AngryCorvair (Forum Supporter) said:Congrats! I know how unnerving the first drive at speed can be. OMG what was that sound?!?!
The first time I had this car majorly apart years ago (trans rebuild, axles, clutch) we put it back together, drove it down the road, and the header had rubbed a hole in the trans cooler lines and they leaked directly onto the header. Filled the car with smoke. I have lots of stories like that.. I'm absent minded.
OK, I figure it's time for another update in the Cursed Z06 tale.
TLDR: We put it on the dyno today, it's making good power but oil pressure wasn't going up with RPM as we'd like so we cut it short.
I had dyno time scheduled for this morning so last night I started to load the car on the trailer so I would be able to just head out in the morning. The C6 has a tubular structure that forms the bottom of the radiator support and bolts to the frame. I have used this a number of times to pull the car up onto the trailer.. last night I learned that was a dumb idea when I broke it. One side broke at the mounts to the frame and it bent and broke the cross tube to the other side. E36 M3. So it's 9 PM and the bumper cover has to come off, mangled rad mount unbolts in pieces.
Where'd that rad support go?
Oh, there it is.
That led to welding random aluminum angle to it in order to put it back in the car and make the dyno time today.
This is what my aluminum TIG welding looks like when I am welding random scraps found in my metal stack at 9:30 PM. I loaded it on the trailer at 10:30 PM.
This morning I get to the shop, unload it, and when we go to put it in the bay, it won't start. Jump box, start the car, it's leaking oil at the oil cooler lines. The oil cooler bolts to that rad support I took out last night, and when I unbolted it I loosened a fitting. Easy fix, that, and I even brought AN wrenches. Order a battery from the local auto parts place, replace my two month old battery (!).
All of that done, it fires up, it's running on the rollers, and the tuner did some part throttle tuning and loaded a couple of iterations of the tune. Finally, he loaded it down at low RPM, then did a couple of brief shots at WOT to about 3600 RPM. These were 2-3 second burps but man was the car making some noise.
Shut it off, look at the logs, oil pressure is not coming up with RPM. After it was warmed up it's seeing perhaps 35-40 psi at 3600 RPM and 28 at idle. That would be awesome for my old Buicks but this thing should be making more pressure with RPM. It sounds fine and drove out of the bay just fine, but caution is the better choice right now.
I really, really, really don't want to drop this thing out again. I'm going to drain it, cut the filter, look for sparkles. Then I will probably pull the pan and see if the suction side and o-ring look OK. It's possible it's something simple. And it's possible that bad things are imminent. Guess we'll see.
Finally, a couple of printouts just for kicks. We tuned the car years ago when it was a NA LS7 here and Ajay found the file and overlaid it on today's brief hit. Same peak HP! Only today's was at 3600 RPM. And it's making locomotive torque down low as well. If I can get the oiling system up to par I think it's going to make some really good power.
496 HP and 720 ft-lbs at 3600 RPM
In reply to Kendall Frederick :
496 HP and 720 ft-lbs at 3600 RPM
jeebus maing that's pretty stout!
That's stump pulling torque right there, you giving Cummins, DuraMax and PowerStroke a run for their money with that torque number. Peak HP should be a sight to see once you get the oiling sorted.
In reply to 06HHR (Forum Supporter) :
I hope so! I don't know if the parts in it are good enough for the power it can make. LOL. That torque is the reason I wanted to go with the LS9 supercharger over the centrifugals. It made 16 psi of boost on that 3600 rip; it looks like it's slipping after that though as it declined when he ran it up a bit higher in RPM. I think I'm going to de-pulley it a bit with a larger upper pulley; the belt tensioner is close to max travel and it needs a shorter belt. The larger upper pulley will soften the hit a bit, tighten the tensioner, and hopefully have less slip.
AngryCorvair (Forum Supporter) said:In reply to Kendall Frederick :
496 HP and 720 ft-lbs at 3600 RPM
jeebus maing that's pretty stout!
We need to put one of these new fangled LSs in your car. I have a whole extra LS7 sitting around here...
I just wanted to say that I took the car down the road and rolled into the throttle a few times today. It's a death trap in the best possible way. It will blow the tires off from a 70 mph roll, and probably a 100 mph roll, if I were stupid/brave enough.
Motivation to keep working on it..
Kendall Frederick said:AngryCorvair (Forum Supporter) said:In reply to Kendall Frederick :
496 HP and 720 ft-lbs at 3600 RPM
jeebus maing that's pretty stout!
We need to put one of these new fangled LSs in your car. I have a whole extra LS7 sitting around here...
You heard it, folks, he offered to trade anyone on the planet with a mid engine LT1 Corvair challenge car to trade that LT1 straight across for his extra LS7. That offer was open to everyone on the planet who met those criteria, and I just happen to be the first to respond. That's for budget purposes right there.
In reply to AngryCorvair (Forum Supporter) :
Absolutely!
Kendall Frederick said:In reply to AngryCorvair (Forum Supporter) :
Absolutely
let's head over to your shop on the way home from 2026 Challenge!
AngryCorvair (Forum Supporter) said:Kendall Frederick said:AngryCorvair (Forum Supporter) said:In reply to Kendall Frederick :
496 HP and 720 ft-lbs at 3600 RPM
jeebus maing that's pretty stout!
We need to put one of these new fangled LSs in your car. I have a whole extra LS7 sitting around here...
You heard it, folks, he offered to trade anyone on the planet with a mid engine LT1 Corvair challenge car to trade that LT1 straight across for his extra LS7. That offer was open to everyone on the planet who met those criteria, and I just happen to be the first to respond. That's for budget purposes right there.
You didn't actually respond to the deal.
I'll take that offer!
(Now I just need to get some corsair body panels to fit on a Mazda 3 and put the engine in the back...)
AngryCorvair (Forum Supporter) said:Kendall Frederick said:In reply to AngryCorvair (Forum Supporter) :
Absolutely
let's head over to your shop on the way home from 2026 Challenge!
In all seriousness, that motor needs some budget busting refresh work. But when you're done with the Challenge, I would absolutely work something out with you.
Just to keep it real, here's the Vette tonight:
I drained the oil, cut the filter, everything looked good, no glitter. Motor sounds healthy, but I want to look through it to try and get the oil pressure issue resolved. I also found my main ABS issue (it had a loose ground), verified an open in the wiring to the RF wheel speed sensor that I need to fix while the motor is out.. etc. etc.
I have a list on my whiteboard in the shop now, I'll take a pic of it when I have a few things crossed off.
Working on it...
Pulled the pan to be greeted by this:
Water in the oil. I should've probably seen it when I drained it but the oil wasn't fully chocolate milked (can I make that an adjective?). Gaskets were MLS Cometics, and after some close inspection, I think this was my leak:
There's a slight relief in the head surface where the rivet is on the gasket, but you can see that the deck surface deformed that rivet, and I think held the gasket up enough to leak water here. There was water in between the gasket layers, thus the puffy wrinkled look.
Additionally I pulled the barbell out of the back of the block and the o-ring was ripped on it. It could've happened during extraction but I think/hope that was my oil pressure issue, maybe combined with the water dilution.
Good news is that the bearings all look great.
Going back together now:
Factory LS7 gaskets with a light coat of Coppercoat. I waffled over doing this but I have used it with good results on other engines with MLS gaskets. It's just a bitch to clean up if it ever has to come apart again..
Also filed the corners of the relief where the rivet goes; the LS7 gasket rivet is much smaller than the Cometic anyway, but I figured this would be a good thing.
And here we are this afternoon. I need to consolidate my whiteboard lists now; I bought two giant whiteboards for $2 at an auction a couple of weeks ago.
Going back together. I'm headed out of town for a week, but hope to keep making steady progress when I get back.
I've changed the senders in both fuel tanks, bought a replacement crossover tube for them because mine had a broken retainer for the internal hoses. Also bought a replacement column and intermediate shaft and changed them, which necessitated pulling and swapping the air bag and steering wheel over also. Fun times.
Oil pressure issue was the barbell in the back oil galley -- I had it in reversed, which allowed pressurized oil to dump out the back into the pan. I hate to confess that, but when I make mistakes, they're good ones!
OK, I have excuses.. two different totally disassembled LS engines in the shop, a derelict truck outside waiting for me to make one good one out of the mess, travel, yada yada. Enough of that. I'm still working on stuff. A local guy who has a lot of ZR1 stuff (3 complete motors with superchargers) wanted to duplicate my power steering bracket, so I told him where to source the bracket I started with (Holley LT5 power steering conversion bracket). He bought a few and did 3 brackets, with the idea of putting the pulley in the exact OEM location, which I did not do. He had a couple of local shops machine and weld them, and they turned out better than my first one. So, I borrowed one to check it out with an eye to making another for myself and improving on Rev 1.0.
They come with the pulley shaft and bearings press fit into a cast aluminum bracket. You pretty much have to press this out to machine and weld the assembly. So, first order of business: press the pulley into the bracket. I tried the press without heat, no bueno. So here comes try #2. Yes, my wife was at work:
About 5 minutes at 220F, apply Loctite 609 retaining compound, and Shooouunk! It slides right in. So satisfying.
Next, bolting it on and checking for pulley alignment: I just bought this laser alignment tool that uses a little laser with 3d printed blocks that fit in the pulley grooves. Dead on.
Next I wanted to verify X-Y position against the factory bracket; we found a drawing that shows these measurements (though I doubt it's a GM drawing, I hope it's accurate..)
Rigged this up for a quick check. Short version: it does not match the factory dimensions, it's about 1.5" too low.
There are only about 3 belt lengths available in either 11 or 12 rib that will work on this setup, depending on your pulley and idler sizes. I tried the belt I've been using on my bracket; it's too long for this one (see tensioner marks).
So, I ordered another Holley bracket, I'm going to do some fixtures so I can mill it, and I'm going to build some jigs to allow locating the next one more precisely to factory-ish dimensions, with the goal of being able to have more belt options by changing idlers if necessary.
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