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You can stroker the 6G74 to a 4L. Pampena sold the shortblocks. The 6G75 is capable of more.
I don't think Ray even knows the full capacity that you can bore and stroke a 6g74/6g75 to, the only limiting factor to how much you can stroke either engine lies in the piston skirt to counterweight clearance, not to mention that when a 6g75 is at BDC on any cylinder, the piston skirt slightly protrudes from the cylinder itself, when I have time on Friday, I will attempt to take a measurement of both
 

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boring out gives greater results per changes of dimensions, ie, a millimeter overbore on a 6g75 gives you 3908.7 5 cc's, meanwhile a millimeter increase in stroke give you 3870.2 cc's

price wise, boring out is so, so much cheaper than a stroker crank, oversized forged pistons cost a minumum of $900 (roughly, I have a spread sheet for calculating the price of custom Ross pistons) depending on which manufactor you use, Mitsubishi has oversized cast pistons for less, but these are much weaker, the greatest variable here is how much your machine shop charges you
anyway, a stroker crank from Ray Pampena costs $3,950, and you would still need custom pistons at a minimum, which brings the cost up to $4800 at the minimum for parts alone, at which point, you might as well bore out you engine while your at it, add in machining, well to put things in perspective, a stroker short block from Ray costs $8,499.00
 

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Discussion Starter · #25 ·
Holy shit! I'll say.
So what if a guy does an over bore and all internals,but still wants the option of going with a turbo down the road. What compression pistons would you recommend where you would gain substantially in an n/a application while still being safe with running 6 to 8 lbs of boost later on?
 

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in general, when your building an engine, it will be for one purpose, all N/A, forced induction or nitrous and so on, this is because of two things (ignoring fueling here), the cams and ring gap, of the two, once an engine is assembled, you can't change the ring gap, for nitrous oxide/nitromethane/forced induction, you have to run wider ring gap, for naturally asperated, you can run smaller ring gap (go by the manufactor's reccomendations for all ring gapping)

so a multi purpose engine is difficult to say the least, for lower boost levels, you could run a ring gap between the rec'd for N/A and forced induction, but that seems half ass to me, on the one hand when you are N/A the extra ring gap will at a minimum you will have a lot of blow by, loss of compression, oil consumption and possible complications with break in, and when you go with forced induction, you are limited in the boost and power because beyond a curtain power level because of the heat, the ring ends will butt together and that will kill the engine, from what has been posted on this forum, you can run that level of boost with a stock engine

so based on this, with a built bottom end, you could get away with the stock compression ratio, which is 10.5:1 if I recall correctly, but honestly just for long term durability and so you can run more boost later, I would take the compression ratio down a little bit, maybe 10.0:1 to 9.7:1
 

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good information. with the stroker kit for the 6g74... is there anything anyone can get for the 6g75, i want to go to a 4.0 as well. but i live in milwaukee wisconsin and have no clue where to take it too.
 

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To go beyond the existing stroke of the 6g75 (which is basically a bored and stroked 6g74), you will have to go custom, there are no shops outside of Pampena Motorsport (and maybe Brian Crower, but that's up for debate) that make a kit (for Pampena, they make the crank and (can get) pistons, they can make rods for both the 6g72 and 6g74&6g75) and the engine (using your stock engine block, heads and so on) itself should be assembled at the best machine shop you can find, the bottom end must be balanced, you must (or it will generally be quite expensive) a torque plate, and so on

Once again, with a simple overbore to 97 mm, you will hit 4.0 liters, it will cost a fraction of the price this way over using a stroker crank
 

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Pampena is price gouging people, because the "stroker crank" thst he uses in this 6G74 build comes from one of our foreign trucks. It's a stock crank that he has had made out of some other materials. The measurements were already there for him. All he did was change the face of it to sell it as something new and not out in the market.
 

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*raises eyebrow*
while this entirely doesn't surprise me, it is difficult to entirely engineer an crankshaft that follows different specifications than a stock one, especially a one that is as complex of a design as a 6g7X crank, I don't entirely blame him, however, it might be possible to get a stroker through Brain Crower, they are somewhat denying that the Hyundai G6DA (Genesis Coupe v6) crank could be interchangable with a 6g74/75 crank (G6DA rods are shorter 6g74/75 rods, dimensions outside of center to center length are the same), they didn't say not interchangable in what dimension of what part of the crank (main bearings too wide, overal length too long, snout is too long or too short, and so on), then agian I was speeking only to one of their sales people, of which he didn't refer me to one of there engineers, I'll give them a try again in a week or two
I should point out that the main bearings of the G6DA iirc is larger in diameter, the point of using one of these crankshafts as a design base is that a 93 mm stroker for this engine exists, it might be possible to go larger, I'll let you guys know when I find out later
Wingo, do you know what family the crankshaft of the engine Ray is basically manufacturing billet versions is? if possible, I would rather use one of those crankshafts (because forged is actually stronger than billet most of the time) than a billet one




before anyone gets the idea of using a super long stroke with the G6DA rods, there are problems called 'pistons exiting the bottom of the cylinder' and 'piston skirt coming into contact with counterweight', I say myself when I was pulling apart my 6g75 that a portion of the bottom of the piston skirt actually exits the cylinder, if you reduce the length of the rods and(or) lengthen the stroke too much, the wrist pin will exit the cylinder and this usually spells bad news for ring, sleeve and piston skirt lives
 

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near 9 year old thread, but I feel like I should follow up as there are unanswered questions and since my re entry back into the car world, I have found some things I wish to shair so people digging aren't lost

first; the (then billet cranks) from Ray Pampena were 3.75 inch in stroke, which follows a spec from monkeywrench that came into existence even farther back, I did measure a sleeve length of roughly 105mm many years ago, the re measure will be in my comparison thread soon

second; G6DA has a slightly wider bore spacing meaning that any derived crankshafts would not work, but the VQ family and VR38DETT have the same 108mm bore spacing*, but have different bearing sizes; the VQ35DE has undersized mains and rods vs the 6g74/5, the VQ35/37HR has oversized main and undersized rod bearings, and the VR38DETT has oversized rod and main bearings. So by all weirdness, these Nissan crank designs could work as a basis for aftermarket crankshafts for the 6g74/5 platform

*when I was having my 6g74 block bored, the shop initially thought that it was a VQ block until I told them it was an iron Mitsubishi block because they checked the bore spacing
 
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