no prizes but really???

hi All,

here is a wee tale as now its gone beyond my mechanical comprehesion ...

Stude Lark 1963 259V8 has Chev Delco distributor from a 61 Stude..

happily driving along around 55mph, when engine starts 'pulsing' as in brrrmmm brrrmmm brrrmmm...
eventualy comes to a stop on the side of the road...
swapped condensor and coil.. away again
5-6 miles later same deal this time still runniing . gapped cleaned points
7-8 miles later stopped for gas
annndddd 3-4 miles after that stopped again
so on like that for a few hours , a new fuel pump change and change back to old until early evening from a about 5pm to 10pm car ran fine - one small hiccup.
next day same as day before .. 3rd day no power up hills ,, low 2nd gear just to keep momentum where 3rd and brakes wouldve been normal - and now add a few minor backfires for good measure on the downhill.
found vacuum advance blown replaced with old spare ,, thought that was the problem and since decided that had blown as well but when that was replaced with new the 2nd one was found to be fine
checked spark wires , refitted a couple of faulty ends resistance ok although up there - these are less than 5000miles old
plugs : 2 have high resistance - also less than 5000miles old - but seemed to have good fuel burn color and good gap ..


my wits have ended at this point
will do plugs and probably leads

am i missing anything else other than a good portion of my marbles collection ??

TIA

I`d check bowls for crap / moisture.

dutch said:

I`d check bowls for crap / moisture.

Click to expand...

done .. fuel bowls cleans as a whistle

Gas cap? Recently bought a pickup that would chug after driving awhile. Locking gas cap wasn't vented. Have seen this before. A very small hole drilled in the cap will fix.

earthman said:

Gas cap? Recently bought a pickup that would chug after driving awhile. Locking gas cap wasn't vented. Have seen this before. A very small hole drilled in the cap will fix.

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nope got an oem locking gas cap a while back ,, tank has a 1/4 breather pipe

Make sure the wire from the coil to the points isn't frayed where it goes through the distributer body and intermittently grounding out against the distributer body. Eliminate the vacuum line to the vacuum advance and plug it at its source. All it does is add advance at part throttle for slightly better gas mileage. That will take it out of the list of potential causes.

funny thing about all this is the car had travelled some 600 miles over the previous 4 days ..

just started the cyclic run / not run, after an 1hr or so driving . what does puzzle me was from 5 pm to 10pm when the night air was cooler the car ran perfect except for 1 hiccup length moment.. going up a long hill the temp gauge was way down cool so put it down to that thinking fuel pump swap had maybe cleared the problem

will recheck that wire thanks Bob

i had just fitted new fuel hose (continental brand) only a few days before , and the hose at fuel tank etc are all ok.

Sounds like your new hose may be delaminating and slowly blocking flow. May just be a flap of the inside lining that got shoved back when you stuck the hose on the nipple,mand is now restricting flow.

What a fun trip can’t wait to see what you find

sounds temperature related, a weak coil or a shorted out condenser.

ok stripped the carb down and found this.... thats a surprise i thought !! careffully straightened and smoothed the ever so small burr on the end ..

fitted new accerator pump, blew out all the galleries i could find, and issued new gaskets
the only thing i didnt like is one linkage on the accerator side floats partially goverened by the choke butterfly seemed to lock in place not allowing the secondaries to open fully (edelbrock 1403) and current linkage assy doesnt allow full opening anyway ..

after checking resistance on all leads and plugs, will buy new of these and fit as some were equal or slightly higher that max recommended. then i can set idle -- re plugs leads etc,, i had really thought they wouldnt be the issue due to their young age ( way less than 5000 miles ) must be budget copies of once well made stuff....

i had thought over the last few months the car seemed a bit slower overall thinking a trip away will give a good clean out ...

todays test drive saw a vast improvement and infact scared myself a little when a corner arrived far quicker than i had expected ... some forcefully gentle but "ooohhhh my thats really close" braking saved me - you may like to insert more colorful words ..

stay tuned for more on the errant Stude

sigh it may turn out to be a good weekend after all ...

I've had two different things that showed the same symptoms as you have. One; a bad coil will heat up and cut power badly, and then whatever you fix or change, [even circling your car a few times cursing] will let the coil cool down and away you go for a while again. Two; the little wire from the coil to the distributor can start breaking the little copper wires inside the plastic coating until there are only a couple left. Those last few strands keep getting hot and shutting you down, but they cool down quickly and away you go again for a while. Food for thought, if you haven't solved it yet. Good luck.

MercuryMac said:

I've had two different things that showed the same symptoms as you have. One; a bad coil will heat up and cut power badly, and then whatever you fix or change, [even circling your car a few times cursing] will let the coil cool down and away you go for a while again. Two; the little wire from the coil to the distributor can start breaking the little copper wires inside the plastic coating until there are only a couple left. Those last few strands keep getting hot and shutting you down, but they cool down quickly and away you go again for a while. Food for thought, if you haven't solved it yet. Good luck.

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tHanks Mac,

coils .. im up to my 3rd coil thats a left over from an isuzu p'up i sold a few years back ,, added a resistor and checked seemed pretty good.

think i may spend bigger bucks and stop buying cheap rubbish..

before my trip i bought a "gauss" brand (made in china) and fitted - im not convinced its a good buy, or the previous one which from memory got so hot the decal melted off it... (same brand) Im thinking ive been walking similar circles ....

i still havent checked the coil / dist wire yet but will do over the next week when i next get under the hood...

keep you posted...

sigh.....
have replaced all spark wires with new copper wire versions , new spark plugs all checked for resistance before fitting ... yet still misfires and backfires under load or around 50mph - good speed under that

multiple coils have been tried - all have yeilded no result - same as others after 3-4 think coils can be ruled out ?!

wont idle by itself but noticeable power increase ..

frustratingly close ....
next will be sucking on the vacuum advance hose to see if the points plate shifts

if not will blast some brake clean down the small oil tube under the dizzy and refill with machine oil

seems odd to me that this has just started while cruising ast 50mph

this weeks happy update concludes

think splitting wood is next

I get my best bad idea`s when splitting wood...

I've had distributor advance plates short out and cause this problem.
Are you running points or Hei distributor?
If points, set them to .017 and make sure you have a ballast resistor to drop the coil voltage to around 8 volts.

That's why I suggested eliminating the vacuum advance for the time being. Vacuum advance as OI states, rotates the breaker plate, mechanical advance rotates the distributor cam. You don't need vacuum advance. It gains you a couple miles per gallon at light load, part throttle cruising speeds.

Old Iron said:

I've had distributor advance plates short out and cause this problem.
Are you running points or Hei distributor?
If points, set them to .017 and make sure you have a ballast resistor to drop the coil voltage to around 8 volts.

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thanks OI
is points distributor set to .016 coil includes ballast resistor dwell is 32*

bob w said:

That's why I suggested eliminating the vacuum advance for the time being. Vacuum advance as OI states, rotates the breaker plate, mechanical advance rotates the distributor cam. You don't need vacuum advance. It gains you a couple miles per gallon at light load, part throttle cruising speeds.

Click to expand...

Bob, the dizzy is at the back of the block ,1" away from the firewall.. I thinking of pulling it to get some sunshine into it to see clearly .. clean it out thoroughly and make sure its not worn beyond pratical use which is fairly generous..

i can advance the timing a couple of degress, to offset the missing vacuum .. keen to know more as i thought vacuum advance played a larger role . also i want to change spring weights - mech advance. replace the earth wire and fit a grommet to the bottom of the housing

i want to check vac advance plate is free moving and suck the vac advance pot directly to see if i came move the vac plate, checking for any scarring from an unknown shorts ..