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Hesitation Revisited
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Author:  61 V200 [ Sat Mar 01, 2008 10:16 am ]
Post subject:  Hesitation Revisited
Quote:
you might try disconnecting the vacuum advance hose and capping the carb nipple, then see what happens if you floor the gas. If the hesitation disappears, you'll want to rework your vacuum advance configuration
I've learned here that MY distributor that came with the orange box may be the source of hesitation on my stock 170. My question is " How much performance upgrade would I need to do to compensate for an inappropriate curve and get the hesitation out?" I've got a super six on the shelf with Dutra's exhaust. Would that change do it or would a cam and headwork also be needed?
Author:  Reed [ Sat Mar 01, 2008 12:20 pm ]
Post subject: 
If you have the distributor that came packaged with the Mopar Performance ignition conversion kit, then the problem lies with the distributor, not your engine. The distributors in those kits were calibrated for 1/4 drag racers. Accordingly, the distributors are calibrated for motors that operate 99% of the time near or at wide open throttle. Not good for a daily driver.

You will need to open up the distributor and fine tune the advance curve. Mostly, you will need to replace the light springs with heavier springs to slow down the timing advance.
If you still have your original points distributor then you may be able to just swap the springs, weights, and armature into the electronic ignition distributor, or swap the pickup and reluctor from the electronic distributor into the points distributor.
Author:  DusterIdiot [ Sat Mar 01, 2008 1:25 pm ]
Post subject:  Woohoo.... yep...
It's just like Reed said, the MP distributor is 'all out' by 8-1200, so you have max spark @ idle... no good for the street...

You can rob the springs out of your old distributor like Reed said... or if you want to 'play' with the curve a bit, I would suggest you respring with this recipee and try it...

Order Mr. Gasket #928G (the GM kit)
Pull apart MP distributor, remove springs if they exist... pull apart old points distributor... rob the light spring out of it and put in MP distributor, grab one silver spring out of the 928 kit... reassemble, check your reluctor gapping/etc... make sure the counter weights move...

Reset engine to 10BTDC...install distributor, check timing with dial back timing light (30 @ 27-3100 rpm?), and reset carb mix if necessary...test drive... hook up vacc. advance pod and test drive again/check timing in driveway first( 47-50@ 27-3100 rpm right?)...

That should get you much closer to a 'street/performance' timing curve...(and will work well with the super six/duals combo when you step up to it...)

good luck,

-D.Idiot
Author:  61 V200 [ Thu Mar 27, 2008 11:03 am ]
Post subject: 
Found some time to get the Toad out on Easter Sunday. (It's almost boat season so my efforts have been focused on my skier)
Plugged the vacumn tube and went for a spin.
The big hesitation went away and now it hiccups for just a second. I'm assuming that is because I have no vacumn advance?
THanks
Author:  Aggressive Ted [ Thu Mar 27, 2008 11:25 am ]
Post subject: 
61 V200
Quote:
Plugged the vacumm tube and went for a spin.
The big hesitation went away and now it hiccups for just a second. I'm assuming that is because I have no vacumn advance?
Yes, to far the other way now but proves the point. You must have a very low initial timing. I run allot, 16 degrees is my favorite, but allot folks like 12 degrees. The idle is smoother and response is mellower at 12.
What do you have yours set at?

Do as D.Idiot says, it is good advice. I have been there done that. The springs are too light for your rig so it comes on too quick. Not good if your engine since it isn't built for torque and can make use of the quick advance.

I built a low rpm torque monger 225. My recipe is a the red medium spring on the primary with the spring pin cam rotated all the way out to make it tight, and a heavy looped secondary spring with the spring pin rotated all the way in for an extra long throw. This provides full advance at 2000 rpm and the last little bit at 2500 rpm. I cruise at 2500 rpm so it is perfect for me. You need to know what rear end ratio you have or a tach to monitor rpms at cruise so you can tune the secondary spring for that rpm. I robbed these two springs from a 400 big block distributor. If you aggressively mash the throttle, the wheels break loose even though I am running a posi. The response is immediate, no hesitation or lag. Your engine will want a little slower response. :D
Author:  61 V200 [ Wed May 07, 2008 8:23 pm ]
Post subject: 
I now have D.I.'s spring set-up in place. (light spring from stock points dizzy and 1 silver from Mr. Gasket 928G)
10-12 degrees BTDC
Much improved.... however a slight hesitation when I gas it in the range of 35-45 mph.
I'm timing off a TDC mark only so I may be off a bit.
I'll resolve that with timing tape.

Any ideas as to why I still have some hesitation?

Thanks to all

[/b]
Author:  dank10fenny [ Wed May 07, 2008 9:25 pm ]
Post subject: 
a million reason, ha. vacuum leaks, cam timming/chain condition...
Author:  DusterIdiot [ Wed May 07, 2008 9:49 pm ]
Post subject:  Hmmm....
I'm thinking either:

Swap in heavy points spring for points light spring or...

Carb needs retuning (acc. pump shot not timed right, or big enough... or off idle circuit not fat enough to take the transition)


Carter BBD might fare better...

-D.Idiot
[/quote]
Author:  61 V200 [ Thu May 08, 2008 10:40 am ]
Post subject:  My guess is Carb.
I'll try changing spring set-up however my gut feeling is the carb (1920) is crap.
Based on....when I bought the car I rebuilt the carb and found someone had sabatoged it by cranking the idle mix screw in to the point of creating a ridge on the needle. We re-cut the taper but I'm sure the seat is hogged out. It is erratic (at best) when setting idle.



I've got a BBD on the shelf but have some concerns about its workability.

I'm hoping SSD cuts loose with some of those NOS BBDs that I hear he has.

Thanks again for all the help.
Author:  Aggressive Ted [ Thu May 08, 2008 1:42 pm ]
Post subject: 
What size jet are you running in the 1920?

Do you have a dual plunger type power valve on the economiser body or a single?

You could have a vacuum leak at the top of the power valve. Check to see if the 3 screws are tight or loose? or is the diaphragm ruptured?

Is the low speed idle bleed plugged? See if you can get some fine piano wire down it or fishing leader wire.

How strong is the accelerator pump shot? Is it immediate?

As DI says the transition is off, but can be easily fixed.

After checking let us know what you have?

Don't give up on it yet, my 1920's are incredibly responsive when you mash the throttle! If you feather it, everything needs to be working correctly.
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