Hot Rods The Belly Button Bucket Build Thread

This morning, I leaned all 3 carbs by 1 jet size, so now I’ve got 62 pri and 61 sec.

Did some driving today- it was supposed to rain but the forecast shifted …

The AFR readout today was not consistent with previous testing, also not consistent throughout the test, so I’m not going to make any changes. If anything, after confirmation of some more driving, I may go back to the previous jetting. The drive out, after the car was warmed up, was what I expected to see, although the weather should have made a richer condition. On the drive back, I was lean everywhere like back before I started tuning. Like I said, invalid test session. Plugs are a golden brown and it looks like I could probably tickle a couple more degrees of timing into it, but I’ll wait for better weather and more testing.

I drove out to the lake and to a spot where I like to look at birds. As soon as I got there… pouring rain. Managed to get home without issues, and took some decent pictures of the outing.

 

You might want to try giving it a little choke on the next drive to confirm AF is reading well. Quick, easy way to confirm, and gives you numbers (if it's accurate) for amount of enrichment gained on the knob.

 

Another successful outing- about 20 miles round trip out to look at birds and enjoy the river. Only one picture taken though.

 

Drove the car 50 miles today. Went to show the guys who welded the suspension and chassis, and all around Vancouver. I adjusted the squirter pump shot again- didn’t do anything, so I drilled out to the next size- that showed an improvement. Might need to go one more size up, but the off idle stumble is about gone. I also bumped up the main jets from 62 to 64 - much better at cruise. Previously at the top end, it was pretty lean, and I hadn’t seen that in previous testing because I wasn’t getting up to freeway speeds. I also leaned out the secondaries from 61s to 59s because as best I can tell, AFR was in the 10s. Holy cow that woke it up. Not sure what the AFR is now because it spun 1st from a roll and kept spinning when I grabbed 2nd. Absolute rocket ship lolol. I love this car.

I also adjusted the rear proportioning valve so it’s all the way open now. The car brakes decently now - I think it needed that fluid being sent rearward to help slow the rotating mass of the rear tires- front brakes weren’t really doing it. Not sure if I’ll have any more test sessions this season, but the last couple days have been amazing.

 

Awesome

 

MAN! how did I miss this!?!?

First drive, tuning, and a bunch of photos out in the wild?

I'm here for it!

looks great and sound like you are dialing it in.

It's interesting to hear the differences from your tri-power and my single, i'm running a 66 jet on mine.

 

Thanks! On the carb, I threaded them for Holley jets, so for all I know, a #64 Holley jet may be equivalent to a #66 Rochester lol.

 

oh nice! yeah I have no clue on holley jets, rochesters are in thousands of an inch.

 

@BigJoeArt Judging by your own thread you have been all over the place, often out on the road at or before sunrise. Glad you got caught up!

 

This might help?
https://www.carburetor-blog.com/knowledge-base/holley-jet/
I remember reading that it wasn't just the hole, but the taper above the passage that determined the flow. Note 80-82.
Anyone watching water go down a funnel should get that.

 

More testing today. Went to the hardware store, came home to make a change, then drove out to the lake. I’m just about there I think. Famous last words. Made a sound clip by setting the phone down and hitting record. Fuel pump is right under the floor so you hear that more than you hear the exhaust note, but it still communicates the feeling inside the car.

 

Sounds good
Dan

 

Drove the car again today. I managed to clear the off idle stumble for the primary carb, but I realized I need to do the same thing for the secondaries, so that’s the next step. I’ll capture the process once I’ve gotten to the other side.

 

I am so going to send you my stuff. Too bad there’s a contingent in between us, or when the time comes to get mine set up, I’d be at your place, A LOT!

 

Reminds me of the defunct local carb shop we used to deal with.
They usually did decent work, but when there were issues, the stock answer was "It worked on our engine". They had a caddy 4-6-8 engine with adapters to test every carb. Makes sense, until you got an engine that didn't develop the same vacuum signal as theirs (every one with mods or worn).
It was the best use for that 4-6-8 I heard of, though.

 

WHOA! That's awesome. Stoked for you that you're driving it! It looks... seriously cool. And fast

 

Son, I'm gonna have to write you up!
That is such a cool T roadster Tim, there must be something illegal there somewhere.
Dig that tire/wheel combination.

 

Thanks! I drove the car again today after adjusting the secondary accelerator pump rods, went down one jet size in the secondaries, and adjusted the valves in the engine. I had a slight tick when the oil was hot, and they haven’t been adjusted since we built the engine. Everything looked good under the valve covers. On the drive, smooth sailing but I still have a hesitation (much better but still present) when slamming open the secondaries. I believe I’m to the point where I need to drill the secondary squirters, but I wanna try to find a less permanent procedure- I was only halfway successful attempting this on the primary so I’m keeping things quiet until I’m successful. In order to keep the picture starved people happy, here’s a plug read after a full throttle pull yesterday. Still rich, but getting closer.

 

Is there an RPM where it takes WOT better or does in have the hesitation at any time?
I wouldn't expect most engines to respond to mechanical WOT under say 2000-2500.

 

Apologies for the delay- spent the weekend getting rained/snowed on in the woods- my brother and I had the brilliant idea to go tent camping. The hesitation is a result of how quickly the secondaries are opened- roll into throttle, no issue. Slam the secondaries open- hesitates before it takes off. It doesn’t seem to matter rpm wise as much as it does speed of opening the throttle.

 

Seems like it needs a bigger initial squirter shot, followed by some delay over the next bit of throttle travel.

 

Easier said than done with a 2 Jet compared to a Double Pumper or something similar.

 

Yes it is. Hopefully you’ll get it figured out before I have to tune some Rochesters… I’m counting on you!