Why only 8*? That is going to be a limiting factor in of it self.

 

A few  questions

1.  what is your vacuum reading at idle?

2.  Idle rpm?

3.  What is your total timing at say 3 to 3.5K rpms?

4.  Is the vacuum line hooked to the correct port on the Eddy carb?

5.  What is the number stamped on the vacuum advance canister arm that goes inside the distributor?

6.  Does 8 TOC mean 8 Before Top Dead Center? 

7.  What did you use to set your timing?  stock markings on balancer

8.  Does the timing mark move around a bunch when viewed under the timing light?


OK thats enough for now.  Ooops one more, does it only overheat when the vacuum is hooked up or just overheats all the time?

Cheers

Chris

 

1.On the pass side of the edelbrock thier is no vacuum at idle and is when you accelerate.
2. No tach but around 600 rpm
3. I didn't check my timing at a higher RPM.
4. Yes, the other port has vacuum all the time.
5. I still need to check this one. Some people tell me that I need a HP distributor if I have a different cam.
6. 8 degrees ATDC above top dead center, is what the stock setting shows.
7. I used the stock marks on the stock balancer.
8. The timing mark stays in one spot with the light.
9. It overheats with the vacuum advance unhooked from the carb. I can't even drive it with the vacuum advance hooked up. The car when parked with pulsate when you accelerate and back fire.

 

Ok good asnwers!

I would still like to know your vacuum reading at idle.  You may have to 't' into a line and borrow a gauge.

ATDC I have always read that as "AFTER TOP DEAD CENTER"  which is wrong for the motor.  You want your timing mark to be to the left (when looking at the engine from the front) of your "0" mark on the timing chain cover.  8 degrees is ok but stock is 10 BTDC.  We can start with 8 and sneak up on 10 as we fix the problems.

Overheating is a problem.  Do you have the stock fan shroud installed?  Do you know the condition of the water pump, radiator, hoses?

Is this a manual or automatic trans?  An overworked auto trans can contribute to overheating.  How about the grill opening?  Free of obstructions (lights etc) all the fins straight and free of mud/dead bugs etc?  What is mounted in front of the radiator (a/c condensor, trans cooler. ps cooler?)

You dont' need a HP distributor, but is it a points (ick) type or electronic type distributor?

Yeah I know I just asked a bunch more questions but first make absolutely sure your engine is timed for 8-10 degrees BEFORE top dead center, once we know that then we can progress with more diagnosis.

Cheers

Chris

 

The timing is set to the left of the 0 mark if you are looking by standing in front of the car. Newer radiator, hoses ,  and water pump are good. The fan blade and shroud are all stock and in perfect condition.

Automatic tranny with a external cooler. The whole front is completely stock and clean.

A/C condensor is in front of the radiator and a small trans cooler.

Electronic distributor with a stock wiring harness and stock ign module. It is now set at 10 degrees.

Thanks for any help you can give!

 

Let me ask this "dumb" question...

How do you know it is over heating?

If you say because the stock gauge says so, that isn't enough of an answer, the stock gauge is less reliable than an idiot light. A good mechanical will be needed.

If you said it is boiling over, well that is more of an indicator, but a weak cap can "boil over", so can a concentrated mix of antifreeze. Not necessarily meaning over heating, the waterpump can build up enough pressure to force water out of a weak cap, even when cold.

Now if you have confirmed it is overheating some other way, well, I would have said retarded timing (from leaving vacuum hose off) can do it, but you have changed timing.

 

Dang it I always forget to ask about the cap!

OK, now you are going to have to check one thing and measure another.  You will need a vacuum gun or a device that can apply vacuum.  Hook the hose to the vacuum advance canister and apply say 15" of vacuum.  Do this with the cap off and you should see the plate inside the dist move.  Or you can do the same while the engine is running with a timing light hooked up.  Slowly apply vacuum and see what happens to the timing mark.

Also bring you #1 cylinder to top dead center.  remove the dist cap and make sure the rotor is pointed at the #1 cylinder.  Then pull the valve cover and make sure valves and cam are also matching top dead center.  You can do it all at once of course.  This will confirm the cam was installed properly and is in phase with the rest of the engine.

I would still love to know what vacuum your engine is pulling at idle.

Be careful with this next idea because it is easy to burn yourself.  With the engine idling, pull off each spark plug wire and listen for an rpm drop.

Pull your plugs and note their condition and color. 


Cheers

Chris

 

I have a mechanical autometer gauge hooked up and after about 10-20 miles it starts to run in excess of 230 degrees and does not stop. When I turn the engine off it moves up to 240 and back down as it cools. It is hard to start when it is hot also.

 

That is with vacuum line connected?

 

He overheats with it disconnected, he can't drive it with it hooked up.


Something very wrong with base timing or a wildly malfunction distributor, which seems unlikely as it is an electronic one.  I have never heard of a ignition box failure causing this, they just quit out right and you can't start you motor.

Cheers

Chris

 

is the distributer drive a tooth off? making it more advanced than it shows with a lite.

 

The distributor rotor is pointing at number 1 when i take the cap off with it at top dead center on the compression side. The distributor has a hex head on the bottom so it would be impossible to be off a gear. I still have to borrow a vacuum tester to check the vacuum pull. The engine is hitting on all 8 cylinders.

Can overtightened lifters cause this problem? They are all tightened to torq specs but I have ran out of ideas.

 

is the distributer drive a tooth off? making it more advanced than it shows with a lite.

A timing light is triggered by the plug wire, it wouldn't affect the reading. The only problem with having the dis drive off would be the inability to adjust the distributor enough to get the proper timing before it encounters it's stops.

 

With rocker shafts it is hard to FUBAR lifters unless  your pushrods are too long.  What was done to the heads during rebuild?  New bigger vavles?  non stock springs?  custom camshaft? 

What I am getting at is in order for your engine to belch out the carb, fuel/air mixture and an ignition source is getting past one or more intake valves.  This is why we have been obsessing on timing as it is usually the case. 

But if the valve train wasn't measured properly or installed correctly then we may have problems.  Need to look at things like spring height installed, how the rocker arm moves on the valve tip, length of pushrods, type of lifter etc.  All of this is assuming you no longer have stock valve train componets.

Where do we stand with knowing condition of anti freeze and radiator cap?  Have we checked thermostat for proper opening?  (pot of heated water with thermometer works best (ask wife if she has a cooking therm) 

Fan clutch is always a tricky one, the only way I know of checking its operation is to start the engine (cold) with  the hood up and then turn it off, fan should continue to rotate for a few revolutions.  Same test with the engine hot and the fan should stop moving very quickly.

Cheers

Chris

 

The entire valve train was reused with the exception of a mild RV camshaft with hyd lifters (nothing fancy). The cooling system seems to be fine. I have replace the antifreez a numerous times with the right mixture. The radiator is newer and the car doesn't use a fan clutch. It is a direct stock fan.

If the cam is larger than the stock valve train can handle, what should be done to compensate for this?

 

If timing is set 8*ATDC you are 18 degrees off  - as stated above  it should be 8-12* BTDC

 

There is no wrong vacuum port. Both will give vacuum at partial throttle. They only differ at idle. With manifold vacuum offering vacuum at idle. It's not factory but it's also not incorrect. It has many advantages.

Now back to the original topic. If you can recreate the vacuum with an external source. If it only misfires during vacuum advance. The vacuum advance mechanism may be pulling the pick up too far from the reluctor or it my be the rotor to dist cap phasing.

To check phasing drill out a slot in the top of a dist cap so you can see the rotor's relationship to the tower. Now connect the timing light to that same tower. With the engine running you should see that rotor line up with the tower. Apply vacuum and watch the rotor move away from the tower. If it moves too far you need to reindex the reluctor to fire a few degrees over.

 

Is there a bad wire, inside the distributor? Sounds like the movent off the vacumn advance plate is opening a circuit somewhere.

 

Is there a bad wire, inside the distributor? Sounds like the movent off the vacumn advance plate is opening a circuit somewhere.

If the pickup wire opens, the vehicle will die instantly.

 

Maybe it doesent completely break the circuit, just guessing at possibilities. I wasted half a day once, trying to fix a car that had a dodgy ground wire on the points base plate(yes, I know the electronic ign doesent have one) since then i always push/pull on the wires to check for internal breaks. I put Chrysler's electronic ignition kit on My '71 Roadrunner, one of that first batch that came through with the defective pickup coils, walked home several times before I figured that one out.