It's begun! - 2nd Gen W-Body 3800 5-speed F23 Swap

[GtpKo]

I've wanted to do this swap for about 10 years. Ever since coming across Kuntzie's 5-speed swap thread from back in 2009, and then Noah Brainerd's F40 swap thread from around the same time over on GPF, it's been on my someday-to-do list. Back in around 2013 I think it was, I came across an F40 for something like $150 that was missing 5th gear. I thought it was going to help me finally get started but then family medical issues set that back into the "someday" list. Fast forward to this past summer of 2022, I came across the F23 swaps of Tyler Pitman and Terrell Smith. At the time, I had the same reaction as everyone else and thought "There's no way it could hold, it's rated for..." and so on. Then I found out that those GM ratings are just the max that GM planned on putting it behind, not necessarily what it can actually hold. For example, the F35 is weaker than the F23 as has been learned by the J-Body guys. Internally at Getrag, the F23 was known as the 287, the successor to the 284. So far it's proving it very well could be. Watch this and this.

There is more than one way to do this swap, I am taking what these guys have done and trying a couple of changes.

 

Background story aside, here is the current parts list - will update this list as necessary:

Some of the model years given are an example and should work for the same model range.

F23 from 00-03 Cavalier or Sunfire with the 2200 SFI - not Ecotec as the bellhousing is different. Look for 8th digit of VIN is a 4.

From same car get the shifter, full clutch pedal assembly, shifter cables, clutch reservoir, clutch cylinder w/ hydraulic line.

EDIT 6/27/2023: 32" long passenger side cv shaft is the best option unless you can manage another option such as mounting a 4T65E output shaft as an intermediate shaft.

For the one really long cv axle, get a "front right" passenger side axle from a Jeep Grand Cherokee 1999-2004 4WD Quadra-Drive w/ Vari-Lok. The Selec-Trac w/o Vari-Lok axle may or may not work, since it's an inch shorter and therefore leaves less room for the axle shop to work with. The axle shaft is super long and can be used as bar stock basically for an axle shop to re-spline into the new shaft you'll need. The thicker end is the end to be re-splined as it has enough material to cut down while retaining heat treat strength. This will be the new outboard end that will go into the "star" or hub end. The narrow end of the shaft has the correct splines to go into the tripod end and will be the new inner. You have to have a slot cut for a retaining ring right at the end of the existing splines and widen the existing narrow slot at the end. I believe you'll need the inner from a J-Body car since I think that's where I got my inner from. The splines need to be 1.05" not 1.1". I had a couple of these inners lying around and I thought I had the GP inner but it may have been a Cav one. But that's it for that end. The overall shaft length needs to be exactly 32". I have measured this myself and have found that measurement also quoted from others who have done this before. The inner tripod is j-body and the outer is your stock w-body hub end. Reassemble with appropriate grease, boots, and clamps and you're done.

Stock passenger side CV Axle from 2nd gen W-Body such as Buick Regal or Grand Prix GT(Not GTP or Regal GS) - this will be the new driver's side axle.

Flywheel - 2 options:

    4th-gen (96-02) Camaro RS or Firebird (3.8 w/ 5-speed) flywheel, shaved down to about 0.81" to 0.84" - or about 0.25" shaved down on the clutch surface. Have them check the balance with your auto flexplate's balance if they can. This option should have a better balance if the engine is N/A.

    Or, and especially if the engine is supercharged, an aluminum flywheel from SPEC. Part # SC94AC. This will run you about $400. 

Clutch - many options:

    SPEC, Exedy, off-brand, they all have pressure plate and clutch disk combos that will work. Some better than others. You can go with a cheap risk, or more expensive sure thing, up to you. Look for a combo for a Fiero 2.8 w/ 4-speed. If you go with SPEC(sure thing) then look for a combo under "Conversions" for Fiero 3800 w/ 4-speed. Part# SC771, SC772, SC773H, etc. Important note: if you go with off-brand or Exedy or whatver, you should verify the depth of the pressure plate fingers vs. HTOB range. Also, too thick of a pressure plate may hit the inside of the bellhousing. That's why a stock Camaro pressure plate won't work. I've tried it. For more detail than I can give, search the Fiero forums for HTOB measurements. This thread is useful - Measuring HTOB to determine need for spacer?.

Longer F-Body flywheel bolts. GM Part#24505092. Make sure they get the 5/16-18 bolts 0.9" length. I got burned on this once when I received 7/16-20 bolts the first time.

Smaller brake booster from around an '02 Monte Carlo. Turbo guys do this often as it's smaller but still effective. I've had this mod for a while.

 

Here is the car I got my stuff from:

 

Here is the easiest part, the brake booster swap. I found the easiest way to remove and install these is to use a long bar on the studs to twist it out instead of struggling with the tab in the back.

 

Since I wanted to include a hand brake, I wanted to keep the shifter to the right a bit instead of centering it. Basically, the same orientation that it originally came with in the Cavalier. But to do that I needed to fab up a new mounting plate. First I used some thin sheet metal to make a template and then welded up the plate from that. I know - my welding sucks, but I'm still learning, getting better.

 

To mount this, I'm taking advantage of the extra slots for these clip-on stud things and modifying one of them to be longer

 

Here is where they go, notice longer stud on the lower right - also holding the e-brake bracket.

 

Next, with the new mounting plate installed - note the narrow nut on the bottom left. Also, you can't see it but sound-dampening rubber foam is underneath the plate.

 

And with shifter installed - now you can see why that nut had to be narrower. There is also some interference from the plate/cables and the rear seat air duct, but I'll sort that out later.

 

Next, modifying the brake pedal assembly. Note - be careful with cutting magnesium alloy, not sure how flammable the magnesium shavings could be.

I tried to keep the 2nd bolt hole for where the steering column attaches, but that has to come off too. It's a minor bolt anyway, there are 3 more, 2 of which are the major ones, so it's fine.

 

Steel part that bolts to the firewall and what needs to be cut off

 

Here is approximately how they will be installed. Different than how it looks in this pic, I have the clutch pedal mounted a bit lower than this with its bolt studs even horizontally with the bottom right brake bracket stud. I have a better pic of the firewall later on.

 

 

I have much more to post, but I'm out of time for now. More to come soon.

 

 

Edited June 28, 2023 by GtpKo
More info

[pwmin]

Sick! Maybe this will help me get motivated to get the Monte done 

[GtpKo]

I should mention, this is not a power build. I don't need a stage 3 or 4 clutch quite yet. Not even a stage 2. Sure, on the next swap, for sure I'll go all out stage 3+ or something since I'll need it then but not for this test mule of a car.

This dimple on the passenger side firewall area is made for guiding a hole saw to the right location for shift cables. It really appears that the engineers at GM wanted to leave the door open to making a manual option in future model years. 

Drilled with a 2" bi-metal hole saw, less than a minute. Same on the engine bay side.

 

Sorry for the portrait mode photos at times. Trying to work and remember to pause to take a pic now and then. 

Here is the wiring harness that needs to be pulled back into the cabin for relocation. However, as I found out later, you may not need to do this if you can just remove the huge rubber plug and enlarge the top portion of this hole.

 

Now this is what I ended up doing - this pic is from the inside of the cabin. You can see where I tried opening up the hole at the bottom for the wiring harness to go through, still seemed to interfere with the clutch pedal a bit. Also, the wiring harness through the bottom seemed to barely have any slack in it when reconnecting. I decided it would be better to enlarge the top of the original wiring harness hole and feed the wires through there instead, going above the clutch pedal mount entirely. You can also see where I ended up drilling holes for the studs on the clutch pedal mount, where the clutch master cylinder bolts to.

Now that I remember, there is a pesky inner plate that slides up and down where the brake pedal bracket bolts to the firewall. The holes never stay lined up on their own, I used aluminum tape to hold it in place so I could get the dang thing back in place.

 

Here is the best pic I could get of the wiring harness fitting nicely above the clutch pedal bracket once bolted in.

 

And here is my 2nd attempt at cutting and re-welding the clutch pedal arm to the right angle and height to be even with the brake pedal when both are fully installed and hooked up. Not pretty, but that's what you get when you weld it at the wrong angle the first time. I've decided I will do this whole swap twice. First time works the bugs out. Next time will be on a rust-free car that I will keep for a long time.

 

Here are a couple of pressure plates I have to choose from, first on the left is for a Fiero 2.8, the one on the right is a used one from a Camaro. Both will work but the Camaro one is stronger & bulkier. I'll test fit both and see when I get there. I'm not dropping $400 on a clutch combo until I need it.

 

Anyways... Looking exciting already! Positioning is good for my feet. It's important to make sure you position things where you like while you have the chance.

 

Edited April 24, 2023 by GtpKo
left/right

[Bake82]

On 4/20/2023 at 3:34 PM, GtpKo said:

 

Intermediate shaft from 94 Sunbird with a 3.1. (Possibly could use an intermediate shaft from a Saturn Vue?)

Passenger side CV Axle from 2nd gen W-Body such as Buick Regal or Grand Prix GT(Not GTP or Regal GS) - this will be the new driver's side axle.

Longer passenger side CV axle from 04 LeSabre. Swap the female tripod from the drivers side axle onto the LeSabre axle. This creates a longer new passenger side axle to match the length of the intermediate shaft.

 

im a huge fan of this swap!  You will love the 5 speed with the 3800!   
 

When I did my getrag 282 swap with a 3800 I tried to use the stock intermediate shaft and axle and nothing would fit around the oil filter adapter.  
 

I tried the reatta adapter but that didn’t work either (works for the 284 but not the 282 as the 282 intermediate shaft is .5-.75 inches longer than the 284 and the reatta hit). 
 

Before dropping the trans and engine back into the car I would highly recommend making sure you have clearance around the oil filter adapter and oil filter.  
 

if you do have clearance issues, running one long axle will clear and doesn’t cause any issues.   I’ve run my car like this for 5 years now making 300+whp and no driveability issues at all.  
 

 

this was one of the part of the swap that caused me huge grief.   
 

the other was pressure playe to trans clearance!  Because the flywheel needed to be cut to 0.81 not 0.84 as commonly used.   But I’ve seen this hit or miss over the years!  
 

 

lookinh forward to seeing more progress!

[GtpKo]

On 4/24/2023 at 8:35 PM, Bake82 said:

 

im a huge fan of this swap!  You will love the 5 speed with the 3800!   
 

When I did my getrag 282 swap with a 3800 I tried to use the stock intermediate shaft and axle and nothing would fit around the oil filter adapter.  
 

I tried the reatta adapter but that didn’t work either (works for the 284 but not the 282 as the 282 intermediate shaft is .5-.75 inches longer than the 284 and the reatta hit). 
 

Before dropping the trans and engine back into the car I would highly recommend making sure you have clearance around the oil filter adapter and oil filter.  
 

if you do have clearance issues, running one long axle will clear and doesn’t cause any issues.   I’ve run my car like this for 5 years now making 300+whp and no driveability issues at all.  
 

 

this was one of the part of the swap that caused me huge grief.   
 

the other was pressure playe to trans clearance!  Because the flywheel needed to be cut to 0.81 not 0.84 as commonly used.   But I’ve seen this hit or miss over the years!  
 

 

lookinh forward to seeing more progress!

 

Thanks for the info on the Reatta adapter as that was an option in the back of my mind. I was thinking of also trying a relocation kit. And I also have a 32" axle shaft as an option as well, but that would still need to go to an axle shop and add $$$. I'm at just under $1k in parts so far. 

For F23 swaps, there is an issue with flywheel teeth barely hitting a bulge for the differential, but that is usually solved with grinding a small nick into it. I chose a pressure plate that has a low profile to ensure good clearance(hopefully). There is also a low profile option from SPEC I understand. I'll look into that when I do 5-speed build #2 next year. (cammed/pulley'd L67 in a rust-free chassis - that kind of thing)

 

How was attaching the intermediate shaft to the 3800? That is another item on my list that I'm getting close to. Here is what I have for an intermediate shaft. Is this like the one you tried?

[Bake82]

I am running a long axle on the passenger side, and do not have the intermediate shaft so I did not have to fabricate anything for that to work.  I would check the Fiero groups to see how they have fabricated theirs as it's a common enough thing in the Fiero world to add the intermediate shaft.  

 

 

Me getting an axle made cost me $100 Canadian.  I provided the inner and outer tulips, they found a Honda Accord axle that was the same length and used the same spline counts and put it all together for me.  Cheaper than the relocation kit, and it works!  

[GtpKo]

Good to know it may not be as expensive as I was thinking it could be. I'd rather keep the axles more easily replaceable if I can though. If I do go the long axle route, I have a guy I can ask about it. The guy that shaved the flywheel down does all kinds of car builds.

That reminds me, for anyone reading wondering how in the heck you find someone to do these odd custom car things, I just started by asking my local auto repair shop. They gave me a phone number of a guy that they send their difficult or machining work to. Tell them exactly what you are looking for and they will help you find the right person.

[GtpKo]

 

Got the engine out today. Woohoo!

 

 

I made one significant mistake though. I forgot to unplug the front knock sensor and the hoist didn't care it was still connected. Whelp... something else to fix. Tomorrow will be mostly cleaning up though, depends on how well the ibuprofen works. The only other thing that I broke was the oil pressure switch, those are a cheap replacement anyway.

 

Here it is, on the stand and ready for some degreaser. Well OK, maybe a lot of degreaser.

 

I should make some good progress this week. I've also pressure washed the carpet, letting it dry with some scented kitty litter. One of the previous owners of this car was a smoker and apparently liked to spill things in the back. It was pretty nasty. Carpet looks OK now. Should improve the freshness of the interior and look halfway decent. 

 

[GtpKo]

3800 with a clutch!

 

Also, I can't seem to make this intermediate shaft work. Just not going to happen.

Sure, I could use an output shaft from a 4t65e with a bearing on it, but that's much more work than the 32" shaft I already have, just needs one end re-splined. So, going with the long cv shaft option after all. That's going to take a few weeks before I can get that done, so I'll move on to other parts in the mean time.

[GtpKo]

The long axle may be done this week..?  In the meantime, I got to work on finishing the interior as well as working on the low-profile trans mount. It's going to be a bit stiffer than a normal rubber mount, but that is sometimes what you want.

Here is the first test fit. It's hard to see in this pic but there's a bit over a half-inch of space between the support plate and the subframe rail. The white paint is primer for covering the bare metal after cutting off the auto trans mount base.

 

[GtpKo]

Might be a bit longer for the axle... anyway, I finished up the low-profile trans mount. I was originally going to cut down a 1st gen w-body mount and use that for the lower part, however, it was a real chore to cut through loads of rubber and metal without making a stinking mess. Looking for possible other options, I read something about in the old days guys used to drill a hole through a hockey puck and use that. That got me thinking. I had a rubber mallet that I hardly use, maybe cut the ends of both sides like hockey pucks and bolt straight through from the mount support plate to the frame. It seems to work really well so far. Solid but has some give to it. I had the entire subframe out and on stands with the engine and trans mounted in position to test alignment.

 - and I know my welding looks like a noob did it, because I am one. I'm confident there's good penetration and the welds will hold, just doesn't look pretty.

 

Here it is finished and attached. I don't know why I went with green paint, maybe because that's all I had left.

 

 

Here are the holes drilled into the subframe once the 4T65e mount is cut off. This lines up with the two holes underneath that are in most 1st and 2nd gen subframes(but not 3rd gen/aluminum ones) which provides easy access for zipping bolts up in there when its in. 

[Pontiac6KSTEAWD]

This is just an idea, as I dont know how long the CV axle is. But a rear CV Axle from a Buick Rendezvous AWD/Pontiac Aztek AWD/ or the U-Van AWD Chevy Uplander/Venture/Pontiac Montana/Buick Terraza/Oldsmobile Silhouette/Saturn Relay is a really long axle. Not sure how long, but pretty long.

 

Autozone shows the Axle length at 31.5 inchs Extended, 28.33 inchs compressed

https://www.autozone.com/drivetrain/cv-axle/p/duralast-gold-rear-driver-or-passenger-side-cv-axle-9407n/401549_0_0

I have a bad one sitting in my garage from a Saturn Relay AWD that I am rebuilding. This is the only reason I had the idea.

I do know the HUB stub should be a standard size, as the front and rear HUBs for the AWD are the same.

You would have to replace the inboard Tri-Pot as its female. Or pull the end stub out of the rear axle and use it.

My thought was that you replace the Female Tri-Pot, and the overall compressed length, because of the Axle stub is now included, should bring you right out to where you need to be.

But this is just a best guess..

Edited May 24, 2023 by pontiac6ksteawd

[GtpKo]

For the long axle, what you want is the inner bar shaft to be 32" long. For the Cherokee shaft, one end needs a c-clip slot cut in on one end, otherwise the splines are good to go, the other end however, has to be cut down maybe a half inch and also the splines are too thick, need to be re-splined to fit the inner spline of the joint. Basically, if you were to disassemble a passenger side CV shaft from a 4T65E car like a GP GT (4T65E-HD axles are different), replace the inner axle shaft with the longer re-splined one and reassemble. Once I have it done(correctly), I'll post up some pictures and measurements.

 

As for progress, I finished the wiring, installed the trans with a new HTOB and .20" spacer, dropped the engine back in and got them bolted together. Kind of on the final stretch.

 

Wiring - I haven't verified the following yet but will update when I know for sure this is 100% correct. -

As for the wiring, the only wires that are required to be spliced together are the fat purple and yellow wires from the 4T65E harness that plugs into the shift mechanism on the trans. That, and the green & orange wires need to be wired into the reverse switch on the F23. Otherwise in order to make it work like it came manual from the factory, you need to splice in some other wires as well. You need to wire the gray, green & black wires to the ground wire.

So far all I've been able to test is the reverse light switch, which works as it should now.

Here is the diagram for my 2002 GT:

Based on this diagram, I wired the PPL and YEL wires(pin G & E from C1) together, ORN & LT GRN(pins B and F from C1) are the reverse switch wires, then GRY, BLK/WHT (pins C & D from C2) together with LT GRN & BLK(pins C & D from C1) all together.

This *should* be an easy way to trick the PCM into thinking its in 2nd gear all the time and so no funny stuff with RPMs, and the BCM to think it's in park so that the trunk release and alarms and all that will still work.

 

 

Also, very important: If you are using the stock rear manifold, it won't work without some modification. The crossover flange will interfere with the shift cables. You'll need to cut the tack welds on the back of the flange so you can rotate it so that it's not in the way of the shift cables. It will be close to the cables so I'm putting in a spare piece of sheet metal as a heat shield.

 

Before:

 

After modification:

[Bake82]

Glad to see you got the flange issue solved!   I also remember them being real close to the 282 shifter in my car.  Glad it fits!!  

[GtpKo]

Update! The finished long axle is on its way back to me and should be here on the 27th. Having it done the first time with the local guy just didn't work out. Meanwhile, I've been keeping busy with tidying up miscellaneous things like coolant drain & flush, and refill with "all makes" green coolant. I got rid of the stock airbox and put in a cone filter intake. Not that it needs it, but it seems those stock airboxes turn into mouse houses all the time and I like the bit of extra intake noise. 

What I'm working on right now is finishing off the retrofitting of the center console. If you go with an e-brake handle, you'll need to make room for it. The shifter has a lot of slop so I'll be replacing the bushings with new parts to fix that as well.

 

Last time I was at the junkyard, I happened across a 40th spoiler. I snapped that up for $30. To install it just needs 3 new holes drilled. I painted it to match and filled the 6 old holes in the trunk lid. Hard to get silver paint to look good with rattle can paint, even if it's exact GM paint match. Even so, this is the only spoiler in my opinion, that looks decent on these 2nd gens. I never liked the look of the "surfboard" stock ones.

[GtpKo]

I've edited the first post parts list to reflect up-to-date info now that I'm this far. My axle should arrive today! I'm excited to finally get this finished. I hope to God that nothings fubared with the axle as I've been waiting a month for this part of the project.

[GtpKo]

First drive tonight! Man-o-man that was awesome! It's been 20 years since I've driven a manual and I'm loving having to get used to it all over again. No strange clunks or shimmys or whatever. Sounds really good in fact. Video coming soon, too bad it's at night.

[GtpKo]

Here's the first drive video. Sorry you can't see much but I finished late yesterday. The custom axle shaft arrived at like 5pm and then it took a couple hours to build, boot, grease and clamp the new completed cv axle and install it. It worked out perfect. Only issues so far are a couple fuses need replacing, a/c compressor clutch makes some noise sometimes, a/c is not cold, and lights don't turn on automatically at night. Must be the sensor in the dash. 

 

[Lukeperrin07]

This is awesome! Just picked up a cavalier and starting to collect parts for a swap. What’s a rough timeline I should expect? And how hard was taking the dash out? Any tips and tricks?

[carkhz316]

Congrats on the completion and being able to drive it. Its such a surreal experience getting to drive the car after doing so much work.

[GtpKo]

Sorry I haven't responded Luke, I'm not on very often. In case anyone is still wondering, the total timeline for completing this swap depends on a lot of factors. Doing it alone, or with help? Power tools? Space to work? It took me around 2 months by myself in a 2-car garage with an engine hoist and the usual power tools while working full time and night school. I suppose it could be done over a weekend with everything ready in advance with proper tools and lots of help.

Getting the dash out(in 97-03) isn't hard, just annoying with all the hard to reach bolts and clips. That is where you need some low-profile ratchet tools. 04+ dashes are hard for sure as they are more complicated and have to be completely removed.

Thinking back, the most complicated part for me was fabbing up the trans mount. There are many many ways of doing this. I am not personally a fan of the outside-the-frame mount that requires tubular control arms, which drain $650 from your budget. I went with a low-profile hockey-puck style mount. Only issue with that is making sure the rubber pucks don't split. Seems to work ok for me the last 11k miles.

I want to modify my mount design though as the nuts underneath are hitting the frame every time the mount flexes, when they should be tight. Not good for the bolt and might be inducing false KR. Imagine a long bolt with rubber in between the head and the nut. If you squeeze the rubber, the nut isn't touching anything. I need to rework that part so it keeps pressure and flexes without getting loose.