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Old 02-17-2012, 03:44 PM   #1 (permalink)
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Default scout 800 304 v8 missing badly

Hey I have a 1969 800b, 304 v8, 4x4, she has been running great. Thermostat was stuck open and motor wouldn't heat up enough to defog window. I put in a 180 thermostat, problem solved. Week later water pump started leaking through weep hole. I put new pump on and flushed system. while I had stuff out of the way I checked my points. They tend to walk a bit. They were closed a bit, reset them to .019. Now cooling system fine, but missing and stumbling badly. fine at idle, fine during acceleration at any RPM. but missing, stumbling, and backfiring while trying to maintain 55 mph. Rechecked points, checked plugs, wires, cap, rotor, plugs, vacuum (22 in steady), fuel pump, and fuel filter. Finding nothing wrong yet problem persists. Any Ideas PLEASE!
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Old 02-17-2012, 07:18 PM   #2 (permalink)
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Default Re: scout 800 304 v8 missing badly

Did you lube the rubbing block and cam for the points? Use a 'dwell meter' to set the point gap.
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Old 02-18-2012, 08:20 AM   #3 (permalink)
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Default Re: scout 800 304 v8 missing badly

Im going to suggest that you try closing the points up to where they were before you reset them. Closer gap = more coil saturation time (dwell) and better spark. See if you can wiggle the rotor shaft and effect the point gap in doing so.
Giver her a test drive. If it is better, then set the dwell with the appropriate meter and see if it bounces around a bunch. Could be worn out dizzy bushings.

I don't see anything else that you did that would have had the effect you are seeing.
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Old 02-18-2012, 03:24 PM   #4 (permalink)
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Default Re: scout 800 304 v8 missing badly

Well... The points were barely off maybe .018. Also I have an aftermarket tach I put on, which takes it's info off the neg side of the coil, and have noticed that when I am cruising the rpms drop all the way out. Meaning the coil is dropping out. When I am accelerating or decelerating the tach reads normally.
Hmmm the plot thickens. Makes no sense as Accelerator is mechanical and coil is electrical. ????WTF???
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65 800- Sold, to my step sons brother in law. She's up for a complete resto!!

75 Scout II-she was kool white with Woody decals, 345 auto. Towed by CHP never to be seen again

69 800A- D30 frt, D44 R, D20 trx, 304 v8, T19 trans, no discs, no ps, no power brakes, daily driver
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Old 02-18-2012, 08:02 PM   #5 (permalink)
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Default Re: scout 800 304 v8 missing badly

Try disconnecting the tach from the coil for a while and do a test drive. Might make some difference.
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Old 02-19-2012, 05:53 AM   #6 (permalink)
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Default Re: scout 800 304 v8 missing badly

Check the breaker plate for a solid ground to the distributor body and the point wire thet runs to the coil. the vacuum advance rotates the breaker plate while in cruise high vacuum conditions. The movement may cause a disconnect in one of the places I just recommended that you check.
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Old 02-19-2012, 06:28 PM   #7 (permalink)
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Default Re: scout 800 304 v8 missing badly

Put a pertronics kit in it and be done with it.
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Old 02-19-2012, 09:10 PM   #8 (permalink)
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Default Re: scout 800 304 v8 missing badly

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Originally Posted by FDChappie View Post
Put a pertronics kit in it and be done with it.
A pertronix kit will not "fix" the possible problems (described above) of a worn-out distributor.
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Old 02-20-2012, 09:42 AM   #9 (permalink)
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Default Re: scout 800 304 v8 missing badly

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A pertronix kit will not "fix" the possible problems (described above) of a worn-out distributor.
It would fix a breaker plate with a bad ground and is much more tolerant of worn bushings. The problem could also be a failing condenser which the pertronix would fix too.
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Old 02-20-2012, 10:59 AM   #10 (permalink)
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Default Re: scout 800 304 v8 missing badly

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Originally Posted by FDChappie View Post
It would fix a breaker plate with a bad ground and is much more tolerant of worn bushings. The problem could also be a failing condenser which the pertronix would fix too.
Could you explain how it could be a failing condenser? The symptoms don't add up
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Old 02-20-2012, 03:35 PM   #11 (permalink)
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Default Re: scout 800 304 v8 missing badly

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Could you explain how it could be a failing condenser? The symptoms don't add up
I've had 2 instances where vehicles would idle ok, but at RPM's would miss horribly, I'd guess the failing condenser would cause points to arc.
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Old 02-20-2012, 03:44 PM   #12 (permalink)
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Default Re: scout 800 304 v8 missing badly

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Originally Posted by Robert Kenney View Post
Could you explain how it could be a failing condenser? The symptoms don't add up
I've had 2 instances where vehicles would idle ok, but at RPM's would miss horribly, I'd guess the failing condenser would cause points to arc.
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Old 02-20-2012, 04:31 PM   #13 (permalink)
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Default Re: scout 800 304 v8 missing badly

The OP stated that there was no RPM correlation but rather a power setting correlation. EG just maintaining a fixed speed 55 as he stated it ran crappy yet under any state of acceleration it would be fine. Actually counter to an ignition defect like coil wires or a condenser.

It rather closely correlates to vacuum advance magnitude.

On the topic of throwing a Pertronix module at it, the problem and point of the OP asking the question I have to assume is the cheapest, simplest fix. $100.00 is not the cheapest or simplest. Diagnose the problem and fix it. That is what I shoot for.
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