Hesitation at 3000rpm

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kenjrduster

kenjrduster

kenjr
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I bought a '70 Duster and can't get it running right. No papers and other info available. It's got a 383 bored out 30 0ver and stroked. Full roller top end with a wedge intake. Topped off with 2 4bbl holleys. I had to put a new MSD distributor in it to get it running. I opted to go without the vacumn advance. Now the problem is how to set the advance correctly. It boggs out at about 3000rpm pings little too. It's got fresh 93 octain in it. This isn't much info but any ideas would be appreciated. Thank You..
 
kenjrduster said:
I bought a '70 Duster and can't get it running right. No papers and other info available. It's got a 383 bored out 30 0ver and stroked. Full roller top end with a wedge intake. Topped off with 2 4bbl holleys. I had to put a new MSD distributor in it to get it running. I opted to go without the vacumn advance. Now the problem is how to set the advance correctly. It boggs out at about 3000rpm pings little too. It's got fresh 93 octain in it. This isn't much info but any ideas would be appreciated. Thank You..
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Automatic? Manual? What's the stall if auto? Rear gears? Initial/total timing? Which port are you using for the vac advance? Full manifold or ported? Cammed? Any idea on duration/lift? What's the idle vac?

I'm far from the most knowledgeable, but the information you've provided is too sparse to even make a guess. It could be spark, it could be fuel, it could be a vac leak or too low a stall on the converter (if auto).

Could be a lot of things. In my experience, a wideband oxygen sensor and gage is a HUGE tuning aid. I use an innovative MTX-L. It's rather inexpensive and can help identify lean/rich spots in a hurry without much guesswork. If you don't have all the specifics, it can be even more useful. A vac gauge can also help to see what's going on under the hood when it bogs/pings.
 
which initial advance bushing do you have in your msd distributor?

stroked?
wedge intake?
holley carbs...list or model numbers?

more specific?
 
Thanks for the responce Guys. As I said there is no technical info available. I bought this blind to keep it in the family when my cousin passed. Is has a "727" withI think a 2500 stall. It didn't run till I put the distributor in it so I have no idea on the timming. To many questions that at this time I dont have or will never have the answers to. I really appreciate your help. It gives me a heads up on thins I have to figure out to eventually get it running good. Thank you all..
 
you put a distributor in in without timing it?
 
kenjrduster said:
How am I to set the timing without knowing anything about the internals of the engine??
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Because most engines run pretty well with similar timing despite numerous variables. Unless it's turbo'd or supercharged, 16~20 base with 35 total should work for most setups. You have some pinging as-is, if you knew what your total timing was you might find the culprit.

You can figure these things out (timing; vac port used for advance, if any) with nothing more than a timing light. Driving it without setting the timing to some known quantity is a disaster looking for a place to happen.

You should be able to check base timing, and at what RPM the timing goes 'all in' as well. These are important factors. The amount of added vac advance is also crucial and can be measured.

Sounds like you have lots to learn, but you've found the right place to learn! Search, read, ask questions. It will all begin to make sense.
 
kenjrduster said:
How am I to set the timing without knowing anything about the internals of the engine??
Click to expand...

the timing we are talking about here is the ignition timing
like Bruce pointed out, you can get a timing light
it has 3 wires (a positive and negative that go the battery and a signal wire which clamps on the #1 plug wire)
inside the timing light is...you guessed it...a light
when the engine is running the signal wire will pick up on the spark traveling through the #1 plug wire and will trigger the light
if the gun is aimed at the harmonic balancer it will reflect off the timing mark and by looking at the dial cast into the waterpump you can see what your ignition timing is

camshaft timing, when and how for which valve opens is something we can NOT see from the outside (I think that's where the confusion came from)
 
kenjrduster said:
ThanKs again Guys. I'll try this all out..
Click to expand...

Do you have a timing light?

If not, you need to get one. I would suggest a good dial back light, that way you can adjust for the initial. Unless it has a degreed balancer on it.

I would start by verifying top dead center and check the balancer mark. Then go from there.

Timing FIRST, carb adjustments second.
 
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