Ok,

So I am not at a total Loss on why my 400 is running 210 at idle. Start the car and it will just slowly get to about 210.

This is what has been done.

-All filler panels verified and good. Two rubber beside the radiator, Upper steel and lower fiberglass panel.
- HD clutch with 19 inch Fan half inside factory shroud.
-New Champion 4 Core Aluminum Radiator
-160 thermostat with two 1/4 inch holes drilled.
-New Flow Kooler Water pump
-New Divider plated clearenced correctly to the pump.
-Distilled water with Water Wetter

Timing is at the mark closest to the top of the timing cover. not sure what degree that is.
Running a MSD complete setup timing is 36 total

So Im at a loss here...

I fill radiator up 3/4 and allow to run and get hot. Meanwhile, front end is jacked off ground 6-8" so the cooling system can burp air pockets, then I fill slowly so all pockets bleed out. Fan placement is critical.

Only thing I can think of is radiator sealing to cowl and shroud sealing to radiator.

I am running 210 with a 520 hp 455 with 4 core aluminum with dual puller fans. In traffic and 90 degrees she will get to 220. \

Lean carb jetting will have some impact, but not much. As well, I screwed with fan placement and changed it to where its only 3" inside the shroud. That got me the best cooling.

Water wetter is snake oil and a band aid.

Is your timing advance adjustable or pinned at the distributor?

A T-stat with holes drilled in it is not a t-stat. These engines run hot as per normal operating. A good 160 t-stat will be open most it's life. Putting holes it will not change that.

Stock rads are just fine so I can't comment on whether your new rad, pump etc are any better or worse.
Where are you measuring the temp of the water? What kind of setup is it?

Stock parts when working correctly will keep the engine at correct temp. So have a lot of new parts and
they may not be better than stock.

However, try putting on a large flex fan to see if that does the job. If all else fails go large with something.

You can get better coolant. Evans has a product that people have been raving about. Distilled won't do anything. In fact any coolant at 50% will cool better than pure water.

This is a joke right??

Agree that all you have done should be delivering lower temps.

I have been following your adventures so I know the car is pretty new to you.

The one wildcard in my mind is the condition of the coolant passages in the block. What condition was the coolant your removed?

My 490 hp 455 warms up to the T-stat set point of 185 and never goes above that. All my factory "helps" for the 400 & A/C cars such as the filler panels (upper/lower/sides) are all removed to minimize deconstruction for the future paint job. I do have a pricey Rodney Red radiator. Our heat indexes here in Central OK are 100 to 105 all summer long.

My next Step is getting a 19" Flex fan with a spacer. which I will buy tomorrow actually. IF that doesnt work. then I am really a loss. at 50 mph she will be at 165 all day. Go up to 80 and it will run at 210 or so.

Essentially at idle its 210

50mph it goes to 165-175

Highway speed goes to 200-210

My timing was setup by a guy with one of those machines that spins the dizzy to get it to 12 24 36

I have the HD 19.5 inch 7-blade clutch fan.

I don't see have the flex is going to make much of a difference. The fan's impact is at low or no speed where the flex and non-flex should be equal. And both fans are designed to zero themselves out at highways speeds where yours is getting hot again.

Looking at your temps vs speed info, I'm thinking you just don't have enough water flow. Is the WP pulley the correct size? Does the Flow Kooler water pump come with the cast impeller vs the stamped design that many have found to make a big difference when looking at replacement water pumps?

The distilled water/water wetter issue is unclear as to whether you put in any coolant/antifreeze. I run 50/50 distilled water/Prestone. I mix it myself vs the pre-mixed versions.

No

Do you have your vacuum advance hose to the switch or manifold vacuum?

Definitely change the stat to at least a 185 degree unit.

210 at fwy speed is not abnormal in my opinion.

We have discussed this before ...

https://firstgenfirebird.org/forums/ubbthreads.php?ubb=showflat&Number=269259&page=1

If you car is going over 35mpg the air passing thru the rad is enough to cool the coolant. If the car get's hot at higher speeds then it cannot be a fan issue.

What you need is Temp sensors in difference places to determine where the bottle neck is. One before inlet to rad, one on outlet of rad etc... Not sure how you can do that,

Maybe you have some flow restrictions in your cooling system like someone else mentioned.

DO you have the filler panels installed and the lower pan? That will ensure maximum air flow thru the rad.

I never heard of jacking up the car to bleed the air. I checked with Google and it appears it can be helpful. Perhaps it's a bigger deal with newer cars. I always had a overflow tank so I filled from the overflow tank and it seemed to do the job.

Have a look at this site for more info...

http://www.popularmechanics.com/cars/how-to/maintenance/1272246

Note last paragraph: Raising the cooling system's pressure also raises the coolant's boiling point, so the radiator cap (which also could be on the engine or on the separate reservoir) has a pressure valve to raise the pressure in the cooling system by about 15 psi. This increases the boiling point of the coolant by about 40 degrees F. So, the boiling point of a 50/50 mix of antifreeze and water in a properly functioning system is about 265 degrees F or higher.

Check your radiator cap!

Im running the new Flowkooler with the Billet Impeller. New Stainless Divider plates correctly clearanced ..

The lower hose has a spring in it. Do those go bad? also the Heater core is bypassed and the hoses are connected by a fitting. not doing heater core right now so thats out of the question.

Maybe I will replace the radiator hoses.

I dont mind getting to 210 at idle, but my A/C doesnt like it very much and wont cool good when car gets that hot.

Difference between a rookie and a pro. A rookie never calls anyone out publicly because "he didn't know".

Basic thermodynamics 101.

Mr Driveability may be on the right track with the vacuum advance hose on the manifold vacuum port not the stepped port.
First you should find out what your timing actually is at idle with the vacuum advance disconnected and set it to spec.
If your timing is not advanced enough at idle the fuel air charge may be burning as it exits the exhaust port which will transfer a lot of heat to the water around the port.
If you have the vacuum hose on the stepped port the vacuum advance will not activate until the throttle opens past the idle stage, if you have the hose on manifold pressure port the vacuum advance will activate at idle and the charge will burn before the exhaust valves opens and the engine MAY run cooler.
I have my car running at 19 degrees at idle and it operates at a lower temp then when I have it set to 9 degrees.
Just a thought.

when I changed my clutch recently I damaged my heater core tipping the engine back against it so I bypassed it. my temps went up.. Try clamping the bypass hose. With the holes drilled in the thermostat it shouldn't hurt anything. With no heater core there that bypass hose has no restriction and can flow a lot of the coolant you want to go through the rad.

Gotta burp your cooling system. Get the air out...Let run with the cap off while keeping an eye on the fluid level. Add as needed. I hadn't thought of Banshee's trick, but it makes sense.

I have the best luck with a 185 degree thermostat. (468...500+ HP)

Flow Kooler water pump...I saw no improvement when I installed this pump...all other details being equal. I removed and re-installed stock pump.

I also run the Champion Aluminum radiator...but it is a 3 core.

I did install a smaller diameter water pump pulley. This seemed to help just enough. I rarely get above 200 degrees.

Good luck!

I'm having similar high temp issues. I am running 68 w/ 350. Radiator shop shows my radiator as correct, flushed radiator and still pushing 210 - 240 degrees.

Any other areas I should be looking at? Any possibility that there might be a problem with motor?

When engine was rebuilt, evidently they forgot it was a 350 Pontiac and put it back together as a Chevy, forgot to put in the oil plug at rear of motor. I installed plug and got oil pumping to the lifters.

Is there another area I might check out?

Maybe... Just maybe have it figures out. I had a 2000 formula a while back that I stripped and remembered that I had the electric fans from it in my shed. So a small amount of trimming and it Fits very Well. Here is a pic of it "mocked up"

They are dirty, but wanted to see if it worked before I spend time cleaning and repainting the assembly.



Thanks for the Info on the Timing, The problem is I only have marks on the timing cover with no indication of what degree they are. There are 3 marks and I have it on the Top one

I will also try the clamping of the bypass

Did you do all the other things I did? filler panels etc? the biggest seems to be getting the Fan shroud. Or go with electric fans which "knock on wood" seem to be helping me at idle.

You shouldn't have to change to electric fans to get proper cooling, finding the problem and rectifying it is the course. You may be able to cool it down by increasing air flow but was airflow the original cause of the over heat? I can't picture your timing marks, but they should be 12, 6 and 0 with 0 at the top. Try setting the timing ,with the vacuum advance hose disconnected and plugged, to the lowest [12] mark, then connect the vacuum advance to the port on the carb which gives you manifold vacuum at idle.
I've got a rather out of focus pic but the top mark is zero degrees and the bottom twelve.

Salesguy,
I'm not saying timing is the cause of your problems, but eliminating it as the cause may help you.
We all tap other's first hand experiences for information and that information may lead us to an answer to our own problem. May not. All the other replies you've received may be on the correct track and mine not.

In my case I had an overheating problem at idle, once I got out on the road it ran at what I thought was an acceptable temperature. When I got back to my garage, idling , it once again overheated. I have my total timing [initial plus mechanical] set to 28 degrees. Twenty eight is the setting I obtained best power and torque with on an engine dyno. My mechanical advance is 9-10 max. At idle the nine degrees of initial timing was too low. The fuel air charge was burning as it went through the exhaust port rather than in the combustion chamber. No, I can't prove that but that's what I surmise after a few years of experience with engines. My vacuum advance can has a range of 20 degrees. The hose from the vacuum advance can on the distributor was connected to the stepped vacuum source on the carburetor. The stepped port connects to vacuum source above the throttle plates, low vacuum at idle. I relocated the hose from the stepped port to the manifold port. The manifold port connects to vacuum source below the throttle plates and has full manifold vacuum at idle. Before I changed the location of the vacuum source my distributor had nine degrees advance at idle, after I changed the vacuum source my distributor had the initial nine degrees plus twenty degrees vacuum for an idle advance of 29 degrees. After adjusting the carburetor to compensate for the increase in timing my engine runs at 600 RPM idle at an acceptable water temperature.

Of course this may have nothing to do with your problem but the info is there if you can or want to use it.

That is for my engine and may not be the same with yours or anyone elses but it may give you a path to follow if all others fail in your quest to solve your overheating dilemma.
Al

Blue Bird. Does Canada Get Hot?? LOL. We are at the peak here 95-100 degree with 90% humidity.

I totally AGREE with the timing. I have Ruled soooooo much out that It is the only varible. My timing cover must not be original because it has NO numbers just 3 lines. I have it to the top which going by the above picture would be 0 I know for sure it needs to be between 9 and 12. It also does seem to run better with full manifold vacuum.

I will post a picture of my timing cover tomorrow

but you have to admit these electric fans look good for FREE right!

Not so much where I live, only 80-90 degrees in summer and relative humidity is forecast at 90% today. The island I live on is surrounded by rather chilly 50-53 degree water. A quick road trip over to the the valley will net 100 plus degrees. I do live below the 49th.

You may have the original cover for that engine, you didn't mention what year the engine is did you?
Do you know the heat range of your spark plugs?

Like I said, timing may or may not be your problem, by process of elimination hopefully you will solve your overheating quandary. Just as likely to be water, air flow, heat transfer, lean fuel/air mixture or a host of other causes. Not knowing the initial timing setting, problems at idle but not road speed and having a similar problem myself led me to think your cause may be similar to mine. One could just as easy think airflow, due to a hot condition at idle and normal operating conditions at highway speed with more airflow through the radiator and over the engine itself.

One can rotate the distributor and set the timing by ear, it's been done before, but I wouldn't recommend that route.

I think it imperative to verify initial timing. Either find out from someone who knows for sure what the marks on you cover represent or establish a top dead center mark using a piston stop.
You stated the distributor technician set your distributor to 12, 24 and 36. I deduce that would mean 12 degrees initial with no mechanical or vacuum advance, 12 degrees mechanical and another 12 degrees vacuum? Or is that the advance curve? You would have to know your initial setting then check at what rpm your mechanical advance started and ended. Same for vacuum. Can you enlighten us as to why he set the distributor with such parameters?

I have no opinion on the looks of the dual fans, I like the free part, and if they solve your overheating puzzle that's grand.

Here is the Pic of the Timing cover. It is a 67 400. original black and heads, so I imagine the timing cover should be as well, but who knows.



36 total at 2800 I think that is the advance curve...

regardless I do have a timing light so will try and get it at the lower timing mark

Here is a picture of my '67 timing marks. They are -4, 0, and +6. The spacing of your marks looks about right, but I can't make out any numbers.

wow!!!!! So I had the timing about -2 ................!!!!!!

I adjusted it to the end of the over which is about 8. Should I go more?

I am having some pinging issues on temporary 389 in my 67 bird. Along with the pinging I am getting hot too. Both high speed and idle. Working through the timing issue, i have found some great information in regards to timing. There also are several good articles in High Performance Pontiac. pm me your email and I can send them over if you want. i just changed to an adjustable vacum advance set timing. havent driven it yet.

Salesguy, where are you in LA? I'm in Mandeville and would be happy to help out.

Also, noted in your photo that you have some "goo" on the top of your water pump. Whats up wit dat?

Re Timing: Adjust/advance to where your engine runs the best without pinging.

haha The Goo, I need to lay some newspaper and paint that. It was the excess of Black RTV that I wiped. should have let it dry and peel it off.

Im in Ponchatoula. Not far from you

Sorry, Its been awhile since I logged in to the site.

I do not have all filler panels installed but I also do not have a shroud or the A/C lines hooked up. No fluid going to heater core and no A/C compressor installed yet.

I have 2 electric fans pulling through rad and 165 t-stat removed so running open. I have not checked the timing. Will do that.

When I park the car, after driving around town, the radiator boils over from the overflow tank. I have great circulation through system according to radiator shop and we verified size and what I have is correct.

I live in deep south Texas, temps are 90's to low 100's about 8 months. I just changed the vac tube on carb and the motor idled ok but revving it sounded poor. May have to make some other adjustments also. I have no tube going from carb to air cleaner (as someone else suggested I should).

Attached are picts of my setup

There are LOTS of things that can contribute to overheating. One thing you mentioned was no thermo (if I understood correctly). You need a thermo to slow the flow of coolant. Even if it's gutted, just having a smaller hole to pass thru will slow the flow and allow the coolant more time to cool, while passing thru the rad.

Those electric fans may not be sucking enuff air. The fan from a Lincoln Mark VIII sucks about 5000cfm. What's the rating on yours ?

Looks like a small Holley carb. If your jets are small enuff to make it run lean, that can increase heat.

Slow timing can increase heat. Try 12-14 initial, at idle, and 34-36 total(unless that causes detonation). But 30 degrees can increase heat. You also need a good, properly functioning adjustable vacuum advance can, on your dist, hooked up to a good vac source. Most recommend hooking it directly to the intake manifold. It needs to add timing up to, but not more than your total mechanical advance. You never want your timing high enuff to cause pinging or detonation.

And if you have too much mechanical advance, you need to rig up a positive advance stop, so that you can run 12-14 degrees of initial timing, without running too much total. It is also a good idea to put at least one slightly weaker spring on your advance weights, so that all your mechanical advance will be in by about 3000rpm. or a little over.

Can't tell for sure what rad you have. But most agree that if you run an alum rad it should have 2 rows of 1" wide tubes. If it has 3 rows of narrow tubes, it will provide less cooling. And if it has 4-rows of the narrow tubes you'll need more fan power to pull enuff air thru it.

And someone usually says to make sure you have the wire spring in the lower rad hose, to keep it from sucking shut and impeding coolant flow. Well hey, that's enuff to get you started. See if any of that helps.

Throw that electric fan in the garbage. It will never move the air that is required.
Factory shroud and 7 blade fan and the HD Hayden fan clutch is all you need providing you have the divider plate clearanced properly.

Yes, historically we find that the vast majority of engine overheat issues that are presented here have an electric fan setup.

My 490 hp 455 (462) is happy all summer long here in hot/somewhat muggy Central OK. Never goes much above the t-stat set point of 185. Aluminum radiator, OEM 19 inch clutch fan, OEM radiator shroud, cast impeller water pump with minimum divider plate clearance. And I don't even have my factory 400 model baffles and block off plates installed.

I agree with bigchief, after $600. in a be cool radiator, a FF Dynamics extreme electric fan. I still had heating issues, my bird still would run at 210, until I hit traffic then it would creep up, this totally sucks. So after reading an article on Team Chevelle, they suggested just what bigchief said, 160* thermostat from Auto Zone, the "duralast" brand, Hayden Clutch with 7 blade fan, 70% distilled water 30% antifreeze, factory fan shroud, seal up all around the radiator and, what do you know, I tested it this weekend, went on a 600 mile trip to a car show/parade, and my Bird stayed between 185-190 this is the best temp it has ever run at, even over 2 passes. During the parade it would creep up to 200-205, but holding the RPM at 1500, it would come back down. I am a true believer in this setup and will recommend this to everyone with temp issues, plus, I have a really nice FF Dynamics fan with shroud for sale.

Awesome that you can enjoy the car now.
A few firebird owners here in AZ have been having the same problems and having the AC cranking when it's 100+ weather only makes the coolant temp creep up more.
Friend with a 67 installed a champion radiator with the factory shroud and 7 blade fan and heavy duty Hayden clutch and he can cruise all day long with the AC on and not go over 185.

I still kept the Be Cool Aluminum radiator in the Bird, (My factory shroud fits it great) but I think the major temp issue was with the electric fan, don't think I'll ever use one again. I've heard good things about the Champion radiators. Hopefully more people with cooling issues read your advice, they will be thanking you as well bigchief. Cheers!!!

I have been keeping notes on all the overheating thread on the PY site and making a list of resolution.

I'm sharing this for anyone to use as a check list. Remember these are just notes. Cut and pasted in notepad. I did not write these.


"What is your definition of "overheating"? There are three common definitions, and I'm not fond of either of the first two:

1. The coolant is actually boiling out the rad cap overflow hose. The temperature required to do this varies with system pressure and anti-freeze concentration. If the coolant is actually boiling out the overflow, the engine has probably already suffered some amount of damage.

2. The coolant temperature is at or above some specified temperature. Different people specify different temperatures. Some "hot" light sensors didn't trigger until 260F. Another issue is WHERE the temperature is measured. Sensors next to an exhaust manifold tend to read higher than sensors in the intake manifold coolant crossover. The engine is in imminent danger of damage.

3. The coolant temperature at or near the thermostat is more than 15 degrees above the thermostat rating, at idle or cruise. A thermostat is intended to set a MINIMUM operating temperature, not the maximum temperature. If the coolant temperature measured near the thermostat is more than 15 degrees above the thermostat rating, the theromostat has no control over system temperature. It has "lost control" of the temperature. The closer the system temperature is to the thermostat rating, at idle or cruise, the better. System temperature will increase somewhat for heavy-throttle or high-rpm use, but when the vehicle returns to idle or cruise, the temperature better go right back down to near the thermostat rating.

A 50/50 is for modern AC cars...if your car does not have AC , best cooling of coolant and water is 33 % coolant 67% water...the most efficient cooling mixture...but AC cars use a higher % for lubrication IIRC.


*Clogged/Dirty Radiator not flowing properply
*Collapsed hoses
* Blow-by finding it way into coolant->Causes foaming->drasticly reduces heat transfer (Do a Pressure Test) Blown head gasket for example.
*Divider plate clearanced appropriately
*Test thermostate in boiling water
*Air pockets? Drill 1/4 hole in thermostate to pass air pockets.
*Type of impeller - Cast is always better and not all cast impellers are the same some are deeper then others.
*Fan shrowd in place? air dams in place? baffles in place? Fan clearence around fan shrowd
*Temp infread gun can be a great troubleshooting tool- compare input temp to output temps of the radiator and look for cool spots or hot spots. Can be used to compare accuracy of gauge/Sender.
*faulty gauge - A second gauge check is always a good idea
*clutch Flex or Electric - Its tough to beat a good factory 7 blade with HD clutch.
*If electric - is your fan a puller or pusher? pusher fans are not good ,they also block radiator
*rich or lean carb setting.
*Vacumm leaks cuase lean conditions Carb bolted down? Orange intake alignment pieces?
*timming issue - Try simply backoff on the timing and see what happens
*Over heating at idle or driving - Generally If at idle or very low speed, then it is likely an airflow problem. If at speed, then it is likely a coolant
*Retarded cam - Cam not degreed in correctly on ILC. Read about this more then once.
*WP pully diameter for trouble shooting
*deck height - Piston down in the hole makes for bad quech.
*8 realief pistons notorious for ping and heat realated issues.
*Clutch fan test See the PDF in Personal->Car stuff. Cold should spin 3 times or more when you shut off the motor. Hot should spin less then 3.
*Adjust Clutch fan for max friction PDF in Personal->Car stuff.

2 row aluminum with 1.25 tubes cured vs 4 row aluminum
radiator flush
cams with too much overlap
Radiator cap pressure
radiator hose is collapsing (needs a spring).
casting shifts hot spots