Missing, shaking

[Viperpete 39]

The engine in my car shakes too much. Its a 302 with a 2bbl. New plugs, cap, rotor, coil, electronic ignition. I bought a timing light for the car but there are no visible marks on the crank pulley for me to time it properly. I can rotate the dizzy clockwise and the idle seems better, than if I rotate it counter clockwise. I detect a misfire at idle as well. I am new to carburetors. That might be the culprit. It has no choke- or it doesn't work at least. I can speed up the idle or slow it down with that screw on the back side. I have tried to seek a balance between cold starting idle, and hot idle in the middle of traffic. I find myself putting the car in neutral at lights because I have to press the brake pedal too hard to keep it from lurching forward. I would guess that the idle is around 1000-1100. I have no tach and no means to tell engine speed.

I have zero working gauges. The car takes a while to start up if I haven't started it in a few days. I usually have to crank it for 2-3 seconds around 4-5 times. After I drive it though it starts up immediately. Even the very next day.

Thanks for anyone's input.

 

 

[barnett468 418]

1. was it missing before you changed the parts?

2. did you verify that the plug wires are in the correct firing order?

3. make sure you do not have a vacuum leak somewhere like a power brake hose or the pcv hose.

4. remove the pcv valve while the car is idling and put your thumb over the end of it. if the rpm is significantly lower than it is when the valve is plugged in, there is an issue with that at the very least.

 

There are 2 different firing orders for these engines depending upon what cam is in them.

1-5-4-2-6-3-7-8 and 1-3-7-2-6-5-4-8

[Viperpete 39]

It seemed to vibrate before I swapped the ignition stuff. I don't remember which way the firing order was. I can try checking to see where it's at now and then changing the firing order to the other way. Have no power brakes. There is only vacuum going to the transmission and to the dizzy i think. Where is the PCV valve?

[fvike 173]

Also, check that your motor mounts isn't shot. If they're the originals, that rubber is 50 years old now.

[Viperpete 39]

14 minutes ago, fvike said:

Also, check that your motor mounts isn't shot. If they're the originals, that rubber is 50 years old now.

Wouldn't surprise me.

[RPM 1,271]

The PCV should be at the rear top surface of the right valve cover.

[barnett468 418]

...and there is a hose that runs from it to the carburetor or the aluminum carb spacer if you have one.  Sometimes the hoses don't fit the fittings very tight and can even split on the ends both of which can cause a significant air leak. When I am searching for an air leak I usually remove the hose from the carb and put a cap on the fitting to make sure it isn't leaking while I check other areas.

[barnett468 418]

5 hours ago, Viperpete said:

It seemed to vibrate before I swapped the ignition stuff.

Another thing that can cause a fairly large vibration is having the wrong damper and/or flywheel on the engine. I have run across this problem a few times , however, this would have nothing to do with the engine running improperly etc.

 

[fvike 173]

On 8/6/2018 at 3:20 AM, barnett468 said:

Another thing that can cause a fairly large vibration is having the wrong damper and/or flywheel on the engine. I have run across this problem a few times , however, this would have nothing to do with the engine running improperly etc.

 

Again, the 50 year old rubber. If it is the original damper, the rubber bonding in it could be weak, and the timing marks could move around a bit depending on the rpm. OP says there are no visible timing marks, so I guess it's set by ear anyways. So timing wise it would make no difference. But if the rubber in the damper is bad and it does move around, crank balancing would be affected I guess.

Of course, all this is hypothetical until @Viperpete chimes in with info. Pictures would be great. It will be difficult  to get the engine running smooth without any working gauges. Temperature will tell alot.

One more thing; what kind of electric ignition did you put in? Did you gap the plugs to take advantage of a stronger spark?

Also, for carburetor tuning, a vacuum gauge is a great tool.

https://www.onallcylinders.com/2016/03/31/vac-visual-quick-guide-vacuum-gauge-readings/

[Viperpete 39]

I installed the Pertronix unit from NPD. Gapped the plugs. I think 0.034 or something if memory serves.

Here is a video of the car. You can see how it is hard to get it started. Once its running for a few minutes the throttle response is good and driving the car is just fine other than the shaking. I really need to just throw it on the lift and check the motor mounts and also the dampner.

 

[Viperpete 39]

The electronic ignition, plugs, wires, cap, and rotor made zero difference in the shaking by the way. And, the stuff I removed was really really shitty. Like the plugs were only threaded in 1/2 way shitty. Car still started up and ran....

[Viperpete 39]

Also, it would appear that the damper and crank pulley seem to wobble a little bit. That is probably related. They don't wobble a ton though. Sometimes at a light the engine makes the entire car shake like it has a big cam.

[barnett468 418]

How long have you had the car?

Has it vibrated since you first got it?

Do you know what cam is in the engine? It certainly does not sound like a stock cam in the video.

[barnett468 418]

How long have you had the car?

Has it vibrated since you first got it?

Do you know what cam is in the engine? It certainly does not sound like a stock cam in the video.

[Viperpete 39]

I got the car from ebay. It was literally thrown together to sell. Almost every bolt i have touched was loose. Leaked everywhere. Rear end SLAMMED into reverse or drive. Previous owner spray painted OVER decades of grease and grime on the oil pan and transmission...everywhere really.... it was not a well cared for car. These are pics to illustrate its condition before I bought it.....I only found these pics by doing some detective work after i bought the car.... I do not know what cam is in the engine. I know nothing. I have replaced the ignition, rebuilt the C4, swapped in a new 8" rear end and completely rewired the car.

[Viperpete 39]

I got the car in January. A friend and I drove from Ocala FL to Lowell MA and back in 3 days. I should have re-negotiated the deal when I got there but I didn';t want to harm my ebay status in anyway so I just paid for it. Even though the car has issues, I still paid thousands less than cars on the market right now- in worse condition. It is edgy and all that, but it still moved under its own power. Vibrated since day 1.

[barnett468 418]

There are timing marks on the damper

 Sand it with 150 sand paper until you find them. You may have to sand the whole thing. They are also often fairly faint.

Once you find them put a mark on the long line next to the letters TDC.

Next put a dot on the 6 degree line and 2 dots on the 12 degree line. 

Next put a mark on the very tip of the pointer that is on the block.

You can use liquid white out or white paint for this.

Disconnect all plug wires from the cap except for number 1 cylinder.

Connect timing light then have someone turn the engine over while you check the timing.

If the marks on the damper are not visible, you can put a small piece of masking tape on the damper then look for it when you check the timing. Move the tape around until it lines up with the timing mark on the engine then put a line on the damper there then remove the tape. Recheck the timing to make sure this line lines up very closely with the pointer. This will give you marks that line up for a starting reference point.

Next put a dot 1/4" to 5/16" to the right of the new line. 

Start the engine and tell us where these new marks on the damper are in relation to the pointer. They will likely be to the left of the pointer looking at the damper from in front of the car.

If the timing marks are different at idle, remove the vacuum line from the vacuum can on the front of the distributor then recheck the timing and tell us if it changed and where the timing marks are with the hose disconnected.

Leave this vacuum hose disconnected and put a screw in the end of it to prevent it from being open to atmosphere.

 

 

 

[Viperpete 39]

FYI this is how it looked when I got it home... He did make it presentable at least.

[1969_Mach1 335]

Am I seeing things correct in that video.  Hopefully somebody else can look closely at it.  The choke doesn't work.  How can it work, there are is no heat source for it.  So it is adjusted to be fully open (off) at all times.  The vacuum lines don't look to routed correctly.  One vacuum line is connected to the vent on the carb that I believe was originally for the hot air tube to the choke.  I might be wrong, but I think you are chasing a few small things that are not correct and all contributing to the running issue.

If the vacuum lines are not routed correctly the motor likely has vacuum leaks.  As much as the throttle is pumped to get an initial fire-up the carb might need rebuilding.  The accelerator pump in the carb might not be working correctly, hence, the need to pump the throttle so much for an initial fire-up.

I would first make certain the vacuum lines are correctly routed.  Without the hot air tubes the choke might have to stay adjusted fully open.  Replace that dual diaphragm vacuum advance with a single diaphragm style and simply connect the vacuum advance to a timed vacuum port on the carb.  That is a port that doesn't have any vacuum at idle.  Don't bother connecting that thermal vacuum switch on the thermostat housing.  make certain the initial ignition timing is set correct, probably 10 to 12 deg BTDC is a good starting point.  If you want optimal ignition timing, Barnett always has sure fire methods to optimize it.  Then rebuild the carb if it doesn't run much better.  At least these are all inexpensive things to do.

Sometimes we tend to look for one source of the issue.  Here's an expression that was preached to me when I use to work as a mechanic,  "if you don't quickly know what is wrong, start checking to make certain everything is correct."  Usually in that process you'll find the cause(s) of the problem.

[barnett468 418]

Mach 1 thanks for the vote of confidence and your advice is hood but i prefer that he does not  move vacuum lines just yet as it may mess up what i am trying to achieve. My friggen computer died this morning so i am posting this from my cell phone which is a pita to do. Hopefully later today i will have my computer working again so i can explain more but i have to leave now for a few hours.

[1969_Mach1 335]

Okay.  If you haven't already, when you can look at the video.  I think there are a several small things that are not right.

[barnett468 418]

The hard starting after it sits could be from no fuel going into the engine.

Look into the top of the carburetor with the choke open.

Open the throttle slowly just 1/8th of the way. There should be two small streams of gas squirting into the venturis.

Next, open the throttle around 1/2 way fairly quickly and look for gas squirting.

Tell us if the gas squirts fairly strongly under both conditions or just barely trickles out. Do this after it has sat for a few days also. If there is gas squirting out after you drive it but not after it sits for a few days, it is hard to start because there is no gas getting to the engine, in which case we need to try and find out why but it could simply be that the gas in the carb is evaporating after a few days and the fuel pump needs to fill the carb back up before the carb will squirt fuel into the engine.

 

[ray1970 88]

Anybody think to do a compression ck ?    You are maybe just trying to run with one dead cylinder.   

[Viperpete 39]

It runs perfect under load and seems to have decent power. I havent done a compression check though. It doesnt shake badly enough for me to think it has a dead cylinder.

[rutkak 0]

There is some outstanding advice here.  To reiterate:

1).  Fix the choke.  Might need a choke stove or whatever they call it or get a carb with an electric choke.  I ran into this with a car that had headers - no provision for the hot air tube to go to the choke. 

2).  Find your timing marks and shoot for 12.  White out is your friend!  Great run down of procedures above to find TDC. 

3).  If you are running Pertronix make sure your coil is compatible.  It looks like a stock coil but I could be wrong.  Verify 12V although you are probably there with that new wiring.  Might need to add a relay if you are getting 6V during crank or run. 

4).  Tune carb with vacuum gauge. 

5).  And in all cases, check for vacuum leaks. 

Ken