Insulating the Corvette

While driving around with the Corvette last summer, I noticed that it got really hot after about 100 km. Especially around the legs. Well, there was hardly any insulation in the car and the engine and transmission did produce a lot of heat so perhaps I should have guessed it. The car was also pretty noisy but that was secondary compared to the temperatures in the cabin. This time I decided to do the insulation right by getting some good stuff.

My friend had used the Stinger Roadkill in his -65 Mustang and said that it was easy to install and worked well. I also went for a small test drive with him and was pretty amazed how quiet his Mustang was. Almost like a modern car. So, I bought three trunk kits that each had 1.85 square meters (20 sq. ft.) of material. Over 5.5 square meters in total. I read from some discussions that 5 to 6 square meters should be enough to cover the whole interior.

My plan was to remove the carpets and some interior pieces so I could insulate as much of the car as possible. Again the small garage worked against me so I had to work one side at a time. This time the weather was also an obstacle. When I started the work, it was about 5 to 10 degrees outside and going down. I would have to work fast before it got below freezing. As the Stinger was mostly meant for sound dampening, I planned to install two layers to the hottest areas: firewall and transmission tunnel.

I started from the driver side. I removed the seat, kick panel, carpet and the old "insulation". It was so crappy that most likely it didn't do anything... The floor that my friend built three years ago still seemed to be in good shape thanks to the rust proofing we sprayed.

Old "insulation"

Floors still good. Maybe a bit dirty.

The Stinger boxes said that no surface preparation would be needed but I still made sure to remove all dirt with some acetone. After wiping the floors, it was time to start installing. The Stinger comes in 30 cm by 61 cm sheets and should be cut to correct shape with a carpet knife but it is so soft that I even used scissors in some places. Starting from the largest level areas, I worked towards the walls and corners. After removing the backing paper and carefully placing the sheet, I used a roller to firmly attach it.

Attaching one of the first sheets

It took me a few hours but finally the floor was done. I also added some Stinger to the lower halves of the doors. The higher parts of the doors have some crash barriers so I couldn't get any insulation there.

Driver floor done.

Insulation in the door.

Next I turned the car around and removed the passenger side interior. The floors seemed good there too so I just cleaned them and started rolling.

Passenger floor.

When both floors were done, it was time to check the trunk. I still had a full box of Stinger left so I removed the carpets and old insulation and got to work. Unfortunately after a while if got too cold to work any more. I got everything else done except the wheel arches until the temperatures dropped below freezing. Then the Stinger just would not stick any more and fell off the walls. Luckily the glue hardens after install so the pieces that were done earlier are fine.

Hopefully the many layers of Stinger in the firewall make the Corvette a cooler place next summer. Unfortunately I won't feel or hear the difference until spring...

Fixing Power Windows

I've had a small problem with my power windows: the motor could not lift the window all the way up. I had to help the motor a bit with my hand. While reading the Finnshark forum, I found an explanation that this is caused by the spring in the window mechanism. It needs to be preloaded by half circle to be powerful enough for the window. The annoying bit is that to do this, you need to pretty much disassemble the whole window mechanism...

Well, all I had was time so off to work. I began from the passenger side as it was still missing the window motor. I ordered one almost eight months ago but still had not received it. First I loosened the two nuts that held the window in place and lifted it out. Getting everything else out was simple job of unscrewing a few bolts.

Preloading the spring was also pretty easy. I turned the window regulator over until I could just put the spring in place. Then loaded it by using the arm as leverage. Putting the mechanism back in the door was a bit trickier now that the spring was loaded. I handled that by putting a zip tie around the arms. Now I could put the glass back in and finally tune all the settings so it moved correctly.

The driver side was the same deal. Only this time I also put the motor in. I tested it and now the window rose all the way up without problems. So the passenger side should also work when I get the new motor.

Passenger Side Emergency Brake

I was messing around the garage tonight and decided to check the passenger side emergency brake. I jacked the Corvette and removed the caliper as before.

Everything went smoothly and I started checking the system. This time the brake mechanism itself was OK but the shoes were not that good. Most likely they had been dragging for some time and overheated. This had opened some cracks in the lining. They were still in one piece though so I decided to put everything back together and hope they would last my light use.

Finally I adjusted the shoes and put the wheel back. I didn't take the car for a test drive but the emergency brake handle was quite firm now so hopefully this problem is finally solved.

Emergency Brake Problems

Like mentioned in the previous post, my emergency brake was not working properly. Because of this the car failed its inspection and could not be driven any more. Luckily the driving season was pretty much over already so I decided to leave the fix for later. This was a month ago so I thought that now would be a good time.

As tuning just the cable or adjusting the shoes through the hole in the brake disk didn't work, I needed to see the mechanism itself. This required me to remove the brake caliper and disk. The driver side was worse according to the inspectors, so I began there.

I removed the two bolts that held the caliper in place and then hung it from the frame with zip ties. Now the disk could be just pulled off. Pretty soon I found the problem. I saw that the actuating lever had slipped off the other shoe and actually didn't spread them at all. A few minutes with a screwdriver fixed it. I couldn't find anything else wrong so I put everything back together.

Naturally I needed to tune the brake shoes and the cable again but after those took a short test drive. The brake felt much better already but perhaps I'll check the passenger side too later...

Winter Time Blues

It's been a long time since my last update as nothing major has happened with the car. Driving season is already over so it's time to start planning for winter and recollect what happened during summer.

I drove only about 500 km (310 miles) with the Corvette but found some small problems during those trips. The interior is pretty noisy, it gets quite hot inside after the engine has warmed up and the coolant temperature rises if driving over 90 km/h (55 mph) for long periods. The first two annoyances should be fixed by adding more insulation to the interior but the last one could be a bit tricky. The problem is, I'm not absolutely certain, that the engine really starts overheating because the temperature sensor is right next to the exhaust manifold. It could just be heating the sensor at higher RPMs. I think I'll just add some heat wrap over the manifold before examining the problem further.

Another problem surfaced when I took the car for annual vehicle inspection. My Corvette didn't pass because the emergency brake didn't work properly. No matter how much I tried tuning it, I could not get it to hold. In the end I gave up and decided to check the brake during winter.

Those problems should keep me entertained for a while.

Corvette Fuel Consumption

When driving to see my friend at Tampere, I also finally measured the fuel consumption of my car. I filled the tank when leaving, drove about 190km and idled a bit while measuring the exhaust gasses. This took 30 liters of fuel.

So the car drinks about 15-16 liters per 100 km. Or does about 15 miles per gallon to US readers.

Could be much worse but with 1,65 € per liter (or $7.9 per gallon) of 98 octane fuel in Finland at the moment, it's not a cheap car to drive...

Wheel Alignment, Carb Tuning And Transmission Fixing

It's been a while since I last fiddled with my Corvette so it was time to go back to business. I drove the car about 130km to Tampere to see my car mechanic friend. We had a few tasks on our list: check the wheel alignment, see if the carburetor was tuned correctly after my rebuild and open the transmission to check the shifter linkage.

The drive to Tampere went fine except for the heat. The cabin of the car got pretty hot after a while and it was quite noisy. The Corvette also didn't seem to like the highway. If driving over 100km/h (62mph), the temperature of the engine rose. Not enough to overheat but enough to limit the speed to about 90km/h (55mph)...

Carburetor tuning

We began from the carb as the car was hot after drivin it to the garage. I had rebuild my Holley 80457-S during winter so I had no idea if it was tuned correctly. We placed the probe in both exhaust pipes individually and checked the readings. Idle HC was about 100ppm on both sides and CO about 1%. This meant the engine was running pretty lean!

We loosened the idle screws and got the HC values to about 300-350ppm and CO to about 5% - 5,5%. This was much better.

Next we tested the engine at 2200 RPM. CO dropped to 1% again. I guess this means the carb needs larger main jets. This could also be the reason why the engine gets hot on the freeway as a lean mixture burns hotter.

Left exhaust reading

Right exhaust reading

Wheel Alignment

Next on the list was the wheel alignment. I drove the car on a lift and my friend set up the gear. I didn't know how to use the equipment so I just stood out of the way and looked. It took some time but finally we had the results: both front and rear alignments were within specifications! This was surprising as a lot had been done to the suspension since the last alignment: front springs had been cut, rear had been risen a bit, rear bearings had been changed etc. Oh well, I'm not complaining as this was a much easier job than expected.

Transmission Surgery

I already opened my TH-350 transmission once during winter to tighten the shifter shaft nut. This cured the missing first gear for a while until the nut loosened again. So I knew the transmission was working but the shifter was not.

We drained the oil and dropped the pan. After some examination, my friend had a revelation. Here's the old photo from winter.

It's a bit hard to see but there is a washer on the shaft. But not between the nut and the plate but between the plate and the clip that holds the shaft in place! We removed the clip, opened the nut and pulled the shaft out. Quickly we saw that with the washer in place, the plate never locked to the shaft but just rotated around. We switched the washer to the other side of the plate and put the transmission back together. Wow, even after working with the car for this long, we still find surprises like this...

Finally we decided to switch the speedo driving gear too. The only one I had found before had 10 teeth but after driving a while, I learned I would need a 8 teeth one. The speedometer was showing way too high. Changing the driven gear would not help as I would need a 24 teeth one, but the largest one for TH-350 had 22.

So we pulled the end of the transmission and removed the old, blue gear. I got the correct black one from US-Parts again but something was wrong! The gear was really loose on the transmission shaft. The old one was really tight but this new one was about 1 millimeter larger in diameter. This also meant that the clip that should hold it in place didn't work.

We had to cut the gear up a bit and push a split pin under it to hold it in place. We could only hope it would work and put the transmission back together. Unfortunately it didn't work as the speedometer didn't work at all after this... *uck!

On the return trip the engine still got hot on the freeway and cooled after a few kilometers of slower driving. I need to adress that issue later and go back to the speedo gear too...

Let There Be Light

Yesterday I took some time to finally change the headlight switch. I removed the four screws holding the interior panel so I could get to the switch. You need a really wide screwdriver to open the screw that holds the switch in place. I didn't have one so I cut a small piece from sheet metal that I could use. Then I just moved the wiring and vacuum hoses to the new switch, started the car and tested the connections. And it worked! The headlamps opened up almost immediately!

Screwing everything back together took a few minutes and then it was time for a test drive. I drove around the block playing with the light and they responded after only a few seconds of hesitation after putting the lights on or off. And even the knob now stayed in the switch without coming off every time you turned the light on. One thing less to worry about again.

Driving Season Is Here

After getting the subwoofer ready, it was time to test the Corvette. I reported it back to traffic so it could be legally driven again. After printing the papers, I jumped behind the wheel and went for a test drive with my wife. We drove about 50 km and the car seemed to work really well. Only problem was the radio. While driving, the USB-reader didn't work that well. It seemed to lose power every few minutes and stop playing. I'll have to check the wiring if it's loose.

I finally also received the headlight switch but still no window motor. Oh well, getting the lights to work is more important anyway so that'll be my next job after enjoying the car for a while...

Subwoofer Ready

I finally got the subwoofer done for my Corvette. It took much longer than I thought because I had some other things to do for a while but at least it is ready now.

I started the build by removing the rear compartment doors and measuring the hole. I used the door assembly to draw the correct shape to a piece of MDF and cut it out. Then it was time to design the subwoofer box itself. The compartment shape was quite problematic as the walls were angled. I wanted to use straight edges as much as possible to make the build easier so finally this became the plan:

The box is about as large as possible with using mostly 90 degree angles. Without the one cut in the front right corner the box would have been too small for just about any element. I also realized that the 10" SPL Dynamics woofer was too large without cutting the car. I didn't want to do that so I had to buy an 8" one. As the main speakers were Kickers, I got a Kicker Solo Baric S8C. It was meant for small, about 9,5 liter boxes so it was perfect. Mine measured about 8,5 liters but I just had to live with it.

After getting all the measurements, building the box was rather simple. I cut all the pieces with a jigsaw and just glued and screwed them together. I used a lot of glue on all the edges too so I could be sure that the box would be airtight. A piece of 3 mm hardwood was also attached to the top. It was a few centimeters larger than the MDF so it would cover the carpet edges in the car.

After completing the box, I had to test all the components. I wired the amplifier and subwoofer and put all the pieces in the car.

Then the moment of truth. Carefully I attached the negative cable to the battery and checked that no fuses burned and that all seemed OK. As things seemed to be as they should, I turned on the ignition and the radio. And voilá, I had a working subwoofer in my car! I tested a few songs from my old rock collection and actually had some bass in them now!

As a happy camper I went on to finalize my installation. But first I had to decide how to install the amplifier. With the box in place, I saw that it would not fit straight away over the driveshaft tunnel. After some thinking, I decided to put it over the tunnel angled. I would just use three pieces of MDF: one as a platform and two under it to hold it in place over the tunnel. I cut the pieces and filed them a bit so they sat nice and tight. This is what it looked like after screwing them together:

Now all the pieces were ready and it was time to cover the ugly MDF. Finding some red felt took a few Google searches but AutoStudio had some. It was a bit lighter red the the rest of the interior but would have to do. One roll would have been enough but I cut the largest piece wrong and had to do it again. And for that I had to buy a second roll. Luckily it wasn't that expensive.

For attaching the felt, I got some spray glue. The instructions said that I should spray it on both surfaces, let it dry for 15 to 20 minutes and then put them together. I did just that and here are the results:

Pretty nice. Final piece was the door to cover the battery and the amp. It was made from the same 3 mm hardwood that was glued over the MDF and then covered with felt. I attached a hinge to it with some rivets and screwed the other side of the hinge to the box. And with that the box was done!

Putting the box in the car went smoothly. I started by screwing the amplifier to its base and placed it over the driveshaft tunnel. Then I needed to cut some of the wires to correct length and attach them to the amp. The box was just dropped over everything and finally the subwoofer screwed in. After attaching the ground cable to the battery again, everything was ready!

A friend of mine that sells car audio equipment also happened to visit right after I got the subwoofer working and tuned the radio and the amp for me. It sounded pretty sweet! The 8" sub seemed enough for the really small space inside the Corvette.

My friend said that the Clatronic AR 817 radio that I had, had a pretty strange frequency response curve. The higher frequences were much weaker that the lower end. Well, what can you expect from such a cheap head unit. I'll have to test a better one when possible.

I might also paint the aluminium rivets from the lid so they won't be so visible. Oh, and I also need a cover for the subwoofer so stuff won't get on it and break it.

Subwoofer For The Corvette

After installing the new gauges for my car, I ran into a small problem: I had ran out of parts to install. Sure there were some jobs like fixing the paint in my door still or fixing the spare tire tray but they were far from critical or impossible to do in a cold garage. I did order a new window motor to the passenger door and a new headlight switch but I wasn't sure when they would arrive. So I decided that I would install a subwoofer to the Corvette while waiting...

I didn't really want to spend that much money to it as listening to the radio wasn't the main point of the car. So I surfed a few auction sites and found an used amplifier and subwoofer set. I was mostly interested in the amplifier as I already had one unused subwoofer element but getting everything for the same price was a good deal. I also went out and bought a wiring kit.

The amplifier was a SPL Dynamics MT-502 and the element a SPL Dynamics V-10S. Pretty basic stuff but enough for me. I was thinking about building a case to the passenger side trunk compartment. I measured it and the maximum case size there would be about 15 liters. Let's see how it goes.

Changing The Ammeter Gauge To Newer Voltmeter

After redesigning and building new wiring harnesses for my Corvette, the old ammeter gauge wasn't really working. I did not really know how it was supposed to work in any case. If I understood correctly, it just showed which way the current was flowing: to or from the battery. With the new harnesses it always stayed dead center, so it wasn't really that useful. A voltmeter on the other hand would be much more informative as I could see how the alternator was working.

1976 Corvette is the last year that uses the ammeter and the 1977 model already has the voltmeter. I bought an used gauge a few months ago and decided to switch them. I heard that the sizes and shapes should be exactly the same but I would need to drill one hole to the back of the gauge panel. This information proved correct and one new hole later, the new voltmeter gauge was installed.

Then the troubles started. I reassembled the console and tested the gauge. A few hours of testing, fiddling and Googling later I learned that the voltmeter must be connected exactly correct or it won't display right voltages. I found an informative page from "European Corvette", that explains what's needed in the gauges. And this is needed for the voltmeter:

• Lowest connector must have the positive wire.
• Lower and upper connector must have the correct plastic resistor (with light blue sticker) between them. This resistor should have 125 ohms.
• The third connector is ground. No wire is needed as the holding nut should touch the body of the console.

With these points in mind, I went through the wiring diagrams. Most likely the wiring junction in the engine compartment would be the best place where to add the voltmeter positive wire. Then the gauge would show the true alternator voltage. Unfortunately then there would be voltage in the wire all the time. I needed this to happen only when ignition was on. Luckily this was easy as all the pink power wires for the other gauges work just like that. So I just added a 10 centimeter wire from the oil pressure gauge to the voltmeter. After all the work, this is how it looked:

I turned the ignition on and the gauge seemed to work. I checked the battery with a multimeter and got a bit over 12 volts. Unfortunately the fuel gauge didn't seem to work even after I changed it too. It is still showing too much. I'll have to investigate it further.

American Sale Document

While trying to get the engine running and waiting for the weather warm up a bit, I happened to find the original eBay sales document of my car. I guess eBay saves them as PDF files after the auction has ended. Well, here it is:

http://dl.dropbox.com/u/132090/corvette_ebay.pdf

Too bad that the images are really small and some of the text is hidden but it was still fun to read through it. All I can say is that bull*hit was strong in this one. Some of the gems include:

• Chance of a Lifetime Project Car
• Good Mechanical Condition
• Re-Built Engine
• Transmission Recently Re-Built
• Needs Shift Cable

Let's see:
"Chance of a lifetime project car": yeah, one that you will have to work on for a lifetime to get it running.
"Good mechanical condition": umm, there wasn't a single working electrical equipment, bushings and bearings were shot, rust damage was covered up with urethane foam, all wiring needed to be changed etc.
"Re-built engine": the block was in pretty good condition but the heads were cracked and needed to be replaced or the engine would overheat.
"Transmission recently re-built" and "needs shift cable": no, the cable was fine, the shifter linkage inside the transmission was not. The linkage bolt was loose and it did not shift properly.

So yeah, I guess this seller is as POS lying bastard as any old car dealer...

The Corvette Lives Again!

Finally, after days of frustration, fiddling and tuning the carb and distributor I got the motor running again! I began by installing the intake manifold and valve covers. The valve cover gaskets were also pretty perished so I installed new, better ones.

I heard that these should last a long time and allow me to remove the valve covers and reuse the gaskets. Next I bolted the carburetor on the engine and connected all the vacuum hoses and cables. Final piece was the distributor. I tried installing it the same way as when I removed it and after a few tries everything seemed to be in the correct place and looking nice.

After double checking that I got everything right, it was time to try starting the engine. It cranked fine but would not run. The engine just shuddered and died after a while. I checked the carb and something was wrong. When pulling the throttle, the accelerator pump did not squirt gas. Only a few drops fell out of the nozzles. But this wasn't the only problem. I had some gas in a canister and poured a little straight in the barrels. This should allow the engine to run for a little while but it did not. Most likely the ignition was off too.

I decided to start from the distributor. I took it off and needed to get the number 1 piston to TDC. Unfortunately more troubles followed when I started turning the engine by hand from the balancer bolt. Pretty soon the ratchet was turning but the bolt wasn't. I couldn't see it but by feeling it, I noticed that the bolt was almost completely round. Only good thing was that the socket still hooked enough to open it. I went and bought something better to replace it.

Old bolt. I'm glad I got it out without too much fighting.

Now turning the engine by hand wasn't a problem any more. Finally I got the crank to the right position and installed the distributor again. And the engine still did not run. Just shuddered and died. Next I investigated the carburetor. After some googling I found that the plastic accelerator pump cam can be installed in two ways. I wasn't sure I had got it right so took it out. It was, in fact, correct so I just screwed it back in. But this made a huge difference! The accelerator pump worked perfectly after this! Perhaps it just did not fill with fuel while under the throttle lever pressure all the time?

Now that the gas issue seemed to be solved, it was time to go back to the ignition again. The engine still did not run so I got the distributor out one more time. It was time to turn to Google again and I found this excellent video from YouTube:

I watched through all three parts and went back to work. It did seem that the ignition was about right so I set the distributor back in and fiddled with the carb a bit. I tuned the idle screw, mixture screws and accelerator pump and tried starting after each change. And behold! After a few tries the engine actually ran! Pretty poorly but still ran enough for me to get out of the car and turn the distributor. Pretty soon I got the ignition timing correct and idle speed to normal.

After all the work, it at least felt that the engine ran smoother and revved better than before. Naturally I would have to take the car for a test drive to see the final situation. Unfortunately this would have to wait for a month or two until the snows melt... The engine bay looked better though.

Painting The Intake Manifold

I got my manifold back from my friend. He had had it media blasted and machined. It looked quite nice and clean on the outside.

The insides were another story. The water channels were pretty badly corroded and the exhaust crossover cover bolt holes seemed pretty bad. One had even corroded through to the channel and was full of dirt. The cover gasket had also perished.

This seems pretty dangerous as the carb is right over this hole. If it is leaking fuel and the exhaust happens to belch some flames, this could ignite the whole car. I could not find a correct new gasket so I bought a sheet of gasket material and cut out a suitable piece.

Then it was time to paint. I already had some POR-15 Chevy orange paint and Metal ready from when I painted my oil pan. Time to set up my sauna paint studio again!

I read some instructions and found that the POR-15 might chip off if painted straight on metal. To make it adhere better, I soaked the manifold with Metal ready. This should leave a layer of zinc phosphate on the surface and etch it a bit. After about 20 minutes of soaking, I washed the manifold with water and let it dry for a bit. When the manifold was dry, I brushed the first layer of paint.

It might not be apparent from the photos, but it was clear that another layer of paint was needed. The instructions on the can were a bit vague but I understood that the POR-15 needs to dry for 24 hours before painting it again. So I continued the next day.

Seems that POR-15 smooths out really nicely and leaves no brush marks. But this attribute also seems to cause it to retract from sharp edges. To get a good surface, at least two, most likely three, layers are needed. And even after three layers, I still had some small gray spots left. But overall, the result was really nice.

 

Unfortunately I ran in to small problems when I started to put everything back together. Some threads popped out from the EGR cover bolt holes when I started to tighten it. After that the bolts were too short to reach the threads with the gasget in place. Damn! I'll have to try to find a suitable helicoil repair kit for it or a longer bolt. That could be difficult in Finland...

Second problem was the heater hose nipple. Its threads in the manifold were in pretty bad shape too. I'll have to try to find a way to fix them too.