Whew...it's been a while since I've updated, and unfortunately not a lot of photos. I've been distracted, but we'll get to that.
The car was essentially trouble free all of March and April, until two weeks before the Hagerty Spring Thaw. I clogged a jet on the way home from Whistler one day, and despite cleaning it out had some serious tuning issues coming back from a parts run (which is about 2hrs each way for me). The tailpipes were showing lean, the wide-band was showing lean, but the plugs looked good. WTF? I hadn't changed any jets...just cleaned them. I worked on some tuning off and on, but was getting very strange results. I'd change the main jets, but the idle mixture would change. I'd move up three jet sizes (in steps) and the first two would show logical changes while the third would blow the wide-band off the scale in some strange way. This was all happening in the final week before the Spring Thaw. My business partner and I were working long hours to make sure everything goes off perfectly at the event. I'd get an hour or two for tuning, get no results, and have to get back to pre-organizing duties. It was incredibly frustrating.
Finally I decided to go all the way back to the beginning. Well, actually the car decided for me when it blew out an exhaust gasket (again). The car went up on axle stands, and I made plans to adjust the valves, set the timing, start with a set of base jets (by the math), fix the exhaust gaskets and try again. The heads had been fully reworked in November by Darren (K-Roc Heads), so I was really confused why
every single valve was tight. I was exhausted, so when I popped on the 3/4 valve cover, removed the paper towel on the heater box and was met with a piece of valve spring…
Really?
Darren and I chatted, and we both realized that I have almost 80,000 miles on this set of springs. More then double what either of us would have suspected. While they were fine in November, clearly that wasn't the case anymore. Thankfully Darren had put dual-springs into my heads many years ago, so when the outer spring failed, He offered me his on-car replacement tool, and had a full set of dual valve springs ready for me…two hours away. Good thing too:
While driving to get the valve springs, I realized my valve adjustment issue. In my stress of organizing and lack of sleep, I had neglected to consider that I have chromoly pushrods and thus adjust to loose-zero, not .006"! Whoops. With springs and exhaust gaskets installed, valves adjusted and timing reset, I cleaned the carbs…finding
mud in the choke area which isn't used by the Empi HPMX version. Mud eh? Hmmm. Don't let anyone tell you I'm easy on equipment.
Well, with that cleaned out I started tuning for lean-best-idle…and still had exhaust popping. Soon a hairline 2" crack was spotted, and off came the apron & exhaust. It would seem that at some point an impact resulted in a crack on the muffler at the #2 inlet (actually on the little pipe sticking out of the muffler to the flange. The resulting movement probably attributed to the gasket failure issues I was having earlier this season. It was 11pm, but my buddy Scott still took it home, welded it up, and brought it back. Killer service, and help from a buddy who leaves for work at 6am. It was too late to tune, but not too late to get a good night sleep.
Amazing how easy the tuning is when there aren't a bazillion other problems causing weird results! Within two hours I had lean-best-idle, idle jets set, mains sorted and the airs figured out. My AFR numbers were spot on everywhere except for a lean condition when cruising at 3000-3200rpm. While I knew Darren and Geoff were going bat-**** crazy with all my calls and texts regarding tuning, I was at a loss. The RPM range said it should be mains, but changing them didn't help and made other things worse. Maybe a combination of Airs and Mains? changing didn't seem to get the results I needed. A final text sent to Darren (with crossed fingers) and a suggestion came back "go one up on the idle jets". I did, and what you know. Running fantastic for the Spring Thaw…with 20 hours to spare!
-Dave