I will be uncorking the headers right after Christmas (no time to devote to it until then). If that doesn't help then I have a date with a chassis dyno. I have an O2 bung already welded in and the dyno will use a sensor. I still don't know if they'll be able to get any readings in 1st gear or not. Every chassis dyno session I ever saw involved a 3rd (or 4th) gear WOT blast. I will keep you posted.
Return line for the fuel? Why would that make a difference? Just curious. The pump is a dead-head pump designed for carb'd cars like ours. With float bowls I don't see how a pump could keep up with a constant siphoning off of fuel?. 6.5 pounds of pressure isn't like the 50+ you see with fuel injected pumps. The filter is relatively new, but I wonder if it might somehow be pinching off the fluid flow at high rpms? Hmmmmm. That's why I have a new trans and converter lined up ready to go in. I'll change every damn part in this car if I have to. I want to race it when it is running right! If the exhaust doesn't fix it, then we'll go to the dyno and rule out everything we can. After that the only thing left would be the trans. Looks like Wednesday after Christmas for the open header test. Stay tuned.
Yards, didn't you yank the fuel filter(s) somewhere along this hellish journey? I thought you had and it made no difference. As to the return line, the mechanical pump cars had them from the factory to prevent vapor lock. This is the first google return when you search "fuel return line reason". You might find it an interesting read, at least the first post. The guy can see bubbles in his glass (yikes) inline filter. His problem is worse as it's dying, but similiar in cold/hot performance. Remember that while fuel in a liquid state is not compressible, in a gaseous state it is. you could still have a decent fuel pressure after the regulator that is made up of mostly fuel and some bubbles compressed to 5.5 or 6.0 psi (whatever you're running). This would still make everything look fine on your pressure gauge. I wonder why Buick introduced a factory electric fuel pump on the Riv only to abandon it? My '72 is certainly mechanical; not sure if they switched back in '70 with the 455 introduction. Perhaps with the stock 430 they had some level of problem and solved it with an olde style return line/mechanical pump? Now you have a MUCH hotter combo than the factory motor and maybe the problem manifests itself more readily? Someone above (Torqued455) offered you an AFR meter, I think. You might want to take that offer as you already have a bung to connect it to and see if you go lean at WOT hot as opposed to cold.
That would apply to Yardley the man, not necessarily Yardley the car. :moonu: Hey, someone was gonna bite on that one, it might as well have been a friend. :moonu: I'm guessing Alan hadn't seen that yet otherwise he would have already pounced! p
Jeff, I have an Innovate A/F gauge setup here you can borrow. It's the handheld version, plugs into a lighter socket. It'll data-log, but I think it needs a USB-to-RS232 cable to attach to a laptop.
My A/F ratio was a tiny bit fat on the dyno. Not by much, though. And I'm even fatter than that now. So I'm confident it's not lean. Unfortunately there's no time with the short holiday week to get the LM1 from torqued455 before I drop the headers then head to the dyno. Anyone ever seen plugs cause this?
I developed a problem a couple of days ago where it was breaking up under load. Bad coil. Only a couple of years old. NAPA IC12. Swapped in an Accel Super Stock coil. Runs great. Still lays over above 5000, though. I'll be dropping the exhaust next wek (Wednesday) so stay tuned.
Update... I now have more questions than I did before!!! I uncapped the headers. As soon as I began getting into it the engine began breaking up/missing. Then all of a sudden it died altogether! I had no discernable spark. I swapped coils and it made no difference. I swapped my new Accel coil back in and it fired right up! So I capped the headers and drove it home. It died 2 times on the way home! Sigh. I'm going to run a straight 12v wire from the battery to power the MSD (yes, I'll put a toggle switch on it) and see if anything is funny with the wiring in the harness or under the dash or with the ignition switch. So, in spite of uncorking it, I have no answer as to whether the exhaust is holding it back. And if need be, I have a replacement MSD box to try.
Loose ground on the MSD box from when I swapped them out last month. Oh well. I'll uncork the headers again on Friday and give it another shot.
At least you don't have to worry about keeping a dairy. :laugh: Can you shoot some video too? All kidding aside, I've been reading this thread over and over the past few months and just can't think of anything for ya. Maybe it's time to put the stamped rockers back in? o No: Hang in there, just think how good it's gonna feel when the final wrinkle is ironed out!
Like I said to you on the phone, get a Priest and some Holy Water. "Demon, by the power of Jesus Christ I command you to leave this '69 Riviera!" Good luck, pal, keep working at it! You'll get it figured out. :Smarty:
Rod Hendrickson has been vigilant with helping me on this. And I can't thank him enough. I'll try it again on Friday and see if it revs with the headers uncorked. BTW, it is FREAKIN' LOUD with uncorked shorties!!!!!!!!!!!!!
LOL....yeah it is! I had to fire mine up the last time I had the exhaust disconnected...pretty wicked.
If I was going to open my headers on the dyno I'd make sure I had some sort of collector extension. Why I say this is last year when I installed headers on my '76 I picked up only .1sec/1mph at the track(12.2's at the time). I didn't expect much but I figured .2 would have been more with the program. Just for an experiment I opened the headers. The car ran down the track but didn't feel too good and ran the same as closed. So I installed 18" collector extensions and the car felt better and actually picked up .08sec/.8mph. My exhaust is a full length 2.5" mandrel bent system with H-pipe and Dynomax Hemi mufflers. On the chassis dyno, closed exhaust, the A/F ratio seems right on so maybe it leans a bit when opened and that may be hurting the open performance but it definitely liked the extensions.
Just googled the definition of perseverence and this thread came up for some reason? Good luck yards...
I have the shorty collector/reducer on them. I had planned on access to a lift so I could tack weld little turn-out on them, but that didn't happen. But for a few 1st gear blasts I should be OK.
