Project C4, 85 Corvette

[Steve85]

Awesome work :thumbup: Looks like the LS6 intake matches up to the L33 cathedral ports? I know GM did different things with the shape and design between heads, I wouldn't have figured the truck variant had the same design as the hot 'Vette motor. Awesome.

I actually went ahead with an LS1 out of a 2000 vette. I would have needed all the accessories, mounting brackets, bolts, pulleys, and oil pan from a vette anyway. Also heard modifying the truck harness is a bit of bear too.

But, to your point, the LS6 intake will match the L33 truck heads because the L33 truck heads are LS6 casting ("243" / "799") heads. :thumbup: Actual LS6 heads had in addition sodium filled valves and yellow beehive springs to handle a bigger cam and more RPM.

[Steve85]

Awesome work :thumbup: Looks like the LS6 intake matches up to the L33 cathedral ports? I know GM did different things with the shape and design between heads, I wouldn't have figured the truck variant had the same design as the hot 'Vette motor. Awesome.

Interesting that they used a more efficient cathedral designed port in the LS6 but switched back to a rectangle port for LS7s... Wonder why.

Efficiency is related to the operating conditions. An LS7 head on a 347 will be lazy and low speed driveability will suck. An LS1/LS6 cathedral port is too small and will choke a 427 very low in the RPM range. The LS7 needed a bigger port so they moved the pushrod over to make it wider and making the port shorter allowed them to raise it. Throw that on a 12 degree valve angle (versus the 15 for LS1/6) and it makes for a nearly straight shot into the cylinder. The aftermarket had been doing this for many years on the SBC, but all the custom parts and porting made it easy to spend 5K - 10K on the top end alone.

[Steve85]

Lots of progress lately, starting with fitting the transmission. I got a stock C5 clutch for $80 delivered, a hydraulic TO bearing/slave for $90, and pulled the big block bellhousing out of my parts pile.

The LS clutch/flywheel is bigger than the old SBC clutches so a big block bellhousing is used. Thank you GM for using the same pattern on the rear of your blocks since.... forever...new all metric block still has english threads for trans mounting 8) . The hydraulic TO bearing comes with spacers that allow me to make up the difference in fw / clutch thicknesses. I measured from the back of the block to the clutch fingers, then from the BH face to the front of the TOB and it was 1/4" off. Using the spacers behind the TOB to push it towards the clutch I got this fitment:

TOB:






Notice the stud in the lower right corner of the third pic - it's usually a bolt that is one four for the front bearing retainer. The slave cylinder comes with a stud that would replace the bolt and keep the slave from spinning. Richmond uses a metric stud and nut arrangement, so had to order an M8 coupling nut and M8 threaded stud.

The next part of this is mating the existing lines to the new clutch slave. I could not find a hard tube adapter that had a -4AN fitting on the other end so I went to a local NAPA truck center that has a sign "we make hydraulic hoses". A few minutes later I had a hose with a right sized compression fitting on one end and a 4AN on the other. This hose in this application will never break, it's some industrial 6,000 PSI rubber/braided/rubber hose.

Original (after cut of course)


New line:


So driveline fitment is nearly done, I will likely have to enlarge some holes on the "C" beam that connects the trans to the diff since I'm betting fitment won't be exact.

Next up was fuel lines...

[Steve85]

Since I'm pretty sure it's somewhere in the hot rod bylaws that you're not allowed to have an engine on a stand not put a cam in it, I installed a cam to comply. And itÔÇÖs soooo much easier on this engine, I should have done this years ago. Intake stays on, lifters stay in, and rockers do not need adjusting. (If you go much bigger on the cam, you do have to get new pushrods because the base circle size of the core goes down and you need make up the difference)

The cam is very mild. I actually got a custom recommendation that turned out to be very close to a GM Performance Hot Cam which I felt was too aggressive for what I want out of this. The goals were a good idle, not too aggressive for the valvetrain and retain some semblance of fuel mileage... and if I could, avoid the need for a custom tune. If I went with an aggressive cam I would be almost $1K into it with springs, pushrods, tune, and custom cam. I found a comp cam 54-424-11 with the right Comp springs on LS1Tech. com for $350 shipped.

Specs:
212/218, .558/.563 lift on a 115 LSA

For comparison to stock cam:
197/207, .467/.479 lift on a 116 LSA

The pics:

Water pump off


Pet grub


Timing cover off


Water pump bolts for a handle (they could have made it the same as early SBC bolt pattern, but it's just off enough that you can't use your old cam install handle..booo!)


cam retainer off, cam out


looks pretty clean in there, and it wasn't easy to get exactly nothing in focus on this shot.


Now, scroll up and you'll see what it looks like going back together

Pedestal rockers, no adjustment necessary


Air line to hold the valves up and super easy to use valve spring compressor allows you to do two at a time.


valve spring compressor


I've been working through all the little odds and ends as well but very close to dropping it in.

[ScottyB]

$350 for that? i'm doing it wrong...time for an LS1.

[Steve85]

I wanted the stock dash to work which meant getting the sending units to mount on this engine somewhere. This is the oil temperature gauge location that I used. This is the way Corvette Central did it.


I took that off, assembled some tools and went to work.


Drilled out the 10mm threads and tapped with 1/4" NPT


Somewhere along the line I picked a set of "star" sockets and they work great for square ends


Using a 1/4" nipple, a 1/4" tee and 1/4 to 1/8 reducer bushing I was able to mount the original oil pressure and oil temperature senders. It is installed and wired...
(this was the test fit pic, guess I never took a final pic)


Update - A friend pointed out that the sending unit and fittings will subject to a lot of vibration here and I have to agree. I do have a fitting in the top rear of the block that replaces the original LS oil pressure sender that accepts the old sensor. If I have room to use it (cowl and firewall clearance) I will relocate the sender and just have the temp sender by the filter with no brass tee, screwed directly into the LS fitting.

This is the fitting, ATM-2268:

[Steve85]

I would try to get the temp sensor close to the way it was prior to drilling it out. You want it to be in the flow of oil. The way you have it now, it's dead-headed on the tee. Really, I don't think it will be a very accurate temperature reading.

I would definitely try very hard to relocate the pressure sender to the top of the block.

[DJ raised the same concern]

:iagree:

It seemed like a good idea when I saw it on their swap [Corvette Central] but, you're right...

[Steve85]

Heeding the oil pressure switch warnings and also having another person confirm my suspicion that the temp sensor is not in a good place to deliver an accurate reading I made some changes.

This is how the pressure switch is fit on a stock 85



I used just the angle piece to go into the metric to NPT fitting





Installed with plenty of clearance



And temp sensor refit so that it is in the flow of oil and not at a dead end to give a much more accurate reading.

[Steve85]

Dash Coolant Temp

I took care of the oil temps and pressure in another post and this is the dash coolant sender, goes directly to dash, does not talk to PCM.

Since the left and right heads are the same, they plug the the hole for the PCM sender on the passenger side head. Here it is with plug removed:



Stock sender of course has english threads so I used a big fat drill bit and a 3/4NPT tap



and done with sensor installed. dash has no idea it's not talking to an old truck motor anymore.



It works great. Dash says 200, fan comes on, then goes off at a reading of 190. It's dead on with the PCM sensor on the other head.

[Steve85]

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 got stuck at 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 :willy:

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]

Success! All the metal parts and fluids stayed in and all the smoke stayed inside the fluids and wires!

Not a particularly exciting video but what the heck. This is the 1.12 mile 7 turn Jefferson Circuit at Summit Point. Not much room to open it up but a good low risk / low cost way of making sure all is good.



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[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 :ack:

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 [TPiS MiniRam - short runner intake that replaces the restrictive long tubeOEM TPI) 350.

The Richmond [aftermarket 6 spd that replaces OEM 4+3] 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.

[Steve85]

I've been commuting in it quite a bit recently. The Integra was in the shop for a week getting a new bumper from a deer hit and it's been so nice this week.

Up to 22MPG, not too bad for a mix of cruising, traffic, and anger management. I should pick up a few mpg with the tune just from getting the idle lowered. I sit in traffic at about 950rpm, way too high.

Need a new radio though. I've been using the phone or old CDs for tunes but I hate wearing ear pods while driving and old CDs are old. Most of the time I just leave the radio set to V8 Noises.

Oh yeah...driving around with messed up hood and bumper for now from this a couple months ago:

New hood emblem!



Exiting a parking lot, she decides she doesn't want to go out that way and starts backing up. I'm on the horn that she doesn't hear. She hits, decides it's a curb, and gets on the gas more and climbs up the hood.

Her fancy SUV is equipped with backup sensors and mirrors which are meaningless when ignored.

Even though it was on private property, I called the cops to make sure she would stick to her "OMG I'm so sorry" story. I could show this pic to 100 people and 75 would probably say I rear-ended her.



I wanted to get rid of the hood scoop since I no longer need the clearance and didn't really like it to begin with so I took the insurance money for a new bumper and went to Corvettes at Carlisle and picked up a perfect hood and bumper. They'll need paint but insurance was going to have cover that anyway.

[PDenbigh]

I love how this thread is full of projects that are explained to the reader as "well I got bored so I worked on the car for a few hours, pulled the engine, put in a new wiring harness from scratch, and now it's back together", when in reality, most people would be like "well I spent 6 months doing this particular project, took three guys and 18 6-packs and a lift, it's almost back together but still having some small issues, and not quite buttoned up."

[Goodspeed]

^truth. Steve's been making us all look like lazy bums since the inception of this thread :lol:

[Steve85]

haha...it's a lot like your thread Pete. "Hey I like this body kit, so I'll build a paint booth".

I just wish had time to tend to the details the way you do Goodspeed. I think if I did though I'd find myself locked out of the house a few times.

It's so easy to have a project like this end up collecting dust on jack stands, I see it all the time, and refuse to let it happen.

[Steve85]

Update on the damage repair...

I found a hood and bumper at Corvettes at Carlisle in late August for a little more than insurance allotted for the new front bumper. Labor hours for crack repairs on the hood will be used to repaint the entire hood. I had to get the new hood on just to get it to the shop and these things are heavy and bulky so enlisted some child labor at the right price.

phone does not like taking pics in foul weather...

"flexing" after the big lift


removing the headlights (buckets will be fixed and repainted)


ready to go to the shop

[REED]

ha, you must have some crazy weather - is he wearing shorts and snow boots?

[Steve85]

It's not the weather that's crazy...

A little update...

I noticed while test fitting for my swap that the valve cover, specifically the breather outlet, interfered 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.

So the solution to retain the C4 wiper motor (using the VetteWorks motor mounts) 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. I did it in such a way that no special tools or fab skills are required to continue showing how the swap can be done with little to no special fabrication. (as is often claimed by the naysayers)

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!



So nice to have wipers again. I always avoided driving the car in the rain just because it wasn't much fun so I didn't think it would bother me. I didn't consider all the other times wipers are used...like cool mornings with heavy dew.

Sold the "Monster Tach" and bought a Dakota Digital box to correct the tach signal and use the dash tach. I needed to double the pulses from the LS PCM to get the tach correct. Pretty simple device, basically tell it it's a 4 cylinder engine and an 8 cylinder tach.

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.

Also installed a new Bluetooth head unit, so nice especially on the long drive to work. I have a few pics I'll try to get on here. I removed the Bose system (each speaker had its own amp and tuned box) many years ago so it was a pretty simple install.

[ScottyB]

solid fixes! glad to hear its getting put through its paces too, if you've already covered over 5k miles since the swap happened. doing it right :thumbup: