building a cobra from basically scratch

[thefordguy]

Originally Posted by BBQCYCLEWERKES

The level or quality and workmanship is measured on what is normal and customary within the automotive field and within the accepted standards of the automotive repair industry. In the case of welding together a water pump pulley, this is not an accepted practice within the repair industry. In the event this part fails, which it may very likely, both you and your boss could be held liable. Depending on the pulley diamater and crank shaft pulley diamater, your pulley can be turning in excess of 6000 rpm. If not perfectly aligned and balanced you will not only receive vibration stress but possibly sonic metal fatigue which could cause the pulley to shatter, not to mention metal fatigue and molecular realignment at the weld area. Best case is if it brakes and only damages the vehicle. What if the new owner is working on the car and say timing it while running at a high rpm and the pulley shatters and flys apart. This would possibly cause injury and possible death to the person working on the car. That could come back against you and the business owner. This type of suit could cost millions of dollars and who do you think the business owner will blame. In the end, the tech doing the work is most responsible for the quality and liability as he should know better and therefore open to a huge judgement in the event of damages. I've seen too many product liability cases where the jury award has been great so that a message is being sent to the entire industry. Just my 2 cents though. Be careful.

I have a question I thought of today. I'm not saying any of you are wrong at all. You say metal fatigue and molecular realignment at the weld, driveshafts are welded together and they spin in excess of 6000 RPM all the time. I'm not trying to be a smart ass, I just want to know why a driveshaft welded together is OK but a water pump pulley is not? It spins the same RPM and has much less load. Again, not saying your wrong or trying to be a smart ass, just curious.

[BBQCYCLEWERKES]

Originally Posted by thefordguy

I have a question I thought of today. I'm not saying any of you are wrong at all. You say metal fatigue and molecular realignment at the weld, driveshafts are welded together and they spin in excess of 6000 RPM all the time. I'm not trying to be a smart ass, I just want to know why a driveshaft welded together is OK but a water pump pulley is not? It spins the same RPM and has much less load. Again, not saying your wrong or trying to be a smart ass, just curious.

A driveshaft is balanced for rotating weight after is it welded. Any misbalance in the pulley will cause fatigue and cracking. Also, there will be tension on the pulley from the belt which will cause addt'l metal fatigue if not balanced. A drive shaft is also welded on a fixture and in most cases computer assisted welding equipment used. This is not only to make the welds pretty but used to set the temp more accurately to decrease the metalurgy issues from welding. I can understand your welding the pulley if this was your car as you would then assume the risk, but this is not the case. You are potentially playing with the life of another person here and if failure accures with damages, you cana be held liable. Just looking out for you as I realize you are doing the best you can. I was young in the auto fabrication field years ago and wished I had more people looking out for me and mentoring me back then. Best of luck and I hope the worst case never happens.

[thefordguy]

Originally Posted by BBQCYCLEWERKES

A driveshaft is balanced for rotating weight after is it welded. Any misbalance in the pulley will cause fatigue and cracking. Also, there will be tension on the pulley from the belt which will cause addt'l metal fatigue if not balanced. A drive shaft is also welded on a fixture and in most cases computer assisted welding equipment used. This is not only to make the welds pretty but used to set the temp more accurately to decrease the metalurgy issues from welding. I can understand your welding the pulley if this was your car as you would then assume the risk, but this is not the case. You are potentially playing with the life of another person here and if failure accures with damages, you cana be held liable. Just looking out for you as I realize you are doing the best you can. I was young in the auto fabrication field years ago and wished I had more people looking out for me and mentoring me back then. Best of luck and I hope the worst case never happens.

I'm pretty good friends with my driveshaft guy. I asked him if he could balance the pulley on his machine and he said he could. If it was balanced, would you deem it as acceptable. He said he would do it for free, so if this will work let me know.

Thanks

[thefordguy]

I got the steering joint angle to 31 degrees by modifying the power steering bracket to move the pump lower. I took the car for a test drive today around the bock a couple times. The first time around I took it kinda slow, getting a feel for everything, and watching all of the gauges. I brought it back in, put it on the lift and checked everything out. It all looked good so I made a few adjustments to the carbs and took it for a second drive and purposefully hit a bunch of pot holes to jar the suspension, on the way back I revved it to about 3000 rpm and dropped the clutch doing a massive burn out, hit second still spinning and got it up to about 60 before I let off, then took a corner sideways with the pedal to the floor. It handled surprisingly well, stops well, and takes off like a rocket. I took a pic of the car as I was walking back to it from opening the shop door. I spilled a little brake fluid on the header when I was bleeding the brakes(thats whats smoking) But I put it back on the lift and everything looked good even after putting it through a little hell. I still need to tune the carbs a little. The next test drive I do I will hit the interstate and see how she does at high speeds. oil temp stays at 75 degrees and water at 90 degrees Celsius. Im not sure what that is in Fahrenheit but its not even half way up on the gauge so I think its ok, I got 40 PSI of oil pressure at idle.