height plus obtain more cid. Thanks.

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Re: offset ground cranks

Post  colorado ford man on February 25th 2018, 10:41 am

It seems like a sensible wayto do a lot of things, get a more comprehensive deck height, more Compression, and more Cubes all in one operation, If it was something that was paid out might not be economical, but Iwould think with help of my friend, cost and time would be little more than the 150-200 to grind a crank anyway.

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Re: offset ground cranks

Post  jasonf on February 25th 2018, 6:13 pm

How do you offset a stock crank and still use the same size rod? The offset grinding makes the journal smaller???
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Re: offset ground cranks

Post  colorado ford man on February 26th 2018, 1:39 am

its real simple, you buy 0.020 under or 0.030 under bearings, then instead of cutting all the way around just set your rock to only cut the inner radius, leaving the outer radius, pretty cool, the rock actually comes off of the crank at the high spot and then cuts the center, thus moving the centerline away from the mains, and presto, an offset crank.

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Re: offset ground cranks

Post  QtrWarrior on February 26th 2018, 5:36 am

If you're just trying to get closer to a "zero deck", wouldn't it be easier to just deck the block ?
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Re: offset ground cranks

Post  dfree383 on February 26th 2018, 7:04 am

.013 strokers are the norm in stock eliminator
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Re: offset ground cranks

Post  jasonf on February 26th 2018, 8:14 am

colorado ford man wrote:its real simple, you buy 0.020 under or 0.030 under bearings, then instead of cutting all the way around just set your rock to only cut the inner radius, leaving the outer radius, pretty cool, the rock actually comes off of the crank at the high spot and then cuts the center, thus moving the centerline away from the mains, and presto, an offset crank.  

Cool.
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Re: offset ground cranks

Post  colorado ford man on February 26th 2018, 8:42 am

if there was a machine shop close by that decked blocks, that was not an idiot, then yes. Due to the competence level of the one or 2 in the area that deck (or atleast make up an invoice that reflects something like that) then yes. But last time I checked I didn't think ups would ship a 460 lock in one piece, and if I make it into smaller pieces some of them might get misplaced and then I wouldn't be able to utilize my new cool go fast stuff. My neighbor has been cutting crnkshafts longer than I have been alive; The other machine shop decks 460s on a machine for like heads or something and he supports the "other" side with an overhead hoist, it kind of jerks and shakes as he cuts it. He said "well, it aint right but it should be ok for our head gasket" Answer the question or you want me to elaborate on the guy that put rear main seals in backwards, tore it down, and said he fixed it, then I found the problem, the rear main was in backwards, either still or again. He doesn't like me anymore after I told everyone in my community that he lied about his repair than wouldn't make it right.

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Re: offset ground cranks

Post  colorado ford man on February 26th 2018, 8:45 am

thanks for the input. There is about 2machine shops left in driving range that I will use for anything past stock. The other 12 or so are black listed unless it is a kubota 4 cylinder diesel, youcan cut corners on those, as they don't last that long anyway!!

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Re: offset ground cranks

Post  6t6mustang on February 26th 2018, 4:41 pm

Last time i checked local here, it was $350 to offset grind a crank, too much..
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Re: offset ground cranks

Post  colorado ford man on February 26th 2018, 11:23 pm

I should think that roughly $150 would do that, then the mains might be another $75 or so. $600 does the guides, bores it, mills the heads, and grinds the mains and polished the rods, on the last couple I've done. on an 8 cylinder anyway.

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Re: offset ground cranks

Post  BOSS 429 on February 26th 2018, 11:26 pm

colorado ford man wrote:if there was a machine shop close by that decked blocks, that was not an idiot, then yes. Due to the competence level of the one or 2 in the area that deck (or atleast make up an invoice that reflects something like that) then yes. But last time I checked I didn't think ups would ship a 460 lock in one piece, and if I make it into smaller pieces some of them might get misplaced and then I wouldn't be able to utilize my new cool go fast stuff. My neighbor has been cutting crnkshafts longer than I have been alive; The other machine shop decks 460s on a machine for like heads or something and he supports the "other" side with an overhead hoist, it kind of jerks and shakes as he cuts it. He said "well, it aint right but it should be ok for our head gasket" Answer the question or you want me to elaborate on the guy that put rear main seals in backwards, tore it down, and said he fixed it, then I found the problem, the rear main was in backwards, either still or again. He doesn't like me anymore after I told everyone in my community that he lied about his repair than wouldn't make it right.



ups freight ,yellow, yrc, holland, there are some will ship blocks
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Re: offset ground cranks

Post  dfree383 on February 27th 2018, 7:34 am

colorado ford man wrote:I should think that roughly $150 would do that, then the mains might be another $75 or so. $600 does the guides, bores it, mills the heads, and grinds the mains and polished the rods, on the last couple I've done. on an 8 cylinder anyway.

You’re living in a cheaper area
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Re: offset ground cranks

Post  colorado ford man on February 27th 2018, 9:12 am

Not really, I am just good friends with the guy that grinds crankshafts, If I knew how todo it, I could just take my cranks over there and do it myself, but he said If he hasto do it, I pay for the time. He said his prices are from 1990, and he only takes cash, and he does NOThING high performance, He said "those darn racers are always needing something special" I likebuilding engines, but I don't have a good place to put all of them!!

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Re: offset ground cranks

Post  dfree383 on February 27th 2018, 9:30 am

Like I said your getting the work very cheap
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Re: offset ground cranks

Post  colorado ford man on February 27th 2018, 10:47 pm

Yeah; and the guys that charge more don't do a good job; why does that not surprise me. What is the "going Rate" for an engine, mill heads, new guides, hot tank parts, bore, grind and polish crank, hang pistons, and final hone to size. How much roughly?

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Re: offset ground cranks

Post  rmcomprandy on February 28th 2018, 1:15 am

colorado ford man wrote:Yeah; and the guys that charge more don't do a good job; why does that not surprise me. What is the "going Rate" for an engine, mill heads, new guides, hot tank parts, bore, grind and polish crank, hang pistons, and final hone to size. How much roughly?

You're talking out of your A$$ ... you probably have never had anything done like that by a reputable crankshaft guy who knows what he is doing and charges correctly, (not high and not low), for his labor ... or you couldn't spew that kind of rubbish.

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Re: offset ground cranks

Post  colorado ford man on March 1st 2018, 12:54 am

I'll ship you one; you can do it then. RMCOMP. I have had that guy cut crankshafts and/or do head work probably 20 times, john deere 4cylinders, cummins 4 cylinders, my 181 4 cyl boat engine, my 400 in my 1978 f250, a 390 in a f250, some wierd european diesel engines, a kubota diesel or two, a yanmar diesel, an isuzu diesel, a 7.3 powerstroke diesel, and probably a handful that have escaped me. bring your stuff and lets cut a few cranks, we got 2 or 3 going right now; That guy really doesn't want to offset grind anything, the set up alone is the holdback. I have no issue with the work or prices, and talking out my a$$ has nothing to do with it. Some people are content to work for less, all over the world, and forever, it has always been the same, the horse does all the work but the coachman gets the tip.

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Re: offset ground cranks

Post  colorado ford man on March 1st 2018, 12:58 am

I asked a simple question about obtaining zero deck, as well as more cubic inches, makes sense. What does it matter if I OWN MY OWN crank grinder? Really makes no difference. It is my engine. If I can get the crank offset for little to nothing, that remains my business. If a guy asks the time, he doesn't want instructions how to build a clock.

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Re: offset ground cranks

Post  pmrphil on March 1st 2018, 9:18 am

Not wanting to get into a p***ing match, but YOU were the one who said "the guys that charge more don't do a good job"
Kind of a hard slap to most current shops/machinists, don't ya think???
Cost of living varies greatly depending on where you live (and work) so any associated costs are also going to vary.

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Re: offset ground cranks

Post  Albert Clark on March 1st 2018, 9:31 am

colorado ford man wrote:I asked a simple question about obtaining zero deck, as well as more cubic inches, makes sense. What does it matter if I OWN MY OWN crank grinder? Really makes no difference. It is my engine. If I can get the crank offset for little to nothing, that remains my business. If a guy asks the time, he doesn't want instructions how to build a clock.


You are the one arguing, you know that this will only yield you 1 cubic inch and absolutely no gain in compression don't you? Which means you will still be .015 down the hole. Sounds like a lot of Bother for nothing in gain.... I know if I ask a friend to do all this setup and work for nothing he would not be my friend for long....Sounds to me like you are a cheap A$$ Shocked so do us all a favor don't come on here arguing what you don't know and how much of a cheap person you are STFU

have a nice Day

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Re: offset ground cranks

Post  colorado ford man on March 1st 2018, 9:58 am

There are 3 machinists on my area that can cut cranks, I have used all 3. The one would likely take close to a year, the second would doit promptly, quote a price then charge cleaning on top plus add another charge and say well we ran into some problems, you don't have to pay but you don't get your stuff back, and the third charges less than 50% of the rate and gets the work in and out. Trust me, I have used these guys plenty. Now, across the country I am sure there are hundreds of competent machine shops. Now, as for no additional compression, the closer to zero deck you get the better quench, and the closer to zero deck, the compression ratio increases, no different that decking a block. the piston ends up closer to the deck. If everyone got extremely upset that I haven't utilized every single machine shop in the country I am sorry, I was only implying that the 3 shops available to me that grind crankshafts, 2 are not reputable, by my measure. I am self employed and if I treated my customers the way I have been treated by these facilities, there isno way I would be in business.

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Re: offset ground cranks

Post  dfree383 on March 1st 2018, 10:13 am

Make up your mind you want to talk about engine theory, machining costs, quality of work or just argue in general. Please advise so I can formulate an appropriate response Razz
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