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Old 05-22-2022, 10:35 PM   #26
geezer#99
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Re: Frustrated overheating, timing issue?

Also for a vac advance limiter on your hei they make one like this.
You can make one for other distributors too.

https://www.holley.com/products/igni...ts/parts/84281
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Old 05-22-2022, 10:57 PM   #27
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Re: Frustrated overheating, timing issue?

Condensation out the tailpipe until the truck warms up is normal, within reason. It's only when it keeps up after the engine is warmed up that it becomes an issue.
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Old 05-22-2022, 11:22 PM   #28
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Re: Frustrated overheating, timing issue?

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Originally Posted by geezer#99 View Post
Another one!
Do you have a catch can/overflow coolant return system or just a vent line to the ground?
I’m excited to report that I have a line going from the overflow nipple into a yeungling bottle. I’ve driven it like this for almost 2000 miles.
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Old 05-22-2022, 11:25 PM   #29
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Re: Frustrated overheating, timing issue?

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Originally Posted by Steeveedee View Post
Condensation out the tailpipe until the truck warms up is normal, within reason. It's only when it keeps up after the engine is warmed up that it becomes an issue.
It was coming out the tailpipe after warming up in the driveway again tonight. I’ll have a better idea in the morning after driving to work.
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Old 05-22-2022, 11:27 PM   #30
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Re: Frustrated overheating, timing issue?

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Originally Posted by geezer#99 View Post
Also for a vac advance limiter on your hei they make one like this.
You can make one for other distributors too.

https://www.holley.com/products/igni...ts/parts/84281
I adjusted the rate with the allen screw, got it down to 10 vacuum advance at manifold
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Old 05-22-2022, 11:27 PM   #31
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Re: Frustrated overheating, timing issue?

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I’m excited to report that I have a line going from the overflow nipple into a yeungling bottle. I’ve driven it like this for almost 2000 miles.
Is the line always covered with coolant and is it set up to return the coolant to the rad when it cools off?
AKA a closed coolant system.
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Old 05-22-2022, 11:44 PM   #32
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Re: Frustrated overheating, timing issue?

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Is the line always covered with coolant and is it set up to return the coolant to the rad when it cools off?
AKA a closed coolant system.
There’s only one line, the outlet of the line is always in coolant.
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Old 05-22-2022, 11:59 PM   #33
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I’m excited to report that I have a line going from the overflow nipple into a yeungling bottle. I’ve driven it like this for almost 2000 miles.
Mmmmm, Yuengling
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Old 05-23-2022, 12:12 AM   #34
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Re: Frustrated overheating, timing issue?

The engine that was in my truck when I bought it had a leak in the intake manifold gasket that was allowing coolant to be pulled into one of the cylinders. The spark plug was all caked up. I'm not saying this is the problem with your engine, but have you looked at your spark plugs recently? Their condition might tell you something about what's going on.
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Old 05-23-2022, 12:15 AM   #35
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Re: Frustrated overheating, timing issue?

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The engine that was in my truck when I bought it had a leak in the intake manifold gasket that was allowing coolant to be pulled into one of the cylinders. The spark plug was all caked up. I'm not saying this is the problem with your engine, but have you looked at your spark plugs recently? Their condition might tell you something about what's going on.
I have, I just changed out plugs two weeks ago - still have them all actually. Didn’t do a good job keeping track if which went to what cylinder. They all looked normal at a glance - nothing crazy like that.

A family member is mailing me an air gap soon, so I’ll have the intake off and will instal felpro printoseals. Guess I better figure if I’ve got to replace the head gasket before I do that work - I’de be almost halfway to removing the heads anyway.
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Old 05-23-2022, 05:51 AM   #36
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Re: Frustrated overheating, timing issue?

I have a cold case rad and 12" fans as well and a LS motor and I am having the same over heating issues, I am running about 204-206 deg. and with their rad cap it is blowing fluid out onto my inside hood, I tried a different cap and have the same issues, so I ordered spal fans and will see if it helps, they should be here tomorrow or weds if it does not help then I am going to see about getting the 14" shroud and fans from cold case.
I have a jeep cj7 with a 400 small block and I spent a ton of money trying to get that thing to quit over heating and found that it was the fan shroud was too close to the rad and it was the same style as cold case has, I went from 210 deg to 190 deg just from getting rid of that shroud and now here again I am having issues with the cold case and it has the same style shroud.
I will post my results with the different fans later this week.
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Old 05-23-2022, 06:57 AM   #37
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Re: Frustrated overheating, timing issue?

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I have a cold case rad and 12" fans as well and a LS motor and I am having the same over heating issues, I am running about 204-206 deg. and with their rad cap it is blowing fluid out onto my inside hood, I tried a different cap and have the same issues, so I ordered spal fans and will see if it helps, they should be here tomorrow or weds if it does not help then I am going to see about getting the 14" shroud and fans from cold case.
I have a jeep cj7 with a 400 small block and I spent a ton of money trying to get that thing to quit over heating and found that it was the fan shroud was too close to the rad and it was the same style as cold case has, I went from 210 deg to 190 deg just from getting rid of that shroud and now here again I am having issues with the cold case and it has the same style shroud.
I will post my results with the different fans later this week.
Sounds like you’re right in the LS normal operating temp, they run hotter. My cold case rad cap was dog crap - i’m using the style with the red pressure release lever on it. If you’re going with bigger rad fans don’t waste your money on cold case ones man, go with derale or something. Sounds to me like you have a pressure problem, not a fan problem.
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Old 05-23-2022, 12:27 PM   #38
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Re: Frustrated overheating, timing issue?

Are your electric fans pushers or pullers? If they are pushers then you have them on the wrong side of the rad. Just something to look at.

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Old 05-23-2022, 01:49 PM   #39
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Re: Frustrated overheating, timing issue?

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Are your electric fans pushers or pullers? If they are pushers then you have them on the wrong side of the rad. Just something to look at.

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They’re pullers
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Old 05-23-2022, 03:42 PM   #40
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Re: Frustrated overheating, timing issue?

spal fans came in and did not mount in the same holes so I sent them back, I guess I will have to buy the 14" shroud set up so I will post how that goes.
I did try a different cap but it is basically the same design just a different manufacture, I will try the cap like you mentioned. and post how this turns out and maybe it can give the original poster some suggestions.

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Sounds like you’re right in the LS normal operating temp, they run hotter. My cold case rad cap was dog crap - i’m using the style with the red pressure release lever on it. If you’re going with bigger rad fans don’t waste your money on cold case ones man, go with derale or something. Sounds to me like you have a pressure problem, not a fan problem.
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Old 05-23-2022, 05:14 PM   #41
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Re: Frustrated overheating, timing issue?

Trying not to hijack but on the LS question I've had super good luck with a single 16" Spal fan and no shroud. 180 degree thermostat in my summer hot rods. 187 ish in my LS6 swapped 98 Wrangler. I use the Wrangler to plow snow in the winter so I need some heat in the cab. Same 16" Spal fan and it has been great for over 14 years. Novak swap radiator.
ECM turns the fan on at 205 and off at 195.
You need to make sure that you don't have any air pockets. I finally bought a vacuum radiator thing at Harbor Freight and it works great.
I always run a 50/50 mix of antifreeze.
Just FYI my 2020 Silverado runs at 210 day in day out.
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Old 05-23-2022, 09:59 PM   #42
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Re: Frustrated overheating, timing issue?

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Originally Posted by LS short box View Post
Trying not to hijack but on the LS question I've had super good luck with a single 16" Spal fan and no shroud. 180 degree thermostat in my summer hot rods. 187 ish in my LS6 swapped 98 Wrangler. I use the Wrangler to plow snow in the winter so I need some heat in the cab. Same 16" Spal fan and it has been great for over 14 years. Novak swap radiator.
ECM turns the fan on at 205 and off at 195.
You need to make sure that you don't have any air pockets. I finally bought a vacuum radiator thing at Harbor Freight and it works great.
I always run a 50/50 mix of antifreeze.
Just FYI my 2020 Silverado runs at 210 day in day out.
Yeah my wife’s 2017 silverado 210 all day long
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Old 05-23-2022, 10:41 PM   #43
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Re: Frustrated overheating, timing issue?

OK folks evening update

Cold in south georgia this morning, ~60F, leave it to nature to mess up overheating troubleshooting. Mechanical guage read 160-170 throughout the drive to work, a little low, but not my biggest issue. Truck had a rough start, trying to stall (like 100 rpm until it started warming up, picked up to normal idle in park, in R and D it wanted to stall, So in the driveway this morning all i did was turn the throttle screw up in increments until putting it in R and D would let me get some kind of movement. During the drive, at stoplights, give it gas and it lugs, tries to stall, until combustion or something catches up, when it does start moving at speed it feels really rough and choppy - almost like a cylinder isn’t firing. same behavior as before - idle got worse as i i drove it, having to put it in park at stoplights. 20min drive to work.

Get to work and I open the hood while running to check the spark plug fitment at both ands, everything is connected. But these are cut to fit MSD wires that I just made so I’m going to check the resistance of the wires again - this wasn’t a behavior of the truck after these wires were installed, it developed later. But the new pertronix distributor is smaller diameter so a few of the wires are tighter - that could be causing an issue. Checking resistance of each wire tonight and have more superconductor wire and ends to make new wires for the tight ones.

Also in the parking lot at work this morning - there was an eye crimp piece not connected to any wire smoking connected to the junction post by the battery. Luckily truck started after work, but once I got home it wouldn’t. Ammeter fused lead was blown. I figured it would be a good idea to be unsafe, keep the positive terminal attached to the battery, and promptly shorted the battery accessory wire to the fender. After a small and frightening electrical fire, I figured i should probably do some rewiring if i wanted the truck to start again. Embarrassing - but everybody poops.
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OK finally on to the carb. Here I am right now getting started on my 6pm task at 1040pm. Very rectangular transfer slots - looking up the procedure to set the two idle screws correctly now.
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Old 05-24-2022, 07:27 AM   #44
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Re: Frustrated overheating, timing issue?

What temp were you running at to consider hot?
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Old 05-24-2022, 07:43 AM   #45
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Re: Frustrated overheating, timing issue?

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What temp were you running at to consider hot?
As stated in the beginning idk what temp I was at that started this whole ordeal - I’ve since at least solved the (maybe overheating issue)

I rebuild the carb again last night, there was some gunk under the jets that I didn’t get before, got my square transfer slots.

https://youtu.be/WD_bhDq_8tY

My brother sent me this, never heard such a good explanation on why to run ported for stock cam, Uncle Tony’s garage also makes the same argument.

I advanced the mechanical quite a bit up to 19, have it switched to port, we’ll see if that fixes the stalling on part throttle from idle and at stoplights this morning. Seems to go better in the driveway.

Also ran a fluid combustion leak test on the rad while warming it up - no yellow fluid at least up to 175F.

Last edited by 69swb; 05-24-2022 at 09:40 AM.
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Old 05-24-2022, 10:36 AM   #46
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Re: Frustrated overheating, timing issue?

Read the following article, it was written by a GM engineer who had a hand in developing the systems. http://www.camaros.org/pdf/timing101.pdf
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Old 05-24-2022, 12:57 PM   #47
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Re: Frustrated overheating, timing issue?

Ran way better from the driveway for about 10mins , then the last half of the drive these symptoms got worse and worse. Stumbling when braking (especially braking hard) to a stoplight, hesitation at part throttle. I wish I could attach a video, there’s a sound pretty close to what an manifold exhaust leak sounds like near cylinders 6/8.

PO “rebuilt” the engine by employing his brother “mechanic”. They put it on an engine stand, pulled off the valve covers, spark plugs, headers, didn’t cover anything but the intake valley with a piece of cardboard, and spray painted the
Block orange. See the collage. The valve photos are in order from cylinder 2-8. I’m feeling like cylinder 8’s umbrella looks quite crooked.

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Old 05-24-2022, 03:48 PM   #48
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Re: Frustrated overheating, timing issue?

I'm just a half a** shade tree mechanic but unless I missed it, I see nowhere where you performed a compression test. This will give you some insight as to the overall mechanical condition of your motor. Not a perfect science but a good gauge to go by.
I would suspect you have a leak opening up with heat added to the equation, could be a head/head gasket or cylinder wall crack.
If the compression test is a good report, then look into the fuel delivery and ignition sources.

The important thing is quit throwing money at it, take it to a reputable mechanic who has the knowledge to sort it out.
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Old 05-24-2022, 04:31 PM   #49
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Talking Re: Frustrated overheating, timing issue?

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I'm just a half a** shade tree mechanic but unless I missed it, I see nowhere where you performed a compression test. This will give you some insight as to the overall mechanical condition of your motor. Not a perfect science but a good gauge to go by.
I would suspect you have a leak opening up with heat added to the equation, could be a head/head gasket or cylinder wall crack.
If the compression test is a good report, then look into the fuel delivery and ignition sources.

The important thing is quit throwing money at it, take it to a reputable mechanic who has the knowledge to sort it out.
I didn’t mention it,but i did conduct a compression test but suspect it wasn’t warm enough (symptoms weren’t present when I conducted the test, because I didn’t think of the valve seals until this morning). Will conduct another one later. I did take it to a reputable mechanic today that agrees there is certainly an issue with that seal on #8.

I’ll throw as much money at it as I want.

Last edited by 69swb; 05-24-2022 at 06:32 PM.
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Old 05-24-2022, 09:31 PM   #50
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Re: Frustrated overheating, timing issue?

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Originally Posted by my kids toy View Post
I have a cold case rad and 12" fans as well and a LS motor and I am having the same over heating issues, I am running about 204-206 deg. and with their rad cap it is blowing fluid out onto my inside hood, I tried a different cap and have the same issues, so I ordered spal fans and will see if it helps, they should be here tomorrow or weds if it does not help then I am going to see about getting the 14" shroud and fans from cold case.
I have a jeep cj7 with a 400 small block and I spent a ton of money trying to get that thing to quit over heating and found that it was the fan shroud was too close to the rad and it was the same style as cold case has, I went from 210 deg to 190 deg just from getting rid of that shroud and now here again I am having issues with the cold case and it has the same style shroud.
I will post my results with the different fans later this week.
Those temps are normal for a modern engine
You are not overheating
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