fastzcars Posted May 25, 2004 Share Posted May 25, 2004 I'm about to shoot this car. I can't seem to figure this out. Now I consider myself a good trouble shooter, but I need some help. O.K. A little info. I have a freshly rebuilt 383 SBC. All new forged internals. new MSD billet distributer, Digital 6 plus box, coil. Holley 3310 vacuum carb. Holley blue pump, Aeromotive bypass gas regulator. Total rewire of the car using centech wiring harness. New exhaust system.O.K. so the problem is this. The motor starts great. oil pressure is 40 psi. Gas pressure set at 7.5 lbs. compression test are 6 cylinders are right @ 180 and @ 190 psi. New bosch platinum plugs read slightly rich( black soot? alittle wet and smell of gas) No smoke of any kind out of the exhaust. Timing set @ 8 degress with the mechanical 28 degress total, no vacuum advance. When the water temp rises to 180 it's O.K. but as soon as it reaches 190 power starts dropping alittle, no bucking os stubeling, just starts sounding like it's laboring. Then right before is stalls, I sware, it sounds like detonation. Not like marbles in rattle can loud. just a little. at first I thought maybe I install the wrong heat range spark plugs so I install 2 heat range colder plugs, still stalls, Then I thought air lock in the water pump. so I raised the front of the car and filed the radiater and filled with 50/50 mix water/anti freeze.and a bottle of redlines water wetter. still stalls. Then I even thoght maybe the exhaust shop left a rag in one of the pipes. I changed the MSD box with a friends AL6 box and Coil. I'm at my wits end. PLEASE< PLEASE<PLEASE HELP. I sware i'm gone shoot this thing. O.K. rant over. Quote Link to comment Share on other sites More sharing options...
GreenSamo Posted May 26, 2004 Share Posted May 26, 2004 No smoke of any kind out of the exhaust. Now does this mean no smoke at all.. or the smoke isn't colored? Cuz if the exhaust isnt coming out.. wheres it going? Quote Link to comment Share on other sites More sharing options...
Tim240z Posted May 26, 2004 Share Posted May 26, 2004 Maybe fuel boiling in the bowls? Try running with hood cracked open to vent the hot air.... Quote Link to comment Share on other sites More sharing options...
fastzcars Posted May 26, 2004 Author Share Posted May 26, 2004 Hi GreenSamo. What I mean by "no smoke" is No colored smoke, The exhaust out the tail pipe is blowing my pant leg while I'm standing 4 feet behind the car, so the exhaust is clear. Thanks for response. I'm thinking maybe it's my ign.switch. Or the wiring from my battery to the remote solenoid, since I have my battery in the back. Any other ideas guys? Thanx. Quote Link to comment Share on other sites More sharing options...
fastzcars Posted May 26, 2004 Author Share Posted May 26, 2004 Thanx Tim. I thought of that too. I even took off the inspection lids. You know I ran 2 aluminum 1/2 inch lines up in the tunnel where the stock lines are located. Ya, I'll try that maybe the aluminum is picking up heat from the exhast. Thanx Tim for the lead. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted May 26, 2004 Share Posted May 26, 2004 Do you have any kind of isolator between the carby and intake? Quote Link to comment Share on other sites More sharing options...
fastzcars Posted May 26, 2004 Author Share Posted May 26, 2004 Thanx Tim, I don't have a isolator on the carb, just the gasket. Should I make an aluminum sheild ,to shield off heat rising from the intake to the carb bowls? Or are you thinking along the lines of a Phenolic spacer? I'll give anything a try now. How about some fiberglass/aluminum sheathing around the fuel lines? Well I just finished making some new starter cable out of some 0/2 welding wire. I had regular 2 gauge in there before. Thanks again for responding guys. Keep'm com'n. I need all the help I can get. Quote Link to comment Share on other sites More sharing options...
Corzette Posted May 26, 2004 Share Posted May 26, 2004 I see another potential problem of which I experienced as well. First your fuel pressure is set too high in my opinion. Holleys like between 3 and 7 PSI but mine would over flow the bowls and cause the engine to run like crap then die. Afterwards it would take alot of time to get it started again. I run a 750DP and it likes about 5.5 to no more than 6 PSI. Back your pressure down....that could also be making your plugs wet. After backing your pressure down to 6 PSI, make sure to reset your idle mixture screws in front. Also, I would think that a good starting jetting for that 383 would be 72s or so in front....Ive been there in your situation...try it and see..... Corzette Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted May 26, 2004 Share Posted May 26, 2004 Sounds like a combo of what Corzette, and Tim said. Fuel pressure too high, and the need of a carb heat shield. I had the same problem with my 409 Impala, and put a heat shield in place and never had the problem again. http://store.summitracing.com/productdetail.asp?p=2859&view=257#largerimage Quote Link to comment Share on other sites More sharing options...
fastzcars Posted May 27, 2004 Author Share Posted May 27, 2004 Thanks alot for your input guys, I'll make a sheild and back down the pressure. I'll report back with my findings, Thanks again.I really do appreciate your input. Quote Link to comment Share on other sites More sharing options...
fastzcars Posted May 30, 2004 Author Share Posted May 30, 2004 Just an update guys, I made an aluminum heat sheild out of .050 sheet. I also install sheething around the fuel line by the engine. The fuel lines coming from and to the fuel tank are warm to the touch. NOT HOT at all. I don't think the lines in the trany tunnel are picking up any significant heat from the exhaust. I give up I have no other recourse but to shoot it, and put me out of my misery Quote Link to comment Share on other sites More sharing options...
Tim240z Posted May 30, 2004 Share Posted May 30, 2004 OK...don't give up yet...let's keep going. First let's rule out the fuel system. Make sure that the needle ans seats are sealing well. Do you have the fuel pump wired to a toggle switch? If not, try a temporary switch....turn off the pump when it starts acting up, although this doesn't sound like a fuel problem, but you said that your plugs were sooty, so.... Next: Check all your plug wires, maybe they are arcing. Try this in a very dark place and look for the arcing. Then, if that is OK, it has to be coil/ignition box...... Quote Link to comment Share on other sites More sharing options...
fastzcars Posted May 30, 2004 Author Share Posted May 30, 2004 Hi Tim. Thanks for your input. You know I have been at this problem for almost a month now. I'm begining to think that this car has a mind of it's own. I think I'm going to have to step back and take a break from it. I guest it's like that saying" You can't tell the forest from the trees" or something like that. Anyway, The whole ignition system is new. From the plugs to the coil. I even borrowd a freind's MSD box and coil. One of the symtom's is it doen't sound like a mis in the ignition. The motor sounds like it's laboring to stay on? Would ignition problems cause this symtom? Maybe. Oh one more thing I did notice is that my volt meter in the dash suddently drops to 12 volts from 14 right before the motor shuts down. Could a bad of overheating alternator shut down the whole electrical system? Thanks again for your response Tim. I'll keep at it. I'll post my results if I find the problem, so that other's could learn from my adventures with this crazy car. Quote Link to comment Share on other sites More sharing options...
labrat Posted May 31, 2004 Share Posted May 31, 2004 The 12 volts instead of 14 is more likely a symptom of the reduced RPM. The alternator can't hold the voltage up turning that slowly. They (at least MINE) have to turn around 800rpm before putting out full voltage. My voltmeter swings between 12 and 14 volts at idle with my brand new summit 100AMP chrome 1 wire alternator. I also have a huge current drain on mine just for engine systems. Electric fan, petronix electronic ignition, MSD 6-AL, and electric fuel pump. All together, about 50 amps or more. Maybe you have something like this? Bill Quote Link to comment Share on other sites More sharing options...
fastzcars Posted May 31, 2004 Author Share Posted May 31, 2004 labrat, you might be right. I do have a taurus fan and full MSD igition system and a 60 amp alt to keep it all running. I'll need to buy a 100 amp alternater now . I can almost keep the car running by giving throatling the peddel, I can see the voltmeter sweeping back and forth from 12 to 14 volts and the motor labors to stay on and evenually it die's. It almost sounds to me that the motor is leaning out and predetonates and shuts down for lack of gas? But if that is the case by throatling the gas pedel I can see the squirter's dumping gas into the barrels? I wish I had a Air/fuel ratio meter to tell me if that is happening. Tim240z I have my holley blue pump wired directly to my fuse panel which is getting power from the stock igition switch. I'll need to buy a new switch just to rule it out. Thanks for the input guys, keep them coming , I need all the help I can get. Quote Link to comment Share on other sites More sharing options...
fastzcars Posted May 31, 2004 Author Share Posted May 31, 2004 Hi guys just a update. I decided to clear my mind and started over again. I didn't take any of the parts for granted. So I checked everything over from the induction to igition. I think there is something wrong with the motor, It's probably machined too tight. I have spark and fuel. I hav to take the motor out and take it apart to check clearences. . I should have assembled the motor myself. That way I could check clearences along the way of assembling it. DAMN. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted May 31, 2004 Share Posted May 31, 2004 Have you tried disconnecting the fan, or checking to see if it switching on coincides with the problem.... Quote Link to comment Share on other sites More sharing options...
fastzcars Posted June 1, 2004 Author Share Posted June 1, 2004 Hi Tim. Ya I did that too. It is seem's to be heat related. I can reproduce the problem by getting the motor warmed up. before it would shutdown at 190 degrees. now with all the mods that i did it happens when it reaches 220. This morning I decided to start over. And not take anything for granted. I assumed nothing and did a step by step elemination of all the possablilties. Like Sherlock Holmes, I checked pressure with a separte gauge,O.K. Removed the fuel line from the carb to check actual flow,O.K. Removed the carb and checked the needle and seats, all clean, Turned the separted bowls upside down and blew threw the input ports, seals nice and tight, moved the floats down, unseats and let's air through O.K.Reinstalled the carb. checked float level ,perfect just weeping out of the sight plug. Then I double checked for gas line kinks, I removed the fuel cell access panel to check to see if the pickup fuel sock was pluged. Ok. I installed an internal return line from the bypass reguator to sump box in the ATL fuel cell itself, Thinking that maybe the fuel pump was sucking the sumpbox dry, and the gas was not entering the sump box fast enough. Test drove it, NO DICE, Still stalls, I reurned after it let sit for 30 seconds and I barley got it back to my garage, Yhe temp gauge read 220 and the motor sounded like it was deiseling? Like the bearings or the pistons were too tight, creating extra heat. I shut it down for fear of it freezing up , it sounded so bad. So I quickly got a connector to check to see if the igntion was the problem by diconnecting the distributer and jumping the connector lead , I can hear the MSD box making spark in the disy. I'm porbably taking the car to a local race car shop. for thay recommened me this builder and have them confirm, or at least find the problem out for me. Wish me luck. Thanx again. Tim. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted June 1, 2004 Share Posted June 1, 2004 Just an update guys, I made an aluminum heat sheild out of .050 sheet. I also install sheething around the fuel line by the engine. The fuel lines coming from and to the fuel tank are warm to the touch. NOT HOT at all. I don't think the lines in the trany tunnel are picking up any significant heat from the exhaust. I give up I have no other recourse but to shoot it, and put me out of my misery Did you use just one piece of aluminum? That's not enough. You need 3, aluminum pieces, and 4 gaskets. Gasket-aluminum-gasket,aluminum,gasket,aluminum,gasket. When the engine stalls, touch the carb, if you burn your fingers it's way too hot. You should be able to leave your hand on the carb. It still sounds like boiling fuel. Quote Link to comment Share on other sites More sharing options...
WickedWild Posted June 1, 2004 Share Posted June 1, 2004 Could be a real simple awnser, or a stupid sugestion. Have you tried loosening your rocker arms? Quote Link to comment Share on other sites More sharing options...
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