Slow 242 GT Build Log

[benson0021]

Follow this build on Instagram: @rallybenson


So, I picked up a new 240 a couple weeks ago. It's a 1979 242GT that lived in San Diego its whole life (meaning there's no rust ).

It made the entire drive home without a hiccup. The drive did leave me wanting more... a lot more. The car handled like crap. It felt like the shocks were diagonally mismatched, and it was disturbingly floaty over bumps.

Damn does it look good though:




Anyway, I drove to work a couple days, and made a mental log of all of the problems I wanted to address. I then proceeded to put it up on jack stands in my garage and started to go to town on it.

The first thing I did was removed the crappy Volvo 240 seats. I don't care what anyone says, but I find the Volvo 240 seats to be very uncomfortable. They're too squishy and unsupportive.

The previous owner got covers made for a set of Supra seats that match the interior of the GT. He was nice enough to include them with the car. I welded up some brackets that adapted the Supra seats to the Volvo rails. Now I have firm, supportive seats with bolsters!

Next, I got rid of the commando bumpers and the GT air dam. I know the air dam is unique, but I prefer the regular 240 air dam. I scored a big one when I went to the local junkyard and there was a silver 1984 240 with both 'slim' bumpers and the air dam (that matched my car's color)!


Popped those bumpers on and painted my grille and light bezels black.
(I fixed the rubber trim after I took this photo)

As all of this was happening, I was slowly taking the suspension apart and cutting things up and making a general mess of things...



Taking measurements...





And cutting things up


And then, one day, a bunch of new parts showed up.


I took care of my trans mount and propshaft bearing and support first because those scared me the most from a 'it's making scary noises when I accelerate' standpoint. I initially though the banging from the tunnel on a spirited start was from propshaft slap, but I later concluded that it was from the trans mount being mushy and the transmission was banging into the tunnel...

So I replaced all that stuff.

Then I cut the bump stops in the rear down a notch (before and after)




Finished procrastinating, I made the strut housings shorter


Basically, I chopped 1.5 inch out of the length of the strut housing. Why? I dunno... Maybe you'll find out later. I kept them straight by fixturing them up like so when I welded:


and voila! 2 shortened struts:


Then I turned some stuff.


And then these showed up. 2 weeks earlier than expected!!!


They're a little shorter than the old bilsteins that were in there...




And then yesterday, mysteriously, a LS6 and a T56 out of a CTS-V found their way into the bed of my truck...




My Plan is simple:
LS6, T56, IRS.

[soclosenotnear]

Whoa nice gt!

[JerryJS8]

Lot of project in the first post, afraid what'll happen for the second

Please keep the wheels and the chasis original looking, Gemini's are nice, otherwise it's gonna look ricey! Would be a shame to loose such a nice GT...

[Funkee]

Oh yeah

[Stiggy Pop]

nice to see a true high performance aluminum block going in one of these for a change!

[runt262]

Nice looking GT! I'm with you when it comes to those GT seats, as well as the GT Air Dam. I much prefer the stock dam.

That thing is going to rip with that LS6 in there! If I can request, can you outline how you are going to integrate the ECU and all that fun stuff? Good reference for future builds

[stick70]

Originally Posted by runt262

Nice looking GT! I'm with you when it comes to those GT seats, as well as the GT Air Dam. I much prefer the stock dam.

That thing is going to rip with that LS6 in there! If I can request, can you outline how you are going to integrate the ECU and all that fun stuff? Good reference for future builds

Agreed on all fronts. I'm jealous of your paint and interior, looks like a nice score.

[cube860]

Keep it coming!

[benson0021]

So, my roommate has been taking up the garage for the past couple months because he was doing some work on his 911. Meanwhile, I was in China for a month for work, then out of town for thanksgiving, then I was skiing in canada for a week, then out of town for christmas, then i was skiing in montana for a month...

Being away from the car so much has given me lots of time to daydream and plan

Current High-Level Plan:
- 1979 242GT Chassis
- LS6 Engine (2005 CTS-V)
- T56 Transmission (2005 CTS-V)
- Custom Independent Rear Suspension
- Redesigned Front Suspension

Updates in this post from last time:
1. Custom Coilovers Installed, Tested, Adjusted
2. Toyota Supra Seats Installed
3. New Blower Motor, Power Door Locks, and Alarm System
4. New Stereo Setup (80% Complete)
5. Review of High-Level Plan and New Toy!!

1. Custom Coilovers.

I finally got the car put together and back on the ground on Sept 19 with the new suspension. Below is a photo of the first time it sat on the new gear:



Unfortunately, the front tires rubbed ever so slightly on the new springs. I bought a set of 5mm spacers to remedy this. These spacers had too small of a bore diameter, so I had to put them on the lathe and bore them out to 66mm /ugh.



I then lowered the front of the car an additional ~2 inches and the rear an additional ~1 inch.



I actually lowered the front a little more from there but I don't have any photos of that (oops).

The 450lb/250lb springs are stiff. The car now feels very planted; no more wallowing. Bumps on the highway are no longer disconcerting.

Initially, I left the dampers adjusted fully loose. After driving it around a bit, I've adjusted them quite a bit stiffer, and the car has become much less bouncy and it now recovers from disruptions beautifully! I might borrow an accelerometer to log body movement in order to properly dial in the dampers - we'll see if that happens before the big redesign though...

2. Toyota Supra Seats Installed

When I bought the car, the previous owner included a set supra seats with custom seat covers that matched the car's interior. I welded up brackets and installed these seats in the 242GT. They're a big improvement over the stock seats! There's now some bolsters, so I'm no longer struggling to stay in my seat on curves lol.

They're not great though . I'm not satisfied by their support. I'm going to need to find a different pair of seats long term. Any suggestions? I want seats that have good hold, good support, are lightweight and manual. My friend's mk7 GTI seats fit the bill pretty well... My old B7S4 Recaros were really comfy, but they're heavy and power...

Sorry I don't have any photos of the seats (fail). I'll post some soon.

3. New Blower Motor, Power Door Locks, and Alarm System

Blower Motor

Yay Defog! OMG WHAT A PAIN IN THE ASS REPLACING THE BLOWER MOTOR IS! The entire interior needs to be removed to get it out. When I redo the car, i'm going to put an HVAC system from some other car in here because this sucks, there's no filter, and the blower is a terrible design (i want a squirrel cage so it's quiter and blows more).

I replaced the blower motor with one that was like $40 from summit I think. It required a little bit of dremeling of the housing to make it fit, but it works! I also added a PWM controller to give me more variable fan speed control .

Door Locks/Alarm System

I added universal electric door lock actuators and a viper security system to the car. It was an easy install while I had the entire interior torn apart.

The doors even already had holes for the door lock actuators, so mounting was cake!



Those two bottom screws hold in the actuator:


I wired the security system up to flash the parking lights upon arm/disarm and beep the siren. The alarm goes off based on accelerometer input and if a door is opened when the system is armed.

4. New Stereo Setup (80% Complete)

Specs:

- Pioneer DEH-X7800BHS Head Unit
- Alpine MRV-F300 4-Channel 50W Amp
- Pioneer GM-D9601 1-Channel 2400W Amp
- Morel Maximo 5.25 Component Speakers for front doors/dash
- Polk DB651 6.5 inch Coaxial Speakers for the rear deck
- 2X Alpine SWS-12D4 12in DVC Subwoofers

Wiring:

While I had the interior torn apart, I added wiring for the new stereo system.
- RCA cables from the head unit to the trunk for the signal
- Speaker wires from trunk to doors
- Power wire from battery to trunk for amp

Subwoofers/Amps:

While writing this post, I realized that I built and installed all of this without taking any photos. I'll update with some details eventually. For now, here's a view of the mess in the trunk (I have the hardware to organize the wires, I just need to find the time and motivation to sit in the trunk for a half hour to make it happen...



Subwoofer enclosure was custom designed to fit dual 12 inch subs behind the rear seat. The front face of the enclosure is 20 degrees leaned back, to match the rear bulkhead angle. Sealed enclosure with volume of 0.97 ft^3 for each driver.

Rear Deck Speakers:

With the subwoofer enclosure right below the rear deck, through-mounting the rear deck speakers presented an issue. On top of that, the subwoofers would likely cause some nasty distortion on the rear deck speakers. In order to keep the sound clean, I made an enclosure for the rear deck speakers.

I added carpet and the vents from the old parcel shelf, and it looks stock!







(I need to glue down the end of the left vent :/ )

Door Speakers

I actually just put these in tonight.



I had to modify the door handle and the door card a tiny but, but they lined up with some original screw holes in the door oddly enough...







The tweeter is up on the dash, and the crossover is hidden under the dash.

Of course I failed to take a photo of the door put back together with the new speaker... /smh

5. Review of High-Level Plan and New Toy!!

LS6+T56 installation will be pretty straightforward; put it in the damn car.

Engine Wiring Harness - I have the engine wiring harness and ECU from the CTS-V, so that'll stay like that. I just need to figure out how to deactivate the authentication on the ECU so it's not looking for the CTS-V key. I'll wire up an OBD2 port so I can check on things.

Chassis Wiring Harness - I plan to redo the car's entire wiring harness (I've done this before on past cars) for a couple reasons.
- it's 40 years old
- it uses crappy connectors
- I hate those european ceramic fuses
- I want to add a couple circuits
- general tidyness/ocd.

Fuel System - high flow pump, bypass fuel pressure regulator, new filter, new lines.

Suspension

Front suspension - complete custom suspension. I'm not sure if I'll stick with MacPherson - I'll need to review what I can package/design/fab.

Rear suspension - complete custom suspension. Double A Arm probably. First step is to select a diff/axles/hubs. Once I can settle on that, I can start the geometry design. Currently looking at r200 diff, s13 axles, and 05-08 sti hubs; I need to double check compatibility and see what kind of hub-hub width that puts me at...

New Toy

I picked up a 3D Scanner.



I'm planning to use this to make CAD models of the car and all the components I plan to put in it. This will enable me to design everything in a way that makes it all easy to evaluate and manufacture.

This way, these mods won't necessarily be one-off . I would like the ability to copy-paste these mods on other 240s. I used to have an '83 wagon, and I kinda like the idea of having an old volvo wagon that can outperform supercars... maybe next project.

Trust me, I'm an engineer.

[Tuff240]

Originally Posted by benson0021

Trust me, I'm an engineer.

Is that why the pics don't work?

[benson0021]

Originally Posted by Tuff240

Is that why the pics don't work?

so needy.... fixed. I forgot the trick for hosting with google photos.

[Uncleknucklez]

Originally Posted by benson0021

Unfortunately, the front tires rubbed ever so slightly on the new springs. I bought a set of 5mm spacers to remedy this. These spacers had too small of a bore diameter, so I had to put them on the lathe and bore them out to 66mm /ugh.



I then lowered the front of the car an additional ~2 inches and the rear an additional ~1 inch.

I need a set of those spacers! 5mm would be perfect. The car already looks rad, Can't wait to see the progress.

[MadDog_945]

nice project, subbed !

[MDVLN]

Originally Posted by benson0021

so needy.... fixed. I forgot the trick for hosting with google photos.

What does that entail if you don't mind me asking? No matter what I do they always disappear or "grey screen" after ~3 days.

[benson0021]

Originally Posted by MDVLN

What does that entail if you don't mind me asking? No matter what I do they always disappear or "grey screen" after ~3 days.

This seems to work:
1. Open image in Google photos.
2. Right click image and open image in new tab.
3. Right click image in the new tab and copy that image's url.

[runt262]

budward. Calling it Slow 242 GT Build. You're moving at a good pace with this. Everything is coming together rather well.

Did you get that scanner new? I checked out their website and it seems to be a pretty capable scanner for a consumer scanner. I used to work with Creaform scanners and they have always been an outrageous price. The market is driving those prices down, and the capability way up there.

Are you open to sharing your scan files eventually once you get some data?
Where is the states are you located anyway?

[Harlard]

I really like your car. Looking forward to some more good stuff.

[benson0021]

Originally Posted by runt262

budward. Calling it Slow 242 GT Build. You're moving at a good pace with this. Everything is coming together rather well.

Did you get that scanner new? I checked out their website and it seems to be a pretty capable scanner for a consumer scanner. I used to work with Creaform scanners and they have always been an outrageous price. The market is driving those prices down, and the capability way up there.

Are you open to sharing your scan files eventually once you get some data?
Where is the states are you located anyway?

Thanks! I say slow because there is a long list of things to do. I'm basically looking to reengineer the majority of the car save for the chassis...

Got it new. It's decent. I played around with it a bit last night. I put some videos up on my Instagram @rallybenson. I'm still learning how to prep the surface with powder and fiducials to improve the scan quality. For example, it had trouble scanning the hood without fiducials because it would lose it's tracking over a large feature-less surface. Scanning the t56 was cake though!

I'm in the bay area, california.

[benson0021]

***I FIGURED OUT HOW TO SCALE MY IMAGES WOOOOOO***
and clearly forgot how to embed them successfully :(

Things since last time:

1. New Speakers Review
2. New Front Seats (again!)
3. Scans!
4. Pull engine and Transmission out of car
5. More Scans!
6. Next Steps

1. New Speakers Review

The sound system in my 242gt consists of the following:
- Front Speakers: Morel Maximo 5 - Tweeter mounted on dash next to windshield, woofer in stock speaker location.
- Rear Speakers: Polk dB651 Coaxial Speakers Mounted in a custom enclosure on rear parcel shelf.
- Subwoofers: Dual Alpine SWS-12D4
- Speaker Amplifier: Alpine MRP-F300 - 4 channel, 75W RMS per channel
- Subwoofer Amplifier: Pioneer GM-D9601 - 1200W RMS at 1Ohm
- Head Unit: Pioneer DEH-X7800BHS

I set the system up with crossovers controlled via the head unit so I could adjust the cutoffs, dropoffs, and EQ to find what sounded best in the car.

It took me a while to adjust things to get a tone I liked, but I'm very happy with the setup and would recommend the Morel speakers. They're full and warm; just the way I like speakers. The forward firing subwoofers can be very overpowering if I want them to, but punch cleanly with minimal air noise. I was worried that the enclosure for the rear deck speakers wouldn't be enough volume for the coaxial car speakers, but the bass response of those speakers in those enclosures is surprisingly good! The front speakers punch harder than I expected, which was certainly nice.

The detail which surprised me the most was how few rattles the Volvo had! There were really only three rattles: the driver door lock, the passenger door latch mechanism, and another rattle from somewhere in the dash. The driver door lock rattle was fixed by bending the post a little to give it preload, I stuck some felt in the the passenger door latch mechanism, and i haven't bothered to fix the dash rattle.

I still haven't found a good speaker grille for the rear speakers (i lost the original),
and the front speaker grilles interfere with the window crank, so I'll probably wait to install a grille until after i convert to power windows. They also interfered with the armrest, but I solved that by removing a little material from the armrest.

2. New Front Seats

The seats which I had put in the car were out of a 1980s Toyota Supra. They were a big improvement over the stock seats, as they had bolsters, but I didn't like them. I found them to be a little too small for me (height-wise), which left me often sitting hunched, and I reused the stock Volvo sliders which were rather loose and disconcerting.

I picked up a pair of 2001 Audi TT Front seats (made by Recaro). These seats are in great condition; the leather shows hardly any signs of age. I welded up some adapters to mount the Audi seats with the Audi rails into the Volvo.

I'm really happy with how they turned out. They look decent in the 242GT; I miiiiight get them reupholstered eventually to add some orange piping if I feel motivated...

The Audi seat rails provide a ton of forward-backward adjustment, and they're double-locking, sprung vernier scale slides, which means they have basically zero slop; the seats are firmly locked in place once you let go of the adjuster. They're also probably a lot safer in the event of a rear end accident than the old supra seats.

Additionally, these seats have seat heaters built in; I just need to run the wiring!

Old Supra Seat:


New Audi TT Seat Installed:


TT Seat Rails with brackets for Volvo:


New Seats Looking Good!

3. Scans!

I began scanning the 242GT in order to create a digital copy of the car on my computer to design around and analyze.



In order to scan the large, flat, feature-less panels, I needed to add a bunch of retroreflective fiducial stickers. ~2500 stickers later:









I also scanned the interior:



And the T56:


... And the LS6+T56:


So, why did I scan the exterior? Because reasons.

4. Pull Engine and Transmission out of car.

I've got to say; this was one of the more difficult engines I've removed... so many tools required! seems like every nut required a different size socket; then you needed ph2 and ph3 screwdrivers; and to get the front clip off i needed to drill out 4 spot welds... Why were the front clips welded on? there's a hole right next to the spot welds that's CLEARLY meant for a self tapping screw... oh well.

Side note worth mentioning: the AC system in this car is soooo heavy. As in it would be lighter if you replaced it with an equivalently-sized block of steel.





Once I had the engine and trans out, I put it next to the LS6+T56. Surprisingly, the LS6+T56 doesn't look any larger. It looks maybe an inch longer, a little wider, but shorter in height! I know (by reading someone else's build thread here) that the transmission requires some tunnel modification to fit, but I'm not too worried about it.

Also, I bought a scale online today so I can get accurate weight numbers soon. I'm curious if the LS6+T56 is heavier than the Redblock+M46. The Redblock felt heavy on the hoist.

5. More Scans!

With the engine and gearbox out of the way, it was time to get the important scans of the engine bay. This will let me package everything and design my mounts, exhaust, plumbing, etc. in CAD.

6. Next Steps

Next, I'm going to continue removing things from the car and get more scans. I'm going to take it all the way down to the shell.

I'll be designing a custom rear and front suspension. I want to be able to actually design a suspension with a complete engineering analysis backing the design (motion and FEA). I don't want to make something that fits; I want to make something that's amazing.

That being said, I would like to modify the chassis as little as possible in order to make this suspension easy to replicate/install on other 240s.

This is where the scans come in. If I know where the unibody is and where the existing mounting points are, I can feasibly design subframes which use those!

Also, I think I'm going to go with a 2010-2015 Camaro SS rear differential and hubs. The diff is plenty strong, and thanks to an aluminum carrier, it's only ~80lb all up. Unfortunately, the axles may be too long (too wide of a track width to fit in 240).

I've also considered a ford 8.8 IRS differential from a 2007-2010 explorer, but details are somewhat scarce with regards to axle options.

I might go junkyard hunting this weekend if the weather is good; we'll see what I come back with

Here's to getting dirty under an old Volvo!

[benson0021]

I spent some time removing things from the car this evening.

I removed the dash and all the wiring harness, HVAC, pedal assemblies. I also removed ~20lb of crusty foam and rubbery noise insulation.


Engine bay is now even more vacant!


Also, the HVAC system is really heavy... I'll get a number once my scale arrives.



I plan to replace the HVAC system with a new unit (non-volvo240) that won't be so heavy or need all the volume in the dash.

I also plan to replace the entire rat's nest of a wiring harness because I hate ceramic fuses (and messy wiring harnesses).

[amerbritcan]

pics not working in latest 2 posts

[Tuff240]

All of this stuff you are doing is neat and all, but I never understood why people need to modify them so far that they are no longer a 240. And you say you want an "amazing" suspension. 99% of people can't use a decent suspension to it's fullest.

[benson0021]

Originally Posted by amerbritcan

pics not working in latest 2 posts

fixed... hopefully

[Vol242vo]

Originally Posted by Tuff240

All of this stuff you are doing is neat and all, but I never understood why people need to modify them so far that they are no longer a 240. And you say you want an "amazing" suspension. 99% of people can't use a decent suspension to it's fullest.

Agreed.

This is clearly on its way to an impressive build and at the end of the day this is your ride. Just too much molestation happening for my take on a Volvo build.

That said, the TT seats look great in there!

[RP80242GT+T]

So much for it being a GT. You could have done all this with a 242.