I do not have a pressure gauge on it, so I'm relying on the manufacture s 5.5 that they claim. Sent from my Pixel 3 using The H.A.M.B. mobile app
Well blackish plugs with no WOT hit or lean backfires and “silent” flat spot kinda speaks to changes to the Wong circuit. Might be minor jet changes needed yet. Little down on primary and a little higher on secondary. Might be a piece of shit in an air bleed too. Getting the transition between is the hardest.
What I meant there is I didn't do the wot tuning procedure from the manual that required multiple wot pulls through the rpm range. So I went to wot, had a long pause/ hesitation, then some popping out the exhaust and I then let out. Barely gained a few hundred rpm Sent from my Pixel 3 using The H.A.M.B. mobile app
Long story but parts quality seems to have gone down in the last ten years or so at least from my experience (for what that is worth) when I was a dealership counterperson, both OEM and aftermarket. I just am wondering if you created a secondary problem, making the low and midrange too rich while during the whole time the engine is starving for fuel at the high end.
Ok so you’re jammed up for sure on tuning this thing till then. You need to at least check the fuel pressure. Imperative! It’s way better for your sanity to have a gauge you can see while driving. Temporary under a wiper is fine.
I have yet to attempt anything with secondary. I've got some rods that could lean it the primary a bit before having to change a jet. Sent from my Pixel 3 using The H.A.M.B. mobile app
Alright, I'll get a pressure gauge on the pump to verify that portion and get some miles on it so I can calibrate wot. By the way you said it, I'm assuming I've got to do that part first before moving in to the mid and low throttle conditions. Sent from my Pixel 3 using The H.A.M.B. mobile app
I'm going to sound stupid here because I have zero experience with Edelbrock carburetors. Are the primary and secondary jets the same physical size? If so how about a swap around. I ran into that problem with one of the original Holley Spreadbores in '72. Secondary jets were smaller than the primary jets, did that Ram Air III ever fall flat on it's ass the first time out. Swapped the jets around, instant improvement.
Don’t shit can the warranty! Powerful engines need more fuel quicker in higher rpms because they have the ability to rev faster and that’s where they use fuel most efficiently. Powerful engines don’t run well or use fuel very efficiently at low RPM because they make less power and need less fuel. looking at how the carb is delivered for basic stock engines and Looking at ALL OF that from a tuning stand point, the primary need probably needs leaned out and transition fatter and secondary quicker and fatter. Make sense?
What CFM carb, manifold, and ignition system was used on the dyno. You've got a lot of new variables and your baseline seems to be that it ran well on the dyno. Seems you need to simplify where you can, do the easiest stuff first (plugs, diode), and figure out how to eliminate possibilities.
One other question. Is this car a new build, first time running and driven or was it a repower of a car that ran ok before? I'm just thinking out loud, maybe a restriction in the fuel sender or the lines?
Yeah! Basically lean out my primary and fatten up the secondary. And help the transition to it quicker. I can bump up the jet in the secondary and change it the meeting tomorrow in the primary. Thank you. I'll give this a try as well as adjusting how quickly the secondary comes into play via the flapper valve above the secondary. Sent from my Pixel 3 using The H.A.M.B. mobile app
Is this the engine ? It calls for 600 cfm not 650. https://blueprintengines.com/products/355-ci-crate-engine-small-block-gm-longblock-bp35513ct1 34 degrees total in by 3500. Did you change plugs? .45 gap?
You are right, something could have happened to the fuel system during the interm. Original poster, another question. Fuel cap vented or non vented?
That's the one. Other than using a 650 rather than 600, I've got everything they specify. Sent from my Pixel 3 using The H.A.M.B. mobile app
Check all the wires inside the dist. above and below the plate, change the coil just might be weak, its rare but possible.
Best to remove the feed wire from the ignition coil/control unit and check it's voltage reading. To some extent, it's possible for an engine to start and run with low voltage supplying the ignition, or a bad/ high resistance ground connection, but putting the engine under a load (wot or climbing a hill) will usually blow the fire out. If there isn't enough voltage feeding the coil, it can't make enough energy to generate a strong spark at the plugs....when the engine most needs it.
Blue spark or yellow? Yellow is weak. Also check pressure as many have said-many stock pumps over pressure.
What ignition was used on the previous engine in the car ? I would borrow a known good carb and try it, I've heard of some quality control issues on some of the new Edelbrock carbs. The size of the carb and jetting are not at issue here, these carbs only let in fuel in the secondaries per amount of air being drawn in, I run two 600's on a pretty mild 355 with no issues. I'm wondering if you had a points setup in the car previously and are running the wires through the ballast resistor trying to power the MSD setup.
Wow! Excellent article. Good info. for gearheads who like performance. It may get lost on those that just want to bolt on stuff and expect it to perform without doing any research. Thanks for taking the time.
I run a Dart air-gap on my 355, in all sorts of weather down to 2 degrees out. Below 35 I have to let it really warm up and it cools down fast between the manifold and aluminum heads.
I run an HEI on my 355, 700 Holley and no vacuum advance. Initial is around 14, all in by 2500 RPM at 36 degrees.
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