Brand new 340 and no balls

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MrBubbles211

MrBubbles211

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Ive read a few of your forums and I see to have a simular problem as a few other people... this is i have to admit fustrating big time.


I have a 69 Dart nbrs matching with a 340 4spd. The engine has been recently rebuilt and I have just finished breaking it in. My problem is like a lot of other people the engine does not make the power it should... I remember 340's from the days and they pulled a lot harder than this thing.


t is a pretty much stock and original system, I have a Carter 650 AVS and Prestolite Dual point distributor, factory coil. Spark plugs are Autolite and the wires are Mopar Originals.

It is running really rich, lots of soot around the tail pipes, the throttle doesn't seem responsive at all.. it is almost like the first 1/8 th of the pedal is all there is. Today it started popping when getting into it and while it was running in the driveway I goosed it and it popped out of the Carb.

The timing and everything was set to factory specs by the guy who restored the car completely and he is very knowledeable with the 340 motors.

I've seen previous formums on this topic, and I guess I am jst as confused as the rest.
 
I would swap the distributor for an electronic unit. You can hide the ECU under the dash. Most carb problems turn out tp really be ignition issues.
 
First things first, unless you got a dwell meter and lots of patience get rid of the dual point, like Adam says. Last one I had on a 440 got plowed under on a farmers field after I threw it as hard as I could over the fence, POS.

Terry
 
Factory timing parameters were set up for a lot of factors other than performance.

Give the engine as much initial timing as it can tolerate, set it with a vacuum gauge, then limit mechanical advance to get you desired total.
 
crackedback said:
Factory timing parameters were set up for a lot of factors other than performance.

Give the engine as much initial timing as it can tolerate, set it with a vacuum gauge, then limit mechanical advance to get you desired total.
Click to expand...

thats the most logical and simple explanation i,ve ever heard. timing for dummys lol
 
Definetly ditch the dual point. Get electronic and be done with it.
 
Way back when... the late 70s, I was setting the dual points about once a month on my 340 to keep it running great.
Mine really slipped out of adjustment quickly.
Today I would put the original dual point on the shelf and run electronic.
 
yours does sound like an ingnition prob...but Did you put adjustable rockers on it....When I had a guy rebuild my 340...he had the valves so tight it was laboring bad....and wouldn't rev up....readjusted them properly....came right to life...totally diff car
 
Thanks for the help so far. Yeah if I find out the Dual Point is causing the problem we it is become a lamp and I will install a electronic distributor. I think also think the carb is running really rich could it have the been set wrong.

It has hydralic lifters in it so it won't be valve lash, however worst case it could be a wiped cam.

Still playing around with it
 
daredevil said:
Cam not centerlined will cause a sluggish motor
Click to expand...

Oh yea, let me tell you! Mine was a bone when I bought it and one day I
had the pump eccentric spin free on me so when it was all torn down I
figured hey I'll check the cam set up with my degree wheel. Well it was
off a tooth on the timing gears. Run wayyyy better now!

I have a pertronix set up in my stock disty, it works pretty well.

I guess I could have gone with an elec. but I kind of wanted to keep the
stock look. I think the modules are like 100 bucks. FWIW
 
I know the electronic setups are nice and normally trouble free but I don't think the dual point deserves the bashing it's getting. Anybody who doesn't want theirs, send it to me!! The Prestolite dual point is a very nice piece. They were standard in all the early hemis! Crackedback put you on to good stuff. If the cam is properly phased and not retarded, you should pick up a lot of power with timing advance and carb adjustment. USE A VACUUM GAUGE! A lot of people never consider it. If the cam is installed retarded, it will effect the distributor timing, etc., all down the line. If the valves are too tight, vacuum will be low and it will run like stink! If the cylinder heads were cut (to level it or gain compression) it puts more preload on the lifters so the valves don't close right. Check these thing out and good luck. If anybody wants to throw away a point distributor, throw it in a box, contact me, and I'll pay the shipping!
Pat
 
whether you use a point or electronic distributor...the advance curve needs to be adjusted...

and if you plugs are fouled....you probably are having issues with the carb too..
 
PFogel said:
I know the electronic setups are nice and normally trouble free but I don't think the dual point deserves the bashing it's getting. Anybody who doesn't want theirs, send it to me!! The Prestolite dual point is a very nice piece. They were standard in all the early hemis! Crackedback put you on to good stuff. If the cam is properly phased and not retarded, you should pick up a lot of power with timing advance and carb adjustment. USE A VACUUM GAUGE! A lot of people never consider it. If the cam is installed retarded, it will effect the distributor timing, etc., all down the line. If the valves are too tight, vacuum will be low and it will run like stink! If the cylinder heads were cut (to level it or gain compression) it puts more preload on the lifters so the valves don't close right. Check these thing out and good luck. If anybody wants to throw away a point distributor, throw it in a box, contact me, and I'll pay the shipping!
Pat
Click to expand...


Im not really bashing the Duel Point set up.... It was the hot ticket back in the day.... Its simply that these days we have better options.
 
I just found the build sheet for my engine, here are some of the specs.

Comp Cam 20-232-4 Lift intake .480 exhaust .480
Duration at .050 230 degrees intake and exhaust
Spring type Com 901-16 assembled pressure open 320 closed 110
Installed height 1.850 installed at 0 degrees

Head gasket thickness is .041

Heads machined .010

Pistons are seal pro forged 10 1/4 to 1

It was all balanced and blue printed
 
Welcome to FABO! Good to have you.

Sounds like it needs a tune up. Dial in the timing then look at rejeting the carb.


Allso have some one get in the car and put the gas peddle to the floor and hold it there. Then check the cam on the side of the carb and make sure the throttle cable is giving you full throttle. You should not be able to rotate the cam any more. If you can you will need to ajust the cable.
 
I would not recommend ditching anything, until it is known what the problems are. The dual point can work real well if tuned properly.
 
With that camshaft, you'll need somewhere in the 18-22 initial timing range. DO NOT fall into the trap of setting total and ignoring initial, that's the backwards way of doing things.

If initial is set any lower, that requires the throttle blades to be open more and gets you the really dirty idle, no low end.

Get your timing sorted out first, then dial in the carb. Timing almost always effects carb, carb rarely effects timing.

There are some good threads on here about setting initial and total timing. I think member Shane started one and got his car sorted out pretty good.

I also agree with the don't ditch anything at this point. If the parts are bad, then make that determination. Otherwise, run what you have and make sure the points are in good shape, set properly.
 
In this day and age I wouldn't run a points distributor in anything unless it was a concourse restoration, which I just can't bring myself to do anyway. The Chrysler electronic ignition is great for a stock or near stock vehicle. An MSD is even better and you can still use the Chrysler electronic distributor. In fact you can use a points distributor with an MSD but I wouldn't even bother with that. Just because you can doesn't mean you should.
 
I set up my distributor the way crackedback segjested and it worked grate.wound up with 15 initial and 20 centrifical.that was good advise. Had a bad coil that caused pore idle pore throttle response and high rpm miss when it got warm. It runs so good now it scares me.By the way its a 340hp.455 268 cam
 
Take compression measurements on it. The engine should be hot, remove all plugs, and wire the throttle open. Then get teh cylinder pressures from all 8. My impression is that teh engine was not bloueprinted, which means it has an older grind hydraulic cam and a static compression that is closer to 9:1 if that than 10.25. If that's the case, your 340 specialist put in a cam that's too large. Comp is usually very good in terms of quality, but the cam should have been degreed anyway. Chekc the pressures and report back. If a dual point scares you, disconnect the wire between the points and run a single set to diagnose. Also, this should be checked with a dwell meter, not feeler gages. Points are easy, and dual points dont get any more complicated really. You do the same thing twice.
 
If you are using the dual point then you need to use a dwell meter to set them and check the dwell angle with the engine running at various speeds. The dwell should remain at a constant point, not change. One degree change in dwell will change the timing by two. This will indicate the distributor and/or points need attention. Get the ignition system sorted out before you even mess with the timing and carb.
Have fun,
Wayne
 
Thanks for the excellent advice. I am getting a guy that knows Dual Points to check the dwell on in the next few days. I will let you know how it goes. Hopefully that will be all it needs. Will keep you informed can't wait to see how this thing is going to really pull once it is set-up properly.


Ed
 
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