hazmatic Posted June 6, 2003 Report Share Posted June 6, 2003 ;ok i posted befo bout doin a 3.8 supercharge swap but now im sayin fuck it i wanna do a 3.1 conversion sounds easa in cheaper i can probally do it my self but i got a couple questions how much power5 does the 3.1 got no turbo for now and what r therre fir aftermarket parts then the same questions for the turbo 3.1 n while i got my engine out n apart wut else should i do Quote Link to comment Share on other sites More sharing options...
patgizz Posted June 6, 2003 Report Share Posted June 6, 2003 unless your 2.8 blows up, theres no reason to go thru the work of putting in a 3.1, unless you step up to a newer 3100, then you may as well get a 3400. Quote Link to comment Share on other sites More sharing options...
hazmatic Posted June 6, 2003 Author Report Share Posted June 6, 2003 i wuz just browsin the site n found the 3.1 conversion n im guessin the 3.1 has more power then the 2.8 n i plan settin it up for a turbi while i got it apart n eventualy actuallt get the turbo i dont really wanna do a engine swap but is therre a way to convcert a 2.8 to a new 31000 or a 3400 but iznt the 3400 the dohc that has alot of problems Quote Link to comment Share on other sites More sharing options...
rglguy Posted June 6, 2003 Report Share Posted June 6, 2003 to convert or not to convert , that is the question... you want to make ur 2.8 to a 3.1, heres waht you do. 1, geta oil pan gasket, new main and rod bearings, get enought 1 1/2" studs to go around the oil pan and nuts to fit. 2, get 4 liters of oil, a new filter now that you got the basics, 1,get yourself a crankshaft from a 3.1. as well as the upper intake from a 3.1 (that way it will look liek a 3.1) swap the 3.1 crank in for the 2.8 crank, be sure to chage the bearings and stuff and drain the oil first, (that would not be cool to not drain th e oil) and dont froget to lube the new bearings beofe you put em on and dont get your skin oil on the bearing surfaces, will ead to failure and it will suck 2, take off the throttle body or not if the 3.1 manifold comes with one, remove anyting atached to the 2.8 manifold...,next undo the bolts for the 2.8 manifold, pull it of. 3, clean the new manifold, paint it nice, and clean gasket surfaces...may as well replace all the vaccuum hose casue they are probly broken any how, i would advice chaning your pcv valve while you can get it easy, maybe the plugs to and anything else you need to change behind there put the 3.1MPFI manifold on the engine, bolt it on, using a cris kross paterns tightening a bit ant a time starting from center to avoid warping it..if you do your fucked fora real looking 3.1..... 5, bolt back anything you took off... dump in the oil and put the new filter on and fire it up...and voila you havea 3.1 if you want to get fancy, change the airbox, but i wouldnt thats it, any questions email me or pm me, ill get back to you on your amp PM Quote Link to comment Share on other sites More sharing options...
JS91Z34 Posted June 6, 2003 Report Share Posted June 6, 2003 i wuz just browsin the site n found the 3.1 conversion n im guessin the 3.1 has more power then the 2.8 n i plan settin it up for a turbi while i got it apart n eventualy actuallt get the turbo i dont really wanna do a engine swap but is therre a way to convcert a 2.8 to a new 31000 or a 3400 but iznt the 3400 the dohc that has alot of problems No the 3400 is the pushrod version. The 3.4 is the DOHC engine. The 3.4 is not a bad motor. One person has a problem with it and goes off half cocked bitching about the motor to his friends or whoever, and those people start believing it. The 3.4 is just stereotyped too much. Quote Link to comment Share on other sites More sharing options...
patgizz Posted June 6, 2003 Report Share Posted June 6, 2003 gotta change pistons too, just cant toss in a crank. even thothe bore is the same(as with 327 and 302 and 350 small blocks) the pistons are different wherein the pin is height wise. slap a longer stroke crank and the first time you turn the key your'e in for a rude awakening when your piston collides with the head. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted June 6, 2003 Report Share Posted June 6, 2003 It would probably be easier to drop $200 on a used 3.1L and completely replace the old 2.8L than it would be to rebuild the 2.8 into a 3.1. I'm almost certain you can't drop the oil pan without either pulling the engine or pulling the subframe either. Either way, it's not worth it though. 10HP and 18ft-lbs torque is all you'd gain. I would either do a turbo or a 3400. The 3400 minivan movers produced 185HP. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted June 6, 2003 Report Share Posted June 6, 2003 i'm with Shawn. just find a complete preferably low mileage 3.1 with the engine wiring harness and ECM (you'll be going from MAF to MAP system), swap the engine out, clean it, and replace motor mounts & whatever gaskets etc. the only reason to swap to a 3.1 is if you turbocharge it later with TGP parts (bolt on). i guess you could turbocharge your existing 2.8 with TGP parts, but why? 3.1's are everywhere. if not a 3.1 MPFI i would swap to a 3400 SFI and eventually turbocharge that (all custom). joshua Quote Link to comment Share on other sites More sharing options...
hazmatic Posted June 7, 2003 Author Report Share Posted June 7, 2003 i'm with Shawn. just find a complete preferably low mileage 3.1 with the engine wiring harness and ECM (you'll be going from MAF to MAP system), swap the engine out, clean it, and replace motor mounts & whatever gaskets etc. the only reason to swap to a 3.1 is if you turbocharge it later with TGP parts (bolt on). i guess you could turbocharge your existing 2.8 with TGP parts, but why? 3.1's are everywhere. if not a 3.1 MPFI i would swap to a 3400 SFI and eventually turbocharge that (all custom). joshua i do plan on turbo chargin just not right away Quote Link to comment Share on other sites More sharing options...
mdelorie Posted June 7, 2003 Report Share Posted June 7, 2003 While we're on this topic, I was thinking of a swap "road-map" on my way to an L67. Starting with my existing '91 3.1, which is the easiest to step to next? ie. one that doesn't need a different PCM (if possible). as in, which is the most compatible engine to mine? Then from there, move to another one maybe... gaining more experience each time. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted June 7, 2003 Report Share Posted June 7, 2003 there is alot of info swapping the L67 into a W-body. just do a search. you'll need a new PCM & wiring harness for sure, probably a new subframe, and about a million other parts. i would buy an entire engine, trans, and wiring together and buy new motor mounts, replace any gaskets that need it, blah blah blah. i myself haven't looked into it much; i'm more into turbocharging the 3.1 MPFI and my turbocharged 2.2 T2 GTS. joshua Quote Link to comment Share on other sites More sharing options...
Baddflash Posted June 9, 2003 Report Share Posted June 9, 2003 I thought the 3.1 turbo was a different block than the 3.1MPFI? Isn't it built stronger to handle the boost and extra strain? Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted June 9, 2003 Report Share Posted June 9, 2003 I thought the 3.1 turbo was a different block than the 3.1MPFI? Isn't it built stronger to handle the boost and extra strain? Nope. It has a .01" taller deck height to lower the compression. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted June 10, 2003 Report Share Posted June 10, 2003 The crank of the turbo 3.1 is supposed to be a little better than that of the n/a 3.1L. Something like, when they had all the cranks ground, they took the best ones for the turbo and gave the others to the n/a. But, both cranks are made of the same stuff. Robby Quote Link to comment Share on other sites More sharing options...
hazmatic Posted June 10, 2003 Author Report Share Posted June 10, 2003 ok i decided im goin to do the 3.1 converstion n seetin it up fo the latta turbo setup but im wonderin if therre is a aftermarket crank n pistons that will add hp but still supprot the turbo upgrade n wut otha 3.1 aftermarket parts out therre that support the turbo has to be done while the engine i removed from the car so i can do it all at once Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted June 10, 2003 Report Share Posted June 10, 2003 I thought the 3.1 turbo was a different block than the 3.1MPFI? Isn't it built stronger to handle the boost and extra strain? Nope. It has a .01" taller deck height to lower the compression. and turbo 3.1 VIN 'V' MPFI engine got 8.8:1 CR. the n/a 3.1 MPFI VIN 'T' engine got 8.9:1 CR. oooh BIG differance huh? the 3.1 TGP engine is basically a normal 3.1 MPFI V6 with turbo stuff bolted to it. it even has the same camshaft i think. the pistons & crank *might* be a little stronger tho, i'm not sure. still tho it's not a forged crank. joshua Quote Link to comment Share on other sites More sharing options...
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