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.
Wednesday, November 7, 2012
Tuesday, July 3, 2012
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)...
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...
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.
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| Left exhaust reading |
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| 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...
Friday, May 25, 2012
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.
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.
Monday, May 14, 2012
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...
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...
Friday, May 11, 2012
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.
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.
Saturday, March 10, 2012
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.
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.
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