John's GM 3.1 V6 (from a 94 Corsica) powered VW Baja
Here's info I have from John via emails.
Email # 1 > howdy, I was checking out your v-6 baja project and was wondering how it was going... my baja buddy and me have put the gm 3.1L 60* v-6 engines in our bajas and they work perfect.... we used the engines as they were in the gm cars, mpfi and dis ( distributorless ignition system) 100 amp alternator, and real heat... not sure on the weight difference but guess about 100 lbs increase, we reinforced the wishbone that supports the trans and it seams to hold everything up just fine... the 3 rib bus trans is ok, the 5 rib gives a little longer legs on the freeway... my car with the 5 rib is turning 3100 rpm at 70 mph ( about 115 klicks ) which it seems to like just fine.... kennedy engineering in california makes adaptor kits for most any engine to a vw trans in the $400-$500 range.... here's a pic of my car with the chevy in it.... looks like it belongs there .... john
Email #2 > Hi Wes,
i can give you a brief history on the 3.1 engine.... gm stole the design
from ford... they used it in the mid 70's in the pinto and little mustang 2
cars.... i remember it first coming out in the chevy citation in about 81...
it was a real pile of shit then.... it had a lot of trouble with the
oil seals and oiling.... in 84 they got the seals figured out but
still had crank problems till 87 when the second generation 2.8 came out....
this one was great... the camaro, chev s-10 pickups used it in a rear wheel
drive setup with mpfi and an electronic ignition ( HEI as it is called here )
whereas the front wheel drive cars used it transverse mounted with mpfi and DIS
( distributorless ignition ) the front drive motors also have aluminum
heads and intake which keeps them much lighter... in 1990 gm
stretched it out to a 3.1L which was the same configutation... just a stroke
increase... they also stretched it out a little more to a 3.4L which
they used in the chev lumina minivan... the 3.4 had iron heads and a throttle
body injection though... i think it also had a distributor... also
in 91 gm made a hotrod version of the 3.4 that had double overhead cams and 24
valves... these engines are great till they puke a timimg belt... which destroys
the engine..... they are near impossible to work on in the car
they came in.... (4.5 hours to change an alternator)... there is
also a 1 year only 3.1 turbo, which i've never seen.... the 2.8 had
about 145 hp at the wheels.... the 3.1 has about 158.... not
sure about the turbo 3.1.... i've heard the dohc 3.4 is rated at 220...
these motors with proper servicing seem to run forever... we've had a few in the
180,000 miles range that still run great....
we use all the factory electronics in our bajas... we use the computer,
harness, and relays from the donor car.... fuel pumps are from vw jettas
or gulfs... the radiator is from a pontiac fiero, (which was a 2 seater mid
engine plastic body sports car that used the 2.8 engine ) we mounted the
radiator in front and cut out below the gas tank to expell hot air...
also cut some round holes in the nose piece... this seems to keep them cool in
moderate weather.... we also used the biggest electric fans we could find...
the computer controls the fan... i also have a manual switch on mine...
for the plumbing we used 1"x2" x1/8" wall steel tubing under the
car.... i've high centered my car on a dirt pile and it didn't even
scratch the tubing.... at the end of the tubing we welded 1.5"
round tubing for hose nipples... we used exhaust pipe to plump to the engine and
radiator.... the exhaust is pretty easy too... it's way too tight to bend,
so we used a chop saw and cut and welded angles... my total pipe is
probably 20" long with a high flow muffler and a 3" tip... and
surprisingly it's fairly quiet...
as for economy, this setup is beter than a bug motor... a baja here will
run an average of about 18 mpg (with our crappy gas) on the highway...
my car runs a solid 24 mpg on the highway.... i'm running a 4.88:1
bus box with 31x10.50 tires...
another bonus to these motors is that most of the cars came with a 100 amp
alternator.... we removed the power steering and A/C pumps and
rigged idler pulleys... still use the sepentine belt, only a little
shorter...
we did have to cut a hole in the firewall to accomodate the v-6...
we used angle to frame a box inside and skinned it with aluminum... it's
kinda nice to unscrew the lid to work on it... the air filter also fits inside
the box.... i know they don't work good on a vw powered baja,
but i have air shocks to firm up the rear when we are offroading... they seem to
work fine, and it's nice to drop em down when traveling on the road... my rear
torsion bars are up 2 notches with the stops cut off, which is about the
limit... the oil pan sits about the same as the vw crankcase also...
the only glitches so far (after 1 year) are idle control....
occasionally they hunt at idle and when you let off the throttle when stopping,
you have to tap the throttle as you push in the clutch or about half the time
they will die before the idle control motor can catch up... i think both
problems can be cured by fooling the computer into thinking the A/C is turned on
which will increase the idle speed by about 200 rpms....
all in all, our cars are a thrill to drive... they won't pull the front wheels
up from a stop (lack of traction), but they will kick ass on most of the jap
hotrods on the road and are perfect offroad..... john
ps... here's a few pics... hope you like... it's a
lot of work, but worth it i think... john
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