Runs good then bad

V4F

V4F

Well-known member
i have a 1931 ford . 4 cylinder , downdraft (81) , hc head , cam . it will run great , then just go to crap . cant come up with a common problem . changed coil , plugs , timing , carb , points , cond , rotor body , cap , wire . this has been going on for a couple of yrs now . cleaned fuel , filter , carb , etc .
any ideas greatly appreciated . im sure i have left out info , so please ask . i do use a timing lite .......... thanks ....

kzsteve@yahoo.com
 
When does it go to crap? Is it when it gets hot?
I've seen an engine loose compression very bad as it got hot. It was only a 1 cylinder engine though.

You didn't mention what crap means, runs rough? no power?
 
Steve, please give us more details when you say "just go to crap". It might help if we knew exactly how it's acting. How long does it run great before it starts acting up?
 
i knew i wouldnt get all the info the first time .
1) it runs like 2 cyl are not workin so good . it backfires out the exhaust . it does this sitting in my garage (flat ground) . it ran good at one time for quit awhile . its like it has its "time of month" . itll miss so bad i cant get around the block . not hot , more trouble with being cold . fuel pressure is 3# to the carb .
ive been having some trouble since i put the 97 on , now the 81 . with a winfield "BB": it ran like a rabbitt . rich at low speed with the 97 . havent got a good run on the 81 . it seems to likes to be chased . new coil (12v) , poiunts , cond , etc . timing is dead on with my lite . i think im to close to the forest to see the trees ............
thanks all & ill get er done , hopefully ...............

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the 81 is stock !
 
Isn't there something about you having to use a resistor when running a 12V system with a coil? I thought even 12volt cars from the 50s and 60s had a resistor which was temporarily bypassed during starting and if you did not use the resistor it would burn points and or cook the coil.
 
yes i had one , but bought a new "resistor" coil that doesnt need on ...... good ideas .................. thanks
 
MrTube said:
Isn't there something about you having to use a resistor when running a 12V system with a coil? I thought even 12volt cars from the 50s and 60s had a resistor which was temporarily bypassed during starting and if you did not use the resistor it would burn points and or cook the coil.
Click to expand...


It is not necessary to use a resistor if you use an internally resisted coil.
 
they make an internal resisted coil, it says internally resisted on the out side of the case, take an induction timing lite with you on your next run, when it starts crapping out put the induction lead on all the wires to see if all are firing the plug, at least you will know if its electrical or not, put it on the coil wire to to check if the coil is firing every time
 
steve norcal said:
ive been having some trouble since i put the 97 on , now the 81 . with a winfield "BB": it ran like a rabbitt . rich at low speed with the 97 . havent got a good run on the 81 .
Click to expand...

Steve,
Why not use the Winfield? At least, if you still can, put the Winfield back on and see if the car will run like it did originally. That way you will be able to isolate your problem. My first thought is carburation since it ran good until you went to the 97 and then even worse with the 81.
 
had to sell the winfield . should have gone weber , but thats hindsite . found a possible intake leak . thats where im at now , replacing the gaskets . will let you know . great help , thank you ....
 
If you do a compression test cold and then when running its like 'crap ' , I'd be interested in knowing if there is any difference.. It seems like you've looked at about everything, how about the valve lash ?? When this thing heats up and stretches I'm wondering if you're losing clearance. I'd also check to see that your coil is connected correctly and that you're only getting 6-8 volts to the points..
 
Patrick L. said:
If you do a compression test cold and then when running its like 'crap ' , I'd be interested in knowing if there is any difference.. It seems like you've looked at about everything, how about the valve lash ?? When this thing heats up and stretches I'm wondering if you're losing clearance. I'd also check to see that your coil is connected correctly and that you're only getting 6-8 volts to the points..
Click to expand...


You will not see 6-8 volts at the points. With them open there will be no load on the coil to see a voltage drop from the resistor so you will see 12 volts. With them closed you better see zero.
 
Wow! The intake manifold may have a heat riser tube burnt thru, if it has one, letting exhaust into intake. Not familiar with that manifold. Try original manifold if you have it. Does the coil get hot to the touch?
Richard in Florida
 
aluminum intake (new) . found another intake leak , but just fixed it (i hope) .

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NEXT PROBLEM .... HOOD BRACKET .......
how do you remove the rearhood (top of firewall) bracket ??? .. thanks
 
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