Underhood heat

SuperDave

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Scenario: 73 Newport with a Musclecar makeover; rebuilt 400 with flat top Pistons, shaved heads, "Stage II" camshaft, 4 bbl, headers, MSD ignition, aluminum radiator, dual electric fans, electric fuel pump, lots of chrome, open style air filter, etc... Looks, runs & sounds badass. Dismal fuel economy however, passes everything but a gas station. Not a problem really, this is to be expected. But it gets HOT under the hood! Already melted some plastic wire looms that were too close to the exhaust (replaced & rerouted now). Car runs warm to hot now, hard to keep it under 190 unless the hood is open. A 20 minute drive on a warm Texas highway can heat it up to 200, then on the side streets it would boil over. I've since learned it HAD an oil leak from the back of one of the valve covers (fixed now), low oil levels contributed to that.

Is there any way to vent the heat, besides cutting up the hood for vents and/or louvers? I've considered a pair of GTX hood scoops mounted backwards with vent holes underneath, but they're kinda pricey. Also considered a pair of stainless marine bilge vents, but I'm afraid it would look too much like a 69 RS Camaro knockoff.
titan-marine-vent-small-8-slots.jpg

Placement would be important, too far back and it's in the high pressure zone and act as cowl induction, forcing air IN when I want the heat OUT. Cutting or removing the front fender wells is out too, I don't want mud and dirt sling up on my shiney bits, plus there's the added issue of brake heat adding to the mix.

Now I do have some leftover asphalt sheeting from redoing the roof, I might try to replace the missing "sheeting" that went from the grill shroud to the radiator support, force grilled air thru the radiator rather than up & over it. Then there's maybe making a pseudo chin spoiler under the radiator support from some plastic garden border, not too low of course, the front end has been dialed as low as I dare with tweaks to the torsion bars (gotta have that hot rod rake). If I can create or enhance a low pressure zone under the car, that would help draw air & heat from under the hood, at speed anyways. Might also help with high speed handling too. That's why race cars have them, right?

I don't want to wrap the headers, as much as I want to, they guarantee to rust out the headers inside of a year. Coated headers from TTI are outside of my budget right now. If I had that kind of spare cash, I'd get a Holley Stealth Fuel Injection unit, 440 Source aluminum heads, or a 500+" stroker crankshaft.

Back in my youth, I had a 76 Formula Firebird, always ran warm (190-210°). After adding Trans Am fenders with the side scoops, the car never ran any warmer than 180°. With the motor running, you could feel the heat blowing from the fender vents. So venting the engine bay looks attractive right now. I'm open to suggestions. AFFORDABLE suggestions.
 

413

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Put in a lower temp thermostat.
Make sure it’s not lean, that will make it run hot. I had a car do that, you would swear it had a cooling issue, swapped on a known good carb and it was totally different, and ran just fine.

Should be able to run an engine with no scoops or vents and have it not boil over.
 

Davea Lux

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The extra horsepower also means that the engine will generate more heat. You may also need a bigger radiator. Might also want to consider an engine oil cooler to help dissipate more heat.

Dave
 

livininharrow

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190 up to 200 is nothing to worry about. i run 190 stats in all my mopars. maybe your rad cap is not allowing the system to pressurize. i have seen my temp guage as high as 220 in traffic with no puking. i would put a new rad cap on first if you already havent tried that. cheers
 

CBODY67

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The issues I see are that with all of your enhancements to the engine, it should still operate well at 190 (which is only 10 degrees F hotter than the beloved 180 degree F benchmark AND what all factory cars have had since about 1969 or so). If it might get to 210, no problems, either as that's where all modern cars tend to run (which usually equates to "mid-gauge"). NO need to ventilate the hood, with all of that space under there for air to go under the car after it goes through the radiator.

How wide is the radiator? Was/is this a factory a/c car to start with? When are the electric fans programmed to switch on and then to "full blast" operation? Have you checked the radiator temps with an IR heat gun to verify what's going on? In any event, spark plug wire looms should not be melting.

Other than the easiest thing to change, the radiator cap, you can also wrap the headers with ThermoTec wrap to cut underhood heat. Kind of tedious to do it right and have it look good, but certainly doable.

THEN put the car on a chassis dyno and "road load check" the fuel mixtures to see where THEY are. Plus verify the ignition timing as THAT can affect how much heat is in the exhaust system, too. Something sounds a bit out of whack, there, to me. While many carbs are plug-n-play, most need some fine tuning for engines which have many aftermarket components in them. They will be good enough to run well initially, but not as good as they might be, all things considered. Getting those things more dialed-in might also help fuel economy too.

What torque converter stall speed and rear axle ratio/tire size does the vehicle have. A high-stall converter with normal rear axle gears will possibly have more slippage at slower speeds unless a steady foot is on the accelerator pedal, by observation. Which can also contribute to poor fuel economy.

What constitutes a "Stage II" camshaft? What specs and such? Just curious.

Just some thoughts,
CBODY67
 

cbarge

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Big blocks run hot by nature.
As mentioned 210 is normal and not a huge concern.
Add musclecar mods it will get hotter.
Thus radiant heat under the hood will feel hot.
Are you running a hood to yoke seal?
Is there a lower air dam?
Both items will help direct air to the radiator.
Check the ignition timing and as mentioned check if she is running lean.
Retarded timing and a lean condition can make an engine run hot.
You can forget using factory specs with the mods and today's gas.
With a vacuum gauge and timing light see where the engine likes to be.
Trail and error, test and tune.
Take notes as you do the fine tuning.
Hope this helps
 

SuperDave

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Because y'all asked, here it is:

At present, there is NO thermostat. Takes longer to get hot, but it still does get hot. Maybe I will replace the rad cap, couldn't hurt, it's only $5. Present one is rated 16 psi.

Fans are hotwired to the ignition circuit (via a relay of course). Full tilt high when the key is on. Car was originally AC equipped, but not at present. Came with an aluminum radiator, unknown brand. I'll measure it later, it's dark now. It is a thick one, equivalent to a 3 core. Had it cored & rodded before pressing it into service, as well as brazed to patch the micro holes.
It does have a trans cooler, as well as power steering cooler, headers were nearly touching the steering gearbox so I decided having a cooler wouldn't hurt it. Converter is a 2800 stall, TF 727 with a stage 2 shift kit, red line clutches, HD sprag & servos, and a 1.77:1 1st gear setup. Rear axle is 3.23:1 (I think, somewhere near there anyway) with a Sure Grip Posi unit upgrade in a 8.25" axle.

Stage II cam is a hydraulic version of the Purple cam that was standard issue for the 383 Magnum. 214/224° At .050" // .444/.466 Lift // 112° Lobe Separation. Nice, fat & lopey, like a Musclecar should sound. Speedmaster adjustable roller rockers arms, 1.5:1 stainless steel - not those self destructing aluminum versions. MSD Street Fire CDI box, rev limiter set to 5k on account of the single valve springs, any faster and they'll likely float the valves and have me walking home. Machine shop decked both the block and heads, with the pistons in it yield between 10 to 10.5 compression. Cold crank compression is 185 psi with a shot of WD40 in the plug holes. Cheap gas isn't an option, last fill-up cost me $85.00. Price went up since then. Yea me.

It wasn't the plug wire looms that melted, but the split loom sleeving I used to clean up the factory wires. I think wrapping wire with black tape to be tacky & lame. Did have the alternator wires routed outside the valve covers until they melted, now they run on the intake side.

Headers are cheap Chinese shorties, big ports that require Indy head gaskets. Only thing we could find that would fit, and even then they needed "massaging" to clear the gearbox & passenger side suspension. 2 1/2" pipes thru glasspacks with side outlets. No crossover.

The Edelbrock 1406 4 bbl ran fine out of the box so we never touched the jetting. Doesn't smell rich, which is fine as the side exhaust belches dangerously close to the cabin. With no AC, windows down is standard operating procedure. If I jet it rich, I'll have burning eyes. Nothing stock about this motor except the block, crank, rods & oil pan, everything else has been replaced, modified or removed. Tuning by the book doesn't apply here, it's all tuned by ear & seat of the pants. Ma Mopar never made a 400 Magnum, so I did.

I'm debating on pulling one of the advance springs out of the distributor and retarding the timing to compensate. If I retard it now, it's lazy off the line, so recurving it may help. Any more advance and it knocks, even with ethenol free 91 octane. I could rejet it some, I have a Chinese knockoff rejet kit, but none of the springs are color coded, so it'll be trial & error tuning. The jets and needles are labeled though. Nobody near me has a Dyno, not that I know of anyway, and even if I did, that's expensive. Last I heard was a grand for an afternoon just tuning a carb.

I can tune it to run cool and for better mileage, but then I give up power & torque. Not what I really built this for. It's a weekend toy, something to drive to town once or twice a month when the weather is nice, and monthly jaunts to Cars & Coffee 2 towns over. It gets tons of respect. Folks around here have never seen anything like it, nobody makes a hot rod out of a 4 door grandpa grocery getter, especially a huge Chrysler like mine. I know I dig it. But I want it to be a touch more reliable. Musclecar motors don't usually motivate something this big and heavy, so it sweats some, it gets hot. Therefore I'm asking y'all C-Body enthusiasts for advice. Yeah, I might offend the numbers matching purists, bite me. I didn't build it for you. But at the same time, I don't want to butcher the hood unnecessarily. If I could vent it without sacrificing the skeletal understructure and still look classy, then I might. I did that once to a 71 Chevelle. It looked wrong. And it wiggled at speed. I might mock it up with tape and foil just to see. It could give it some agressive bling (like that sinister snarling sound isn't intimidating enough), or it might end up looking like a boy racer. I don't know. We'll see.
 

cbarge

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Eddy carbs run lean out of the box.
A tuning kit with metering rods and jets will help.
 

SuperDave

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Big blocks run hot by nature.
As mentioned 210 is normal and not a huge concern.
Add musclecar mods it will get hotter.
Thus radiant heat under the hood will feel hot.
Are you running a hood to yoke seal?
Is there a lower air dam?
Both items will help direct air to the radiator.

Yoke? Is that the firewall cowl? There is a weatherstrip along the top that touches the hood. I know there was some black paper like substance between the front header (shell that houses the grill, lamps, and front trim) and the radiator support, it was ripped and shredded when I got it. There are also holes where attachment clips went to, another set of holes at the bottom between the support and the bottom of the bumper. Is that the yoke?

I have asphalt paper I'm thinking to use to replace the torn/missing sheeting. I also have some modern plastic body clips to secure it. If nothing else but to direct incoming air thru the radiator and not around it like it can now. There is no weatherstripping on the hood or radiator support to seal it, was there ever?
No air dam underneath feeding air to the radiator. However I do have access to some black plastic landscaping border I can repurpose as a dam. Would I want it to extend below the bumper, and if so how far? How much ground clearance is enough?

From my understanding a front dam, or chin spoiler if you will, doesn't shovel air up to or thru the radiator. What it does is prevent air from going under the car. That in itself creates a low pressure zone under the car, which "suctions" air & heat (headers, radiator, etc) from under the hood, aiding cooling. It also aids in high speed handling too. This is well and fine at speed, but in slow traffic & at stoplights, heat stagnates and bakes everything in the engine bay. I want to address that too.

Eddy carbs run lean out of the box.
A tuning kit with metering rods and jets will help.

As I stated above, I have a Chinese knockoff "kit" that has everything, including the springs. However, the springs lack the color coding the Eddy kits come with. And of course, no instructions. Lucky me, I downloaded the PDF from Eddy online. (Google to the rescue). Unlike the Eddy kit, it doesn't come in a sectioned box with each size in its own slot. NOOOoo, it all came in a single ziplock baggie within a padded envelope, the return address showing street names and town names I cannot pronounce, and a postage stamp with asian glyphs instead of letters. 11 bucks on fleabay, free shipping.
Now if I can figure out the springs in one weekend...
 
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CBODY67

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One thing, there WAS a 400 "Magnum" that was in '73-'74 Chargers and Road Runners (just not called "Magnum", but "400 HO"). A slightly massaged cam when compared to the orig B/RB HP cam of 1967 GTXs, but still "the same" for the most part. Chrysler has seemed to play on the "Purple Shaft" name with their OEM-spec cams, it seems, when the original "Purple Shaft" was a B/RB cam with Hemi timing events and a daub of purple paint on the shaft, up front. Now, it's more of a marketing game than it originally was, by observation. FWIW

All of that motor with a 1.77 low gear in a 3-speed TF? That's PowerGlide territory! 2800 stall speed, not quite needed with that cam, but 2300 was probably factory spec.

"Rich" has a cooler exhaust than "lean". Lean will actually make more real power, but not too lean. Too lean will heat the exhuast system more than rich, as will retarded spark timing (total not initial by itself). Headers typically (at least the ones my friends used) do not heat the underhood area more than exhaust manifolds did, by observation. IF they did, we'd have heard about that way back in the later 1960s, especially from the Chevy guys, much less the Road Runner/GTX owners who put headers on their cars back in the later 1960s. But they will heat up quicker than the cast iron manifolds they replace. Metal thickness/gauge can be important here, too.

Very few headers actually just fall into place without some "clearancing by ball pein hammer" in selective places. Some need more than others, though.

Agreed, an air dam makes a low pressure area which makes more air be drawn through the radiator and exit under the car. BUT you also need to close off any gaps between the radiator and the behind the grille sheetmetal so that all air does go through the radiator. There was a Chrysler recall and TSB for such on the 1972 Chryslers, also covering the area between the bumper and the bottom side of the radiator, where air could be re-cycled from the underhood area to re-enter the radiator, causing elevated underhood temps, which then caused the a/c lines to fail. Our '72 Newport had that stuff installed on it, in about 1973 or so.

The yoke seal seals the bottom side of the hood to the radiator support (yoke). It attaches to the bottom of the hood. A factory a/c car should have had one on it from the factory. If you desire an upper outlet for underhood air, remove the hood-to-cowl seal from the cowl, leaving a gap between the back of the hood and the cowl.

When the radiator shop cleaned the aluminum radiator, did they un-weld the tanks and then re-weld them? Just curious. An aluminum radiator, to me, is nothing special unless the core is a thin-finned higher efficiency model. Otherwise, it's just a copper radiator made out of aluminum, but still might work a bit better than a full copper unit. Sorry if some might disagree. What cfm rating on the fans?

In any event, the majority of the Edelbrock carbs have Chevy calibrations in them, which might work decently well on a bigger Chrysler V-8, but for best results, they still need to be dialed-in via a chassis dyno which will monitor air/fuel ratios under road load.

What I see is a replicated '68 Road Runner motor with a .070" overbore (4.25" bore 383 that became a 4.32" bore with a new block around it)? NO thermostat? THAT could be an issue as the thermostat is a flow restriction to ensure that the water does not run through the engine too fast, so that it removes more heat as it should. I'm presuming that the people that built your motor hot tanked it with the block core plugs removed?

If you don't desire to run a thermostat, then get a Moroso kit of thermostat replacement washers. Varying inside hole diameters to get the restriction correct for the desired engine temps "under load". More things to play with!

Did the richer fuel calibrations you tried cool the exhaust/underhood? Just curious. What about the factory coolant overflow reservoir being installed? There's a reason the spark plug wire holders are spaced the way they are, but you desire to "loom them all together"? That reason is to decrease the possibility of spark energy getting into a wire it does not belong in. BTAIM

Just some thoughts,
CBODY67
 

SuperDave

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1st gear was the lowest I could find, converter listed as 400 rpm looser than stock. This big honking 4 door is heavy and was a dog at the lights with the original 2bbl big block. I wanted to give it a leg up at bottom end without sacrificing too much top end. I could have had the trans rebuilt stock and installed a 4:11, but then the motor would scream at 70 mph. So a low 1st gear & loose converter was a compromise. Trans cooler and a finned deep dish pan to keep it cool and maybe last a little longer. Last thing I wanted was to build a big block hot rod that gets humiliated at the lights by a Prius.

TBH, I haven't played with the fuel mix any, other than the idle mix to get the best vacuum. It ran great out of the box. If it ain't broke, don't fix it. The rejet kit was bought while the engine was being built, anticipating a tune needed. It's still sitting on the shelf unopened.

Spark plugs wires do have a loom, or separator if you will, made of zip ties. One long tie around all the wires (spaced 8" apart) and another tie between each individual wire, so they all lay flat and parallel to each other. None of the wires touch. There's 1/4 to 3/8" between each wire. This is in addition to fiberglass heat braid on each wire. So ignition cross fire is kept at a minimum. And the whole assembly is held up with more zip ties to the long chrome Tee bolts on the valve covers. It looks neat & sharp, organized, away from the headers & all professional like, can't tell they're zip ties because the "clasp" is hidden behind or under the wires. Those never melted, only the insulated boots and the right angle plug caps. Those fat Indy Head primaries are dangerously close to plugs 2, 3, 6 & 7. The insulated boots sleeves scorch where they touch the header and cook the plug wire boots, leading to shorts, a dead firing cylinder and loss of power. I'm on my 2nd set of wires & insulators now and it's barely broken in.

When I said my wire looms melted, I meant the split loom that covers not the plug wires but other wires. They come in varying sizes and colors. I got a 4 pack of 10' each to organize and clean up the engine bay. The wires to the alternator used to run above the header, THAT'S the loom that melted. Burnt they one of the wires and dead shorted one of the field wires to the header, sending volts to 18 when I pulled over and fixed it. It's been replaced and routed along the intake now.

Not real sure what my timing is at, the timing mark is nowhere near TDC. It's off nearly 90°! Sometime during the 48 year lifespan the inertia ring on the damper has slipped. Mileage also unknown, speedo has never worked, even with a fresh cable and new worm gear in the tail shaft. Odo reads 8K and the title says mileage exempt, meaning it's rolled at least once. I use a GPS app on my phone to track my speed & mileage. But it's safe to say it's at least 108,000.

Radiator shop had the radiator 2 weeks, cost a pretty penny too on account of it being aluminum. Most radiator shops wouldn't touch it. They cleaned up all the rust and scale inside & fixed all the pinhole leaks. It flows really well.

Machine shop that did the block & heads vatted the motor, bored the cylinders, decked the block & heads, installed new cam bearings, freeze plugs and did a 3 angle valve job. We had 2 sets of heads, the original 2 bbl smog heads and a pair of motorhome heads we picked up at fleabay. They chose the best heads, valves and springs from both and provided me fresh heads and the rest in loose parts. We (my brother & I) assembled the rest of the motor ourselves. So yeah, there's no sludge in the block.

The original puke tank was missing when I got it. So I "recycled" a 24 oz NOS energy drink can. It's mounted with the NOS label showing, complete with a stainless braided hose and anodized fittings. The ignorant kids point to it and say, "Oh look! It has nitrous!" And it works, as a puke tank anyway. I keep it half full.

Thermostat was pulled after my last trip to Cars & Coffee to see if it would help the overheating issue. It didn't. Still got hot, just took longer to do so. It was a high flow 180° version. Playing with the timing didn't help. Retarding it makes it slow, advancing it makes it knock. So I guess I need to jet it up richer. I only feed it ethanol free super, 91 octane. When I built it I replaced ALL the rubber hose with ethanol friendly fuel lines & viton seals in the carb (expensive!), in the event that I was out of gas and have no choice but buy blended gas. Ethanol does burn cooler and cleaner, but it has less thermal BTUs, meaning less power. It also absorbs moisture, leading to gas tank rot, corrosion in the carb & fuel lines, and it separates over time. Seeing as my car may sit for weeks at a time, it's not an attractive option.

On a side note: There's a guy across the street with a 64 Corvair he's had me work on. Drives it maybe once a couple months, keeps the tank full of the cheapest gas he can buy (E15 blended 87 octane). And he wonders why it runs like shit. I've had to replace the fuel pump, filters and rebuild the carbs. Gas is yellowed, smells funky, carbs were varnished big time. And there were purple crystals in the carb horn vents, lots of funky green varnish inside and out. Ethanol. He doesn't live there, it's his vacation lake house, he keeps his Corvair parked there. My dad & I talked him into letting us (dad) take it with us to Cars & Coffee once a month, let it stretch it's legs, charge the battery, keep it running good.

There is no heat blanket lining the hood of the Chrysler, and after a 20 minute drive the hood is too hot to touch or sit on. I haven't used my IR gun on it yet, but next time I go to Cars & Coffee (August 21, my birthday) I'll bring it to see. I'll also check the headers, radiator, and other places too.
 
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commando1

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How about going through the ENTIRE cooling system correctly???
From A - Z. Soup to nuts. The whole enchilada.
You're chasing your tail.
Do you even know how to thoroughly troubleshoot overheating?
That should have been your opening post.
 

jollyjoker

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Didn't catch if anybody mentioned it, but fan shroud . . . ? Are the electric fans supplemental, or replacing the factory setup?
 

Big_John

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Yoke? Is that the firewall cowl? There is a weatherstrip along the top that touches the hood. I know there was some black paper like substance between the front header (shell that houses the grill, lamps, and front trim) and the radiator support, it was ripped and shredded when I got it. There are also holes where attachment clips went to, another set of holes at the bottom between the support and the bottom of the bumper. Is that the yoke?

I have asphalt paper I'm thinking to use to replace the torn/missing sheeting. I also have some modern plastic body clips to secure it. If nothing else but to direct incoming air thru the radiator and not around it like it can now. There is no weatherstripping on the hood or radiator support to seal it, was there ever?
No air dam underneath feeding air to the radiator. However I do have access to some black plastic landscaping border I can repurpose as a dam. Would I want it to extend below the bumper, and if so how far? How much ground clearance is enough?

All that stuff is huge in keeping air flow through the radiator and not escaping under the car.

Easiest, most cost effective and the best way is to replace them with the correct stuff from these guys: Detroit Muscle Technologies, LLC Mopar & AMC muscle car restoration gaskets It will look good when done too.
 

CBODY67

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1st gear was the lowest I could find, converter listed as 400 rpm looser than stock. This big honking 4 door is heavy and was a dog at the lights with the original 2bbl big block. I wanted to give it a leg up at bottom end without sacrificing too much top end. I could have had the trans rebuilt stock and installed a 4:11, but then the motor would scream at 70 mph. So a low 1st gear & loose converter was a compromise. Trans cooler and a finned deep dish pan to keep it cool and maybe last a little longer. Last thing I wanted was to build a big block hot rod that gets humiliated at the lights by a Prius.

TBH, I haven't played with the fuel mix any, other than the idle mix to get the best vacuum. It ran great out of the box. If it ain't broke, don't fix it. The rejet kit was bought while the engine was being built, anticipating a tune needed. It's still sitting on the shelf unopened.

Spark plugs wires do have a loom, or separator if you will, made of zip ties. One long tie around all the wires (spaced 8" apart) and another tie between each individual wire, so they all lay flat and parallel to each other. None of the wires touch. There's 1/4 to 3/8" between each wire. This is in addition to fiberglass heat braid on each wire. So ignition cross fire is kept at a minimum. And the whole assembly is held up with more zip ties to the long chrome Tee bolts on the valve covers. It looks neat & sharp, organized, away from the headers & all professional like, can't tell they're zip ties because the "clasp" is hidden behind or under the wires. Those never melted, only the insulated boots and the right angle plug caps. Those fat Indy Head primaries are dangerously close to plugs 2, 3, 6 & 7. The insulated boots sleeves scorch where they touch the header and cook the plug wire boots, leading to shorts, a dead firing cylinder and loss of power. I'm on my 2nd set of wires & insulators now and it's barely broken in.

When I said my wire looms melted, I meant the split loom that covers not the plug wires but other wires. They come in varying sizes and colors. I got a 4 pack of 10' each to organize and clean up the engine bay. The wires to the alternator used to run above the header, THAT'S the loom that melted. Burnt they one of the wires and dead shorted one of the field wires to the header, sending volts to 18 when I pulled over and fixed it. It's been replaced and routed along the intake now.

Not real sure what my timing is at, the timing mark is nowhere near TDC. It's off nearly 90°! Sometime during the 48 year lifespan the inertia ring on the damper has slipped. Mileage also unknown, speedo has never worked, even with a fresh cable and new worm gear in the tail shaft. Odo reads 8K and the title says mileage exempt, meaning it's rolled at least once. I use a GPS app on my phone to track my speed & mileage. But it's safe to say it's at least 108,000.

Radiator shop had the radiator 2 weeks, cost a pretty penny too on account of it being aluminum. Most radiator shops wouldn't touch it. They cleaned up all the rust and scale inside & fixed all the pinhole leaks. It flows really well.

Machine shop that did the block & heads vatted the motor, bored the cylinders, decked the block & heads, installed new cam bearings, freeze plugs and did a 3 angle valve job. We had 2 sets of heads, the original 2 bbl smog heads and a pair of motorhome heads we picked up at fleabay. They chose the best heads, valves and springs from both and provided me fresh heads and the rest in loose parts. We (my brother & I) assembled the rest of the motor ourselves. So yeah, there's no sludge in the block.

The original puke tank was missing when I got it. So I "recycled" a 24 oz NOS energy drink can. It's mounted with the NOS label showing, complete with a stainless braided hose and anodized fittings. The ignorant kids point to it and say, "Oh look! It has nitrous!" And it works, as a puke tank anyway. I keep it half full.

Thermostat was pulled after my last trip to Cars & Coffee to see if it would help the overheating issue. It didn't. Still got hot, just took longer to do so. It was a high flow 180° version. Playing with the timing didn't help. Retarding it makes it slow, advancing it makes it knock. So I guess I need to jet it up richer. I only feed it ethanol free super, 91 octane. When I built it I replaced ALL the rubber hose with ethanol friendly fuel lines & viton seals in the carb (expensive!), in the event that I was out of gas and have no choice but buy blended gas. Ethanol does burn cooler and cleaner, but it has less thermal BTUs, meaning less power. It also absorbs moisture, leading to gas tank rot, corrosion in the carb & fuel lines, and it separates over time. Seeing as my car may sit for weeks at a time, it's not an attractive option.

On a side note: There's a guy across the street with a 64 Corvair he's had me work on. Drives it maybe once a couple months, keeps the tank full of the cheapest gas he can buy (E15 blended 87 octane). And he wonders why it runs like shit. I've had to replace the fuel pump, filters and rebuild the carbs. Gas is yellowed, smells funky, carbs were varnished big time. And there were purple crystals in the carb horn vents, lots of funky green varnish inside and out. Ethanol. He doesn't live there, it's his vacation lake house, he keeps his Corvair parked there. My dad & I talked him into letting us (dad) take it with us to Cars & Coffee once a month, let it stretch it's legs, charge the battery, keep it running good.

There is no heat blanket lining the hood of the Chrysler, and after a 20 minute drive the hood is too hot to touch or sit on. I haven't used my IR gun on it yet, but next time I go to Cars & Coffee (August 21, my birthday) I'll bring it to see. I'll also check the headers, radiator, and other places too.
Thanks for the information and clarifications!

I'll tend to concur on the torque converter, but it can still be a tad loose for a street engine with normal rear axle ratios, which should be a 2.71 unless it had the optional 3.21. Be that as it may. But the 1.77 low gear makes no sense, as the orig TF low gear is 2.45.

There was a 440 Motorhome Head and a normal 440 cyl head that could be on a motorhome. The real MH heads have individual exhaust ports and a normal intake port side, with what looks to be to be a LA open chamber combustion chamber. Two different breeds of B/RB head, but the real MH head has exhaust ports which seem to be better than the normal B/RB cyl heads.

Many people like to talk about "smog heads" as if they are all bad, but after somebody actually put some Chry 452s on a flow bench and ported them like they would do a 906 head, they seemed to be surprised that both castings were really very close together. Enough so that the former condemnations were invalidated. On flow numbers, that is. What is also important is combustion dynamics, not just hard and fast flow numbers. Which makes the quench dome pistons with an open chamber head work so well, in that it makes that open chamber act like a closed chamber head, getting more active air flow, which usually means a better burn of the mixture. A side note.

Spark plug/wire touching the headers IS usually a normal part of exhaust header installation. Just have to find the correct routing (sometimes from underneath or from behind the rear cyls to get things done. Parallel routing of the wires can look good, BUT at some point in their paths, the wires usually need to cross at a 90 degree angle so better minimize near-wire cross-firing.

One of the real purposes of the underhood fiberglass "insulator" is to (as the late, old-line Chrysler service manager at the local dealership told me back in the 1960s, the real purpose of that pad is not to dampen noise (as it does), but to keep engine heat from cooking the paint off of the outside of the hood, with time. Add that to heat from the TX sun, so the paint is attacked from both sides of the metal. Which, even with a hood pad, means that the horizontal paint surfaces would fade after a year or so as the vertical surfaces would look shiney and newer, especially the lighter metallic colors on GM cars.

Crank dampers don't just turn on their hubs with age, they also usually move outward as they turn. This is usually a visual situation. But there usually is a physical relationship between where the crankshaft keyway is and the connecting rod angle when #1 is at TDC. For example, on a SBC, which is very similar to a B/RB Chrysler in many architectural areas, when #! is at TDC, the keyway's projected path parallels the #1 connecting rod (crankshaft certer to center of the piston pin), regardless of where the timing mark on the balancer might be. Have you checked the timing using #6 cyl, as it's 180 degrees after when #1 cyl fires? Just a reference point. In any event, might chase down a new balancer before the inertia ring on your existing one flies off and hurts something expensive, for good measure.

Timing "by ear" can be troublesome and problematic. It was done decades ago when having a timing light was something that only serious racers or repair shops had (their relative expense was an issue, plus availability), but now that they are comparatively inexpensive (with many turning up on online auctions, even the dial-back ones), everybody really needs one. A "light trace rattle" on mild acceleration is not that bad, but a big solid clatter at WOT or heavy throttle is. Both are not desired, but one is more critical than the other one is. It is possible that you can have well past the 12.5 degrees BTDC (initial timing on our '66 383 2bbl Newport) and the engine still start pretty good and quickly. Unless somebody has modified the advance curve from stock, there can be other "too much" issues when the vacuum advance is working. Like at part throttle cruising speeds on the highway, sometimes. But knowing exactly where the ignition timing is is important. A good dwell tach and a dial-back timing light are good items to have for accurate tuning and diagnosis. Better solutions than the old "timing tape" we used to stick to the dampers in the '60s-'70s.

In the mean time, set the timing to prevent ignition clatter (regardless of how slow the car might feel) and go out and drive it about 10 miles or more on the highway. Use the IR heat gun to check underhood temps (radiator tank, radiator core, radiator hoses, surrounding sheet metal body parts). 180 is where things used to run, with particular engine areas being a little bit hotter, with 20-30 degrees F not really being that critical for coolant temps, but when things get close to 260 degrees F, THATS when concerns of non-performance should become operative on a 16psi pressurized cooling system, by observation. Also reference where the needle on the instrument panel gauge is while all of this is happening, too.

For good measure, find a factory-style coolant recovery jug for the car. Your "catch can" might have been legal for drag strips, but unless the cooling system is "tank full" ultimate cooling capacity can be compromised a bit (which is usually compensated for in the original sizing of the radiator and such).

Unfortunately, you've got some more "playing" to do as you learn about, diagnose, and tune the engine in the car. Part of the fun of making things work as well as they can, together, and THEN knowing how to operate the car for optimum obtainable results. Like only part-throttle from a dead stop before applying WOT under hard acceleration. Heavy car with good traction is not a mix for "giant smokey burnouts", usually, without a much deeper rear axle ratio. Or some upgraqded u-joints!

Enjoy!
CBODY67
 

SuperDave

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Didn't catch if anybody mentioned it, but fan shroud . . . ? Are the electric fans supplemental, or replacing the factory setup?

Replacement. Original factory fan, clutch & shroud long gone before I got it. In its place was a pathetic slender electric fan that had less power than a hamster on a wheel. This was when it still bore the original 2bbl carb and it was adequate at the time, it never overheated the stock motor. This was also during winter/spring of 2019 in coastal Florida panhandle.

Replacing it is a dual fan assembly from a Town & Country minivan. Side by side with power applied, the twin setup would blow empty cardboard boxes away where the single struggled to move leaves, so we decided to use that. Double sided foam tape seals the sides, top & bottom edges of the fan to the fins, but there is an inch along the top & bottom of exposed radiator fins. Ya think maybe they should be blocked off? The minivan relay (with a massive heatsink) was retained and is triggered by an additional relay slaved to the ignition key circuit. Hotwired to run on high speed, it pulls an impressive amount of air thru the radiator. It ran fine when I lived in Florida, but since moving to East Texas it's been running warm. It has only overheated and boiled over once. At the time it also has a minor oil leak at the rear of one of the valve covers and I discovered it was also 2 quarts shy, so that may have been a contributing factor. Oil pressure dropped and temps were up, which came 1st? Not sure but they went hand in hand. Either way, the gasket has since been fixed. So far it hasn't lost any oil, but I haven't taken it out on a long drive since then to see if it still overheats.

However, it has ALWAYS been very hot under the hood. That is the issue I'm trying to address.

Let me say it again: aside from the block, crank, rods and oil pan, NOTHING on this motor is STOCK! It's a hot rod dressed as a sinister sedan.
 

Mr C

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How about going through the ENTIRE cooling system correctly???
From A - Z. Soup to nuts. The whole enchilada.
You're chasing your tail.
Do you even know how to thoroughly troubleshoot overheating?
That should have been your opening post.
Commando1...don't bother...he'll just get defensive, claim you're a "stock numbers matching guy" and tell you to "bite me" like above.
Brags about the expensive stainless rockers, then demands a cheap solution to his heat issues and he's not even running a thermostat. I'm having flashbacks to the downfall of the C Body Drydock.
I have no time for that crap.
 

SuperDave

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Crank dampers don't just turn on their hubs with age, they also usually move outward as they turn.

It tried, the 3 groove bottom pulley stopped it. It's maybe 3/16s of an inch forwards from flush. We tried to use timing tape but it won't stick. The paint on it isn't conducive to adhesive.

Heavy car with good traction is not a mix for "giant smokey burnouts", usually, without a much deeper rear axle ratio.

No Shit! The tires do boil but they also bulldoze the locked front tires forwards, leaves 2 pairs of scratch marks on the pavement. Only way to achieve a legit burnout is to cheat and start with the rear tires in a puddle!
 

CBODY67

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No Shit! The tires do boil but they also bulldoze the locked front tires forwards, leaves 2 pairs of scratch marks on the pavement. Only way to achieve a legit burnout is to cheat and start with the rear tires in a puddle!

(Boils the rear tires, pushing the locked front wheel, but takes the rear tires in a puddle for a "legit burnout"? Interesting! All with a 1.77 low gear ratio and 3.21 rear axle ratio? No bat guano!)

What rear tire sizes and tread widths?
 
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