ghlkal

Awesome

What kind of mileage did you get? (Not on the course )

Steve85

First off - question - does anybody know what this white module is? It lives behind the passenger knee bolster. I suspect theft deterrent but cannot confirm in the FSM. I tied into a wire on it for 12V and would like to update below connection definitions with more specificity



Old wiring and grommet removed.

The wires that are still there are the VSS wires, oil pressure and fan relay ground and one or two others not sure where they go. All other underhood wiring goes through a connector on the driver side and is untouched for this swap (and when putting the DFI in some years ago)




To help with feeding everything from inside the car to the engine bay, I ziptied connectors to wires. This way as I gently pulled things through, the wires didn't "double back" as connectors reached the firewall. The entire harness behaved more like one wire than a bunch of separate loose wires.




Once I got everything fed through I went to work identifying the wires I needed to tap into. Most go right through this - Connector 237




As I identified the wires I needed I labeled them with names and numbers and corresponding names/numbers on the PSI harness.




I connected everything without regard to where anything would be mounted or wires would ultimately be run for testing purposes. I wanted easy access to all wires and connections in case anything was wrong. It was kind of a mess in the footwell to be honest.

The car drove great so it was time to find a permanent mount. I tried squeezing it into the same place the old ECM came out but the new PCM is too thick and the much larger connectors interfered with the HVAC blend door.

Under the seat we go!

I cleaned up all the wiring that I needed to tap into.




Then pulled back the footwell carpet and ran the main harness through there and cut a slit in the carpet under the seat.





After that, it was just a matter of connecting the right wires, number coordinated, connecting the PCM connectors and tucking the underdash stuff up behind the knee bolster where it came from.

Patience with numbering wires is crucial to making sure the connections are right. Trying to remember colors or trying to read whatever abbreviation you wrote at midnight after only 4 hours a sleep the night before can be frustrating

I think if were to do it again though, I'd keep the PCM under the hood as in the later model cars and what ch@os is doing.


C237 pinouts defined and PSI harness connections:

Steve85

I used so little gas I decided to go ahead and do the track session before filling up. I have 150+ including the track session and I think it's still above the 3/4. Although, we know once it hits 3/4, it starts moving faster...

I want to drive some more and then fill up. I'll definitely post it up though!

Steve85

I really need to get some completed pics, all I seem to have are "along the way" shots...

So I've gone through I think 3 or 4 tanks so far and getting about 20mpg. That includes driving the car aggressively and some highway / stop-n-go commutes. The 408 managed about 10 in similar driving

It's running a stock f-body tune (for cable drive TB) so I'll probably get better results with just a mail order tune to compensate for the small cam, Z06 intake and better exhaust configuration. Nothing radical.

I'm really enjoying the power level and delivery. I've been through a mildly cammed L98, then same long block with MR (and exhaust, etc.), 408, and a 434 and this is the most overall fun to drive. If I were to go back, I'd refine the MR 350.

The Richmond seems to be a good match for the engine with the 3.07 rear. A pretty steep 1st gear at 3.28 makes up for the tallish rear. And the 3.07 + 6th gear .81 OD makes for nice cruise RPMs right around 2K. Not as low as the .6 ODs in the T56s so probably won't ever get quite the highway mileage a LS/T56 combination is capable of.

Plans from here:

• Get AC installed
• Tune
• Different air filter and filter to TB stuff
• Coil covers
• Eventually detail - painted covers/intake and powdercoated WP, accessories and brackets.
• New hood (stock - purchased at Carlisle yesterday - perfect condition white hood from the yellow tent guy "Ted")
• New smaller Autometer tach or Dakota Digital box for dash tach.

ch@0s

I'm ready for those pics

Steve85

Really need to get those pics..lol.

I posted in a separate thread about the front end being damaged in an accident where a MB SUV back into..onto...me. All fixered up from that with new no-scoop hood.

Drove it the other day after sitting for a while and all is still good.

I originally put all water in since I knew I'd be hitting the track so I drained some and put some AF in there to get through the DC area winter.

I do have a check engine light and when I went to AZ to have it scanned they couldn't connect so I need to try again somewhere else. If I had to guess, it's going to be related to no speed input (not needed in this application) but obviously I want to know for sure...damn thing runs great so I doubt it's anything real. All the smog stuff was supposed to be programmed out, although I'm sure a custom tune would be beneficial at some point.

UPDATED Plans from here: (not much going to happen until it's warm again, I'm over the whole 30° in the garage crap)

• Get AC installed
• Tune
• Different air filter and filter to TB stuff
• Coil covers - not sure why I put this...do not want
• Eventually detail - painted covers/intake and powdercoated WP, accessories and brackets.
• New hood (stock) - Done
• New smaller Autometer tach or Dakota Digital box for dash tach.

Steve85

A little update...

I noticed while test fitting for my swap that there would intereference with the wiper motor. I've seen a modified wiper motor from a blazer used and I've seen several have no issue and I've seen a couple race cars that don't have wipers. Turns out, LS6 and beyond (LS3 etc..) have a different breather system so they do not interfere with our huge wiper motors. I wanted to make it work with the most readily available mounts from VetteWorks which allow the drivetrain and everything to fit nicely but pull the engine too close to the wiper with the LS1 breather setup.

So the solution to retain the C4 wiper motor with LS1 is actually quite easy. Swap in the LS6 breather and steam pipes and modify the valve cover. I did this in the car but if you're doing the swap and do this on the engine stand...even easier. And I did it in such a way that no special tools or fab skills are required.

And if you've ever removed a complete TPI intake, you'll LOVE how easy this is...a few very easy to get to bolts and less than 1/2 of a cup of coolant spills.

For a better how-to guide on the LS1 to LS6 breather job go here. It has bolt sizes and torque specs. I didn't try to reinvent the wheel below because this is so good:

http://www.ls1howto.com/index.php?article=18

Here is the interference between the valve cover breather outlet and the wiper motor.




Removed intake. SOO easy on this engine being a dry intake.




Removed water pipes and pulling knock sensors




This little nub is not on LS6 blocks and interferes with the LS6 breather. It serves no apparent purpose and is easily cut off with a Dremel.




Here it is cut off. (I had about 10 more towels in there protecting against dust etc. during the cutting)




New breather on and torqued to 18 ft-lbs




LS1 steam pipes do not work. Need to get the LS6 version which is the front pipe and two block offs for the rear outlets. Parts are like $50 for the LS6 steam pipes.




Valve cover breather outlet cutoff and test fit to wiper




Flat piece of aluminum rough cut to size and shaped with a round end hammer and JB welded into place. Nothing fancy here, I do have a welder with an aluminum spool attachment but wanted to do this in a way ANYONE could do it, no special fab skills or tools - Dremel and JB weld.




Trimmed and ready to install.




Installed and plenty of clearance!




Wiper motor interference is no longer an issue and they work great!


I'm currently getting the tach readout corrected through a Dakota Digital box and will post that up hopefully later this week.

Then I'll tackle the AC probably using the Holley bracket for the original style compressor on an LS. It's something like $150 plus $40 for a spacer kit. Again, looking for bolt-on solutions that others can easily follow.

I think I'm well over the 5K mile mark on the swap and loving it. Really need to get the AC back in though. These things are a damn greenhouse in the summer with the steep windshield, plexi top and glass hatch.

ch@0s

Wow mine is close but the nipple is at least an inch away. The early C4s have it worse.

mcm95403

First, congrats on a great swap

Awesome to see a real car guy do this the old-fashioned way - hunting down a bell housing, sorting out the little things that need to be done, etc.

All your documentation is certainly great for anyone wanting to do this swap - thanks for sharing it with the community!

COPO

Great another one that will be done before I am. Looks good man

Steve85

Thanks!
I learned so much from others before me and I hope I can add an idea or two to help the next guy.

The bellhousing credit really goes to a guy on LS1Tech "Garys 68" who had a C3. I was hesitant to do the swap because I didn't want to buy a new trans having the Richmond six speed. I starting putting 2 and 2 together though as I did my research - the 4+3 is Doug Nash, but it's really a Super T-10, and there were T-10 to LS BHs available. So I went to Richmond's website where they have a ton of detailed measurements and sure enough the DN 4+3 replacement by Richmond matched bolt pattern and input shaft length with the Borg Warner. The search was on and I came across "Garys 68" on LS1Tech that found that a "621" big block BH worked just the same. BAM! Swap was on!

Don't worry, as you know, none of us are ever really done. I'm driving it a lot but still working to improve things anywhere I can

Yours is a sh!tton more involved and detailed so the time will pay off

Steve85

Quick little update...

Still going strong and AC install is imminent. I have the Holley bracket and just need to work out the details.

Since no more high rise single plane to feed, I went back to a stock hood (and threw the CCWs back on for a change)

ch@0s

Looking good Steve

Steve85

Going on 5 years with the completed swap!

A few outstanding items I'd like to address are finally getting AC in the car, need a better air filter to TB solution and clean up the exhaust. Here are a few updates from the last couple years copied from another forum. It's long, but oh well, wanted to update this here even though I'm not here much anymore.

TL;DR: I replaced a welded inner wheel barrel, fuel tank, fuel pump (finding a bunch more power as the old one was not enough), balancer/dampener, and throwout bearing. The LS itself has been solid! Discovered loose rear camber rod mounts, tightened those up and it felt a lot better at the latest autox. So 5 years on the swap and it's been great!

September 2017:
I decided to finally get new inner barrels for the front wheels since one was welded.

The plan was to get get a diff't width and then swap the front / rear inners to go from a 12.5 / 10.0 setup to 11.5 / 11.0. I bought second hand and the barrels ended up being same size as rears so the fronts got bigger but the rear didn't get smaller. (weird because I had pics with a measurement, so not sure what happened) New tires were in order and I found some Yoko Advans on ebay that were brand new, just a couple years old and they mounted and balanced with minimal weight. The previous setup took a fruit roll up length of weights to balance and never felt right.

I was very excited until I got 100 yards from the house and couldn't accelerate. So pissed...

It seemed the problem was with #8 so I did all the usual swapping coils, plugs, wires, and injector. Fuel pressure was good even when it started to stumble. It was just a funny thing, no matter long it idled in the driveway or I revved it without load, it was good, take it on the road and 100 yards out, it would **** itself. I had to try something so I went with an O2 sensor for that bank, no change. Then I noticed this:

I decided on a 25% underdrive unit for mad HP gains. And to hopefully not kill the AC compressor I plan on installing that was originally designed for about a 4500 rpm redline.



The side hope was that the vibration was causing a false knock. The pull and install took a total of 4 hours, 3:45 of that was finding just the right mix of stuff to pull the balancer (borrowed a kit fro Advance but the LS crank has a stupidly deep snout). Got it done without having to pull the steering rack so that was a bonus. I heated the damper as instructed by the manufacturer and it went on smooth.

Unfortunately, the car still ran like crap. Back to the basics, fuel spark compression. Which really means, the right amount of good fuel, hot enough spark at the right time and enough compression.

I decided to get into the tank and noticed a murky fluid settled on the bottom. Like, you could see stuff floating 3/4 of the way down a full tank. It was actually pretty cool, like a layered B52 shot. Here is a comparison of the fuel from the bottom of the tank and the top layer:


I hooked some fuel line to the pump outlet and pumped out 4 gallons from the bottom of the tank to gas cans. I timed it, it took 1:55 to pump out 1 gallon, which becomes very important... Reinstalled the pump and test drive was great! I had shitty water filled gas. I think it was actually the HEET I put in the night before that pulled all the **** to the bottom.

During the test drive I still had the FP gauge taped to the windshield. At full throttle, and not falling on its face anymore, it quickly dropped from 60 to 40, whoa! I always thought it was a bit flat up top but figured I needed a tune. It has a slight cam and Z06 intake on a standard LS1 tune.

So I pulled the Walbro 255 out of the drawer (I have no idea why it wasn't already in the car..) and installed it. The tank in a C4 is not in a great spot from an engineering perspective, but it sure is user friendly! WOT pull and it stayed at 60 psi, yay! And by yay I mean..

HOLY CRAP, WHAT HAVE I BEEN MISSING!?!

Probably 50 HP at WOT from 2500 rpm on up, that's what! It pulls hard all the way now. I'm not sure at this point I gave up anything to the previous 408.

I'm not sure if I got shitty gas after putting in the O2 sensor when I topped off the tank or it just built up water from sitting for a while. All I know, I've been missing out for years and it was a great discovery!

OCTOBER 2017:

I got a new tank since the sending unit mount on the original was finally rusted beyond usability and pretty sure the rubber bladder was breached somehow.

I had to pump an almost full tank out so I set up my battery charger to power the pump directly and ran some fuel line into a few gas cans. I roughly measured the flow to compare to the other fuel pump that was leading to the fuel starvation at higher RPM. The old pump did something like 130 lph and the Walbro did 226 lph. It's rated at 255 but the charger was a low setting and probably only delivering 11 volts or so.

The actual tank replacement wasn't as bad as I thought, the worst part is really getting the tail lights out (and back in) which you have to do through the hole behind the license plate. I don't know what the original assembly procedure was for these cars, but I can only imaging they hired the fairest of folks in all of Bowling Green, KY to reach in there...



Once the tail lights are out, it's just feeling around for the 10mm nuts at the sides of the bumper and a few screws along the top. A couple more 10m along the side above the marker lights and the bumper just slides off backwards revealing the tank and impact bar.



4 bolts on each side to drop out the tank and impact bar as a unit.



And the impact bar was apparently put to good use at some point in the car's life. You can see the up right corner is bent in and the absorber is mangled. It's a big piece so shipping is killer. I'll try to find one locally and if not, ask one of the parts vendors for Corvettes at Carlisle to bring one on the truck.

New tank strapped in and ready to go.



Fired it up and checked for leaks and so far all is good. Nice to have a working fuel gauge too. The old sender would just read down to about half tank and stay there. Also cleaned up the antenna ground and radio reception is much better!

Next up is addressing the loss of fluid in the clutch system.

NOVEMBER 2017:
My hydraulic throwout bearing finally gave up the fluid for good. I had to fill the reservoir a couple times over the years and now it was just emptying out after a few presses of the pedal. This is the old one, a "stock" version from Speedway motors since I'm using a stock C5 clutch.



Turns out, using the threaded rod there as the stopper was eventually going to kill this thing anyway, it had rubbed a good indent in the bleeder outlet!

The new one is an updated heavy duty version from RAM, recommended for street car use. I made room in the garage, pulled the car in, put it up on jack stands, removed a bunch of bolts and this fell out:



I just looked on my phone and apparently I was NOT in a picture taking mood during this job. This is it. It makes sense though, I was on my back almost the entire time. There is a little area on the garage floor now where can see that I rubbed everything that fell off the bottom into the floor Drained the old fluid (most by accident) and replaced with new gear oil. I had to take a few measurements to set up the bearing clearnace so I had to go back in and remove the clutch and flywheel. I measured about 15 times and felt pretty good I had the right number of shims in there.

This pic is from the original install of the old bearing, the gold rings are the shims to give an idea how it is set up. This new bearing has more travel and took less shims.


Had a delay in getting new lines, the old bearing used -4 lines and the new one -3 lines. I tried to source locally but all the hose makers around are more industrial focused and don't have anything that small.

I really thought it would be easier but forgot the LS sits farther back and only tilted a few degrees before it hit the firewall and made it difficult to clear the trans tunnel with bellhousing. There was jusssssst enough room, which meant going back in was going to suck. And it pretty much did, try this, try that, then another thing and finally it jumped right back in. Didn't help at all that I was trying to balance it on a regular jack. The C beam makes everything a real PIA. Put all the other parts back on, bled out the bearing and hoped like hell it didn't blow out right away, I've heard horror stories. It was a little soft at first with some tiny bubbles coming up into the reservoir but after a driving it a bit the pedal firmed up and has been good!

While I had it up in the garage I decided to tackle a couple other small things.

The power steering setup used the original 85 reservoir with some molded hoses to the pump. It's like they were made to fit except belt clearance was minimal and I had a ziptie providing insurance. The hoses were also slightly different sizes so it never really sealed at the reservoir. I went with easy button and ordered a kit from Summit that came with a factory C5 reservoir, bracket, correct hoses etc. Took about 5 minutes and it's much cleaner look and no leaks!

I also needed to finish my rear brake job and put new pads and rotor on the right side. And since it was up in the air I finally decided to tackle the parking brake which hasn't worked I think ever. I broke out the manual, followed the adjustment procedure and got it working again. Until I put everything back together and pulled the car out... I pulled the brake handle and it wouldn't hold. I got out, knelt next to the car, pulled the handle and...it worked. Got back in the car, pulled the handle, no worky. :huh:

So, while in the car I pulled the handle up and pushed it a bit towards the outside at the same time and it worked. (When you are sitting in the driver seat, the parking brake handle is at your left knee. After it's pulled up and engaged it goes back down to get out of the way) It seems the ratcheting mechanism has become a bit finicky after 30 years and a million pulls and just the different angle made the difference! This is one of those little things that is soooo nice to have working again.

With new inner barrel and fresh rubber up front, new leak free fuel tank, working fuel gauge, some new found power up top thanks to a proper pump, good rear brakes, good clutch and working parking brake, it all felt a little refreshed. Some much needed stuff after a few years of overall neglect and it feels good to drive again!

DECEMBER 2017

Some time ago at an autox (this was the first college solo I think) i looked at on course pics and had a lot of positive camber in the rear around turns. First pic looks normal (driver rear) but second pic shows how positive it went when loaded up.






I got an alignment and used the VB&P specs for aggressive street which included going with offset bushings up front. (occasional casual autox) At rest, there is definite negative camber in the rear.

At an autox last year, I decided it would be cool to get a shot of the rear suspension in action. Here it is below. I was very surprised to see the inboard mounts for the camber rods deflecting in/downward when turning. If you pause at the :32 mark, you can really see the deflection, the adjustment bolt is lower and more inward than the other side. That point on the course was a medium right hand turn after a straight, so it would load up the left pretty good.


It's hard to maintain camber when the mounting point is moving and the way it mounts there is no (or shouldn't be) pivot point.

I tested the bolt tightness and it wasn't loose, but it wasn't as tight as it likely needs to be. I think this probably allowed just enough movement to make things worse over time.

As suspected, the lower bolt hole has been worn and is now a bit slotted. You can see in the pic how much wider the bracket hole is than the hole the bolt goes through. It looks like it is offset, but as the photo was taken the left side of the bracket hole lined up properly with the diff mount such that the bolt could go through.



I tightened the bolts and then went for a test drive to see if they would hold for now until I can get to a permanent solution. In the video, it looks like they holding for now. (And the rear definitely felt more stable)


My solution will be to either get new brackets (but they are apparently out of business) or have these welded to repair hole, order new flange headed partial thread bolts, and double check torque on installation. Then go back in after a few drives to make sure they aren't coming loose.
Anywho, pretty cool to see the suspension in action (which was really the point of this shot to begin with ). It's amazing how much movement there is despite feeling so stiff.

MARCH 2019

Did my first autox in the vette since fixing the rear camber rods and it confirmed the "test", felt sooo much better. The back end used to be pretty quick to come around, especially through esses without any throttle provoking it.


So, yeah, if you made it this far, thanks for hanging on!

pooled

Thats a very good looking car, I really like the paint. Are those windows tinted slightly?

Steve85

Thanks! No, no tint, would definitely like to get it done though to reduce the sun load, especially the back window.

slow_zo6

Nice work! I'm about to get back to work on my LS swap. Using Novak parts to mate my 4+3 to a 5.3.
I'm sure Ill have to do some massaging to the c-beam. Did you have to get your driveshaft lengthened any?
I'm in Martinsburg btw.

Steve85

Thanks!
Yeah I had to massage C-Beam but not lengthen drive shaft. The slip yoke doesn't go in as far but still goes in plenty far enough. My engine seems to be a bit further back than others, I had to massage the valve cover to get it under the wiper motor.

Yeah, I think I responded on your original thread a few times before you left the country and remember you were just up the road a bit. Glad to see you're getting back to it despite picking up the newer vette!

slow_zo6

Hopefully I get lucky on the driveshaft length.
Do you still make it out to Summit Point? Last year I bought a set of C6 wheels from one of the instructors there. I'd love to be able to take the C4 on the track.
Are there any Corvette groups in the area?

Steve85

First off, sorry slow_zo6, I must have missed your post! I haven't done Summit in a while, mostly doing autox at one of the local high schools. The Greater Washington Mercedes Benz Club does one every month right down the road (the HS my kids actually go to) so I try to make as many as I can. I think there is a Shen Valley owners group but I'm just not into the "Corvette Club" thing
--------------------------------------------------------------------------------------------------------------------------
Decided to finally get off my butt and get the AC installed and working. The plan again is to do it in a way that is very DIY friendly way which mostly means avoiding custom welded brackets and such.The plan is to also flush, vac and fill the system myself (never done it before) because you can get the tools at HF for about the cost of one hour of shop labor.

I've had a Holley bracket for a while now that allows the old GM R4 style radial compressor to be mounted on an LS. A few things had me putting it off -

1. The area it sits in was already pretty crowded with heater lines and I wasn't sure the compressor bracket would fit without modifying the water pump to change the heater core outlets
2. I would need custom lines made
3. The bracket did not fit my slightly older style R4 compressor (it's made for slightly updated versions of my compressor)
4. I have very little AC experience.
5. And just being lazy about it...

Decided the other day though it was time to take this box of cold air and get it installed.



First issue was the compressor didn't quite fit the bracket so I needed to grind away a very relief in the bracket. Not sure what the "boss" is there for, but it's not on the 89ish+ R4 style compressors.



With that out of the way I was able to install the compressor in the bracket and test fit to the car for belt alignment and see exactly what I had to do to the water lines. The green line I think is going to be OK, it fits under the bracket. I think I can make the red one work by shortening the hose piece that comes up from the water pump. It's funky because the inlet to the pipe points up but the hose is coming from below it. Just needs to be a "tighter" install.



I dropped it in for a test fit and it does look like I can squeeze the second water line underneath the bracket. This is a pretty big deal for the install since removing and modifying the pump was going to be a big PIA. Belt alignment also looks good so I think I'm good to go with this compressor.

With it dropped in, I started planning for the lines I need to make.

The large line from the accumulator to the evaporator will work so I only need to make two lines, the line from compressor to condenser (orange) and another from the accumulator to the compressor. For the comp to accum line, I have 3 possible paths, red, blue and yellow listed in order of preference. (long live MS Paint!)



I ordered about $250 worth of lines and fittings from Nostalgic AC but will only end up using about $50-75ish worth. A lot like a home plumbing project but the store isn't right up the road so a little overkill to hopefully not get stuck.

I just need to figure out the wiring which really shouldn’t be difficult. It’s all still there for the cycling switches and control unit, I just removed the compressor pigtail a long time ago so need to make sure I rebuild and wire that correctly. I ordered a new pigtail from Amazon for $8.