Spark there is no accelerator pump arm to clearance on a street demon carb. And I've tried every combination of jetting and pump cams and squirters under the sun on my holley 600 and the 4150 650 I had on there. Thats why I'm looking elsewhere because it has done this across 3 different carbs with no tuning success. I've got a brand new fireball coil from my neihboor in the shop that I will put on today and see if it makes a difference.
I think Bryant is on the right track. It sounds like an instant bog/lag/whatever is immediate as the pedal is mashed. Not even time for the the fuel pressure to drop by much, if any. The bowl should still be full. Just my 2 cents worth......
New coil in and still have the same issue. I've got the holley 600 set back up with stock jetting to stick back on with a 33 squirter to see if jetting back to stock will help at all.
has this motor always done this or is it something that developed? while you have tried the coil, the ignition box is still a possibility. also have checked the screws that hold down the petronix? ive seen loose components in distributor cause weird problems.
Have not checked the petronix in a while. Honestly I can't remember if its always done this or not. This is a fresh build but I've had the ign parts for a while.
I paid a little closer attention yesterday to what the carb was doing and when I get the bog and black smoke its opening the secondary flap......the flap opens and closes with the bog until it clears....... With the demon 625 you can delay the opening of the flap but that didn't help. Starting to suspect to rich of jetting causing a bog when the secondaries come in. I'm more familiar with the holley so I jetted it back to near factory jetting....64 primary 68 secondary and I will give that a go with a 33 squirter and see if that helps.
Throttle bog is fuel related. It's not a flow issue if the floats are set correctly, so rule out the fuel pump for this problem. It's either a squirter or timing issue for fuel if you are sure your jets are correct. Sorry, was posting at the same time you were. If it does it while sitting in neutral, the secondaries have nothing to do with it, they won't open since there is no load in neutral. Vacuum secondaries should only kick in when actually driving the car. SPark
I did not degree the camshaft. Just put it in dot to dot and put it all together and broke it in. The demon has a flap over the secondaries and it starts to open at about half throttle....it flutters when it starts to open and it bogs then it smooths out after a second and opens up all the way. I'll try the smaller jets in my holley and if it doesn't work guess I'll need to pull the motor and degree the cam.... Never done it so any pointers on how its done?
the cam can be degreed in the car. you need to pull the front timing cover and the passenger side valve cover. get a degree wheel, a dial indicator and a piston stop. their is endless info on the internet on how to do this that is much more through than i can be. its not very hard to do. make sure you have your cam card. the trickiest part will be properly setting up the dial indicator to read the cam with out being messed with by the hydraulic lifter. im sure some where on line a solution is their. i would think tightening down the rocker arms till they bottom out the lifter would work but double check with online instructions.
Cam phasing will effect bottom end vs top end, it wouldn't cause a bog. A bog is a fuel shot issue, period. That said, you have to put a solid lifter in to degree a cam. We used to gut a lifter and tack another to it top to top so you had a good spot to set the dial indicator. Wouldn't waste the time with it for a street motor that is already running personally. If you used all the same brand (Comp cam and timing set) you are probably fine. Only way to know for sure is to degree it but you have a funning engine with a tuning issue. SPark
Well I'd be screwed anyways I don't have the can card Lmao. Hopefully the Rejetting works. Unrelated but I have a roller block at the house with everything. Can I convert my non roller 50oz block to a roller by tapping the dog bone keeper tray and putting in the roller rockers on top of a roller cam?
The lifter bosses are taller on a roller block. Some newer blocks had the taller lifter bores without the roller cam setup. What year is your non-roller block? That is why the retrofit roller cams use a reduced base circle cam. SPark
Not sure of exact year. Early to mid 80s? Its a 50 oz imbalance motor so has to be somewhere in that range......
Rejected holley on and I can noe get full accel..... Think my float is stuck I am getting a steady trickle from my second dart boosters...... I've got the quick fuel plate and float back there.....must have got hung up when reinstalling the bowl.
