I know people have asked in the past about an L61 to LSJ swap on 03-05 Cavaliers and the complications, but my question refers to a partial swap. It revolves around mantaining the original Cavalier PCM. Now I know that some of the issues with the swap include its coil-on-plug ignition, the harness, transmission, fuel rail (not to sure, if someone could elaborate on this issue) and fuel delivery, intercooler, engine mounts, and others I can't think of right now.

Well here is the thing, I have a 2003 Cavalier with an L61 at 104,144 miles and have been planning on doing a performance rebuild on the engine. Then I thought about the swap and pondered further. Since the LSJ block is stronger and built for forced induction, instead of building up a beat up L61 (I would rather start with a brand new race prep GM L61 block) by boring it, putting new sleeves, pistons, rods, head, etc. couldn't one just:
1.) take an LSJ engine (oil pan, block, head, header, intake monifold, s/c) from the junkyard,
2.) installed the L61 valve cover (since the the bolts for the middle cover, or CDI in the L61, are different), so one can put on the L61 CDI,
3.) connect the L61 harness to the sensors on the LSJ block,
4.) maintain the (in my case) automatic transmission from the L61 and bolt it on to the LSJ (I'm not sure on the bolt pattern, though, but I am pretty sure they would be the same since it is the same basic block),
5.) install an aftermarket fuel pump (or maybe even the LSJ fuel pump),
6.) take the resovoir, aftercooler and pump from the LSJ and adapted it to the Cavalier like bolting on an intercooler,
7.) if the lower mount and/or oil pan is different then excahnge the LSJ with L61 oil pan and lower bracket,
8.) and take the Cavalier to a GM dealer and have them reprogram the PCM for the GM Cavlaier/Sunfire Supercharger Kit #17800003 (although that reprogram is for 8 psi or boost not the LSJ 12 psi, maybe slip the tech a 20 to boost up the fuel table).

I would get a stronger block, higher flowing stronger head, 12 psi S/C with the easy-ness and stock-like, medium difficulty, swap. Not just that, but couldn't one use the stage kits for the S/C LSJ and upgrade the pulley, 2-pass intercooler, injectors, etc.

If anyone can tell me why this might not work or if I have forgotten any issues, let me know, because this swap would only cost me no more than 3k with an extra 5spd tranny laying around for sale to recouperate some of my money.

http://www.j-body.org/forums/read.php?f=2&i=411449&t=411449

as mentioned on ecotec forums.


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my carDomain updated 8/2/08 Boosted at B-day!

1.) take an LSJ engine (oil pan, block, head, header, intake monifold, s/c) from the junkyard,
*You can't use the oilpan for the 2.0 because the lower engine mount won't bolt to it.

2.) installed the L61 valve cover (since the the bolts for the middle cover, or CDI in the L61, are different), so one can put on the L61 CDI,
*Can't do it, the bolt patterns don't line up. When I attempted this I simply modified the coilpack to bolt to the lsj valve cover

3.) connect the L61 harness to the sensors on the LSJ block,
*Possible excluding the crank sensor which you needs to be swapped

4.) maintain the (in my case) automatic transmission from the L61 and bolt it on to the LSJ (I'm not sure on the bolt pattern, though, but I am pretty sure they would be the same since it is the same basic block),
*Bell housing bolt patterns are the same

5.) install an aftermarket fuel pump (or maybe even the LSJ fuel pump),
*Ok, if necessary? Not sure the pumps are even remotely the same on the two though.

6.) take the resovoir, aftercooler and pump from the LSJ and adapted it to the Cavalier like bolting on an intercooler,
*Yep, same thing everyone else has already done or an alteration of since many are intercooled.

7.) if the lower mount and/or oil pan is different then excahnge the LSJ with L61 oil pan and lower bracket,
*Noted in #2

8.) and take the Cavalier to a GM dealer and have them reprogram the PCM for the GM Cavlaier/Sunfire Supercharger Kit #17800003 (although that reprogram is for 8 psi or boost not the LSJ 12 psi, maybe slip the tech a 20 to boost up the fuel table).
*They won't, unless you somehow know someone or actually purchase the supercharger kit.

All this work seems silly to me, I don't see how the lsj is really any better then the L61 aside from being stronger off the bat. Cobalt guys are breaking engines with smaller pulleys. Get some rods, pistons, bore the block if necessary and finish the L61. Don't even bother touching the head unless you have a decent amt of money for the upgraded valvetrain and head modification necessary for most upgraded cams.


12.770 @ 111.99 Intercooled Eaton M62

^^^What he said^^^^ If I were to listen to anybody when it came down to the S/C L61 it would be Airtonics, look what he has done with his

Well here is the problem, like most guys, I'm dirt poor, and it would be easier to convince my wife into buying a block from the junkyard than saying "honey, I'm going to buy a superchager, rods, pistons, boring, etc.". Also the S/C alone cost 2500+ on top of the other mods plus ripping apart the block when I have no back-up money incase I kill the block. It does seem silly, just thought it might be a crazy, different, cheaper, easier alternative.

Quote:

crazy, different

Yes it would be

Quote:

cheaper, easier alternative.

No.

Jesus Jacobo wrote:Well here is the problem, like most guys, I'm dirt poor, and it would be easier to convince my wife into buying a block from the junkyard than saying "honey, I'm going to buy a superchager, rods, pistons, boring, etc.". Also the S/C alone cost 2500+ on top of the other mods plus ripping apart the block when I have no back-up money incase I kill the block. It does seem silly, just thought it might be a crazy, different, cheaper, easier alternative.

Not to pry or tell you how to spend your money, but I would suggest if you're having money troubles that you shouldn't be modifying your car. There will always be time for the car, but as anyone on this site knows - they're just hobbies, there is no gain when it comes to cars really. So you can go faster, it's fun but its expensive and that money could be put to better uses.



" To study and not think is a waste. To think and not study is dangerous. "

BTW airtronics, not trying to be a dick, but you can get the reflash without buying the s/c kit. At least here in Canada you can. I know when you buy the kit they give you a number or whatever it is, but you don't need it. You just need a tech that knows what he's doing. The guy that did mine found the reflash, took about an hour.

Mr.Choo wrote:BTW airtronics, not trying to be a dick, but you can get the reflash without buying the s/c kit. At least here in Canada you can. I know when you buy the kit they give you a number or whatever it is, but you don't need it. You just need a tech that knows what he's doing. The guy that did mine found the reflash, took about an hour.

Just so you know, if GM catches him doing that his dealer could be in for a world of hurt from GM. I used to work in a dealer. I know how this is supposed to work. I have done the reflash the "back door" way. Not really worth the risk I put the dealer through.

seeing as I've taken countless L61s apart, and tore down an LSJ to practically nothing, and I have an LS61 (L61 head+ LSJ block) in my car at the moment, allow me to elaborate (much like airtonics did)

Quote:

1.) take an LSJ engine (oil pan, block, head, header, intake monifold, s/c) from the junkyard,

thats fine. They can usually be had for $2500 out of a junkyard for a complete engine (including s/c and harness)

Quote:

2.) installed the L61 valve cover (since the the bolts for the middle cover, or CDI in the L61, are different), so one can put on the L61 CDI,

Can't put the L61 valve cover on the LSJ, the LSJ has two flanges on the backside of the engine (driver side if you think sideways FWD style) and the L61 valve cover only has one bump (where the power steering mounts).

L61 head:


LSJ head:


you can only use the appropriate valve cover (cam cover, whatever you wanna call it) with the matching head.
The ignition systems will also only bolt onto their matching valve cover. I'll double check this tonight since I have both an L61 ignition and LSJ ignition sitting at home.

The LSJ also uses different style spark plugs than the L61. I'm pretty sure the cobalts have a small washer to seal, while the L61 has a taper seat.

Another risk is that the flange for the cam sensor on the LSJ (the one closest to the firewall, or to the left in the picture above) has a possibility of running into the brake booster of the Jbody. Since nobody has tried that yet, its still not really known whether or not it would physically fit.

Quote:

3.) connect the L61 harness to the sensors on the LSJ block,

several problems here.
first, the LSJ moves some sensors around. The coolant temperature sensor being the biggie. The L61 has its sensor on the back by the thermostat housing. The LSJ has it in the head near the upper coolant hose. You'd have to cut and extend the wire to way up there, but this also leads to another problem...

the LSJ has an oil cooler, which gets in the way of the L61 thermostat housing. The LSJ's thermostat housing interferes A LOT with the F23 transmission.

You can either make a bypass hose for the cooler by threading into the sleeves in the oil filter boss, or some other way. YOU CANNOT just block them off, because the cooler is situated so that oil is forced to go through it. Blocking both holes off will cut off oil recirculation, and starve the engine of oil. If you bypass the cooler, you can use the L61 thermostat housing no problem, as well as the L61 lower radiator hose.

The problem with this is I'd want to keep the cooler since you want the supercharger, AND the LSJ has piston squirters and while I'm no genius engineer, I'd imagine they absorb quite a bit of heat from the underside of the pistons (why they're there) so the cooler probably helps keep the oil from getting heated, and keeps the engine and oil healthy.

If you do keep the cooler, you have to re-arrange your coolant hoses because you now have 2 extra connections for the oil cooler (its plumbed with coolant to cool the oil.. yes an oil to water cooler)

secondly, no one (including myself) knows quite how the LSJ will interact with the F23 transmission yet. The LSJ has an 8 bolt flywheel and a larger diameter clutch. The O.D. is the same so it fits inside the bellhousing no problem, but the depth of the clutch is different, and the bolt patterns are VERY different from L61 clutches so its impossible to make a hybrid of the two, you have to use either one or the other (I'm using a stock cobalt SS clutch with my F23 transmission, and a cavalier clutch actuator.. still HOPING it works but I haven't finished the project just yet)

Quote:

4.) maintain the (in my case) automatic transmission from the L61 and bolt it on to the LSJ (I'm not sure on the bolt pattern, though, but I am pretty sure they would be the same since it is the same basic block),

The bolt pattern is indeed the same, but getting a flex plate and a torque converter for the LSJ might be hard since they were never offered with an automatic transmission. Custom units could be ordered I suppose. IDK if the thermostat housing will interfere with the auto or not.

Quote:

5.) install an aftermarket fuel pump (or maybe even the LSJ fuel pump),

I would leave the LSJ fuel pump alone. Racetronix is the best in-tank fuel pump upgrade for the jbody at the time (unless you go insane)

Quote:

6.) take the resovoir, aftercooler and pump from the LSJ and adapted it to the Cavalier like bolting on an intercooler,

ok

Quote:

7.) if the lower mount and/or oil pan is different then excahnge the LSJ with L61 oil pan and lower bracket,

L61 pan has to go onto the LSJ block.

You also need to use the L61 upper engine mount, the cast aluminum peice that bolts to the block just above the timing chain access cover (the LSJ's cast engine mount is different) as well as the L61 alternator, and belt tensioner.

Quote:

8.) and take the Cavalier to a GM dealer and have them reprogram the PCM for the GM Cavlaier/Sunfire Supercharger Kit #17800003 (although that reprogram is for 8 psi or boost not the LSJ 12 psi, maybe slip the tech a 20 to boost up the fuel table).

this is your major oversight. The L61 has a 6+1 reluctor ring that is CAST onto the crankshaft. This tells the crankshaft position sensor where it is, and gives it a reference for the ignition system (as well as the fuel injection system)

the LSJ on the other hand, has a 60-2 reluctor ring thats bolted on. Getting to it however, requires disassembly of the block and removal of the crankshaft.

you can use a trigger wheel and feed the sensor signal to the jbody pcm and get the reflash.
or, you could have a custom trigger wheel made and bolt it into the LSJ (again you have to COMPLETELY DISASSEMBLE the bottom end to get to it.
or, you can run a megasquirt or other stand alone computer system. the jbody ecu is not something you really want to retain.. like, ever.

quick breakdown:

L61 (2.2 n/a)
86mm bore 94.6mm stroke
cast crank, 1015 steel rods, cast pistons (dish)
10:1 compression ratio

lost foam cast head
one cam flange

7 tooth trigger wheel (6+1)
6 bolt flywheel
5 rib serpentine belt

wasted spark coils on plug (twin coils)
"compression sense" cam source generator



LSJ (2.0 s/c)
86mm bore 86mm stroke
forged steel crank, 5115 steel rods, cast Mahle pistons (donut dish)
9.5:1 compression

sand cast head
two cam flanges

58 tooth trigger wheel (60-2)
8 bolt flywheel
6 rib serpentine belt (reverse spun alternator)

true coil on plug ignition (four coils)
cam sensor spun by exhaust cam


note: you CANNOT mix and match rotating assembly components (crank, rods, pistons) they have to be a matching set. However, it is possible to use a L61 rotating assembly in an LSJ block, or an LSJ assembly in an L61 block.



with all that said, here's my advice:

an LSJ/L61 hybrid isn't for the faint of heart (or someone with money or wife problems). If anything, buy a fresh L61 out of the junkyard (much lower mileage) and bolt the s/c kit onto it and be done. The amount of work you're looking at doing is NOT for someone who isn't prepared to throw a lot of cash at their car.

Yeah, I've looked into it some more and with all your advice and help I think it's best if I just stick to building up my L61. I might go turbo for now till the engine blows and get a new race prep block then. By the way, it's not that I have money problems, it is that my car budget is small cause I wan't to buy a Z06 and my wife doesn't want me spending so much money for two cars. Well thanks for all the help (kudos to you airtonics and DaFlyinSkwir(LS61) /PJ/ OEM+) and lets see how my turbo idea goes (any tips or advice for turboing my stock block would be greatly appereciated).

Advice?

Boost it till it blows and then back off 2 PSI.

i dont know what the smog check is like over in arizona but on "track days" you can get o2 simulator form caspers and hallow out your cat "just for track days" then get a cold air kit and a wet nitrous kit
all could be had for about 700 dollars new also go find a spare motor and watch for fuel puddling

all can bought at www.turbotechracing.com

Jesus Jacobo wrote:(any tips or advice for turboing my stock block would be greatly appereciated).

Get the Hahn Stage II kit, pistons, rods, a set of valves and be done with it. Hahn made 400+hp with just that, after 400whp you'll get blow-by...


1997 Sunfire SE