She's A Slug..help!!!

[Wilnutt]

Been a while..i have the demon back..finally...but i have a problem,...

being i paid this guy to do all this stuff i'm not sure what all is exact, but this is one hell of an engine..340 bored 40 over, total edelbrock top end package, forged everything etc etc. est 425hp, i have figured...

i get on her, and in first she's a slug.. is it fuel pump ignition ??? idk...it feels liek it bogs down and is about to die....all help woudl be greatly appreciated

 

[daves66valiant]

float level adjustment maybe?

centrifugal force and the fuel pump not keeping up?

my guess

 

[Wilnutt]

keep the comments coming please ..thank you btw

 

[daves66valiant]

sorta have the same problem and that was going to be one of the first things for me to check on mine.

 

[Wilnutt]

once she gets the idea we'r goin she'll burn rubber but...just doesn't feel like 400+hp to me

 

[mguner]

Timimg specs? Sounds like the distributor needs a little curve work.

 

[Wilnutt]

all righty...that's 2 things i should check..any more suggestios?? thanks to all!!!

 

[doktor_x]

Does it bog to the verge of dying and gradually work out of it? I'm thinking accelerator pump (either way too aggressive or non-existent) is a possibility.

 

[Longgone]

I think it might be timing too, maybe start at 12 degrees BTDC initial and work up to around 34 total without vacuum advance. Like mguner said ,the problem may be with the centrifugals in the distributor.

 

[Max340]

You don't mention the CR or cam specs, any problems with those?

 

[SpeedThrills]

I'm a little confused. You paid "this guy" to do what? Machine work? Engine assembly? Did he put it in the car and get it running? I mean, where's he stand on all of this?

 

[Wilnutt]

this guy has had my car for over a year with stuff that originally was supposed to take 3 months.. he's replaced everything on the drivetrain..i mean from radiator back to the rear..only thing not new is teh springs, which i'm tryin to replace, and paint.He bought an edelbrock RPM performeer top end kit....all kinds of crazy stuff..i shoudl just stayed 318 i swear... i mean, i spent 20k on everything being built

 

[Wilnutt]

OHH AND ABOUT THIS GUY..every time i take him in to do something, as simple as fixing the brakes, it's in the shope for at leats a month, if not two...so i refuse to take it back to him

 

[onehellofadart]

What rear gear ratio do you have. Mine felt like a slug also till I changed the gears to match the engine build.

 

[SpeedThrills]

OHH AND ABOUT THIS GUY..every time i take him in to do something, as simple as fixing the brakes, it's in the shope for at leats a month, if not two...so i refuse to take it back to him

Yeah, I see what you mean. I'm in Joisey, if I was closer I'd stop by. You're in Florida? Seems like it would be a lot easier to diagnose in person. I'm guessing it's a combination of things.

 

[Wilnutt]

i have a 3.23s, non posi...i owuldn't have gon any steeper then a 3.55 anyways..i got a balsy 727, stock converter... i can see if i can find my pics, bc i have some pics of the part #s of teh top end package....but again..i romp on it(not full throttle, like 60-75%), and she like dies...if she's warm, if i give it 100% she burns rubber, but still feels weak, my charger daytona rt feels like it has more balls, as did my hemi ram..and i mean, that was a 15 second truck.

also, she gets perdy hot, i'm not thinkin this is a ver good thing..idk...she doesn't smoke or anything..just hoods hot and all, can feel the heat come out teh front..lol

 

[moparmaniac59]

What kind/size of carb are you running. Is it mechanical or vacuum advance??. Are you using an electric fuel pump or mechanical. Got good fuel pressure?? Any vacuum leaks?? Stock or aftermarket ignition?? Is your coil putting out good voltage? I'm with checking timing first also. Make sure you've got good fuel flow. Float level adjusted right?? Could be accelerator pump. When you manually pull the carb throttle back, do you get a full solid squirt of gas?? If not, it may be the accelerator pump. Fuel pressure at a minimum should be 5-7 lbs. Some of the other areas have already been suggested. I'd be picking my builder's brain. He may be able to provide some insight w/o taking the car to him. I would think if he was a decent engine builder, he'd have the thing finely tuned before leaving his garage!! just my two cents!!

Matt B

 

[fishy68]

If it truly is making 425 hp it most likely needs more converter than a stock converter and preferably more gear too. The bog sounds like a vacuum sec carb opening too fast or a accellerator pump not up to snuff.

What is the total build specs? Compression ratio, cam, heads, exhaust, carb. etc. Without these facts it's nearly impossible for anybody to guess over the internet as to what your problem is.

 

[Wilnutt]

i'm not going back to this guy.i end up forking over $500 min and a month w/o the darn thing..u don't know how frustrating it is...i'm thinkin it's between 9.5-10 to 1 keith black forged pistons etc etc.i'll look and see what i got..i'm on campus...i'll try to have specs up later in the week

 

[Wilnutt]

ok this is what i got..i can't remember the compression ratio, but it's close to teh one above, i can run on premium fuel..here are the specs of head carb and cam

ENGINE: CHRYSLER 318-340-360 V8

CAM

RPM RANGE: 1500-6500

Duration at 0.006" Lift: Intake: 308° Exhaust: 318°
Duration at 0.050" Lift: Intake: 234° Exhaust: 244°
Lift at Cam: Intake: 0.325" Exhaust: 0.340"
Lift at Valve: Intake: 0.488" Exhaust: 0.510"
Timing at 0.050" lift: Open Close
Intake: 10° BTDC 44° ABDC
Exhaust: 59° BBDC 5° ATDC
Centerlines: Lobe Separation - 112° Intake Centerline - 107°

HEADS
Chamber Size Intake Port Size Valve Sizes (in/ex)
65cc 171cc 2.02"/1.60"

CARB
600CFM Electric choke




BTW..I have vacuum advance

 

[fishy68]

ok. With a cam that size you probably need the dist. re-curved and eliminate the vacuum advance. That'll help low end torque. Was there any work done on the heads, i.e. porting? If your engine has too much vacuum it may be sucking the secondaries open way too fast. Try a heavier spring on it. (Assuming it's a vac secondary carb).

 

[toolmanmike]

Pure speculation without hearing the engine run but I would guess valve timing or ignition timing. Carbs with a weak acc. pump won't bog that much but run great if you full throttle it. It'll never get there without a bunch of farting and backfiring through the carb. It sounds like a pooch until you get to full
throttle. I wish you were closer. We could swap carbs and distributors
and eliminate those parts. You've got a nice cam but not radical enough
to need a high stall convertor.(allthough that could make acceleration
more dramatic)Find a Mopar racer in your area and ask for help. toolmanmike

 

[Wilnutt]

Pure speculation without hearing the engine run but I would guess valve timing or ignition timing. Carbs with a weak acc. pump won't bog but run great if you full throttle it. It'll never get there without a bunch of farting and backfiring through the carb. It sounds like a pooch until you get to full
throttle. I wish you were closer. We could swap carbs and distributors
and eliminate those parts. You've got a nice cam but not radical enough
to need a high stall convertor.(allthough that could make acceleration
more dramatic)Find a Mopar racer in your area and ask for help. toolmanmike

thanks..that's what i'm thinkin on...
i really rgegret taking it to this guy...
he's more of an import guy, i can tell...and anyone can build up a 350 chevy, should just bought the crate from mopar..sigh.

if i floor it out of the gate, she roars..but i'm still under 500 miles on the rebuild, so wantin them to seat ok b4 i rip-it...but low acceleration then knockin it up to a half to 4/5 throttle, and she bogs and backfires... i've never been a cam guru or with heads..the whole timing and intake exhaust and what-not..but i'm sure it's not that radical of a cam, being i was stayin auto i dind't want somethign that woudl overload the plugs sitting at a light.

 

[Wilnutt]

ok. With a cam that size you probably need the dist. re-curved and eliminate the vacuum advance. That'll help low end torque. Was there any work done on the heads, i.e. porting? If your engine has too much vacuum it may be sucking the secondaries open way too fast. Try a heavier spring on it. (Assuming it's a vac secondary carb).

heads are just the stock edelbrocks straight from teh box

 

[Wilnutt]

BTW..With these parts..does 425 at the crank sound about right?