340 with edelbrock heads overheating

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I have an Eddy Headed 340... Fought overheating for awhile, flushed everything to the point of popping the freeze plugs so I could get everything completely clean... Tried a couple radiators, shrouds, high flow water pumps, thermostats, tried a viscous drive fan, a solid fan & currently dual electric two speed fans with a shroud....... went through the carb, rejetted a little fat even though the A/F was reading good... Had 14 degrees of base timing & 35 total.... And if you weren't paying attention it would still slowly climb till it buried the needle...

The thing that fixed it I still don't understand.. But after talking with a buddy who's pretty well known for tuning hot rods, his comment some engines don't do what you expect, but they will tell you what they want.... I just accept it...

I increased base timing & it got better... I kept increasing base timing till I had base at 34 degrees.. The distributor advance is now locked out... It starts easily, it doesn't ever ping, it runs great, pulls down 17-18 mpg and it runs 180 all the time....
 
dano said:
What are you running for fans? The Champion electrics with their shroud are known to cause issues at bot idle and driving.

Is all the air burped out of the system?
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regular 7 blade metal fan no fan clutch. Same set up as I had before the head swap and was cooling just fine before.
 
1WildRT said:
I have an Eddy Headed 340... Fought overheating for awhile, flushed everything to the point of popping the freeze plugs so I could get everything completely clean... Tried a couple radiators, shrouds, high flow water pumps, thermostats, tried a viscous drive fan, a solid fan & currently dual electric two speed fans with a shroud....... went through the carb, rejetted a little fat even though the A/F was reading good... Had 14 degrees of base timing & 35 total.... And if you weren't paying attention it would still slowly climb till it buried the needle...

The thing that fixed it I still don't understand.. But after talking with a buddy who's pretty well known for tuning hot rods, his comment some engines don't do what you expect, but they will tell you what they want.... I just accept it...

I increased base timing & it got better... I kept increasing base timing till I had base at 34 degrees.. The distributor advance is now locked out... It starts easily, it doesn't ever ping, it runs great, pulls down 17-18 mpg and it runs 180 all the time....
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hmmm, ok yeah increasing the timing just seems like too easy a fix lol- very rare that i have an easy fix on anything lately, my luck has not been that good. , But I will give it a try i am at 12 right now I do have the fabo plate in it to lock it at 20 degrees initial. Ill bring it up till all in at 35 degrees and see what my initial timing is at.
 
RogerRamRod said:
I'm running hot as well. I "think" my issue is coolant flow. My crank pulley diameter is small because that was the only one I could come up with that was the right height (if thats the correct description) to line up with the other pulleys. The damper I bought (on the advice to run the best one I could afford) is thicker than original, which I didn't think of, I went with what they said "fits small block mopar" . I did at least learn through this whole process that "fits" probably means- fits but requires many other modifications.
I could move the Alternator out, but then the W/P doesn't line up, if I space the W/P pulley out, then the fan gets too close to the Rad. etc,etc.
PS, Does anybody know a good source of mopar crank pulleys with different heights and diameters? Or smaller diameter W/P pulleys?
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I run this larger CVF crank pulley. Their pulley kits come with an under driven crank pulley so I bought them all separately. Not sure if it would work with your other pulleys but you always could swap them all for the CVF versions, sell what you have to recoup some $$$

Chrysler Small Block Crankshaft Pulley 2V - High Flow

BC53FDB1-8769-4392-BB9B-0320D4BBB2BD.jpeg


106DC06B-C698-44EC-9773-8A0110DE7C50.jpeg
 
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My 340 in my 64 dart overheats also and nothing but an electric fan helped.

By the way lowering the temp of your thermostat doesn't increase the cooling ability of your system. if it is overheating with an 180 then it will overheat with a 160.
 
trapster said:
My 340 in my 64 dart overheats also and nothing but an electric fan helped.

By the way lowering the temp of your thermostat doesn't increase the cooling ability of your system. if it is overheating with an 180 then it will overheat with a 160.
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yeah i know i had a 160 in there before the engine rebuild. Because of covid could not get another 160 for a few weeks and i had a 180 on hand . I was going to change to the 160 anyways so thought i would do it now in case the was the problem. Nope, not so lucky
 
trapster said:
you have a bigger Radiator than what is in a 64 dont you ?
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now i do. i had a champion 2 core 19 inch and it kept the car at 180 no matter what until the head swap. now a champion 3 core 22inch. Had problems with the 19 inch hitting the hood, the 22 inch does not hit the hood. the neck is sitting further back so it does not hit the hood any more.
 
The way I read post #1, only the heads were changed, existing cam retained. So if it ran cool, I don't see why timing would be an issue if the timing was not changed.
 
Early a body said:
hmmm, ok yeah increasing the timing just seems like too easy a fix lol- very rare that i have an easy fix on anything lately, my luck has not been that good. , But I will give it a try i am at 12 right now I do have the fabo plate in it to lock it at 20 degrees initial. Ill bring it up till all in at 35 degrees and see what my initial timing is at.
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The FBO plate does not control initial. That controls the limit to total. So, if you have it on 20 that means it will add 20 degrees to "whatever" your initial timing is. So if you increase your initial to say 18, you now have 38 total and that's too much. Your engine can likely stand "around" 20 initial......plus the 20 mechanical you have and you now have 40. Way too much.
 
IIRC my initial is 18 and I have the FBO plate dropped into the 14 slot giving me a 32 total. I am just getting started, & expect to tweak it some. I used a vacuum gauge to get the initial, this was how someone told me years ago, but I had to search around to remind myself, had been out of the car game for a while.
Gauge connected to manifold source. Make sure no vacuum leaks, vacuum advance disconnected and plugged, Advance timing. Each time RPM & vac go up, reset RPM back down & repeat. once you reach as much vacuum as you can, back your timing off a couple degrees. Probably find yourself close to 20 somewhere.
34ish seems to be a good starting point for TOTAL (this is NOT incl. vacuum numbers yet), so - Subtract your new timing from 34, and that is the # slot on the FBO plate to start with.
#1- Listen for any pinging, dial it back 1 or 2 before going any further
 
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Early a body said:
hmmm, ok yeah increasing the timing just seems like too easy a fix lol-
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Well, my dad's 440 was getting hot a cruise on a flat road at 80 deg F outside temp going 65 mph, it would creep up to and over 210 deg F. This is in a 66 Coronet 500, 4 speed, 3.91:1 gears. .040 over 440, 4th largest Voodoo cam, ported 915 heads. He has a 3 core Champion radiator and fixed fan, no shroud. He was ready to buy an even bigger radiator and I told him don't, see if it's a tuning issue first. He has a Holley 870 Avenger. I said kick the initial timing up to 18 degrees (he was at 16) and give the idle jets about an 1/8 turn and go for a drive. First drive it crept to 195 and stayed. He gave it another 1/8 turn and goes to 180 now under the same conditions.

So small easy changes, big difference in outcome.

But, you should also check the rest of the system as other have noted to be sure they are correct too. Pulley size, spring in lower hose, pump capacity, thermostat flow (there are high flow thermostats too), etc.

My 340 wants 28 degrees initial with aluminum Speed Master heads and would probably take more. Any less and it would bog coming off the clutch. Mine stays at 180 Deg, hot boxed in my garage tuning on it.
 
12many said:
I run this larger CVF crank pulley. Their pulley kits come with an under driven crank pulley so I bought them all separately. Not sure if it would work with your other pulleys but you always could swap them all for the CVF versions, sell what you have to recoup some $$$

Chrysler Small Block Crankshaft Pulley 2V - High Flow

View attachment 1716098557

View attachment 1716098558
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It's too bad they don't have a single groove version of that crank pulley. I also wished they had a set that overdrives the w/p.

If you recall, what water pump pulley do you run with that crank pulley?
 
dano said:
Well, my dad's 440 was getting hot a cruise on a flat road at 80 deg F outside temp going 65 mph, it would creep up to and over 210 deg F. This is in a 66 Coronet 500, 4 speed, 3.91:1 gears. .040 over 440, 4th largest Voodoo cam, ported 915 heads. He has a 3 core Champion radiator and fixed fan, no shroud. He was ready to buy an even bigger radiator and I told him don't, see if it's a tuning issue first. He has a Holley 870 Avenger. I said kick the initial timing up to 18 degrees (he was at 16) and give the idle jets about an 1/8 turn and go for a drive. First drive it crept to 195 and stayed. He gave it another 1/8 turn and goes to 180 now under the same conditions.

So small easy changes, big difference in outcome.

But, you should also check the rest of the system as other have noted to be sure they are correct too. Pulley size, spring in lower hose, pump capacity, thermostat flow (there are high flow thermostats too), etc.

My 340 wants 28 degrees initial with aluminum Speed Master heads and would probably take more. Any less and it would bog coming off the clutch. Mine stays at 180 Deg, hot boxed in my garage tuning on it.
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Makes me feel better knowing mine isn't the only one...
 
RogerRamRod said:
IIRC my initial is 18 and I have the FBO plate dropped into the 14 slot giving me a 32 total. I am just getting started, & expect to tweak it some. I used a vacuum gauge to get the initial, this was how someone told me years ago, but I had to search around to remind myself, had been out of the car game for a while.
Gauge connected to manifold source. Make sure no vacuum leaks, vacuum advance disconnected and plugged, Advance timing. Each time RPM & vac go up, reset RPM back down & repeat. once you reach as much vacuum as you can, back your timing off a couple degrees. Probably find yourself close to 20 somewhere.
34ish seems to be a good starting point for TOTAL (this is NOT incl. vacuum numbers yet), so - Subtract your new timing from 34, and that is the # slot on the FBO plate to start with.
#1- Listen for any pinging, dial it back 1 or 2 before going any further
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I didn't like the FBO plate. It's not accurate. I had to use the smallest slot (10 degrees) and was still getting 16 degrees mechanical. That's just too big an error margin. I pulled it back out, removed the distributor governor and welded the slots and filed them down to get only 10 degrees mechanical. So now I'm at like 20.5 initial and 30.5 mechanical. Slant sixes don't like much more than about 30 total. Yall need to check these plates with a GOOD digital light though, to make SURE you're getting what the plate says, because I was not.
 
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RustyRatRod said:
I didn't like the FBO plate. It's not accurate. I had to use the smallest slot (10 degrees) and was still getting 16 degrees mechanical. That's just too big an error margin. I pulled it back out, remover the distributor governor and welded the slots and filed them down to get only 10 degrees mechanical. So now I'm at like 20.5 initial and 30.5 mechanical. Slant sixes don't like much more than about 30 total. Yall need to check these plates with a GOOD digital light though, to make SURE you're getting what the plate says, because I was not.
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Good to know, thanks for the heads up.
 
RustyRatRod said:
I didn't like the FBO plate. It's not accurate. I had to use the smallest slot (10 degrees) and was still getting 16 degrees mechanical. That's just too big an error margin. I pulled it back out, removed the distributor governor and welded the slots and filed them down to get only 10 degrees mechanical. So now I'm at like 20.5 initial and 30.5 mechanical. Slant sixes don't like much more than about 30 total. Yall need to check these plates with a GOOD digital light though, to make SURE you're getting what the plate says, because I was not.
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ive been using the plates for years with no problems. from slant six to big blocks. so atleast i dont have to worry about this issue this time
 
Early a body said:
340 .40 over with less than 1,000 miles on rebuild
stock pistons
flat tappet cam
initial timing at 12 degrees
edelbrock avs 800 cfm carb
1964 dodge dart

I decided that i would swap out the x heads to eddelbrock 340 heads.
Installation went fine but now i have developed an overheating problem.
At idle it will heat above 210. I have not tried to see where it would stop i just shut it down.

the radiator i had on it cooled just fine would not get past 180. This was a champion 2 row 19"- this is on a 64 dart

Changed to a wider 22inch 3 row champion radiator that i had stored away. no difference
changed to a 160 thermostat . no difference

Using 273 adjustable rockers and double checked to make sure the valves are adjusted properly

coolant looks good . I am using prestone 50/50 premixed

oil looks good Valvoline 10-30 vr same oil i use in all my flat tappet cars

Not sure what else it could be. Did the head gasket blow but did not cause cross contamination of the oil and the coolant?

Thanks in advance.
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It probably overheats or gets warm at low speeds and idle? That's too little initial timing. If it's getting hot it Cruise speeds down the freeway then you have an issue with the cooling system or possibly too much timing and or pinging. If you have stock 10 and 1/2 to 1 Pistons and running Edelbrock heads that are like 65 or something cc's... you might want to try some 91 octane or better but experiment with just raising the timing to about 18 and if you can possibly only drive it at that low speeder cruise at that low speed to keep the total timing down see if all the sudden it doesn't run cooler at idle
 
Keeping an eye on this thread as mine is doing the same thing. It didnt do it in cooler weather only as the heat and humidity changed. When driving it cools back down to 180 degrees. Il have to revisit timing etc as well. Hate to mess with it cause it runs so well.

Tim
 
ok, i pulled the water pump off. Its a high flow one. I am going to replace it anyways. Dont like to reuse them anyways. I am thinking the colling system has a restriction. I stuck my finger into the holes for the coolant intake holes in to the block. One hole was severly restricted the other was not restricted. The restriction was silicon gasket maker i used when i put the timing cover on after the rebuild. This one side of the timing cover was quite pitted so i used alot of goop. I cleaned it out. But again i dont think i am going to get that lucky as the car was running with this restriction to begin with. i guess i will see.

not sure hoe smart this was but i used my shop vac and sucked the rest of the coolant out of the block with hopes of pulling anything else out that may be restricting. if this did not solve the problem off with the heads.

i dont think its the timing it just made no sence where even at 12 degrees of inital it would warm up within 5-6 minutes. i do like more inital and will try bumping it up to 18 and see what happens .
 
Timing is easy & free.. If 18 helps try 24... I was very surprised every time I added timing the temp came down further... Like I mentioned my mechanical advance is locked out & timing is locked at 34 degrees... It runs at the thermostat number virtually without fail...
 
Early a body said:
i dont think its the timing it just made no sence where even at 12 degrees of inital it would warm up within 5-6 minutes. i do like more inital and will try bumping it up to 18 and see what happens .
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Don't be afraid to give the idle fuel each an 1/8 turn and see. Worst case you turn it back.
 
ill give
1WildRT said:
Timing is easy & free.. If 18 helps try 24... I was very surprised every time I added timing the temp came down further... Like I mentioned my mechanical advance is locked out & timing is locked at 34 degrees... It runs at the thermostat number virtually without fail...
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ill give it a try. still waiting on water pump
 
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