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#1
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"When it comes to crankshafts, if forged, you can ALWAYS add material. It's done every day. We shy away from cast cranks with welds, as the surface tension and grain are adversely affected by the process. But a good steel one? If done right, has zero ill effects."
Jim, do you see any problems with adding some material to the counterweights of the cast cranks with nickle rod for balancer purposes? We have also had quite a few "tightened" up at the thrust without any noticable ill effects (never broke one at the thrust journal, even on high HP applications) by welding them up and turning them down........Cliff
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
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#2
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Quote:
Is that such a hard concept to grasp here? So let me get this totally straight,,,your telling me it makes more sense for a guy wanting a standard rod journal 3.75" stroke crank to have to take his brand friggin new forged crank in to get it welded up and reground,possibly straightened and re-indexed to get what he wants vs. asking the folks wanting the smaller rod journal to do a simple re-grind/turn down of the journals on the crank to get what they want??? By the time you spend the $$$$ to do that you might have just as well ordered a custom billet crank the way you want it to begin with... Ask me that's just a$$-backwards,plain & simple. There are plenty of standard rod journal engines out there that run hard with zero issues for doing so,,,are you guys trying to now tell me that every standard rod journal pontiac engine you guys ever built is a ticking time bomb for doing such??? Yeah,,,I did'nt think so... I mean what would your customers think about that scenario? And I dont really care that much for the idea to use Dude's "double top secret/extra special" rod bearings he says he has for this sorta application,flawed logic is still flawed logic no matter what spin is put on it,JMO/FWIW. I'd bet $$$$ these 3.75" cranks wont sell that well at all with the bbc journals,and likely will be the first crank offering they either dump entirely,or end up having to offer them with the standard journals to get more sales.
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#3
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double secret........... Bwahahahahahahaha. No they are available from just about any engine shop source.
That's funny. |
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#4
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Cliff,
Nope. It seems okay when welding in weight for balancing. That portion of the crank isn't under so much stress. As for welding the thrust up to use a large journal crank in a small journal block, I've seen good and bad. IF (big IF) the crank guy goes through the entire process correctly, preheating, and spray-welding, it has been successful on many occasions. I've also seen many Pontiac cranks come out of block in two pieces, broken right at the radius on main #4. We have also seen, from companies like Standard Crankshafts and CRI (Crankshaft Rebuilders, Inc), where the cast crank came out of the "kit" box at standard. These ALL fail magneflux at the radii due to the welding. Had a 400 Ford last year, with nearly 70K miles on the rebuild, start knocking. Took it apart, and crank was broken right behind number 1 main. Stuck another "kit" in it (.020/.020) and it's over 100K now. For those that still don't understand why the racers want the BBC journals more than those that don't, I can't help you anymore. Based on current attitudes and the performance "environment", I doubt the 3.75 stroke will sell very well no matter what rod journal it has. The current thinking is "bigger is better", so the vast majority will be at least a 4.25" stroke. Thankfully, the 4" stroke is on everyone's "list". Jim |
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#5
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__________________
If you cant drive from gas pump to gas pump across the map, its not a street car. http://s207.photobucket.com/albums/b...hop/?start=100 |
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#6
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I'm not making this too serious,but it does bother me that some folks "on high" dont seem to have an open mind on this topic,and only want to look at it from one POV,and that's their own POV,and are not very responsive to the wants of those who spend their hard earned money on these projects. Still the idea of a .050" "thicker" rod bearing is'nt instilling any deep confidence in my mind,,,sorry... Please do explain how that bearing will add strength & durabillity to any 700 hp 3.75" stroke combos? Is that not a "band-aid" approach,if it were'nt why not build all motors that way??? And still no comments on all those stock rod journal motors ya'll have built thru the years... So,do you guys in fact think/feel/admit those stock rod journal builds you've done for customers thru the years were/are all junk,worthless as "race" motors because they're crippled with the stock pontiac rod journal dimension? Would you now refuse to build one for a customer if that were his wish,or those were the parts he already had on hand. How do you guys explain all the many "race" engines out there in the past and as well as nowadays that apparently run just fine with the stock rod journal size??? Do tell,,,enquiring minds wanna know... I agree the 3.75" stroke cranks are a tough sell these days,that is EXACTLY why I said making them even less marketable from the get-go by offering them only with a bbc journal was a boneheaded move,when just a little bit of thought,and understanding of the market for such a piece suggests the obvious market for that 3.75" forging is for the stock journal "replacement" crank first,and the bbc "race" journal secondary to that. Lots of "commercial" grade rebuilds of engines like the sbc and such get forged cranks in them,even when they're not slated to make 700 hp,does it make more sense for a 400 hp 383 cid sbc get a forged crank than a comparable 400 hp 400 cid pontiac? Like I said,the logic here is'nt that deep,or hard to grasp. Folks often like to add some extra margin of quality when replacing a piece like a crank,why not use a forging,if I gotta spend some amount of money on a crank anyways,a little extra premium for the forging would be no biggie really,as long as I dont hafta fork out a bunch more cash buying or replacing parts I already have,or go thru the added trouble or time involved to find a competent crank shop or machine shop to do this extra work to get it in the motor. Not all that different from the cast/forged rod decision making process. Dude has his 8 cast 10/10 cranks for sale in the perf. parts forum for $200.00 ea.,now a fella needing a "stock" 400 replacement crank sees that and goes hmmm,it would likely cost that much to turn my core 400 crank and get it to spec anyways,,,but wait,,,Ohio crankshaft has a brand spanking new 3.75" stroke forging for $575.00,,,whoa now I gotta think a second,,,that's only $375.00 more,,,(wheels turning...) Is the picture getting clearer here,most guys would consider that reasonable cash outlay as long as it does'nt mean an a$$ load more $$$$ or grief to get the crank in the engine. Those 3.75" forgings should have made the cast 3.75" cranks worthless IMO. Not the other way around.
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#7
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Sceamingchief
If there is such a market for these 3.75 Pontiac journal cranks why don't you profit on it. Find some investors, pitch your sale , and sit back and let the money role in. If that doesn't work, morgage your house , tool up , and start forging them. I'm guessing these companies making the cranks may know a little more than you and I both about the "market". However, If you follow one of my 2 ideas you will end up with the crank you want, not to mention broke and homeless. Good luck
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#8
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Ok, since you brought up not liking to use .050 thicker bearings.
Which can handle the heat better. And why. Standard or thicker? Not being a m.a. Have my own theories. Just picking an experts brain ![]() BTY, if i was going to buy a crankshaft to go fast, it would be a 4" with 3" mains.
__________________
If you cant drive from gas pump to gas pump across the map, its not a street car. http://s207.photobucket.com/albums/b...hop/?start=100 |
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#9
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Quote:
Actually I was just supplying info if others wanted to use a .050 bearing. For everyday use. Not a problem. Under load or race conditions, I wouldn't recommend it. I don't really see what people want in a $600.00 400 steel crank with 2.250 journals. But that's me The demand would be less then 10% of the totsl crank market. 99% of those 400 builds are midly stock or numbers matching anyway for my shop. A cast crank will take 650hp anyway. How many broken 400 cranks has anyone seen over the years. I have never personally seen or heard of one on this board in 8 years. The rest I take their 400 blocks and turn them into either 4", 4.210 or 4.250 deals anyway. I don't see a big market for 3.75 cranks, especially when the 4" in a IA2 is the same as a 454. And will rev to 8500 nd live. Installing a 3.75 would be like the old 427 deal of the 70's. This will go on untill the cows come home and don't see an answer or solution. Unless someone puts up the money for this crank. Period. Let the journal wars continue. LOL. |
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#10
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Quote:
The easist is the 4.350 bore with a 4.250 stroke for people not wanting to get into heavily modified heads, etc to make the 535 work efficiently. Ya can twist that combo (505) 7200 and not break a sweat. |
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#11
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#12
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If I was road racing I would use the 4" crank and a 4.350 bore. Better off the corner deal. I have built a few road race combos. All 428 style. All run great. t would run 7000 no problem. But I would get into some serious internal components.
It would be a 476 cu.in. BBC style combo and build along those lines. Just need a good flowing head with great mid numbers and the right camshaft choice. I don't have any info on the durability of the aluminum block. I think the Jury is still out on that deal and long term heavy duty useage. You would need more gear. And I don't think a tremec will hold up. |
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#13
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#14
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Jim, we've never tried to weld one up for the small 3" journal, but have welded quite a few turned 455 cranks that had too much thrust clearance. The shop I send them too has a machine that does it, with a special process. I refuse to run one with more than about .008" thrust, .004-.006" is where I like them, so we have them welded up, costly, but I sleep better at night!.....Cliff
__________________
If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
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#15
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"If people are determined to use Pontiac size rods. I can supply .050 rod bearings for the BBC rod journal size." So in reality you offer a .050 undersized PONTIAC BEARING that fits into a pontiac rod that will fit on the chebby rod journal Pontiac crank. In my mind the Pontiac bearing would work well as the actual bearing material is exactly the same thickness just each bearing shell has a .025" thicker backing material vs stock. This is for street cars. If the car was raced at all I would use the 6.635 Chebby rod and the chebby bearings as they are a much better bearing material and there are a lot more Chebby bearing offerings. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#16
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My stock journal,TRW piston 455 is still running fine.11.20s on pump gas NA.It would be great if the .3.75 forging was a Pontiac journal so if someone wanted to turn it down to BBC size they could if they wanted to.
But I am happy that it is even offered in BBC rod bearings.The only real extra costs is the pistons and you end up with a lighter stronger one anyway.Pay the 575$ for the Ross(or whatever "good) piston you want and be done with it.The 6.8 rods are not expensive,cheaper than 6.625. So you pay 200-300$ more up front and you end up with a 400 with stong light pistons(better)6.8 long rods(better) and thinner rings(also better) It sound like a win win to me with not that much more up front costs. If I were to build a good 400 that is how I would do it as opposed to one with TRWs and 6.625 rods. |
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#17
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"Dude i ask because i whant to at least be equal to this car!!!!! chek this site out......." You don't have a snowball's chance against "Big Red" with a Traditional Pontiac engine. I know the car well. He could start a business just selling the oil coolers he has on that car. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#18
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Last edited by roadrage david; 07-21-2007 at 07:28 PM. |
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#19
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Who told you those numbers?
Do the math on what hp it takes to run 230 mph in a camaro body style. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#20
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Wel Tom they told me so on there website!!. chek out the video chapter and then select the engine and specs .. they detuned there engine to make it last and to be able to reatch that speed(200 miles per hour).there engine builder in that same video says that they could go 20 ore 30 miles faster if they used the engine in a newer camaro ore firebird!(thats the 230 miles you refearing to). because big red pushes a lot of air... im not into drag raceing myself but in vintage transam raceing and the pro-touring g-mashine seen. my frinds 70 formula with only 500 hp and 570 lbs feet of torque with a tr2004r trans is doing a 150 miles a hour and this is a bone stok car with minor suspention upgrades. my own car (68 bird) is build on a mutch better platform lighter no ecspends spared (same transmission) and for a first atempt not to bad for a girls car.it should do 162.5 miles when finished with a 550 hp engine. so a ecstra 300/350 hp should bring 37.5 miles exstra upto 200 miles a hour in a better airodynamic car like the 69 gto dont you think ...ps you ment oilcoolers and radiators and brakes like this........
Last edited by roadrage david; 11-17-2007 at 03:55 AM. |
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