318 Runs like crap

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Pulled the timing cover and the chain looks pretty damn good. In fact it looks like it has been replaced recently. I rotated crank and it seems to only have less than 1/8 of an inch play which is under the accepted minimum of 3/16.

What I did find interesting though is I had what I thought was at TDC, piston at top of cylinder, dist rotor facing forward towards No1 and the Cam sprocket had dot at the top of cam sprocket and the crank sprocket had dot at the top. So it wasnt Dot to Dot it was 180 degrees out.

I removed chain and started from scratch

SO I removed valve cover rotated engine so the piston was at the top of the cylinder with both the Inlet and Exhaust valves closed however it was impossible to line the chain sprockets Dot to Dot as the keyways wouldn't line up.

To get them lined up I would have to rotate the cam in turn moving the valves. What the F@&K am I missing here. Can someone give me a blow by blow instruction on how to install a chain.

Also please tell me if im wrong

1. TDC Compression stroke both valves closed
2. Combustion stroke piston travelling down bore after firing.
3. Exhaust Valve opens letting out spent gasses.
4. Intake valve opens letting in fuel
5. Repeats over and over again.

If I set chain up dot to dot after moving cam this is not the sequence I have.

I am probably the thick head but please someone clarify it for me.
 
Also please tell me if im wrong

1. TDC Compression stroke both valves closed
2. Combustion stroke piston travelling down bore after firing.
3. Exhaust Valve opens letting out spent gasses.
4. Intake valve opens letting in fuel
5. Repeats over and over again.

If I set chain up dot to dot after moving cam this is not the sequence I have.


Sorry left out valves closing in this sequence but you know what I mean.
 
Cam gear dot to crank gear dot is in the number six firing position, not number one, so it was timed up right. All the manuals tell you line the gears up dot to dot because it is easier than timing it up in the number one position, which is cam gear dot up and crank gear dot up. So, when you line the gears up dot to dot, you should point the distributor rotor to number six. If you point it to number one, you will be 180 out. You were timed right to begin with.
 
MY 318 Scamp was doing the same thing. Threw parts at it for days. No luck. Pulled distributor, grabbed shaft, bushing worn out. Wouldn't hold a dwell, replaced bushing, cost $4.25 ran perfect. The big problem IMO with old cars is that they are OLD and parts are worn and gas is crap. It is essential in todays enviroment to light the fire in the cylinder, to keep it lit for a long duration and burn the mix completely. Even M/P ignitions can't even come close to what modern ignitions can put out. MSD, Pertronix, Crane and others are far superior PROVIDED the battery is up to it
 
383Scampman said:
MY 318 Scamp was doing the same thing. Threw parts at it for days. No luck. Pulled distributor, grabbed shaft, bushing worn out. Wouldn't hold a dwell, replaced bushing, cost $4.25 ran perfect. The big problem IMO with old cars is that they are OLD and parts are worn and gas is crap. It is essential in todays enviroment to light the fire in the cylinder, to keep it lit for a long duration and burn the mix completely. Even M/P ignitions can't even come close to what modern ignitions can put out. MSD, Pertronix, Crane and others are far superior PROVIDED the battery is up to it
Click to expand...


No sideways play in dist shaft. Has a little play up and down but very very minimal.
 
moparspares said:
Pulled the timing cover and the chain looks pretty damn good. In fact it looks like it has been replaced recently. I rotated crank and it seems to only have less than 1/8 of an inch play which is under the accepted minimum of 3/16.

What I did find interesting though is I had what I thought was at TDC, piston at top of cylinder, dist rotor facing forward towards No1 and the Cam sprocket had dot at the top of cam sprocket and the crank sprocket had dot at the top. So it wasnt Dot to Dot it was 180 degrees out.

I removed chain and started from scratch

SO I removed valve cover rotated engine so the piston was at the top of the cylinder with both the Inlet and Exhaust valves closed however it was impossible to line the chain sprockets Dot to Dot as the keyways wouldn't line up.

To get them lined up I would have to rotate the cam in turn moving the valves. What the F@&K am I missing here. Can someone give me a blow by blow instruction on how to install a chain.

Also please tell me if im wrong

1. TDC Compression stroke both valves closed
2. Combustion stroke piston travelling down bore after firing.
3. Exhaust Valve opens letting out spent gasses.
4. Intake valve opens letting in fuel
5. Repeats over and over again.

If I set chain up dot to dot after moving cam this is not the sequence I have.

I am probably the thick head but please someone clarify it for me.
Click to expand...


If you would rotate the crankshaft 360° then the marks would line up. The cam turns at half the speed of the crank.
 
step 1 if your timing marks were lower crank at 12* and upper gear at 12* you were on #1 cylinder firing(when the marks are at 6* upper gear and 12* lower gear your on #6 firing, sounds like it was right to start (remember the camshaft turns 1/2 engine speed)
step 2- the intake/exhaust valves are closed almost twice on power (overlap) stroke and compression stroke this is a 4 stroke engine.so watch the intake valve close and when the piston comes back up this is the compression stroke . remember the lower crankshaft keyway should be at about 2* when # 1/6 are at top dead center .


if you have been running unleaded gas for a long time check the exhaust seats they could be bad (valves sunk) with your valve cover off remove rocker shaft place a straightedge across the top of the valve stems and see if any of them are higher .they should be all the same +/- a couple of thousands. if any are higher by .050/.100+
this could be your problem.
 
You might want to loosen the rockers off,, while twisting those shafts,, or you stand a chance of bending a valve..

Did the crank suddenly stop as you were turning it..?? hope not..

Put it back together,, hoping you haven't tagged a valve..

You didn't answer if the problem was always there, or if it occured after you messed with it.. ??
 
inertia said:
You might want to loosen the rockers off,, while twisting those shafts,, or you stand a chance of bending a valve..

Did the crank suddenly stop as you were turning it..?? hope not..

Put it back together,, hoping you haven't tagged a valve..

You didn't answer if the problem was always there, or if it occured after you messed with it.. ??
Click to expand...


Sorry no bought the car and it ran, enough to back it in and out of garage. I restored the rest of it and then tried to get it running better. So it has run really bad since I bought it.
 
inertia said:
You might want to loosen the rockers off,, while twisting those shafts,, or you stand a chance of bending a valve..

Did the crank suddenly stop as you were turning it..?? hope not..

Put it back together,, hoping you haven't tagged a valve..

You didn't answer if the problem was always there, or if it occured after you messed with it.. ??
Click to expand...


No I took the rockers off to spin the cam shaft.
 
moparspares said:
No I took the rockers off to spin the cam shaft.
Click to expand...

Well at this point you should put everything back on and attempt to start it, It's one thing to try different suggestions or buy new parts but you didn't have a well running car to start with.

Once it's back together and if you test start it and find nothing has changed then you will need to back track....

What you did know is it seemed to run fine up in the rpm range....
Based on that, and the fact that it is a simple yet hard to tune system.
I assume it's automatic transmission and you can start the car and let it idle in neutral...

From that info you know that the distributer was able to produce good spark under load, even though it was only up in the rpm range.

This says that the distributer is peeking and not going past it's max mechanical advance.

At this point I would look at 2 things,
1st is the carb settings?
1- air/fuel set screws for position and effect (usually not correct out of the box)
2- visually look at the spray of the jets and accelerator pump
3- inspect test all vacuum ports to and from the carb
2nd is the distributer?
1- check the shaft and electrical connections (as you did)
2- check for free movement in the mechanical advance
3- check for damage to the vacuum pot as well as it's type (adjustable hex head, or non-adjustable)

After you have come to this point and have all the information, post back.
As I said before this sounds like distributer or even a carb issue, which means it could be as simple as adjusting the vacuum advance pot or even lean/rich mixture screw issue.

Keep in mind the 318 is known to just keep going and going because of how tough it is, and internal damage you would be able hear at idle as well as through the rpm range so I would tend to believe that there is no serious internal damage and that this is just even wear based on what you have already said.

Good luck,
and remember your spark plugs can tell you a lot of information, like lean, rich, hot, cold, weak, oil leak-down, and more.
 
Let me update my situation, read above under Torrance00
I'm 60 yo been working on cars a long time, and I know I'm not an expert
and its harder to diagnose my own cars then other people..
So I stopped by and chatted with a friend, he has a very nice collection of
older cars, and he rebuilds flat heads, so we chatted and he got me back to
my roots.
I came home and while the engine was still running I reset the dist by ear,
then I set the carb, again by ear.. then I took it out for a short drive and
it still was not right, so a little more adjustment and now the car does not
ping or miss. One thing I did was to adjust the advance in the vacuum
dashpot...
the car idles better, no ping on excelleration, and no miss when hitting the
throttle. but it still needs work...
all the best on your situation
 
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I left this bad running 318 for a couple of weeks. Now I am back trying to fix it. Here is the things I have tried

New Plugs
New Dist Cap
New Rotor
New Leads
New Carter BBD Carb
Swapped Coil, Distributor.
Checked Timing Chain Slop - Within tolerance

One thing I have found is that if you take vacuum advance hose off and block the hole off in dist and carb the car runs a lot better. Still not right but a LOT LOT better. This is probably a clue to why it runs so rough. Is this a vacuum leak problem?.
 
check for heat riser rusted shut /the exhaust blocked on pass side. how long has the gas been in the tank.
 
So I had the same trouble.. beat me to death..
and here is how I solved the bad running 74 318
I just attached a vacuum gauge, then started to adjust the Dist
and the idle adjustment, back and forth, up and down...until she is running
so smoth. She is at about 8deg btdc, without vac. and around 28 when
vacuum applied. 20\21 inches of vacuum...
on last trip, city driving, did 14.5 mpg give or take...
before I kept trying to start with factory specs and go from there,
so went back to basics and let my ear do the timing...
best
Dave
 
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