340 with edelbrock heads overheating

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the 340-edelbrock heads are machined in the chambers to avoid piston to head contact. edelbrock-360 heads are not machined there. i dont think chinese heads are relieved either. you must make sure you have the correct heads. personnaly, i would measure piston to head clearance. i am sure someone here knows what the minimum clearance should be.
 
Early a body said:
i measured the push rod length and its 7.5. so i am good there. my thinking now is its cam timing and may have been like this prior and the edelrock valves hit again bending valves. not sure how i did not have the over heating problem before. i am going to be incredibly pissed if both heads have bent valves.

I am going to take both heads down to the engine builder and have him check both out and take him the motor and tell him to figure it out since he built the dam thing. He better pay for the repair too.
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When I put 273 rockers on my 340 with hydraulic lifters, the 7.5 pushrods were too long. Are your shafts shimmed?
 
Early a body said:
i measured the push rod length and its 7.5. so i am good there. my thinking now is its cam timing and may have been like this prior and the edelrock valves hit again bending valves. not sure how i did not have the over heating problem before. i am going to be incredibly pissed if both heads have bent valves.

I am going to take both heads down to the engine builder and have him check both out and take him the motor and tell him to figure it out since he built the dam thing. He better pay for the repair too.
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But if I'm reading this right, he built it with the 340 X-heads. And it was running fine.

Then you changed the heads to Edelbrocks and then had issues.

Sorta take's him out of the loop since you did that major change.

But looking back at the original post you swapped 340 X head for Edelbrock heads. Typical 340 X head is around 72cc's. Edelbrock 60779 head is 65cc +/-1 cc. Unless I'm missing something, I've only read about 75% the pages of this thread.

That's a significant compression ratio change from what the engine or originally built at. Can the octane of gas you are using work with this new combo

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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ok, i feel like a dumb a@@, but thats nothing new. So my Dad came over and looked at what I had going on. He said the valve did not hit the piston. The pistons are stock or stock style 72-73 340 those are alignment marks so the piston goes in the correct orientation. So I searched the web and found pictures of a 72-73 style piston and it looks just like mine. Ok cool, but i still feel like an idiot.

so it appears the problem may be head gasket related. At least I hope.

The edelbrock gasket they recommend is .50, but edelbrock also recommends the felpro 1008 . possibly its the same head gasket except the 1008 is .39. Edelbrock has felpro make the gaskets.

So i will try it again this time with the edelbrock gasket and see what happens

i looked at the head gasket i had on there and compared to the head and the block. There is only one way to put them on. i did not see any anomolies.

what .50 head gasket do you all recommend ? I have heard the felpros will fail.
 
Early a body said:
ok, i feel like a dumb a@@, but thats nothing new. So my Dad came over and looked at what I had going on. He said the valve did not hit the piston. The pistons are stock or stock style 72-73 340 those are alignment marks so the piston goes in the correct orientation. So I searched the web and found pictures of a 72-73 style piston and it looks just like mine. Ok cool, but i still feel like an idiot.

so it appears the problem may be head gasket related. At least I hope.

The edelbrock gasket they recommend is .50, but edelbrock also recommends the felpro 1008 . possibly its the same head gasket except the 1008 is .39. Edelbrock has felpro make the gaskets.

So i will try it again this time with the edelbrock gasket and see what happens

i looked at the head gasket i had on there and compared to the head and the block. There is only one way to put them on. i did not see any anomolies.

what .50 head gasket do you all recommend ? I have heard the felpros will fail
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Just use the 1008’s. With those pistons you can use the compression
 
if those pistons are slightly out of the deck at tdc, they are not 72-73 pistons. they look more like a cast piston for a 68-71 to me. compare them to a silvolite 1267, you will see what i mean. even enginetec sell a similar piston. they could even be sealed power 428 pistons.
 
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Early a body said:
deck is dirty from the sealant i put on it . it will clean up
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Sealant? On the deck? Head gaskets go on dry. The deck of the block and the cylinder head needs to be clean, flat, and dry. Absolutely no sealant. There are steel shim and some mls gaskets that advise copper coat prior to installation but you aren’t using those.
 
Rat Bastid said:
Just use the 1008’s. With those pistons you can use the compression
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Torque them down in a 3 step progression, using the recommended bolt tightening sequence.

Also put engine oil on the head bolts and their threads to achieve the proper torque specs.

The Edelbrock .050 will give you a little more sealing protection being the 1008 gaskets leaked before.

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George Jets said:
Torque them down in a 3 step progression, using the recommended bolt tightening sequence.

Also put engine oil on the head bolts and their threads to achieve the proper torque specs.

The Edelbrock .050 will give you a little more sealing protection being the 1008 gaskets leaked before.

☆☆☆☆☆
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Instead of oil use something like arp ultra torque.
 
If it's .040 over. It's got some sort of replacement pistons.

If it was fully rebuilt and bore and honed, the guy that rebuilt it should know the compression and piston specs. Did he installed used pistons?

Anyway you need to figure out what pistons are in there and figure out your compression.

I feel like there's some info left out about this "rebuild"
 
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dano said:
That sucks to hear. My 1008 needed a retorque after a few heat cycles. They would lightly weep coolant on both sides after warning the engine up. No other leaks. It happened out of the blue after driving the new motor 6-7 times. I've never had to re-torque the head bolts but read it not uncommon sometimes with aluminum heads.

Are you using bolts or studs?
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Edelbrock recommends retorquing after a heat cycle.
 
fishmens67 said:
Edelbrock recommends retorquing after a heat cycle.
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But I have Speed Masters!! That didn't come with directions.....I have done other engines with aluminum heads and didn't need to but doing my homework I found that sometimes you do. I did read where some people torque them, wait 24 hours and come back and do it again and have found things relaxed.
 
Early a body said:
ok, thanks everyone for your responses.
The weird thing is not every cylinder has the issue where the valve hit the piston. Some are the exhaust valve some are the intake. Some pistons have a lighter impression than others.

Wouldn't if the cam was installed wrong this would happen to all the pistons, exhaust and intake valves?

Maybe the push robs were to long, or i got over zealous at adjusting them?

i see the edelbrock head gasket is thicker than the one i used. That could explain it too.
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Hyd cam? Valve Float
 
hi everyone. sorry out of town for the week. no computer with me just my phone and i cant really see the writing on my phone.

I agree i never use sealant but the engine builder did , so i did i was just trying to copy him will not use any next time.

In the mean time I have spoken to the cam grinder told him what happened. I measured where the intake lifter is in comparison to the exhaust lifter when at exhaust tdc. the intake lifter is 4 degrees higher than the exhaust. The cam grinder said that is fine no problem. I have been searching on line as i have never run into

cam4.jpg
his before and everyone seems to say i need to retard the cam so the intake and exhaust lifter are dead even at exhaust tdc.

I am really getting confused and a little lost on this now as the cam is possible out of time from the get go? Am I reading that right or is my cam grider correct in saying that i should be good? engine has about 600 miles in it since the rebuild.

I have uploaded the cam specs.


pistons are new, they have a part number on them i will look them up.

cam3.jpg


cam2.jpg


cam1.jpg
 
Screenshot_20230617-091556_Gallery.jpg


Dot to Dot, Fires on #6 at TDC in this position.

Intake and Exhaust Lifters on #1 should be straight across level (same height) when the cam is installed Straight Up.

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Cam installed at 12 O'clock
Crankshaft at 12 O'clock

Firing on #1 TDC compression stroke.

Screenshot_20211231-012657_Gallery.jpg


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Early a body said:
Thanks for the photos. so matter what type of cam you have, unless you are trying to do it on purpose the lifters should be even . This may have been the cause of my overheating problem.
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Not if the cam cam has advance ground in. Most cams do, especially comps. Usually they’re +4 when installed dot to dot.
 
TT5.9mag said:
Not if the cam cam has advance ground in. Most cams do, especially comps. Usually they’re +4 when installed dot to dot.
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so you have seen it where the intake lifter is higher than the exhaust and everything was fine.

The cam grider guy i spoke with did not leave me with alot of confidence. Either he did not understand my question or did not want to tell me i messed up. They are a very reputable cam grinder so when they told me it sounds like i installed correctly i was relieve but then i started looking online...... i am still thinking of tearing the timing cover off again and double , triple check my work.
 
I’ll say this, if you didn’t degree the cam when it was installed you’ll never know. And it’s not (100% sure) the cause of your overheating.
 
I would rule out everything under the sun before I EVER suspected camshaft timing the culprit of over heating. Retarded ignition timing would have more of an effect.
 
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