underhood heat

[moparnation74]

Funny you mention the firecore. I don't have one of those, but I've had this distributor and I was thinking about using at some point. I don't know the brand as there aren't any markings, but I bought it and a 440 from a guy who races a bb dart. He was shedding all of his bb parts for a planned modern hemi swap.
I figured I'd get the current system set up properly before I introduce an upgrade, in case there's issues with it. Don't want to start chasing my tail by changing things.

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I agree....I am not familiar with that dizzy...

 

[Mike67]

Funny you mention the firecore. I don't have one of those, but I've had this distributor and I was thinking about using at some point. I don't know the brand as there aren't any markings, but I bought it and a 440 from a guy who races a bb dart. He was shedding all of his bb parts for a planned modern hemi swap.
I figured I'd get the current system set up properly before I introduce an upgrade, in case there's issues with it. Don't want to start chasing my tail by changing things.

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That looks like one of those Chinese ebay specials I think they are called Attackz... I picked one up for my wife's mustang...it was pure junk, wobbled and ate hei modules. Replaced with a MSD and no issues since!

 

[Glenwood]

Looks like a chinesium hei unit. Interesting older threads from FABO on it. I think I'll resell it and upgrade to a US made unit when I can.
http://www.forabodiesonly.com/mopar/threads/mopar-hei-gm-style-distributor.167820/

 

[Glenwood]

That looks like one of those Chinese ebay specials I think they are called Attackz... I picked one up for my wife's mustang...it was pure junk, wobbled and ate he modules. Replaced with a MSD and no issues since!

electrical minds in sink here Mike! lol

 

[Mike67]

Yep you definitely get what you pay for...lessons learned...

 

[The Rebel]

Some really good points on here that answered some of my questions about my car's set up, runs about 180*-200* with a
383-4bbl Edelebrock Performer 750cfm & Performer 383 intake.

1. last owner of my car killed the fuel pump, so it was replaced and they used 3/8" fuel lines. Now I know why as it's due to the carb & intake needs.

2. Car is missing a shroud. Based on my running temp of 180*-200* is this too hot w/o a shroud?

 

[threewood]

So is the 9* x2 counterweights?
The cam was spot on according to the degree wheel when I installed it.

The 9 stamped on the plate is crank degrees. Cam rotates once for every two crank rotations. Timing is in crank degrees so you take 9 x 2 = 18°

To test with a vacuum pump, I assume this is done while running to see what it advances to at increments of vacuum pressure? I've been reading up on vacuum advance last night and think I understand it a bit better now, although I'm not sure if it should be on the ported or manifold outlet of the carb. I read that ported vacuum for vacuum advance is not helpful for idling when the mixture is leaner, because of low vacuum with non-stock cams. My vacuum is at 15, so it probably doesn't matter in my set up. Is there any issue with the vacuum advance on full time manifold vacuum? This would put the idling timing upwards of 20-30* btc.

My 62 is hooked up to ported vac, my 69 is hooked up to manifold vac. They both run good but I have read that ported was used for emissions. With full manifold you will need to back your idle off after you tune (tune with vac adv unhooked).

Testing the advance while running is easier as you can see the change in degrees on the balancer. On the bench you can use a degree wheel over the distributor shaft and a wire taped to the rotor.

 

[miller]

Based on my running temp of 180*-200* is this too hot w/o a shroud?

It's acceptable. There's too many things that have to be considered, fan, radiator, thermostat...want it to get to temp, but not over 200*.

 

[furyus]

To the OP. You stated the car overheated at low speeds, but is ok at highway speeds. This says you don't have enough airflow. Driving at highway speeds pushes enough air to cool it better than at low speeds. You need a shroud. Period. You also need that hood to core support seal. Without them, the hot air keeps getting pulled back through the radiator. You can play with other things all day, but until you resolve this, you will never cool your car. Also, put a mechanical gauge in it. Saying the engine is too hot to touch, means nothing. My engine at 180 degrees will burn my hand. You need clear numbers to help fix this.
Next, for now, forget about vacuum advance. Plug it until you get the big problems fixed. Set the timing. Around 18 initial, 36 total, again with the vacuum advance plugged. Then set the idle mixture screws by slowly turn them in un til rpm drops. Then turn screw out to highest rpm. Do this for both screws. Might have to do it a couple times till your sure. There is no one setting on idle mixture screws for all engines. Also, Edelbrock carbs have very small float bowls that pick up alot of heat from the engine.

 

[oldbee]

To the OP. You stated the car overheated at low speeds, but is ok at highway speeds. This says you don't have enough airflow. Driving at highway speeds pushes enough air to cool it better than at low speeds. You need a shroud. Period. You also need that hood to core support seal. Without them, the hot air keeps getting pulled back through the radiator. You can play with other things all day, but until you resolve this, you will never cool your car. Also, put a mechanical gauge in it. Saying the engine is too hot to touch, means nothing. My engine at 180 degrees will burn my hand. You need clear numbers to help fix this.
Next, for now, forget about vacuum advance. Plug it until you get the big problems fixed. Set the timing. Around 18 initial, 36 total, again with the vacuum advance plugged. Then set the idle mixture screws by slowly turn them in un til rpm drops. Then turn screw out to highest rpm. Do this for both screws. Might have to do it a couple times till your sure. There is no one setting on idle mixture screws for all engines. Also, Edelbrock carbs have very small float bowls that pick up alot of heat from the engine.

+1 exactly!!

 

[Glenwood]

I mocked up a shroud today with an old plastic one I had laying around and it seemed to make it worse! There's definitely more to this issue then meets the eye.
Timing is set at 18/36 now with mixture at the highest vacuum of nearly 15hg. I also turned the vac advance down abit so that it adds no more than 10*. Seems to have better throttle response but is overheating with the shop temp at only 80F. Once it cools, I need to check flow.

I will add gauges eventuality but the stock will have to do for now. I will have to install an electric gauge as i cannot get the large plug out for a mech sender unfortunately.

 

[miller]

I mocked up a shroud today with an old plastic one I had laying around and it seemed to make it worse! There's definitely more to this issue then meets the eye.

Just went through the entire post, again. Yeah, agree more than one issue.

Any of the RB motors tend to run on the hot side, just nature of the beast. But, that said, simply means they need more cooling. Good air flow, more radiator, so on, such and such. For whatever reason, your's ain't getting it. Combination of things.

My 440 setup is fairly different than yours, using the stock 64 temp gauge, at the hottest will just go over dead center at the gauge. That's after my hot (+200*) break in run, with a 180* thermostat. Later day, let the thing run about 30 minutes, just to see how hot it would get...just over center, after taking the thermostat out.
Even at that point, hand on valve cover, then on intake, quite a difference, aluminum intake being a lot cooler. Could hold my hand on it all day.
Radiator on my 64 is a stock 22", three core a/c, for a 67 Coronet, 7 blade fixed fan, and two piece shroud. Fan is 1" from radiator.

Your intake a steelie?

Guess I'm just saying, not sure your cooling system is up to snuff. Besides the timing, fuel, and like...

 

[Glenwood]

Just went through the entire post, again. Yeah, agree more than one issue.

Any of the RB motors tend to run on the hot side, just nature of the beast. But, that said, simply means they need more cooling. Good air flow, more radiator, so on, such and such. For whatever reason, your's ain't getting it. Combination of things.

My 440 setup is fairly different than yours, using the stock 64 temp gauge, at the hottest will just go over dead center at the gauge. That's after my hot (+200*) break in run, with a 180* thermostat. Later day, let the thing run about 30 minutes, just to see how hot it would get...just over center, after taking the thermostat out.
Even at that point, hand on valve cover, then on intake, quite a difference, aluminum intake being a lot cooler. Could hold my hand on it all day.
Radiator on my 64 is a stock 22", three core a/c, for a 67 Coronet, 7 blade fixed fan, and two piece shroud. Fan is 1" from radiator.

Your intake a steelie?

Guess I'm just saying, not sure your cooling system is up to snuff. Besides the timing, fuel, and like...

Up until Saturday, the car has run fairly well and cool, with the stock gauge staying in the middle majority of the time. Most of my driving has been on the hwy however, with it reving about 3200-3600 rpm. No heating or general running issues whatsoever. After letting it cool down enough, I pulled the cap and watched for flow. Measuring the coolant temperature with a probe, flow started at 184*, which was slightly past the midway point on the gauge. This is normal from what I've seen the past few months. Then the temp gauge usually returns to the middle and so on. Flow was somewhat slow moving at idle and increased with rpms. Seems normal to me. Using a IR gun, the temperature difference on the core is about 20-30* from bottom to top.

I then took it out for a test drive at night with outside temperature around 75F. Car was stumbling/missing and I felt it might stall, so I turned around. I think the timing is too advanced for it at 18* initial. It performed much better at 12-13*, but lacked a bit of power at wot. I'm thinking that it wants to have it's initial at 13*+/- but need the mechanical advance bumped up. I'm on the fence about the vac advance atm, even with it turned down to about 10*. From a stand still, it could spin the tires but was not clean and crisp, like the ignition was breaking down a bit and the temperature gauge was a touch high.

It may be too lean, but I'm currently researching how to determine if it is. The idle screw are turned out to the highest vacuum +1/4 turn, which had both screws at 1-3/4 turns. There isn't much change to vacuum though when turning, until the screw has been turned in 1/2-1 turn. Also no noticeable change to rpms until almost turned in completely. Starting to wonder if there is a vacuum leak. Also, I have not checked the metering rods yet as suggested. The motor and area gets so hot, it's difficult to work around, or even hold the timing light. I'll pull the plugs and see what they look like now.
IR measurements show the rocker covers at about 120F+/-, Aluminum intake at 150F, valley pan at 230F, water pump & stat housing gets up to 205F, exhaust manifolds range from 450-600F, fuel bowl area about 150F.

 

[miller]

Flow was somewhat slow moving at idle and increased with rpms. Seems normal to me.

Yeah, without being able to see the flow, hard to say. Otherwise, yes, seems normal, including all your temps.
Aluminum intake...okay. Cross-over blocked?

Car was stumbling/missing and I felt it might stall, so I turned around.

Somethings breaking down on your ignition. First, I'll note on plugs fouled like your's, at least some of them, sometimes didn't do any good trying to clean them.
Did you ever get a chance to check the spark at the plugs, even just a couple? Don't remember on your distributor...electronic?
For now, anyway, agree on the timing. Try 14*, without vacuum advance. I'm sure you've heard, I'm not a fan of electronic, or vacuum advance, either. No matter. For some it works.
Without vacuum advance hooked up, and plugged, does the mechanical advance work, and how much?

From what your saying, on all your temps, kinda leading back to timing/fuel mixture.

 

[Ranger16]

Some really good points on here that answered some of my questions about my car's set up, runs about 180*-200* with a
383-4bbl Edelebrock Performer 750cfm & Performer 383 intake.

1. last owner of my car killed the fuel pump, so it was replaced and they used 3/8" fuel lines. Now I know why as it's due to the carb & intake needs.

2. Car is missing a shroud. Based on my running temp of 180*-200* is this too hot w/o a shroud?

I have the exact same setup. Assuming you are running a 180 thermostat, add a shroud and you will rarely ever see more than 185. A bit pricey from Mega Parts, but worth the price in my opinion. I am very happy with the results.

 

[The Rebel]

Yea very pricey as I need that as well as all of the mounting hardware....

I have the exact same setup. If you have a 180 thermostat, add a shroud and you will rarely ever see more than 185. A bit pricey from Mega Parts, but I am very happy with the results.

 

[oldbee]

Really the only thing vac adv does is help drivability a little bit & gas mileage when cruising. If ur running manifold vac to it it will drop to almost nothing when wot(no vac in engine). That's why you hardly ever see vac adv hooked up on a racing engine, ur always at full throttle.

 

[Glenwood]

Been having fun trying to diagnose this issue all week. Having trouble finding the timing & mixture sweet spot. Timing advanced from 15 to 20 seems to have little effect. Tried to advance the timing by vacuum and vacuum keeps increasing right up over 40* btdc. Mixture screws don't seem to alter the vacuum or rpm until a full turn either way. The outside temperature has dropped considerably and the engine heats up to normal as before the heat wave. With timing set at approx 18/35* & vac adv disconnected, the engine revs strong, so a quick run felt like it was pulling strong with a little pinging at wot. Then it felt like it was missing and was going to stall when stopped. Back to the shop and backed off the timing slightly and it got worse on the next run. No overheating, but started to sputter and a misfire or two. Tried with the vacuum advance back on and even worse. Ran decent until about 10-20 minutes after reaching operating temp, then not so good.
Fuel filter is full and I do not believe this is a fuel issue at this point, or perhaps not the whole problem. Something changed since that hot day last week and remains an issue even with the cooler temperature. I suspect the ignition has issues and I'm thinking the coil may be the cause. It is very hot and burns to touch even with gloves on, much hotter than the intake. It was harder to tell with the ambient being so hot, but with the cooler temperatures, it is still crazy hot. The resistance hot seems high to me and may be weakening the spark or causing intermittent issues.
Hot: primary 2ohms, secondary 13kohms
cold: 1.5ohms/10.3kohms.
Not sure what the acceptable range is for this accel chrome coil is.
Then I checked the dist pickup/reluctor and the gap was .012. I adjusted it to .008 but have to check all points for consistency. Ran it again while still hot and not change or worse.
Tomorrow I'll check the ballast resistor and voltages to each cold & hot.

 

[miller]

I suspect the ignition has issues and I'm thinking the coil may be the cause.

Coil might be at least part, if not all, the problem. Don't remember off hand, but should be a way to check voltage, both to, and from the coil. Coils will get hot, but not sure as hot as your's. Usually oil filled, to help keep the heat in range.
Had one that acted up, wound up having a broke winding...would work okay, until it heated up, break in the winding would separate, then turn to crap.

And, if your ignition isn't up to snuff, it's a running battle, trying to dial in fuel mixture and timing. It all works together, hot or cold.

 

[Don Gould]

Not enough time in a day to read all the comments but this is a common problem and we gets at least 2-3 calls a week on our tech line with this issue.

Looks like some of you are going in the right direction, it is a timing/ignition issue however the carb is also contributing somewhat to the heat problems.

The 750 Eddy has a chronic mid range lean out condition that is nearly impossible to tune out of it, it's in the design. An expert tuner may be able to band aid it but the time involved and the parts exceed the value of the carburetor. We offer no tuning advice, sales or parts for Eddy carbs the hours of tech line assistance is not worth our time. Also take into consideration that they are more of a stock engine replacement carb and not calibrated for the lower manifold signals of a performance application.

When tuning an engine any good mechanic will always tell you "Ignition First...Then Carburetion"
So lets start with Ignition.....

1st off your running an Orange box which retards your timing under load by 8* or more under load starting at about 3200 and by 5200 or less you have full retard. If you have a transbrake you can lock it up, apply load to the engine and watch the timing going backwards. Mopar hasn't made a real Orange box in years all the ones sold now are just a poor Chinese copy with ZERO warranty.... there's a reason for that.
To make your engine run correctly you need a box that won't retard the timing and you won't find one that's built with antiquated 60's transistors that's just the way they work. I think we all realize that we've come a long way in electronics in the last 50 years.
We've load tested hundreds over the years and they all do the same. Which is the reason we spent 4 years and many $$$ to develop our micro-Processor controlled HRR688 ignition box. So you can spend all kinds of time and money to get the distributor right on but all is lost when you hook it up to a box that will take all your efforts and reverse them.

A few facts:
1. Revving an engine up with the Vac connected and zero load is a Non-Standard automotive test all it tells you is the Vac Can is working. You can never duplicate a zero load high RPM condition in a car on the road.
2. These Non-Emission controlled engines need to be connected to a Constant Manifold port and set up with the correct vac can to read the signal.
3. Under load or acceleration there is no Manifold Vacuum so there is no vacuum timing.
4. Any ignition system will only build enough voltage to jump the spark from the electrode to the ground strap. A naturally aspirated engine on pump gas will almost never under even the most extreme conditions require more than 34KV to fire the plug. My Race motor on the brake at 5200RPM (locked on the convertor at WOT), 13.95:1 compression pulled 31KV.
5. Excessive plug gaps will cause erratic spark, electricity will always find the path of least resistance to find a ground, could be sideways to the threaded portion of the plug, could be the somewhere in the combustion chamber wherever the least resistance is. Relating back to my race engine.... Plug gaps at .026 Autolite Racing plug # AR3911.
6. Mopar engines were engineered to run at 34* under full load this is not an opinion its a calculated engineering formula based on the location of the spark plug within the combustion chamber on a conventional head which is the source of the flame front and the degrees of propagation of that flame front. You might make a little more power by bumping the timing up and flooding the chamber with excessive fuel but consistency and longevity of the engine will be diminished. Chevy's run at 36 and Fords like 35.
7. Magnetic pick-up type distributors will retard the timing by about 2* at high RPM, its just the nature of the beast because of the time it takes for the reluctor paddle to pass over the magnet. The signal is produced on the back side of the pass not on the approach. High quality Ignition systems will read this and correct it with "Adaptive Dwell Technology" our Intel Processor is programmed and burned with this technology.
8. CD type ignitions are usually not required with a street application sometimes the multi spark feature will help with an engine that was designed based on Ebay parts with too much cam, no compression, no gear, no convertor stall.... just a band aid for a real poor combination. The multi spark is gone after 3000 RPM and you back to single spark anyway. The multi-spark has an extremely short burn time whereas a Inductive ignition has a single but much longer burn time and in most cases will perform just as well as a CD ignition with more reliability and consistency. CD ignition systems are for engines turning over 7000 RPM or require multiple rev limiters which is where Inductive ignitions reach their limits.

So why does it overheat?
The optimum point of max cylinder pressure is about 13.5* ATDC, this is where the rod angle and crank throw are in the optimum position to turn the crank and create the maximum tork. Before this point the rod and crank throw are expending the energy to push the crank out of the block and not turn it, too late and the pressure is just chasing the piston down the hole. Both of these conditions will cause poor throttle response and a lazy engine.
If the timing is late it has already lost pressure in the combustion chamber and fuel is not pressurized enough to complete the burn process efficiently. So now the piston is coming back up and the UN-burned smoldering fuel is being forced out the exhaust port at the same speed the piston is returning to TDC. This fuel rich exhaust hits the exhaust port where Oxygen is present and it turns into a blowtorch transferring massive heat to the exhaust port which overpowers the cooling system as well as heating the whole engine, manifold, heads, carb and anything you have bolted to it and now you have extreme under hood temps. This will eventually lead to burned out header gaskets or even the headers, intake gaskets or even warping of the intake, burned up or short life of the ignition wires, overheating of the distributor burning up the winding's on the magnetic pick-up, cap and rotor failure .... you get the idea.
Timing is everything!

Do a quick test of this theory, start and warm up the engine, pull off your vac line and plug it, now advance your timing to 30* at idle. Did the RPM go up? Did the engine smooth out? Then ask yourself....why did the engine RPM increase? You didn't add fuel or air? answer is simple its simply applying more tork to the crank at the correct degrees of rotation which spins the motor faster, your now burning the fuel more completely and getting the pressure applied to the crank where it can turn it more efficiently. now go smell your exhaust.

How do you get it to keep running like this?

Set the initial high enough to get it to start quick and clean, get the correct vac can to bring it up to that 30* (some engine combinations need more some less) limit the amount of mechanical timing so under load it will not exceed 34*. Rework the vac can and set limiters on the stroke so it doesn't overtime the motor at part throttle cruise (This is where you have some mechanical and some vac timing, we like to see it at around 40-45*)
Not having all the details on this whole combination... so in theory we would probably set it at 16* initial, 18* slot for a total of 34*
Vac settings at 14* at 15" of vacuum for a total of 30* at idle
Set the springs to be all in at about 3200 RPM

There's plenty more when it comes to tuning but we always start with the ignition and have since the mid 60's. Between Jim and I we have way over 100 years of experience tuning ignition and fuel systems. Distributor tuning is a lost art and just because a guy has a distributor machine doesn't make him a tuner no more than me standing in my garage makes me a car. It's not the tool it's the man holding it.

You can read more on our website in the technical information section, have a look at the spark plug reading article, we also have a 47 page book on tuning that's available in Email Version or spiral bound hard copy.
Mechanical advance Limiter Plate
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