3.8 liter stroker.fyi guys

[bobbyjoe]

for those of you who know already,bear with me,for those that dont and are interested jp performance sell a forged 3100/3400 crank...and for those who want more displacement,the crank can be offset ground for motre displacement.i spoke with them and if you want they can set you up with the crank pieces for your 3100/3400...also for those that dont want to fool around ,they will sell youa complete engine,minus intake i think..all forged ,crank rods,pistons,oversized valves,titanium valve train parts with a displacement of 3.8 liters for 6600 us dollars....that may sound pricey but if you starting from scratch,youll be suprised how much all the parts and machine work not to mention the headaches and waiting time to have the work done and assembling it takes...so in the long run it saves a lot of headaches and gets you and the road to fry some tires,instead of being on the phone with machine shop,callling for parets,waiting for ups...etc..........any feed back shoot,,,anyone dealt with jp performance?they any good?

[614streets]

Not worth it.

[bobbyjoe]

614,why you say its not worth it,be specific also.dont just make a general statement thats its not..........

[quaddriver]

Re: 3.8 liter stroker.fyi guys

for those of you who know already,bear with me,for those that dont and are interested jp performance sell a forged 3100/3400 crank...and for those who want more displacement,the crank can be offset ground for motre displacement.i spoke with them and if you want they can set you up with the crank pieces for your 3100/3400...also for those that dont want to fool around ,they will sell youa complete engine,minus intake i think..all forged ,crank rods,pistons,oversized valves,titanium valve train parts with a displacement of 3.8 liters for 6600 us dollars....that may sound pricey but if you starting from scratch,youll be suprised how much all the parts and machine work not to mention the headaches and waiting time to have the work done and assembling it takes...so in the long run it saves a lot of headaches and gets you and the road to fry some tires,instead of being on the phone with machine shop,callling for parets,waiting for ups...etc..........any feed back shoot,,,anyone dealt with jp performance?they any good?

I can put a pretty mean buick 3.8 in the same engine bay for 1/3 the price

[SappySE107]

That price is retarded and I would imagine increasing stroke that much will take away the R/S ratio the 60V6 is good for. How much for the crank by itself? I Could think of better uses for a custom destroked crank to make a 2.5. Thats just me though, if you want to increase displacement and not worry about ultra high RPM, the other stroke could be beneficial.

Still, price the crank alone, cause the rest of the parts aren't worth 6600 with the crank total.

[brian89gp]

Now is this .4L of additional displacement soley from more stroke or is the block overbored?

Doing calculations and assuming that the bore was left stock at 92mm, it would increase stroke from 84mm to 95/96mm. If you wanted to go the other way and use a 72mm stroke it would be around 2.9L.

[bobbyjoe]

brian,its all from stroke,with just the usual bor eto straighten out cylinders,nothing outragous....still within safe limits.....hey quad,can the 3.8 be swapped in there w/o any mods?thats the thing now,,ar eyou buying new mounts,will tranny work,will fuel system and ecm work with a 3.8??how much would it cost (w/o engine)to swap a 3.8 in,,,exhaust need custom fab?tell me,if its a straight forward swap,il do it,but if your cutting it up and replacing this and nickel and diming yourself ,then why bother......lets be real guys ,we have the 3.1 cars for a reason..i gather most folk enjoy them for what they are...if we wanted raw power and big engines,heck i could go by a grand prix or monte or ss camaro and roach my tires that way................building engines fine,but i think when you go a swapping to a totally different engine,then it takes away from the car.heck,gm built a all wheel drive v8 beretta,i dont see many folk swapping v8s in

[quaddriver]

brian,its all from stroke,with just the usual bor eto straighten out cylinders,nothing outragous....still within safe limits.....hey quad,can the 3.8 be swapped in there w/o any mods?thats the thing now,,ar eyou buying new mounts,will tranny work,will fuel system and ecm work with a 3.8??how much would it cost (w/o engine)to swap a 3.8 in,,,exhaust need custom fab?tell me,if its a straight forward swap,il do it,but if your cutting it up and replacing this and nickel and diming yourself ,then why bother......lets be real guys ,we have the 3.1 cars for a reason..i gather most folk enjoy them for what they are...if we wanted raw power and big engines,heck i could go by a grand prix or monte or ss camaro and roach my tires that way................building engines fine,but i think when you go a swapping to a totally different engine,then it takes away from the car.heck,gm built a all wheel drive v8 beretta,i dont see many folk swapping v8s in

well, given that this is the W body board - I can find complete 3.8 powertrains that will bolt right in, from W bodies, with no more mods than 'replace factory part "a" with factory part "b"', same holds true for A and N bodies.

$6600 is an outrageous sum of money for what you are talking about.

personally, Id prefer the austrailian lumina....looks a lot like the US lumina, but is rwd and has a 5.7L engine. the way it should be.

[RacerX11]

6600 is a ton of money for only 11% more displacement. Throw that kind of money at a 3400, and you can get the same power, you just have to rev it a little higher.

What size do the crank journals become when you offset-grind them? Unless the crank forging was designed to have this done, there is not enough material to keep stock rod journal sizes.

What kind of power are they going to get out of this 3.8? Sure, swapping in a 3800 may seem like a lot of work, depending on what chassis, but I wouldn't consider it nickle-and-diming when you could probably get the same power from a 3800 for half the price. That's a whole lot of nickels and dimes.

I agree with Sappy....quote us a price on the forged crank, with both stock stroke, and custom stroke. That is what we would be interesting in. Also, you should probably look into 4-bolt main caps for the 3100/3400 engines. Once you start building enough power to really need a forged crank (400-500+HP), you will blow the bottom right out of the block.

Marty

[brian89gp]

I agree on the 4 bolt main caps, as long as they can be made to fit Gen2 motors and the DOHC. The impression I got from reading the site is that the rod journals are made larger then stock so they can be offset ground to stock size.

[Guest]

There was a thread about this started on v6z24.com, a while ago by Mev. It too k me a while but finally got the specs out of him, it's a combination of bore and stroke, not just stroke alone. I don't remeber the specifics, since I don't want a looooong stroke engine, also kinda pointless IMO, yes torque will go up, but so will rotational twist and harmonics leverage arm weight of the crank along with some other not so nice properties. This is why a shorter stroke engine will usually last a little longer, and alos rev a little higher.

If I wanted a 3.8L I would buy a 3.8L, since the stroke is kept to a good length but the bore is larger, 3.8" actually in some variations of the 3.8L.

I have to agree that $6600 is too much for a storker short block. I know the machine shop I deal with has good prices and I also enjoy assembling my own engines, time is not a concern, but the money I'm putting into it. I am hoping that I can build my engine for The Raven for about that price complete or maybe a little more, but that will also include turbo(s), and make more power than stroke alone could do.

Sappy, GM makes a 2.5L crank for the 660, it's just sent over seas.

[SappySE107]

this is a w body board? news to me.

I know about the 2500 over there, didn't even think about that though. Interesting indeed Id have to see the stroke/bore specs on it again.

[bobbyjoe]

ok guys relax...first of all the crank goes for 755 us dollars....for you blown or nos guys forged is a good thing...........second,i didnt think this was a w body chat,last time i looked it was a 60 degree forum chat
third i dont own a w body,im installing this into a beretta,so if any one can answer my original question correctly,does the buick 3.8 fit inot this chassis w/o major work........lfourth,lets be honest,who wants to cut and fabricate ,and redo ecm,and fuel sysytems just to put an engine in that is the same size!!!!!!!!!!!!!!!!!as a general rule of thumb,horse power equates to displacement size.............fifth,after dropping in a buick 3,8 and retro fitting everything,can yoube sure it will work as well as factory?will you be able to cruise 2500 miles to california w/o worry?..sixth,obviuosly if you offset grind the journals,the rods wont fit,they'll need tobe changed,seventh,im not sure about the rod/stroke ratio,but with custom rods and piston,you can change it to whatever the engine will allow,you might be a ble to bring it back up to stock ratio....eigth,a longer stroke guys equals more torque,no ifs and s or butts, and torque is what moves a car,and its the one thing the smaller displacement/stroke engines lack is torque..............yo yo yo keep it real guys

[Guest]

this is a w body board? news to me.

I know about the 2500 over there, didn't even think about that though. Interesting indeed Id have to see the stroke/bore specs on it again.

Stock 3.1 bore (3.503"), with a very short stroke crank. 2.65" Or there abouts.

Bobby Joe, if you want to stroke your engine to a 3800, go for it, you don't need our approval.

Yes, a 3800 will fit in the 'Retta, just some work to change mounts If you use a seriesI stock mountsfrom another car can be used, if it's a '90 and previous, '91 and later should be able to use that retarded timing cover attached mount.

Displacment does not ALWAYS = HP.

There are reasons why most engines do not use a long stroke, not all of which are directly crank related but mostly.

I'll say it again, I have not heard of or seen any 3.31" stroke crank break or snap, so for us blown or nitrous guys, we see no need for a forged crank, at this time.

I'd have more faith in a short stroke larger bore engine to be reliable than a long stroke small bore engine of the same displacment. Also with a longer stroke crank there is more rotating mass, that will reduce HP potential all else being equal. The moment of inertia also changes. There's much more to engine design than just displacement that makes them work.

[brian89gp]

You brought it up so you should expect at least some constructive critisizm.

Except if the rod ratio falls below 1.6 which is not good, 1.6 to 2.0 is what people say the min and max is, stock is around 1.72 or something. To use a longer rod (this was brought up in the 6" rod discussion) the wrist pin would be where the oil ring is, doable but not reliable. With a longer stroke in able to use the stock 5.7" rod the wrist pin would have to be moved up a little as it is, if stock pistons are used and a shorter rod is made then the rod ratio falls even lower.

A steel crank is great but like Marty said, if your making enough power to break a stock crank then you'll rip the bottom out of the motor with a crank that won't break.

mmm, 2.5 crank. That thing would be a screamer. GM lists it as a 89mm bore and 66.7mm stroke. On the 3.4 it would be around 2.7L