car =1972 plymouth valiant
225 slant 6 - holley 1920 / points distributer.
back story:
was running verry nice.
began doing a little ping or miss fire type thing out the exaust pipe every once in a while. more so after the car had warmed up to full temp.
drove down the road great with power and good gas pedal response and +45 mph drivability
at a stop light however at engine idle - the ping or miss would be audable from the exaust pipe - and you could feel a stutter in in the engine thru the car when it happened.

yesterday ....
on the return home trip from a car show 25 miles north of me
the closer I got to home - the worse the car was running.
oil preasure droped to 27 at a stop light at 800 or so rpm and went back up to the 40s driving down the road - engine temp stayed at 190/195 range the whole time. I have guages setup and watch them.
above 1500 rpm going down the road the engine seemed ok
but sitting at a stop light idle or in neutral at a stop light - the car would ping and miss and stutter alot. like probly once per second or more.
arival at my garage I noticed running the car inside with the door open had exaust fumes that made my eyes water and choke me out.
car ran in the garage with the door open for less than 2 minutes while I checked under the hood. - to look for any noticable catastrophy.
today -
I changed the oil. it was dirty but there was no sign of coolant in there at all and seemed like it was just oil.- but it was not alot of miles on it at all.
probly less than a hundred miles on it actually. I think it was 15/50
and I put in some 10/30 tonight with a new filter.
got the car started up - it ran like crap
threw on the timing light - and with the cold idle at about 1100 rpm I could only guess at the timing mark looking like it was about 25 to 30 before top dead center.
I realley need to find a way to mark spots on my pulley like a timing tape would be at... so I can know total advance at 2500 rpm - and also get a better idea of the advance curve thruought the rpm range - as right now I have spots marked for +10 and 0 and -10

anyhow. valve cover taken off.
timing dialed closer to top dead center - car would not start.
put the timing back where it was .. car started and ran rough
all valves were functioning - no bent push rods. everything visualy was looking ok with the valve train.
but the amount of white smoke rising up thru the engine block was amazing. I wish I could take a picture of it to show you guys.
actually ill try that in a few minutes.

blown rings ?
horrible valve seats ?
super wasted valve seales ?
burned points on the distributer ?
terrible carburator settings ?

tomorrows agenda :
get compression tester from autoparts store.
how to test = all plugs out. tester threaded in.
spin engine over with key about 6 to 8 revolutions on each hole.
mark down each cylinders findings ?
whats acceptable for findings on a compression test ?
and how do I determine if its rings or valves ?

pull out the distributer.
check and re set the points and dwell.
what do I set the dwell to with my fealer guage set ?

idealy what should I try to set the timing to and at what rpm do I set it to like that ? im thinking my distributer needs a recurve maby as it has not been messed with in a long time. I know there is a thread about that here I can find.

and the last thing I was thinking that could be causing such horrible running conditions for me here would be a severly stretched out timing chain. or a timing chain that has jumped a tooth.
is it possible for the timing chain to jump a tooth on a slant 6 ? or would it just break the plastic gears and stop functioning all together ?

to check for timing chain slack = turning the engine back and fourth by hand and checking the rotor on the distributer to see for any delay on its spin reaction time ? is there a more percise way about this ?

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1972 Plymouth Valiant / slant 6 auto

the more I think about this and tinker with the car in the garage im thinking I need to definately replace my timing chain. I have no idea how old it is - and I cant get the car to fire off and run unless the timing is extremely too far advanced. the engine is severly hard to crank over now as I feel like the valve train is definately not in correct time with the crank shaft.


pixtures try to capture white smoke escaping thru the engine block but I could only get it to fire up for a few seconds before it stalled out.
also shows the condition of the valve train.




the plugs that came out of the car as it was running horribe on the way from the car show.

note the red / orange ish condition on the white porclin below the electrode. all plugs seem to be firing - carbon deposits at the base.
plugs were cleaned about 50 miles of use to end up looking like this.





I guess a compression test will show me what the deal is tomorrow.

but im still up in the air about how to check for a skipped tooth on the timing chain - and how to check it for stretch with out actually taking apart the front end of the motor to visualy check it.
to do that
I will need a new gasket set for shure I believe.

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1972 Plymouth Valiant / slant 6 auto

I think all you need is to re-set the points. As they wear they change the timing a lot. You need to set points with a dwell meter. Have you set points before?

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50 chrysler,54 Plymouth, 64 Valiant conv 4 speed, 66 Valiant V8 wagon, 70 Challenger R/T 440+6 conv 4 speed,80 Colt, 98 Neon ACR,84 Honda V45 Magna
Taking care of 57 300C conv,48 T&C conv. Missing my 67 GTX and 36 Ply coupe

Let us know how the compression test comes out. Looks pretty cooked under the valve cover. The rings may be in the same shape.

Some thoughts......
Points do burn and change timing.....Try checking the timing at 600 rpm. That will take the vacuum advance out of the equation. At 1000 rpm or more it will be kicking in and throwing off your timing.

I notice you have power brakes. The vacuum fitting on the booster can fail creating a heck of a vacuum leak making the engine run rough.

Good pictures!

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Intial timing should be around 10° BTDC, vacuum advance disconnected.
New points and condensor would be a good idea. A good round figure for point gap would be 18 thousandths. I've used a matchbook cover. Dwell should be around 40-45°.
Have you adjusted your valves? The miss is a classic indicator of tight valve lash.

Keep in mind that a dirty engine may have stuck rings. All the guck on your rockers has me wondering about that. The same stuff can build up in ring lands and keep the rings from moving properly. Add a quart of ATF to the engine oil being careful not to overfill the crank case. Run the car around for a few hours, then change the oil and filter again. Don't run hard with it in there. The ATF has detergent properties that will free up a lot of goo. Most of us like WIX filters. NAPA sells WIX. For cleaning up a dirty engine, you will want to change the oil much more frequently than a normal cycle. Perhaps 500 or 1000 miles while using a quart of ATF at each change substituted for one of the quarts of oil. There are products out there designed to do this also. Up to you as to what you use. If you use something like Rislone, follow the directions on the container.

Various fuel additives will result in strange colorations of the plugs. I wouldn't be concerned about that as much as excessive blow-by. The plugs didn't look oil fouled to me though.
Is the engine using oil? Has it spent a lot of time sitting?

Is your PCV system in good shape? Replace the PCV, it's cheap and will contribute to keeping the oil and inside of the engine clean. It allows air to sweep the crank case, and maintain a lower crank case pressure. The lower pressure contributes to good ring sealing.

Test the timing set by removing the cap from the distributor. Rotate the Engine in one direction, then in the other while you still have the plugs out. If there is noticeable lag before the rotor turns when you change rotation direction, that is a good indicator that the set is worn out.

Looking forward to seeing what your compression check numbers look like. When spinning the engine over for each hole, the throttle plate should be wide open. If not, the pumping action of the engine won't be getting enough air for a good reading.
If the readings are low, add a small amount of oil to a cylinder that is reading low. Just a dab will do. If the reading increases it points to rings. Blow-by doesn't make me think of valve problems.

Get yourself a manual for your car.
Best is a Factory Service Manual. I've found them in used book stores and at swap meets for reasonable prices. Check your local library. They turn up there also.
In a pinch aftermarket motors manuals will do for some basic information. Just check in here before trying to use the removal procedures and so forth.



CJ

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Part of Tyrde-Browne Racing

I had a quart of rislone in the last engine oil 15/50 to try and help "free up" some stuck rings if that indeed was the problem.

and yes the valve train has alot of gunk on it. it has me worried.
also the fact that I can not get the engine to run for more than 45 seconds when I do get it to start also has me worried.

tomorrow will hopefully yeild me some good information.
as of right now - I cant get the engine to crank over sometimes.
like its compression loaded - so when I turn the key to crank - it just acts like its increadibly difficult to spin the motor.

valve ajustment was done less than 300 miles ago - and to error on the side of safety - I used a larger feeler gap on both intake and exaust valves just incase. I set them using the "hot lash" method of engine running and at operating tempature - and laughed the entire time trying to keep my swivel socket on the ajustment nut for each rocker. haha.

I expect to find a timing chain that has jumped a tooth
or has exessive slack in it. my mind can see no other way the engine is struggling to spin over so much unless the valves are totaly not opening and closing at the correct times.

up until right now the engine would crank over verry easily and start up nicely. but now its struggling to spin when I turn the key.

I have a second battery in my garage hooked up with jumper cables to the underhood battery to aid in the starting of the car - and sometimes it still acts like its hydro locked or something to that effect. - both batterys are fully charged - and should be capable of doing alot of cranking before going dead... so cranking voltage is not an issue.
also the starter motor is recently replaced about 3 months ago.

hopefully I can also identify true top dead center on the #1 piston by turning the crank pulley up front by hand with all the plugs out - and poke in to a spark plug hole maby with something to varify true top dead center on that piston to make shure my timing mark on the pulley is actually correct - wich I have a feeling that it is not

about the points - I have replaced them about 300 miles ago with new ones from company Malory - but I did not replace the little circle resistor with them. a buddy tells me that burned up points will have actual burn spots on them - and a failed resistor can lead to burned points - as well as having the gap they open up to ( that is the dwell correct ? ) if the gap is too small some electricity can still ark across it.
I believe Im going to have to pull my distributer also to check it for any damage - or broken parts / springs and to check the movment of the mechanical advance and weights and to inspect the condition of the drive gear. I have a bone yard distributer complete to take parts from if I should need anything.

I will dig around to try and find a Factory service manual - but in the mean time - would a chiltons manual for my car help at all ?

I will report back with my findings.

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1972 Plymouth Valiant / slant 6 auto

Only to stand on to reach someting on the top shelf.
Not worth the paper they are written on compared to the real thing.

regards,Rod

You could empty the content of the fuel bowl in the carburetor into a glass and let it rest for a time, and then check for water/dirt in the fuel. Water in the fuel creates your kind of problems, but usually leaves a different looking deposit on the plugs.
Not very relevant, but the only time I saw a deposit colored like that on the plugs, was when a jerk put a packet of cigarettes in a motorcycle fuel tank. It left a gooey brown residue in the carbs.

Olaf.

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Aspenized

Just got done checking the compresion on my slant.

zip tied the carb wide open - and opend the choke.
took out all 6 spark plugs
cranked the engine about 7 or 8 revolutions for each cylinder measured.
results:
cylinder #1 = 150 psi
cylinder #2 = 135 psi
cylinder #3 = 148 psi
cylinder #4 = 153 psi
cylinder #5 = 156 psi
cylinder #6 = 157 psi

engine was cold / but not like cold cold - I live in south FL. and id guess that the temp in my garage is around 70 deg. or better
I did not attempt to run the engine at all before doing a compression test - and I DID NOT put any oil down the spark plug holes.

is it me or does my readings seem high ? - I would of thought id be getting anywhere around the 120s on a cold engine - that has been sitting all night before being cranked over. ?

now Im back off to the garage to pull the dist. cap and check the points and advance workings of the dist. - along with to attempt to try and check for timing chain slack by turning the engine back and fourth by hand while watching or holding the rotor on the dist.

also I will try and grab a glass full of gasoline that I have in the car.
the car did run down lower in the tank level than I usualy let it go before re fueling up the car. and I got about 7 gallons of 89 octane gas from chevron on the cars last trip out / home from the car show.
before re fueling up at chevron - the car was running pretty ok.
after picking up that gas - on the way home was when the problem started and just got worse and worse.

might be a good idea to grab some 5 gallon gas containers and drain my tank ? seems like a hassle tho. lol.
id rather not if I dont have to.


maby a better quick test to determine would be :
fill up a red plastic 1 gallon gas container I have at my local shell with 89 and dis conect my fuel pump hose from the tank line - and cap it - and run a new test line in to the bottom of the red plastic fuel tank - and hook that in to the fuel pump feed.

then I would just have to replace my in line fuel filter - and dump the carb of its current fuel - to be running on known clean fresh gas.
?

I gota get this figured out tho. I have 6 months left of a garage to keep this car in while im fixing it up to be daily driver status.

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1972 Plymouth Valiant / slant 6 auto

The Holley 1920 carb. may have developed a problem.
Do you have a dfferent carb you can try?
DD

Maybe you got some water in the last fill up-was the station in a swampy area?

_________________
50 chrysler,54 Plymouth, 64 Valiant conv 4 speed, 66 Valiant V8 wagon, 70 Challenger R/T 440+6 conv 4 speed,80 Colt, 98 Neon ACR,84 Honda V45 Magna
Taking care of 57 300C conv,48 T&C conv. Missing my 67 GTX and 36 Ply coupe

Ran rough, stunk, and wont start worth a crap after a fill up? That sounds like water in the gas to me. This is just a possibility to be explored.

Not so common these days, but in Maine thirty years ago, water in under ground fuel tanks was common. If one filled their car’s tank, just as a filling station was receiving or shortly after a load of fuel was delivered, your car got a drink of H2O. Sometimes fuel drier took care of it, and other times the tank & fuel system had to be drained.

Bill

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

dang.
what do you do with 7 gallons of gas that has water in it ?



after taking out my distributer - I found my points to be badly set and burned up. apparently the new malory points I had installed were in my spare distributer to put in the car that I never did yet.
doh !

so spare dist. is set up - vaccume can functions
points set to 18 thousanths.
and I believe my initial timing is somewhere in the 0 to 20 deg. before top dead center mark should be enough to start the car I believe.
im cleaning spark plugs as we speak - and re doing the spark plug wires so they are not routed so messy

and then its on to the carb.
yes I do have a complete spare holley 1920 carb to try and toss on this engine. I bought it from fourm member "thor" as he said it was functioning 100% on his slant before he pulled it to sell to me.
the choke step plate that interacts with the screw ajustment to set choke idle is currently mis aligned - but I bet I can figure that out easily.

if I can get the engine to fire up - I will keep looking for this mysterious white smoke that was billowing out of the breather and try to take a picture of it for you guys if I can.

also a side note -
before I pulled the dist. out - I was cranking the engine back and fourth by hand with my socket wrench on the front pulley = and looking for a delay in the dist. rotor shaft to spin with the diffrent engine movment directions. I noticed a verry slight delay going back and fourth - but not verry much. I do believe down the road a bit I should replace the timing chain - but I do not believe it has become out of spec with exessive slack - or I also do not believe it has jumped a tooth.

all valve train is still looking like its operating correctly - and the valve ajustment seems to be where I set it a couple months ago. - despite the valve train being verry dirty

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1972 Plymouth Valiant / slant 6 auto

engine fired right up.
ran better than ever.

the points were probably the biggest problem - along with the timing that had magicly changed from where I set it before.

all and all - the car runs nice now.
the timing is currently set at 600 rpm at around 12 to 14 deg. btdc.
engine idle speed in park - is currently set at 950 to 1050 rpm
and when the engine in gear with foot on breaks - rpm drops down to about 650 rpm - but runs steadily nice at this rpm.

when I back off the curb idle screw to drop engine rpm down to around 850 in park - when I put the car in drive and hold the breaks - engine rpm sinks down to around 550 rpm and im much more afraid of the engine stalling out like that.

also intresting observation. at 850 rpm my voltage guage is reading in the 13.3 range - and at 1200 rpm my voltage guage pegs 14.5 and stays there on up thru the rpm range - in my car I use alot of stereo equipment - and I would like to keep voltage high at idle so im thinking I should look around for a slightly smaller drive pulley for my alternator correct ?


anyhow - im verry happy to have the car running nicely again.
it seems like the more I work on it - the more I learn and know about the slant 6 engine and engine systems of the car. hopefully one day I will have "old salty dog" knoledge about every aspect of my slant 6 - but until I get there - I thank everyone on this fourm for helping me out.

should I be worried about my #2 cylinder only reading 135 psi and the rest up around 150s ? or is there still plenty enough compression in the #2 cylinder for it to fire and function correctly for the next spell of time.

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1972 Plymouth Valiant / slant 6 auto

Glad your up and running again!

Maybe your valve lash is just a little off on #2. Where as the other cylinders are right on....

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG