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420A to 2.4 swap Avenger 1st Gen by bad venge

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Old 04-08-2007, 03:25 PM
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Default 420A to 2.4 swap Avenger 1st Gen by bad venge

the 2.4 engine used in the swap is the one from Chrysler found in the following cars
Stratus, Cirrus, Breeze, Caravan, PT Cruiser, Sebring convertible, Stratus Sebring sedan 2g

you can use any engine from 1995 up to 2002
2003 was the introduction of the NGC computer and the new crank sensor system which is not compatible with our computers so avoid 2003 and up
that include the pt cruiser turbo and srt-4 engines

to do the swap you also need to replace the 2.4 head with a 420a 2.0l head from an Avenger, Sebring, or 2GNT Talon or Eclipse
if you bought a late model 2.4 (2001-2002) you could have one with the new generation of lifters and rockers knowned as the pt cruiser style lifters and rockers
you could swap those in your 420a head for a nice upgrade
the headgasket are the same 2.4 or 2.0 you could use either ones

the 2.4 used 3 different timming belt tensionner setup over the years
early model 95 to late 96 used an hydraulic system similar to the one on our 2.0 engines, big difference is the tensionner pulley it bolts on the water pump instead of the block, and many neon guys have blown the water pump in pieces when using big cams , the pump is not strong enought and you need a particular model of pump to use it
the second system was used from early 97 to 2002 it's a mechanical tensionner and not a very good one
2003 was the introduction of the second generation tensionner and it's the one you should use, it's the one that you found on the srt-4 turbo engine too

to do the swap you also need an UDP because most 2.4 setup have the alternator in the front and the power steering pump in the back and the oil filter is just near the pulley, a stock size pulley will not fit properly a UDP is mandatory

the 2.4 come also stock with balancer shafts they are in a housing inside the oil pan you need to remove them , they are feeded by an oil gallery that you will need to patch somehow, easiest way is to tap threads inside and put a bolt with red loctite

you will need a custom oil pan, mine and Schoby's pan were made using stratus 2g pan cut and tig welded , a custom pan is needed to make space for the exhaust downpipe and the cross member under the car
some early years of the 2.4 have a nice steel pan easy to work with other years have a double layer pan with insultation material, avoid at all cost
also avoid turbo engine oil pan , not a good choice
late model stratus have an alloy pan

oil pump again here several choices are possible some are better than others
again me and schoeby we used a stratus 2g pump it's probably the best you could get early model stratus put the filter 90's from the engine making a mess when you unscrew it, caravan pump have a very long neck for the filter not a good choice either
turbo engines have the filter separate from the pump and you need the turbo oil pan to use it, not a good choice again

you will also need a custom made engine mount for the timming belt
a simple solution is to buy a srt-4 engine mount , the part that goes on the engine it's also the power steering pump on the srt-4 and it's very easy to put the mitsubishi power steering pump that our cars have right on it
the mount also has 2 nice bolt holes on top
hunt the junk yard for a 1g DSM engine mount that goes on the driver side
i's a big piece of steel with a donut the same size as the one on our cars but since it's steel it's very easy to weld on it, unlike the alloy one that we have
from there you cut the DSM mount to keep the donut only and once the engine is under the hood you could hack and weld yourself a simple and strong engine mount using a piece of square tube and a piece flat metal
it was 1 hour job on my swap

pistons and rods ,you could use the stock ones for a NA setup or for an affordable turbo setup you could use srt-4 pistons rods rings and bearing they are really cheap price wise everything is around 1/4 to 1/2 of regular 2.0 parts
if you are using 2g style pistons either turbo or na you will need to turn the pistons 180 degres the top of the pistons is made with a large and the slope should face the exhaust side on NA pistons you could just unbolt the rod and turn the whole thing on turbo piston it's a floating pin system and the rod is also directionnal because the base of the turbo rod had a oil squirting system you can't just turn them so you will need to split the piston from the rod and turn only the piston 180 degres
you could also have aftermarket forged pistons and rods
srt- parts should be good for 400 hp

electrical compatibilty: the 2.4 and the 2.0 are using the same style of computer but the engine have a big difference, because of the balancing shaft assembly the crank sensor on the 2.4 engine is not on cylinder 1 but on cylinder 2 the cam sensor magnet is also positionned in different way than the neon dohc engine to keep the right timming
the 2.4 computer knows it , our don't
there's an easy cure for that, we need to make our computer think that cylinder 2 is cylinder 1 of a 2.0
first we need to turn the magnet of the cam sensor 90 degres CLOCKWISE by doing so when cylinder 2 will be at TDC the magnet instead of showing cylinder 1 at BDC it will show like cylinder 1 at TDC
second we need to switch injectors from 1 position to the left
cylinder 1 injector is connected to cylinder 2, cylinder 2 is connected on cylinder 3, cylinder 3 is connected on cylinder 4 and cylinder 4 is connected on cylinder 1
last step is to cut wire 1 and 3 of the coil pack and connect them 1 on 3 and 3 on 1

what's happening by doing all this
when cylinder 2 is at TDC by reading the crank sensor the computer thinks that cylinder 1 is at TDC the computer verify by reading the cam sensor, the magnet is turned 90 degres the computer is not sure that cylinder 1 is at TDC
it will send fuel on cylinder 1 and fire on cylinder 1 and 4 (that's how our coil pack always firing 2 plugs at the same time)
but we rewired the injectors harness so the real open injector is on cylinder 2
and since we also reversed how the coil pack is working instead of firing 1 and 4 we are sending fire on 2 and 3
neat and easy
how could also fine tune your timming by playing a little with the magnet

performance wise the 2.4 was design by the truck division of Chrysler using off the shelves parts from the neon/420a engine and refined by the engine division it's a workhorse and not a high speed runner
on stock form the 2.4 is very restricted by a choice of cams made for a smooth low to mid rpm with no air available above 5500
but with a ported head, big or huge cams , a performance computer and all the performance parts available the 2.4 made over 230 WHp in several neons

I don't recommend doing an atmospheric 2.4 in our car because we lack many many parts to really profit from the swap, we almost don't have performance computer except for 97 , we don't have real long tube headers etc etc

for turbo the swap is very interesting since a turbo engine don't really need to rev above 6000 rpm and srt-4 parts are really affordables
with the stock 2.0 cams right now without the turbo i could push the engine to 6000 rpm so far that's enought for me since i have an atx car

the engine can work with the mtx or atx tranny and i strongly recommend a 55 mm tb

that's about it for today

Avenger1stGen
 



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