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Straight 8 engine overheated at idle


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If engines did not need a thermostat, the manufacturer would never ever have put one in! They are so conscious of saving money, that any extra cost must be warranted. A thermostat is essential to correct operating temperature!

there endeth the lesson.

Rodney 😀😀😀😀😀😀😀😀😀

 

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What Bloo said, I pulled my brass distribution tube out as far as I could get it to inspect when I had the rad and pump out. Unfortunately I couldn't pull it completely out unless I started taking body parts off. I poked around with a cloths hanger making sure none of the holes were plugged either. I've got a few posts on my past heating issues. My straight 8 temp gauge sits around 1/2 way while cruising and slowly rises sitting at a red light. Once during a "parade" on a very hot day, I had my gauge max out until I turned off the engine. Had puking and bubbling coolant everywhere. Thought I had baked the engine. Those straights are tough as nails although I don't recommend pushing it that far. I've since installed a 6 blade fan which I haven't tested yet. I will be posting results when that day comes. 

 

IMG_6457.thumb.JPG.c7b02d058ff062a3887ccf2934ef8547.JPG

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3 hours ago, Summershandy said:

What Bloo said, I pulled my brass distribution tube out as far as I could get it to inspect when I had the rad and pump out. Unfortunately I couldn't pull it completely out unless I started taking body parts off. I poked around with a cloths hanger making sure none of the holes were plugged either. I've got a few posts on my past heating issues. My straight 8 temp gauge sits around 1/2 way while cruising and slowly rises sitting at a red light. Once during a "parade" on a very hot day, I had my gauge max out until I turned off the engine. Had puking and bubbling coolant everywhere. Thought I had baked the engine. Those straights are tough as nails although I don't recommend pushing it that far. I've since installed a 6 blade fan which I haven't tested yet. I will be posting results when that day comes. 

 

IMG_6457.thumb.JPG.c7b02d058ff062a3887ccf2934ef8547.JPG

looks like your straight eight has the good brass water distribution tube, i'm waiting to hear how well the 6 blade fan performs for you.

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5 hours ago, rodneybeauchamp said:

If engines did not need a thermostat, the manufacturer would never ever have put one in! They are so conscious of saving money, that any extra cost must be warranted. A thermostat is essential to correct operating temperature!

there endeth the lesson.

Rodney 😀😀😀😀😀😀😀😀😀

 

All arguments be damned, that is a truth.   That is a truth in manufacturing since it started

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3 hours ago, Summershandy said:

What Bloo said, I pulled my brass distribution tube out as far as I could get it to inspect when I had the rad and pump out. Unfortunately I couldn't pull it completely out unless I started taking body parts off. I poked around with a cloths hanger making sure none of the holes were plugged either. I've got a few posts on my past heating issues. My straight 8 temp gauge sits around 1/2 way while cruising and slowly rises sitting at a red light. Once during a "parade" on a very hot day, I had my gauge max out until I turned off the engine. Had puking and bubbling coolant everywhere. Thought I had baked the engine. Those straights are tough as nails although I don't recommend pushing it that far. I've since installed a 6 blade fan which I haven't tested yet. I will be posting results when that day comes. 

 

IMG_6457.thumb.JPG.c7b02d058ff062a3887ccf2934ef8547.JPG

When the water pump comes or I have to pull out the Radiator, I will definitely be inspecting that tube.  Been looking at getting a 6 blade universal fans that look some what original that I can black out to match.  Should install new thermostat next week, waiting on the collar.  Side note where did you source that Generator?  Note:  Called CPR and they are closed due to Virus currently 

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I would pull the rad, you can get a better look at the tube that way. I was also looking at 6 blade fans on ebay before Charles had one he offered. Generator was on the car when I got it. Too bad about CPR, I've purchased many thing from them. 

Mark

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23 hours ago, Summershandy said:

I would pull the rad, you can get a better look at the tube that way. I was also looking at 6 blade fans on ebay before Charles had one he offered. Generator was on the car when I got it. Too bad about CPR, I've purchased many thing from them. 

Mark

 

23 hours ago, Summershandy said:

I would pull the rad, you can get a better look at the tube that way. I was also looking at 6 blade fans on ebay before Charles had one he offered. Generator was on the car when I got it. Too bad about CPR, I've purchased many thing from them. 

Mark

 

23 hours ago, Summershandy said:

I would pull the rad, you can get a better look at the tube that way. I was also looking at 6 blade fans on ebay before Charles had one he offered. Generator was on the car when I got it. Too bad about CPR, I've purchased many thing from them. 

Mark

cpr is accepting internet orders at pontiacparts.net

 

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19 hours ago, Eaglekiller said:

Sweet,  will give that a try, I have just always called

 

 

rich plastino has told my facebook group that telephone orders will resume on april 29th

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Hello Gents,

Given I live in a hot climate and have a couple of the 50's Pontiacs I consider myself well versed in the heat transfer challenge.  In my experience one of the best indicators if you have a partial restriction in the radiator that reduces heat transfer is to view the lower radiator hose when you increase the engine speed.  Many of the vehicles don't run an inner support spring in the lower hose nowadays due to cost. If you have the engine at normal operating temp and then increase the engine speed, see what the lower hose does . If you witness that  the lower hose reduces diameter then its a clear sign of a restricted radiator as its effectively reducing suction pressure to the water pump. This obviously   causes cavitation  and reduced water flow  / heat transfer. The comment earlier in the post that the lower hose was mildly warm when the Temperature gauge was showing hot is a bit of a giveway .    The  delta   T across the heat exchanger radiator using the Infra red temp gun is also one of the best diagnostic parameters you can obtain. 

Both my Pontiacs now run 170 deg F thermostats  and 7 psig radiator caps, and I live in the north of Australia whereby high jacket water temps  and fuel  atomisation in the summer monthes  is a challenge.

To which I have covered the fuel lines and fuel glass bowls with silver foil to prevent fuel boil which has proved  succesfull to date .  Still run the OEM 4 bladed fan on both cars.

 

Both of the cars have benefitted from an air /water blast through the block  / radiator to remove any crud / scale buildup accumulated over the years.    worthy to note that Minimal amount of scale will limit heat transfer as in my time anything over 0.010" of scale reduced heat transfer by approx. 50%.  Combine that with rust and reduced water flows and its an uphill battle to continuously  transfer the heat using air as the cooling medium.

 

One other item I have utilised is the fitment of a catch sock into the   top radiator hose to the inlet of the radiator that catches any junk that becomes dislodged over time , this effectively filters what goes into the radiator core and prevents sludge and solids buildup in the inner tubes.  Since I have fitted these I clean them every year and there is always some sediment and junk to be had there.

The coolant used is de-min water and the long life TEctalloy concentrate mixed at 50 % ratios, so far so good as its prevented corrosion. Given the cast iron bocks - water distribution tubes and freeze plugs are all dissimilar metals then galvanic action is best avoided with the de-min water and coolant for corrosion control.   Hoping this may go some way to identify your rot causes of the higher temps.

 

Russ

 

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On 4/29/2020 at 11:09 PM, RussJagoau said:

Hello Gents,

Given I live in a hot climate and have a couple of the 50's Pontiacs I consider myself well versed in the heat transfer challenge.  In my experience one of the best indicators if you have a partial restriction in the radiator that reduces heat transfer is to view the lower radiator hose when you increase the engine speed.  Many of the vehicles don't run an inner support spring in the lower hose nowadays due to cost. If you have the engine at normal operating temp and then increase the engine speed, see what the lower hose does . If you witness that  the lower hose reduces diameter then its a clear sign of a restricted radiator as its effectively reducing suction pressure to the water pump. This obviously   causes cavitation  and reduced water flow  / heat transfer. The comment earlier in the post that the lower hose was mildly warm when the Temperature gauge was showing hot is a bit of a giveway .    The  delta   T across the heat exchanger radiator using the Infra red temp gun is also one of the best diagnostic parameters you can obtain. 

Both my Pontiacs now run 170 deg F thermostats  and 7 psig radiator caps, and I live in the north of Australia whereby high jacket water temps  and fuel  atomisation in the summer monthes  is a challenge.

To which I have covered the fuel lines and fuel glass bowls with silver foil to prevent fuel boil which has proved  succesfull to date .  Still run the OEM 4 bladed fan on both cars.

 

Both of the cars have benefitted from an air /water blast through the block  / radiator to remove any crud / scale buildup accumulated over the years.    worthy to note that Minimal amount of scale will limit heat transfer as in my time anything over 0.010" of scale reduced heat transfer by approx. 50%.  Combine that with rust and reduced water flows and its an uphill battle to continuously  transfer the heat using air as the cooling medium.

 

One other item I have utilised is the fitment of a catch sock into the   top radiator hose to the inlet of the radiator that catches any junk that becomes dislodged over time , this effectively filters what goes into the radiator core and prevents sludge and solids buildup in the inner tubes.  Since I have fitted these I clean them every year and there is always some sediment and junk to be had there.

The coolant used is de-min water and the long life TEctalloy concentrate mixed at 50 % ratios, so far so good as its prevented corrosion. Given the cast iron bocks - water distribution tubes and freeze plugs are all dissimilar metals then galvanic action is best avoided with the de-min water and coolant for corrosion control.   Hoping this may go some way to identify your rot causes of the higher temps.

 

Russ

 

I use a infra gun and I am seeing 18-20 degrees from top neck to bottom neck consistently.  Do you see similar temp drop from your radiators?

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On 4/26/2020 at 10:31 AM, pontiac1953 said:

rich plastino has told my facebook group that telephone orders will resume on april 29th

Got my order in the mail just yesterday from CPR, great service as always

 

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11 hours ago, Eaglekiller said:

I use a infra gun and I am seeing 18-20 degrees from top neck to bottom neck consistently.  Do you see similar temp drop from your radiators?

only a 20 degrees of cooling the coolant difference ?, that doesn't sound right.

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The Delta T across the radiators varied  with the airflow rate across the core, however at idle speeds after  the engine was at normalised operating temp,  it was approx. ~40 deg F for memory when I checked it with the I.R temp gun.

Im away from the vehicles at present for the next 5 weeks but can check for you when I return back to home base. I work in Deg C so will need to confirm the readings and reply back for you. 
 

Re the blanking panels in the radiator support,   have the 2 round blanking panels removed? ? Not that it will help  greatly at idle and slow speeds but I have the removed both blanking panels on my vehicles to assist the air flow at highway speeds and higher heat loads on the radiators. When my Dad had the '53 it was located in a southern state which is a lot colder than where I reside,  so we had the blanking plates installed to assist with engine temps. I have since removed them when the car came to Queensland so both the 51 and 53 both have the blanking panels removed now. 

 

 

 

 

Pontiac12.JPG

IMG_1985.JPG

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  • 1 month later...

Went for a good ride yesterday got home and let the car cool down. After trimming down the thermostat retainer, cleaning and sanding the surfaces smooth, apply sealant only there appears to be no leaks or weeping around the housing. I always apply minimal sealant especially around cooling systems. Don't need those little blobs floating around inside. 

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On 5/2/2020 at 11:49 PM, RussJagoau said:

 

The Delta T across the radiators varied  with the airflow rate across the core, however at idle speeds after  the engine was at normalised operating temp,  it was approx. ~40 deg F for memory when I checked it with the I.R temp gun.

Im away from the vehicles at present for the next 5 weeks but can check for you when I return back to home base. I work in Deg C so will need to confirm the readings and reply back for you. 
 

Re the blanking panels in the radiator support,   have the 2 round blanking panels removed? ? Not that it will help  greatly at idle and slow speeds but I have the removed both blanking panels on my vehicles to assist the air flow at highway speeds and higher heat loads on the radiators. When my Dad had the '53 it was located in a southern state which is a lot colder than where I reside,  so we had the blanking plates installed to assist with engine temps. I have since removed them when the car came to Queensland so both the 51 and 53 both have the blanking panels removed now. 

 

 

 

 

Pontiac12.JPG

IMG_1985.JPG

I have finished rebuilding the cooling system, new water pump, 6 Blade Fan and radiator boiled out.  It looks like I am showing 35 to 40F, about 20C drop from radiator inlet to bottom outlet at the neck.  It did seem to drop down a bit closer to 30F once the Thermostat opened up.  All this was done at idle, it sure feels like the 6 blade fan moves a lot more air.  Test drive today or tomorrow outside temp should by 100+F going to take some roads with a lot of traffic to simulate cruising.  Sure hope this solves it, if not I guess aluminum radiator would be next step??

 

Always appreciate everyone that responds, all most guys know is put an LS in it and move on.

 

Russ- Where did you get the Headlight bezels?  Are those off a Chevy?

 

 

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On 5/3/2020 at 2:49 AM, RussJagoau said:

Re the blanking panels in the radiator support,   have the 2 round blanking panels removed?

 

I had done this also for cruising but put them back on for shows. I believe they're called inspection covers. Makes getting to the rad drain valve much easier. 

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So heres hoping that the six bade fan and the efforts in your remedial works goes some way to cure the high temp issues as  described in your original posts.  Would be interested in to see the results that you witness.
You may well have checked it but if not then the total ignition advance is another area that you might find some gains in especially if the mechanical advance springs have weakened over time or the advance  mechanism is worn on the spring posts.  One of my vehicles original distributors was gaining way too much advance early on in the rpm range due to the weakened springs and worn mechanism. The initial advance was always ok at =- 5 deg BTDC at idle speed, but the toal advance when checked with a strobe light was approx. 48deg BTDC. Generally in low compression engines this isn't too much a concern with detonation but if the advance is too great then the engine is effectively working against itself and higher het loads results. Any worth a check f you have access to an adjustable strobe timing light.

 

The headlight shrouds  were purchased about 6 years ago when I completed the resto on the '51. They were purchased via ebay and came from the USA ( $47) , but Im sorry I don't recall the vendor.

They were good quality and the chrome finish is excellent. You shouldn't  have to much trouble in locating a supplier  over there as the classic car accessory supplies are way more plentiful than here in Aust for older US models.

They certainly add some appeal to classic look :)

 

Rgds

 

IMG_2653.JPG

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