v2racing

I've been working on my Vette since I got it running. My tach that worked perfectly before I took the car apart failed. Testing says it's the circuit board. Just got one in yesterday from Wilcox. My new oil pressure gauge and sending unit don't work, testing shows it's probably the sending unit. Also got new one from Wilcox. My speedo was reading way fast so I regeared that but not before my cable layed on my header and got fried and failed. My fault, I forgot to put a clamp on it to keep it safely routed.

The first real drive I went on was a 70 mile round trip. The car seemed to run great, but slobbered through 3/4 of a tank of gas, unbelievably bad mileage. I haven't had a chance to wire up my new Wego III to check the afr and just assumed I had a lot of tuning to do. Well I decided to check my fuel pressure to see how my new Mallory pressure regulator that came with my Mallory 140 pump was holding. I was stunned. I had it set at 6.5 pounds the last time I checked it. It was now at 13 pounds. I turned it back to 6.5 pounds and I heard the pitch of the engine change.

I first set the pressure before I started the car the first time at 6.5 pounds and then set the fuel level in the carb. It held that pressure after I started it and I thought all was good. I checked it again right before I went on that first 70 mile drive and it was down to .5 pounds. I cranked it back up to 6.5 pounds and thought all was well again. Evidently something caused to to lose pressure and whatever it was cleared and the pressure soared up to 13 pounds. It seems to be holding now. It took a drive to a car guy party in the same area I drove to the last time, so another 70 miles. This time the fuel gauge hardly moved off the full mark, an absolutely huge difference in mileage. The car ran really good for having a carb I built from old and new pieces, highly modified and not tuned in yet.

I've been spending most of my free time fixing these bugs and working on the interior, but plan on getting to tuning soon. I just recovered my seats, that was another adventure that is a story of its own.

Mike

jim2527

Working through bugs is always fun. My last adventure was trying to set idle speed. I couldn't get it to idle below 1000 rpm even with the screw backed all the way out. Went through the timing from scratch and it dropped idle speed which allowed me to turn the screw in. Sometimes its the smallest things.....

v2racing

Well I can add to my list of bugs to fix. My rear main seal in my 406 has started leaking. It only has 4000 miles on it and when I took the engine out of my 80 Vette I had it in first, the area was bone dry, but the engine has been sitting for several years. I turned it over routinely through the years and even reprimed it a few times to keep oil everywhere, but I guess the seal still dryed out on me.

Another thing that has popped up is one of the braided stainless steel trans cooling lines I had made is seeping oil. They are hydraulic lines with the crimped ends that should hold 3000 psi, so I don't get this one. There is basically no pressure on tranny coolant lines.

Aren't these old cars fun?

Mike

Mike

ctmccloskey

Hey if these older Corvettes did not break so often we would not have a chance to spend as much time with them.

I see you just went to a Weego system, I just bought and am installing a AEM air/fuel ratio gauge that has outputs designed for data acquisition. I need to pursue this as I want to test my car's cooling system. I am using a very custom Holley Double Pumper that I want to "perfect" on my engine, it has been running too rich for too long, I bought the gauge to do the same thing you are, mine is going to be mounted in the car for a while. It shows you exactly what the ratio is at any time you want but I need to test the carburetor at various speeds. I would like to do this work while NOT watching the gauge but looking at the data afterwards. Any ideas?

70 miles and 3/4 of a tank? That is worse than my 1968's 427 gets with a Double Pumper. What rear do you have? I am running a 3.36 rear and that is my "limiting factor" according to the guys at Comp Cams. A local Corvette club made a run like the one you did, we drove 1/2 hour to get there and drove all the way there and back and I still had more than half a tank. My buddies with their "Hot" Corvettes (1970 LT1 and 1969 L89) both had to fill up on the trip home. I am sure glad I don't have a 4.11 rear like they do. To make matters worse, I blew both of them off the road at the drag strip.

Covered your seats yourself? Isn't that fun? I did it and about a year afterwards I saw a thread loose on one of the seams, Al Knock recovered both seats with new leather and rebuilt the rest of the seat hardware. I love that Guy, he makes nice stuff and from now on they can cover the seats for me...

Stainless Braided lines leaking transmission fluid, that is strange. Did you use the PTFE lined stuff or just the plain rubber? I have plain rubber lines that I have been using for about 8 years with ethanol gas and have been fortunate. I am getting ready to replace them all with the newer PTFE style stainless braided hose. I have had no leaks so far but really want to avoid that experience with gasoline.

I have a electric fuel pump connected to -10 AN SS Braided lines going from the tank to the regulator, I have two filters, one pre-pump and one post-pump but I have never seen or heard of a pressure regulator doing what your is doing. I am planning on going to a fuel injection system so the parts are falling into place, so to speak.

One thing you might want to consider since I think you are using an electric fuel pump, Aeromotive makes a Electric Fuel Pump Controller that is really great, it lowers the pump speed while idling and will resume the flow as needed. It uses Pulse Width Modulation to control the fuel pump speed. This way it can always maintain the pressure you want when you need it. It also quiets down the pump dramatically! I just finished installing it in my 1968 C3 as well as the new DeRale PWM Fan Controller that starts the fans at 50% and runs them to full speed if needed. It is a nice piece of equipment that should reduce the fan noise from my engine compartment.

I hope that the SS braided line issue can be explained, that is not a good thing to have them leak. I always thought they would handle high pressure.

Good Luck with your 1980 C3, I would love to hear what caused the SS braided line to leak. That makes me nervous as I run a volume of gasoline through my braided lines feeding the beast!

v2racing

After I reset my fuel pressure regulator the mileage went way up. Same trip barely moved the needle off the full mark.

The braided line is white plastic looking teflon for hydraulic line use an should be good to 3000 psi. I have regular AN line and fitting on my fuel system and that is fine. It's the same as i used on Top Fuel bikes putting 350 psi of nitromethane through, so not worried about that.

The Daytona Sensors Wego III also has data acquisition and can store up to 2 hours of data. It has a tach input wire and a 5 volt input you can hook a throttle position sensor or a MAP sensor to. I have a MAP sensor that I will be able to read as load on the engine I will use when I get all the bugs fixed and turn to tuning. I had a Wego II for about a dozen years and it worked great. It won't work with the new software for live view or data read from the Wego's memory, so I got the new Wego III. The new one also has a couple extra features my old one didn't have.

I built a setup that runs the pump at about 75% until I reach about half throttle and then goes to 100%. The pump is a Mallory 140 gph. They are very quiet and known for their reliability. I also have large high flow filters pre and post pump.

The 80 Vette is what I ran this engine in for about 4000 miles. I sold that car and the engine is now in my 1975 Convertible.

Mike

jim2527

I tell people old cars are like old people, there's always something going wrong!!

Street Rat

I've had my car five years. I'm still working on getting all of the bugs out. I don't think there is light at the end of the tunnel. It is always something and sometimes it's because of something I did wrong.

Craig

terrys6t8roadster

T

v2racing

Update on the oil pressure gauge. I setup a test with a mechanical gauge and an air pressure regulator so I could test the sending units ohms output and test the gauges on the bench. The sending units all tested different than each other but none of them checked at 45 ohms @ 40 psi and 90 ohms @ 80 psi. The new one I got from Wilcox was the closest at 44 ohms @ 40 psi and 79 ohms @ 90 psi. It will read a little low with a good gauge at the high pressure. Both of my new reproduction gauges are junk. I found a brand new still in the box NOS GM gauge with the resistor on ebay. I hope this will be the end of this issue. I'm waiting until I get the new gauge before I take the dash apart to put in the new tach circuit board and fix the problem.

I'm having a hard time seeing where the tranny line is leaking. It leaks to slow to see where it's coming from idling in the driveway and the wind blows it all over when driving. The fitting is tight, so it almost has to be leaking between the line and the crimp fitting.

Another issue I haven't mentioned is my vacuum headlights. I have all new rubber lines and I checked the actuators out of the car. They hold tight with no leakage at all. There is no rust on or in my vacuum tank and I can't see any pin holes in any welds. The relay valves worked properly also. Only my passenger side headlight pops up, well not pops, but raises slowly. It also will go down slowly. They worked fine with the engine that was in the car when I got it. It was a 550 horse 406 with a pretty healthy hydraulic roller cam. When my engine was in my 80 Vette it would pop the headlights up and down with no issues, it made 9 inches of vacuum at idle in neutral, 7 in gear and 20 at cruise last time I checked it. ????? I'm going to borrow my buddie's vacuum pump for air conditioning work and see if I can find a leak or the offending part. The vacuum heater/AC controls work perfectly. I don't have AC in the car anymore, but it changes between the positions immediately.

I did a complete frame off on this car and replaced anything not in perfect shape. My 80 Vette had been sitting for close to a couple decades when I bought it. I put my engine and tranny in it and everything worked perfectly without any issues the whole time I had it!

Fun, fun, fun!!!

Mike

7T1vette

For finding a trans leak, your best bet is to buy a dye kit (little bottle of dye, goggles and UV penlight). CLEAN EVERYTHING OFF FIRST so there is no oil/grease/dirt to mask the site location. Use a final wipe with volatile cleaner like lacquer thinner to get it all clean. Put dye in oil via oil fill tube; run engine for a couple of minutes to get dye distributed through the trans system; then use penlight to look for leak initiation point. If you need to run the engine more to get oil hot enough to start the leakage, do so. But keep watching for leaks as it is heating, because you want to find it where it starts.Oil can drip down onto other surfaces and easily 'trick' you into thinking the leak is at the secondary point.

If you leak test during daylight hours, it is best done in a garage where most light can be minimized. Doing it at night when you can just turn the lights off would be better for doing a leak search. Good luck.

Also, the headlamp relays are the 'usual' site for vacuum leakages in the headlamp system. Since your actuators are fine, the relays are most likely the fault of weak door action.

v2racing

Fixed my leak in the tranny cooler lines. It was leaking between the line and the crimped fitting. Don't know how or why, might cut it apart just to see.

Anyway, went to the Thursday cruise in at the Minnetonka Drive-in. Sat and talked with people and then went to pick up my wife and go for a drive. Got just outside of town and my temp gauge suddenly shot up. I pulled over and it was puking antifreeze out of the vent tube on the overflow tank. Left the fans run to cool it down for a bit and a guy stopped and we pulled the thermostat out. It was stuck closed very tightly. When I put it in you could push it open in your hand and it checked right at it's specked temp. I run 50/50 distilled water and antifreeze, so it should get any corrosion or buildup to cause it to stick, but stick it did. Put it back together without the thermostat and it was back to running normal again. ?????

Mike

suprspooky

I will see your problems and raise you (lol), how about a Distributor (MSD Billet Tach Drive) that moves freely (to adjust timing) when the Engine is cold but at operating temp. it won't budge. I talked with MSD and the Tech. (a real genuis) says, why would you move timing when the engine is hot? Needless to say I didn't spend much time with him. It looks like the MSD Housing OD is a little on the large size where it passes through the intake (427 Tri-power) so it binds when hot (the AFR aluminum heads ain't helping the situation). The real fun began when I noticed moisture on the Distributor shaft during measuring effort, now I'm getting ready to drain the oil to see if I have antifreeze in it. The worst part is every thing was ok last fall after the dyno pulls til I realized the AFR Heads had no provision for a temp sender, which lead to cracking the Heater Hose fitting boss on the Manifold and several weld repairs, adding an extra boss, air tests.......... I think the Car is cursed.
So V2, maybe we'll see each others Cars yet this year at a show, I'm in Blaine and shooting for Frankensteiners Ball show in Cambridge., we'll see (lol)

v2racing

Yes, you have me beat. Most of my issues are just annoyances, not expensive, or serious and can be overcome, it's just wasn't something I was expecting. I tested, rebuilt or replaced pretty much everything is this car down to the bare frame. I've built many vehicles in my life and never had something like this that gives me a new issue every time I get near it. I'll get it all sorted out though.

I hope your engine is OK. What's the date on the Fankensteiners ball? A friend of mine hangs with those guys. I might have to try and make that one. My partially done bodywork will fit right in there.

Mike

v2racing

I put a new thermostat in my Vette to replace the so called high flow high performance Mr Gasket stat that stuck on me. I've owned hundreds of cars and never had a thermostat stick before. Never used one of the high flow stats before either, so I bought a regular NAPA thermostat and drilled a 1/8" hole in it and it is working perfectly.

I found oil leaking out of the driver side valve cover through the bottom rear hole for the mounting bolt. This was leaking down and making its way into flywheel cover and then leaking out the hole on the bottom, so maybe my main seal is not leaking. I had to look really close to see where the oil was traveling to, it wasn't obvious. I need to get it u on a lift and pull the cover to inspect closer to see if the seal area is dry, as I still have a little oil dripping after driving.

I bench tested the NOS oil pressure gauge I got on ebay. It works perfectly. Two new aftermarket gauges were junk.

I have a new issue that just started. The engine shuts off for just a fraction of a second now and then. No other systems that run off the same power source as the ignition are affected, so I think it is in between the MSD Digital 6 Plus and the distributor. There are several connections to check. I use a HEi distributor without the module in it. I only use the magnetic pickup to trigger the MSD. I probably loosened something while working and testing other things. The engine bay also got sprayed with coolant on passenger side where all the ignition parts and connections are when the thermostat stuck. I plan on taking every connection apart, cleaning, tightening and reassembling them. That should take care of this issue.

Still haven't started tuning. I keep having to fix stupid little problems. Hopefully I'm near the end of that.

Mike

gkull

[QUOTE=v2racing;1597956760]

Another thing that has popped up is one of the braided stainless steel trans cooling lines I had made is seeping oil. They are hydraulic lines with the crimped ends that should hold 3000 psi, so I don't get this one. There is basically no pressure on tranny coolant lines.

Aren't these old cars fun?

Mike[/QUOTE

Mike I have the original dyno sheet on the 700r4 those lines have 120 psi in park and N and 250 to 260 psi in each of the gears. That 26 vane pump really puts out holding and clamping pressure on the bands and clutches

v2racing

[QUOTE=gkull;1598043625]Yes it shifts pretty hard and holds firm in gear. The leak was just a bad end, that's all taken care of.

Mike

v2racing

I forgot to mention the vacuum headlights that didn't want to work. I found the new check valve I put in the line wasn't any good. I got two by accident when I ordered this new one. Maybe they sent one extra because there was only a 50% chance of one working. The extra one works fine. The headlights still didn't want to go up and down very well. The acuators hold solid vacuum, the lines are all new, the only thing left is the relay valves. The passenger side was better than the driver side so I disconnected the driver side relay valve and put tee's in the lines to run both neadlights off the passenger side relay valve like early 68's were. The headlights go up and down fine now, a little slow because of my low idle vacuum but they are good. I might leave it this way.

Mike