MY ENGINE BOGS DOWN IN GEAR. HELP SOS

[south tex mopar]

FIRST I WOULD LIKE TO SAY HELLO TO EVERYONE AND WHAT A GREAT SITE. THIS IS MY FIRST TIME ON THE SITE. ITS REALLY AWESOME TO SEE SO MANY OF YOU WITH BIG BLOCK A BODIES. AWESOME. SO ILL GIVE YALL MY SETUP AND WHAT ISSUE IM DEALING WITH ON MY DUSTER, HOPEFULLY SOME OF YALL CAN GIVE ME SOME INPUT. DUSTER WITH 383 STANDARD BORE AND CRANK, MILD LUNATI CAM, M1 INTAKE, 906 HEADS ,HOLLEY 750 CARB.TRANS NOT SURE ON THE STALL( GOING TO PUT 3500 STALL LATER) REAR IS 391 POSI. OK, SO CAR RAN FINE FOR A FEW MONTHS AFTER ENGINE WAS BUILT. NOW IT BOGS DOWN IN ALL GEARS, AND ONLY WHEN IT HITS 2900 RPM. LETS SAY IF IM IN FIRST GEAR AND I SHIFT AT SAY 2700 IT WONT BOG.SAME FROM 2ND TO THIRD.IF IT BOGS DOWN AND I GET OUT OF ITFOR A COUPLE SECONDS IT SHIFTS INTO SECOND AND THIRD FINE, ALSO ON THE HIGHWAY AT HIGH RPM IT SOUNDS LIKE IT HAS A LITTLE TROUBLE. FIRST I WAS TOLD IT WAS A FUEL PROBLEM SO I UPGRADED THE FUEL DELIVERY . GAVE IT THE WORKS,FUEL PRESSURE IS GOOD. SO NO PROBLEM THERE. NEXT PLACE I WAS GOING TO LOOK WAS THE VALVE SPRINGS BECAUSE THEY DONT MATCH THE CAM. THEN I WAS TOLD IT COULD BE SOMETHING ELECTRICAL (THAT I DONT UNDERSTAND) ELECRICAL AS IN WHERE?DISTIBUTOR ETC I DONT KNOW? ALSO I CHECKED THE CAM AND IT HAS SOME LIGHT SRATCHES. MAYBE THATS IT, BUT THEY ARE MINIMAL SRATCHES AND ONLY ON THE LAST LOBE, CLOSEST THE THE TRANNY. HOPE YALL CAN HELP AND THANKS. ITWILL BE MUCH APPRECIATED.  DSTR1972@YAHOO.COM                                                                         MOPAR OR CAR FOR LIFE

[bOb shingler]

welcome tex but turn the caps lock off please. you might try a complete tune up, rebuild the carb and check timing.

[south tex mopar]

Come on BIGBLOCKDART help a mopar brother out. I really dont think thats the problem. We made different tuning, timing adjustments on our last test an tune, with no resolve. We also tried three different carbs. a holley 750, 650, and a divinci 750.  HELP

[bOb shingler]

relax dude, are they vacuum secondary carbs?

[south tex mopar]

The first was a street avenger 750 vac secondary. Next holley 650 was mechanical and third 750 was davinci race 750, not sure on that one exactly, it was borrowed.what kind of carb do you think i should try? Thanks im ok, im  just a little frustrated i cant figure this out.

[67Dart383]

Seems like your fuel pressure is droping, ck your fuel pump and regulator. What times it turns in 1/4. Welcome!

[south tex mopar]

That could be it. Right now when the car is on idle (600 rpm) the fuel pressure is a little above 6 psi. So maybe at high rpm it is going down a bit. What psi do you think i should have at idle? What i dont get is that i had a mechanical pump on it when i first put this motor in, and it ran fine a few months. Then this problem started. So looking to solve it , i took out the stock tank, put fuel cell in trunk, braided lines all around, holley blue electric pump, regulator, psi gauge.

[496dart]

sounds like lack of fuel.

6-7 psi at idle  .  same  down track  is what you want.


Start doing the " gas can test"  at  every point from the cell to the carb.


http://www.barrygrant.com/included/bgfuel/print.aspx?page=81

[bOb shingler]

what size fuel line? is there a fliter before the pump? did you use all AN fittings ? maybe the springs finally wents tits up. if they are to light for the cam they won't last long. in the holly pump the is a screen filter, remove the 4 or 5 bolts on the bottom plate and see if it has stuff from the new fuel cell in it.

[speedymopars]

You could have burned a plug wire and/or fouled a plug. Those issues won't show up at idle or light load.

[B.B.D.of Corpus.]

 I would change the plugs and read the old ones as you pull em out if that dont help check the wires cap and rotor if that dont work put a timing light on it make sure your balancer is or hasnt slipped its tdc mark or youll never get it right if your not sure about setting or checking the timing then just advance it till it clears up or pings but back it off if it pings. does motor skip pop flutter when it bogs? does it do it on hard acceleration or easying in to it ?

[south tex mopar]

The fuel lines are 3/8  and the fittings are russell an all around, filter is aeromotive crome with red cap. I took all the foam out of the cell because that stuff gets in your fuel lines. Your probably right about those springs, what would the symtoms of a bad spring or springs be? Like i said the car  just from one minute to the next  gave up. This is the second fuel setup, since the problem started. Like i said before the car drove great on the initial breakin with only a mechanical fuel pump stock mopar tank and lines. Thanks for all your help

[B.B.D.of Corpus.]

Also does it do it at a dead stop or while cruising?

[south tex mopar]

It always acts the same as soon as it hits that rpm range. No matter how i accelerate, although it is worse under hard acceleration.  No other noises backfires or anything like that. Plugs have been changed twice and read normal. Tan

[496dart]

you've got to do the gas can test to eliminate your fuel system components .

[B.B.D.of Corpus.]

if you yhink vlve springs pull V.covers with valve closed push down on top of each vilve or rocker feel for a spring weeker thn another

[B.B.D.of Corpus.]

check that your gas tank can breathe that its vented

[B.B.D.of Corpus.]

also if you have a holley get some carb cleaner spray it into the air bleeds and check the float level .Had a friend at the dirt track have similar problem and carb cleaner into the air bleeds cleared it right up

[south tex mopar]

Thanks guys  ill check all of the above 

[south tex mopar]

Once at the track while doing timing adjustments we reved the motor around 2800 (while parked). It made the same sound of boging down. On the tank all i did was loosen the top breather screw. What breather  do you think i should put on it?

[satellite65]

Sure it's not an ignition problem?

[496dart]

ahhhh...ok , if it does it while parked ...

id say ignition advance  or possibly  valve springs

[south tex mopar]

I put a cheapy summit  electrontic distributor on it ( cost 165). maybe its time for an msd setup. you think? change the advance curve? change valve springs?

[B.B.D.of Corpus.]

is it vacume adv? if it is is it hooked up? have you have advanced the timing ? I took my dist. apart and locked it set timing at 38 deg. if you have a re built motor after its broke in the timing chain will loosen some and timing goes neg. mines locked cuz of its combo. plus it runs on high octane all the time does the motor clear up after it bogs or does it continue to run crappy through the rpms?

[jess13]

You can get one of those lights that hook upto your ignition system to see if its dying out on you.  They are just a little light in  a housing with a wire hooked to it that hooks up to your plug wire.  The light housing has a suction cup and this allows you to stick it to the windsheild so you can see if flash as you go down the road.  If it stops flashing when it bogs you know its in the ignition somewhere,  if it keeps flashing steady when it bogs then the problem is somehwere else.     


Also using a vacuum guage on th eintake can help.   ALthough it doesnt happen to often,  but a muffler that the baffle cam loose can stop up th eexhuast and make them act this way,  but it has to be pretty bad for it do like that.  Maybe a rat built a nest in the exhaust
and is stopping it up.   If th eexhaust is stopped up to the point of causing problems like this the vacuum will drop like a rock.


What about the air cleaner,  or hood scoop setup  ( if it has one)  .   I have had some strange things go on in this area.   


Doing test that prove if a system is good or bad is the first place to start,  just throwing parts at it only gets you knew parts and a less money.   




Jess

[Matt-67]

I had a similar problem turned out to be the coil.

[south tex mopar]

Im going to try and explain in more specifics. First the motor will not rev over 2,800 rpm PERIOD... Shouldnt it be able to rev much higher in any gear? i thought i should shift at about 3,500. Well it wont ever. lets say i start the car, starts right up, and idles perfect,  in park if i put the pedal to the floor , it will only rev to 2,800 NO more. Sometimes  not always boging at 2,800 in park. Put in gear drives fine till it gets to 2,800 in first then it bogs down. So i let my foot out of it 2 or 3 seconds, till it goes down to about 2,600. Now i can shift to second. Same  story goes for second to third. Also at high rpm in 3rd it sounds like a light popping puttering sound.  If i always shift be that rpm range there are no symtoms.

[south tex mopar]

To answer some questions. its vac advance and it is hooked up. It has a new holley air cleaner on it, and a six pack hood.  msd coil is new. Exaust is new and flowmasters . shumacher pipes(sorry) And thanks for the tips for the electrical stuff, that could save me some money on spending money on it if it turns out to be fine.

[south tex mopar]

heres a pic of it

[satellite65]

I think you should go over your ignition system with a fine tooth comb. You said you tried 3 different carbs and all three did the same thing? Not your carburetor. Even if the ones you borrowed weren't tuned for your combo you would still see some sort of change. Also, just for kicks, check your throttle linkage and make sure you're opening up all the way.

Don't do this: You'll nail it.

[south tex mopar]

throttle linkage, i dont have one. Only a throttle cable, and i only shift it manually. If i just put it in drive the gears go in super early. Is the linkage nessesary? Didnt think id need it if i shifted manually.

[bOb shingler]

heres a pic of it

  could you tell me how much clearance is between the fan blades and the radiator?

[pwmax]

Sounds ignition related to me. For one, the way your wires are zipp tied together, doesn;t help, do you have a rev limiter in there? What ignition box? You can try twisting the wires coming out of the distributor, and electtical tape them so they don;t un-wind. But it definately sounds to be electrical. Valve srpings won;t cause it to not rev beyond 2800, I don;t care how weak they are. Even a totaly wore out stock spring at 70lbs on the seat, will let it rev beyond 2800.

Its definately electrical.

Frank

[speedymopars]

Im going to try and explain in more specifics. First the motor will not rev over 2,800 rpm PERIOD... Shouldnt it be able to rev much higher in any gear? i thought i should shift at about 3,500. Well it wont ever. lets say i start the car, starts right up, and idles perfect,  in park if i put the pedal to the floor , it will only rev to 2,800 NO more. Sometimes  not always boging at 2,800 in park. Put in gear drives fine till it gets to 2,800 in first then it bogs down. So i let my foot out of it 2 or 3 seconds, till it goes down to about 2,600. Now i can shift to second. Same  story goes for second to third. Also at high rpm in 3rd it sounds like a light popping puttering sound.  If i always shift be that rpm range there are no symtoms.

This is always helpful when you are explaining a problem. Bogging at 2800 and not being able to rev past 2800, are two totally different problems.

Please stop using the term bogging / bogs - this is not what you are experiancing and will throw off anyone trying to help you. A bog is when it has too much fuel, and the engine loads up causeing acceleration to slow. In you case, if I'm reading this right, is that you engine will not rev past 2600-2800 RPMs no matter what you do.

What I am aslo reading is you are not moving, and you wing the throttle in gear, it stays at 2600-2800 and goes no further. If that is the case, you have found your torque convertor stall speed and this is normal.

However, if I am not reading this correctly, and you are moving when you are doing this, the limit can come from several things:
1) rev limiter. Do you have one on an MSD box, a rev limiting tach, etc? I had a mallory rev limiting that died and kept the engine from going above above 4000 rpm even though it was set to 7K. Disable it or disconnect it. Don't forget that to a tach a 4cyl tach set to 6000 rpm is the same as a V8 at 3K.

2) coil problems - if you have the incorrect coil (a resistive coil when you don't need one or vice versa, a CD coil with an inductive ignition), or too low of voltage to your coil (IE 3 volts) then the loading of the ignition at higher rpm's could cause the spark to disappear. This can be made worse with a bad (or incorectly) set of plugs, wires, distributor.

3) Timing way off. If your distributor is set at the wrong initial advance, it is possible that when your advance plates kick in the timing gets so far off the engine won't run any more. It is also possible that somehting is shorting out, or the magnetic pickup / points have issues. If the point springs are worn out (on a point system obviously), they could be hanging open at that rpm also preventing a spark.

4) Fuel delivery. I ran in the 12's with a 5/16th line and 7 psi - so don't worry about fuel line size now. However, look at your fuel pressure (drag a gauge in and see what you have). It should be no less than 5 PSI no matter what you are doing. If it is, look at a fuel filter clogging issue as flow will be affected at RPM, but not at idle most of the time.  BTW - those clear glass filters don't flow worth a damn, I kept running out of fuel in my jet boat at 3800 rpm, it turned out to be the new glass filter I put on.