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Old 01-27-2020, 01:53 PM   #1
burner31
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Default Intake manifold getting hot

What would cause my intake manifold to get so hot it's discoloring the paint?
This is something new, it's gotten warm but never this hot before.
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Old 01-27-2020, 01:56 PM   #2
J Franklin
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Default Re: Intake manifold getting hot

A burnt or warped intake valve might do that. A bad exhaust gasket leaking on it might also.
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Old 01-27-2020, 02:41 PM   #3
Bob Bidonde
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Default Re: Intake manifold getting hot

Paint cannot withstand normal exhaust manifold operating temperatures. Try using stove black. Its a coating used on pot belly stoves of olden days.
A manifold that glows red hot is indicative of a retarded spark advance / ignition timing.
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Old 01-27-2020, 02:47 PM   #4
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Default Re: Intake manifold getting hot

I just rebuilt the distributor, so a "retarded spark advance / ignition timing" may be an issue, I'll have to revisit my work and settings.
And it sounds better then a "burnt or warped intake valve", I'll keep my fingers crossed.
Thanks guys...
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Old 01-27-2020, 03:07 PM   #5
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Default Re: Intake manifold getting hot

weak mixture- air leak?
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Old 01-27-2020, 03:21 PM   #6
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Default Re: Intake manifold getting hot

I was going to suggest a timing problem. If you go out on the road with the timing retarded for a length of time the exhaust manifold will not only get hot, it will turn cherry red. Years ago a high school friend tried to drive his Model A from Los Angeles to San Diego. He had no idea what the spark handle was all about and he had it up. At Huntington Beach, about 30 miles into the journey, he notice a red glow through hole in the firewall. It was dark when he pulled over and opened the hook. The exhaust manifold was glowing cherry red.

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Old 01-27-2020, 03:28 PM   #7
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Default Re: Intake manifold getting hot

The rubbing block on new points wear and the gap reduces . When the points gap gets less than eighteen thousands the engine will soon begin not to run as well . Points gap effects timing . Less gap retards , more gap advances . Even slightly retarded operation will cause the manifolds to run hotter .
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Old 01-27-2020, 03:36 PM   #8
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Default Re: Intake manifold getting hot

Yep, new points and everything else, I'll check and reset everything, I have been known to enjoy a beer now and then while working on the old girl, so I could've goofed something.
I'll let you all know how it turns out, going to rain tonight/tomorrow so may be a few days.
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Old 01-27-2020, 04:14 PM   #9
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Default Re: Intake manifold getting hot

Take a different condenser and connect it to the passenger side of the coil and ground. See if the engine runs better. If it does, change the condenser. Easy to try.
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Old 01-27-2020, 07:56 PM   #10
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Default Re: Intake manifold getting hot

Put some Vaseline on the points cam to retard point block wear.
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Old 01-28-2020, 08:27 AM   #11
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Default Re: Intake manifold getting hot

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Originally Posted by Jacksonlll View Post
Take a different condenser and connect it to the passenger side of the coil and ground. See if the engine runs better. If it does, change the condenser. Easy to try.
Curious, what does that do? Is it bypassing the condensor in the distributor?
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Old 01-28-2020, 11:24 AM   #12
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Default Re: Intake manifold getting hot

Quote:
Originally Posted by Purdy Swoft View Post
The rubbing block on new points wear and the gap reduces . When the points gap gets less than eighteen thousands the engine will soon begin not to run as well . Points gap effects timing . Less gap retards , more gap advances . Even slightly retarded operation will cause the manifolds to run hotter .
"Points gap affects timing"? Only when the advance lever is completely up or completely down. Otherwise timing is totally controlled by the position of the advance lever. Most drivers seem to set the timing to where the engine sounds right and feels good. If the point gap has changed, that 'sweet spot' is just a few clicks away from the usual setting.
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Old 01-28-2020, 12:35 PM   #13
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Default Re: Intake manifold getting hot

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"Points gap affects timing"? Only when the advance lever is completely up or completely down. Otherwise timing is totally controlled by the position of the advance lever. Most drivers seem to set the timing to where the engine sounds right and feels good. If the point gap has changed, that 'sweet spot' is just a few clicks away from the usual setting.

What Purdy said was true.
We can change change our timing with a click or two of the lever, but, there comes a point of no return.
There is a reason to set points before the timing.
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Old 01-28-2020, 12:36 PM   #14
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Default Re: Intake manifold getting hot

Old31, it does not bypass it, it just adds a known good condenser.
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Old 01-28-2020, 12:59 PM   #15
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Default Re: Intake manifold getting hot

The spark happens when the points open . More gap will cause the spark to happen sooner because the points will open a bit quicker . The most important thing about ignition timing is where the rotor tip points when the timing pin drops into the indentation on the cam timing gear . The trailing edge of the rotor tip should point exactly at the number one contact in the distributor cap with NO counter clockwise backlash after the distributor cam screw is tightened . It makes NO difference if the lever is up or down , the spark still occurs when the points open . If the rotor tip is very far off , the timing will be off enough that the engine probably won't run at all . Where the rotor tip points is most important but points gap DOES have an effect on timing simply because the spark happens when the points open . More gap will cause the points to open quicker . Rotor tip location and points gap work together for correct timing . For an example , when the rubbing block on the points wears the points gap reduces and retards timing in the process . Ford specs for points gap were eighteen to twenty two thousands . I adjust my points anywhere from twenty to twenty two thousands . The wider points gap gives quicker throttle response and more time before the timing will need to be readjusted . The spark lever should be fully retarded when starting the engine . Ford said full advance at speed . Speed was considered to be from 35 mph on up . If or when knocking or pinging is detected the spark lever should be retarded as necessary to eliminate the knocks . From what I have seen , Many go WAY to the extremes when retarding the spark lever .
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Old 01-28-2020, 01:21 PM   #16
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Default Re: Intake manifold getting hot

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Originally Posted by Patrick L. View Post
What Purdy said was true.

There is a reason to set points before the timing.
That goes without saying. Setting the points first is just standard procedure. But as points wear, initial timing (lever up) changes a little and we compensate with a few clicks of the lever. Then point wear is taken care of during routine maintenance.
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Old 01-28-2020, 01:28 PM   #17
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Default Re: Intake manifold getting hot

Yep , as the rubbing block wears points gap closes and effects timing . Just can't stress this point TOO much .
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Old 01-28-2020, 01:33 PM   #18
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Default Re: Intake manifold getting hot

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Originally Posted by Purdy Swoft View Post
The spark happens when the points open . More gap will cause the spark to happen sooner because the points will open a bit quicker . The most important thing about ignition timing is where the rotor tip points when the timing pin drops into the indentation on the cam timing gear . The trailing edge of the rotor tip should point exactly at the number one contact in the distributor cap with NO counter clockwise backlash after the distributor cam screw is tightened . It makes NO difference if the lever is up or down , the spark still occurs when the points open . If the rotor tip is very far off , the timing will be off enough that the engine probably won't run at all . Where the rotor tip points is most important but points gap DOES have an effect on timing simply because the spark happens when the points open . More gap will cause the points to open quicker . Rotor tip location and points gap work together for correct timing . For an example , when the rubbing block on the points wears the points gap reduces and retards timing in the process . Ford specs for points gap were eighteen to twenty two thousands . I adjust my points anywhere from twenty to twenty two thousands . The wider points gap gives quicker throttle response and more time before the timing will need to be readjusted . The spark lever should be fully retarded when starting the engine . Ford said full advance at speed . Speed was considered to be from 35 mph on up . If or when knocking or pinging is detected the spark lever should be retarded as necessary to eliminate the knocks . From what I have seen , Many go WAY to the extremes when retarding the spark lever .
"The spark happens when the points open." Thus timing of the spark is determined by point opening. Rotor position has no effect on when the spark occurs. Rotor position is fixed by the slot in the points cam. The lobes on the cam are what opens the points, so lobe position is what determines timing. Rotor position is coincidental. It just happens (by design) to be pointing at the number one contact when the spark occurs (at point opening).
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Old 01-28-2020, 02:08 PM   #19
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Default Re: Intake manifold getting hot

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Originally Posted by 40 Deluxe View Post
"The spark happens when the points open." Thus timing of the spark is determined by point opening. Rotor position has no effect on when the spark occurs. Rotor position is fixed by the slot in the points cam. The lobes on the cam are what opens the points, so lobe position is what determines timing. Rotor position is coincidental. It just happens (by design) to be pointing at the number one contact when the spark occurs (at point opening).
Spark does happen when the points open . Where the rotor tip points controls where the spark goes. Rotor position has more to do with timing than points .I tried to explain this in a previous post . Points gap and rotor tip position must work together if the timing is correct . If the rotor tip doesn't point in the correct place , the engine won't run . In other words spark occurs when the points begin to open . Rotor position controls where the spark goes . If the rotor isn't correctly adjusted it won't matter when the spark happens because the spark would be sent to the wrong place . I try to give helpful info. Timing and brakes are the two main things that so many can't seem ton understand .
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Old 01-29-2020, 02:09 AM   #20
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Default Re: Intake manifold getting hot

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Originally Posted by Purdy Swoft View Post
Spark does happen when the points open . Where the rotor tip points controls where the spark goes. Rotor position has more to do with timing than points .I tried to explain this in a previous post . Points gap and rotor tip position must work together if the timing is correct . If the rotor tip doesn't point in the correct place , the engine won't run . In other words spark occurs when the points begin to open . Rotor position controls where the spark goes . If the rotor isn't correctly adjusted it won't matter when the spark happens because the spark would be sent to the wrong place . I try to give helpful info. Timing and brakes are the two main things that so many can't seem ton understand .
Yes, the rotor tip position controls where the spark goes, but not when! The "when" (or the "timing") of spark occurring is at the moment of the points opening. Point opening is not determined by the rotor tip, it is determined by the lobes on the points cam. Thus timing cannot be determined by rotor tip position.
With the timing pin in place in the timing gear dimple, and the points gapped correctly, and the timing lever fully up, and points cam set so the points are just starting to open, the rotor tip will automatically be in the correct position (unless the 'tune up artist' sets the points cam 1/4 or 1/2 turn off somehow). Again, rotor tip position determines which cylinder the spark goes to, but not when.
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