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overheating (?) issues

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tdkask View Drop Down
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    Posted: Aug/12/2017 at 8:07pm
New member here. Posting for some help.

I have a 360 in my '80 CJ7 and I'm having some issues I can't sort out. I'm here asking for ideas or experiences.

The engine was pulled from a '74 J10 and is stamped for a .060 over rebuild, but I don't know anything about any work done to the heads or whether the pistons are stock.

I ran the engine for quite some time with the stock 2 bbl carb and intake, and had really no issues. But I wasn't that impressed for it being a 360, of course. FWIW,  it has an aluminum 3-core radiator.

So during a recent series of upgrades on the Jeep I swapped in a CompCams 260H cam and lifters, a Edelbrock Performer intake, Patriot shortie headers, and an Edelbrok 1406 carb.

I'm having issues with it overheating and not staying running. Basically the engine starts heating up, fuel stops flowing into the carb, and it shuts off. My pre-filter just after pump is clear, and I can literally watch the fuel inflow decrease to a stop as the engine gets warm.

First, I assumed the carb is getting too hot. I added a 3/8" phenolic spacer. The carb still seems to be getting a little hot and it all seems to be little change.

Next, I swapped in a Holley DP I had, and still no change.

I am running the stock mechanical pump, clear pre-filter, and stock filter with "regulator" and return line.

My next steps are to address cooling issues (fan shroud, relocate PS and trans coolers) and a much taller (1"?) spacer.

I just don't know what else could be causing the issues other than overheating, which causes percolating in bowls, and therefore back pressure on fuel system? As soon as the engine cools off the fuel comes back into the clear filter.

When it's not hot yet, it idles great, and runs like a bat out of heck.

Has anyone had these issues before? Will warm carb actually push the gas out of carb and cause back-pressure on the pump? Any other ideas where to look?

Thanks for any help. I'm out of good ideas and getting very frustrated.

I appreciate it.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote one bad rambler Quote  Post ReplyReply Direct Link To This Post Posted: Aug/12/2017 at 8:18pm
Have you tried running the car from a remote tank/gas can from the stock pump?
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tdkask View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tdkask Quote  Post ReplyReply Direct Link To This Post Posted: Aug/12/2017 at 8:40pm
Why would you ask this?

I haven't... but the fuel cell and fuel lines are also all new, so shouldn't be a clog. Fuel cell is vented. And it happens as it gets warm, stops as soon as it cools off.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tdkask Quote  Post ReplyReply Direct Link To This Post Posted: Aug/12/2017 at 8:45pm
With thermostat removed, does water forced into the heater core loop circulate through entire engine water jacket? I was thinking of splicing in there with water hose and forcing cold water through to see if this proves that it's just a cooling issue? I suspect that a really hot carb would cook the gas and cause the issue?
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tdkask View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tdkask Quote  Post ReplyReply Direct Link To This Post Posted: Aug/12/2017 at 9:41pm
One thing I just considered, the new intake (maybe?) has the exhaust crossover? If so, I might try to block that off.
Also, a bigger spacer?

Edited by tdkask - Aug/12/2017 at 10:21pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Someassemblyrqd Quote  Post ReplyReply Direct Link To This Post Posted: Aug/12/2017 at 11:33pm
Did you pressurize the water system to get all air pockets out?   What,s the operating temp climb to when it craps out? Have you checked float bowl for proper height?   Timing? Work one issue at a time.

I,m sure others will chime. Accept all inputs. There,s a wealth of knowledge in this Forum. Greg
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Post Options Post Options   Thanks (0) Thanks(0)   Quote thedowell Quote  Post ReplyReply Direct Link To This Post Posted: Aug/12/2017 at 11:43pm
The Intake you are using has an Exhaust crossover that runs under the carb. This has a tendency to overheat the carb. I had the same issue. Because I don't drive my car in the winter, I removed the intake and welded the cross over shut and my problem went away. If you plan on driving in cold weather you might try restricting the flow through the cross over. or using a bigger spacer to get more distance between carb and intake. Others have gone to the Air Gap intake with good success.
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tdkask View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tdkask Quote  Post ReplyReply Direct Link To This Post Posted: Aug/13/2017 at 9:29am
An air gap isn't in the budget at this point. Also, there's only a couple weeks of cold-ish weather here in S. GA. However, I don't have the ability to weld aluminum. I wonder if that steel putty stuff would work? Or maybe some kind of block off between heads and intake?

I'll be getting a much taller spacer in today and addressing the cooling. Got to get some improvement here. I'm missing out on all the fun.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote scott Quote  Post ReplyReply Direct Link To This Post Posted: Aug/13/2017 at 11:47am
I see you are running the stock style fuel filter with a return line. Try plugging the return line, or replacing the filter with one that does not have a return line.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tdkask Quote  Post ReplyReply Direct Link To This Post Posted: Aug/13/2017 at 12:20pm
Originally posted by scott scott wrote:

I see you are running the stock style fuel filter with a return line. Try plugging the return line, or replacing the filter with one that does not have a return line.
I started that way. I added in the filter with the bleedoff as an attempt to alleviate the issues.
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