Yes - I mean the car http://forums.performanceyears.com/g.../icon_wink.gif

I can't seem to be lucky enough to get rid of the engine driven fan. Here's what I've got:

'69 Firebird 400
Heads have been milled but don't recall amounts
Block decked to zero (not sure if that matters here)

Radiator is Ron Davis 2 1" row. The overall dimensions is the same as the factory 4-row radiator that I had in there.

I've replaced the water pump with the Milodon High flow unit (cast impeller) and clearanced it to the backing plate.

With the engine driven fan, it heats up at idle - takes a while but gets to 210 without fail. The temp drops once I get moving.

I've swapped out thermostats - just prolongs the inevitable.
I've ran straight water and water with water wetter - no dice
Current mix is water, water wetter, and just a little anti-freeze.

The shroud is in place, close, not 100% sealed but pretty close to it. The fan is 1/2 in/out.

This engine showed signs of over heating previously as the engine builder mentioned this to me during the rebuild. Could this just be a bad block?

This week I'll be installing an engine oil temp sender.

Next attempt would probably be to move the oil filter - it's right above the headers and I'm wondering if the headers are heating up the oil which then causes the motor to get hotter then normal. I'm looking for a remote oil filter kit with a built in thermostat; if you have a good supplier, please let me know.

I've tried electric fans - both the Ron Davis shrouded models and the flex a lite ones that are rated at 2950 cfm - 16" puller and 12" pusher. These electric fans cannot cool the motor and in all honesty, the engine driven fan has a hard time.

I'd really like to go back to the electric fans and put that horsepower to the tires. This is my goal.

What have I missed?


Thanks in advance!

Yes - I mean the car http://forums.performanceyears.com/g.../icon_wink.gif

I can't seem to be lucky enough to get rid of the engine driven fan. Here's what I've got:

'69 Firebird 400
Heads have been milled but don't recall amounts
Block decked to zero (not sure if that matters here)

Radiator is Ron Davis 2 1" row. The overall dimensions is the same as the factory 4-row radiator that I had in there.

I've replaced the water pump with the Milodon High flow unit (cast impeller) and clearanced it to the backing plate.

With the engine driven fan, it heats up at idle - takes a while but gets to 210 without fail. The temp drops once I get moving.

I've swapped out thermostats - just prolongs the inevitable.
I've ran straight water and water with water wetter - no dice
Current mix is water, water wetter, and just a little anti-freeze.

The shroud is in place, close, not 100% sealed but pretty close to it. The fan is 1/2 in/out.

This engine showed signs of over heating previously as the engine builder mentioned this to me during the rebuild. Could this just be a bad block?

This week I'll be installing an engine oil temp sender.

Next attempt would probably be to move the oil filter - it's right above the headers and I'm wondering if the headers are heating up the oil which then causes the motor to get hotter then normal. I'm looking for a remote oil filter kit with a built in thermostat; if you have a good supplier, please let me know.

I've tried electric fans - both the Ron Davis shrouded models and the flex a lite ones that are rated at 2950 cfm - 16" puller and 12" pusher. These electric fans cannot cool the motor and in all honesty, the engine driven fan has a hard time.

I'd really like to go back to the electric fans and put that horsepower to the tires. This is my goal.

What have I missed?


Thanks in advance!

I would suggest your timing may be off.
Also the carb jetting may have the car running a little lean.
Is the fan big enough?

The current fan is an 18" flex fan.

The timing is 10 or 12 degrees BTDC at idle, I'll have to double check that to be sure but I believe this is accurate.

I'm feel like it's lean at idle but don't have an 02 sensor (yet). However, with my 825 Mighty Demon it feels a little rich yet still have this same symptom. I've pulled plugs and unless I'm reading them wrong, they confirm this is correct too.

You probably need a smaller pump pulley. That will increase water flow & fan speed. This website has more info:
www.stewartcomponents.com
They also make an electric booster pump that goes in the bottom radiator hose, but this would be a last resort.

Thanks Geoff - another friend said the same thing just this am. I'll check that out - thanks a million!

Joe

Hey Joe,excuse me for asking but did you ever live in Northbrook Illinois?Timber Trails,Lawrence Lane? http://forums.performanceyears.com/g...n_confused.gif

No, never. Alb. NM and now Austin TX.

Joe:
You did not say why the eng. needed rbld.......Overheating?
How old is the radiator?... Cap?...Sender?...
Guage?...
Does the liquid actually blow over?
sealed system w/ overflow bottle?
Drain some fluid, Look down into radiator w/ light,are Passage tubes clear?

My GTO was running warm @ 89' ambient,then above 92' outside,then temp skyrocketed to 210-220 OW!!
once I ran my hand over top of Rad.,about 1/4 inch above it Pass.side half was cooler,I touched it(not smart),Pass. side top of radiator was cold!!!
Driver side was HOTTTTT!!!!
Time for a New One,I Now have Autometer Guages Too!!
SOME aftermarket hoses are made as "trim to fit"
IF your top hose is too long,the begining of curve area around Altnator Rises UP,Because the end,(@ therm. Hsg.)needs to be trimmed.
IF any part of this hose is higher than the Outlet you are gonna have air trapped in there!!! Waterflow becomes a trickle to get passed the air bubble.WHHEEEEW!!!!
OH! mine ? it only warms up to 170 @ 80' outside, 185-190 @ 100+ outside driving @ 70-80 MPH.!! http://forums.performanceyears.com/g.../icon_cool.gifFlush your system,
Check timing, read spark plugs,use elect. fans!

I don't know if you've already seen this, but take a look. Somebody directed me to it, as I also have an overheating problem (350), and I think they've got the answer.

http://forums.performanceyears.com/g...11&m=958104692

You Guys are amazing

I'm running a 1971 400 in a 79 Transam in Australia

Hott was not the word.
The engine is 0.60 oversize
Edelbrock Performer 72cc Heads
9.5 compression
Cruising speed temperatutres were ideal
But less than five mins at idle and the temperature was on 220
as nervous as i was i managed to find a nice backstreet and a coupke of mins driving and the engine was back to 160
There was a problem and i couldn,t put my finger on it. I tried a 160 Thermostat to no avail.
Then going thru a local parts magazine i saw a second hand high flow water pump.
it had dawned here is my problem so i called and was unfortunate as it was sold.
as i was about to hang up i decided to ask if he;d had overheating problems and explained my situation. He refered me to this website and explained the problem.
so i searched thru the stories here and the next day the pump was out
Almost a quarter of an inch
The plate was bent to your recomended clearance and the pump re istalled in just over an hour.
Fired up and drove for ten mins. temperature went to 150 and when returned home was put in the garage and left to idle for 5 mins. temperature was at 180 max.
This modifaction is definately worth the effort.
Thank you for some valuable advice.

also check for exhaust in the cooling system. this usually only causes higher speed issues though. but if the engine was overheated as the builder said, could be cracked, but you think he would have seen that. it could be a crack or head gasket leak, those don't always cause exhaust smoke. NAPA has the coolant testing kit for like $55, woth the investment.

Thanks for the replies guys.

Lil SCAPEGOAT - I'll try triming the upper hose. I recently flushed the system about 3-4 times and added a gallon of a temperature reducing additive. This helped but didn't resolve the problem. I did notice the upper hose angle and pushed it down several times to flush out any possible air. Additionally, the front end of the car was up in the air on a jack and the top of the radiator sits taller then the intake. I also added anti-freeze.

69FbirdPhx - I did review that thread and there was a gap. I closed the gap up and even bought a replacement high flow mechanical pump. Still didn't fix the problem for idle.

Dave - it cleaned up very well. He was refering to the valves mostly. The block was decked and the heads were milled and it all squared up beautifully and checked out clean. That question was mostly referring to internal passages.


The problem is at idle, not when I'm moving. The radiator is fairly new (about 5-6 years old) so I haven't tried to get it redone - it's clean inside and has dual 1" rows. I think I should have opted for the dual 1.25" rows instead.

However... now that it's cooler out it runs fine. Maybe I just need to move to some place that doesn't get about 90 degrees in the summer? I'll figure it out eventually and will post the result when I find it - I'm more stubborn then the car http://forums.performanceyears.com/g...icon_smile.gif


Joe Papa

Joe,
I have seen cases where an engine has sat for years & developed sediment in the cooling system. One engine I had was full of small, hard pieces of rusted block material, a little smaller than a grain of rice. No matter how many flushes I did, I could never completely get rid of this stuff. After only a few hours of driving, it would block many of the tube openings in the radiator & the engine would run hot. I then had to get the radiator rodded out. I ended up fitting a gauze filter in the top radiator hose to catch this stuff. I had to clean it out every couple of months & eventually I got rid of the stuff. I mention this because you said the radiator is 5-6 years old; it could be partially blocked.

Is their a chance that this is fuel related.
I am still having the same hot temperatures as earlier and my performance shop is telling me to richen the mixtures.
Apparently when it is too lean the cylinder walls heat up.
Their is an interesting article in Pontiac Tech Special Summer 2000 Edition pg.70-72 which details the use of different fuels today and this being a contributing factor to the temperature rising on the vehicles. they suggest an aluminium radiator for the quick fix but i do not feel this well solve everyones problem.
I am going to try running an edelbrock performer with a holley 750 to see if their is a differance.
Also i have heard of performance shops running automationg transmission fluid with the fuel for lubricant. Apparently it does the same job as lead. has anyone heard of this.

Michael

I've never heard of running trans fluid with the gas, how much are you supposed to add per gallon? I'd think it would smoke with trans fluid in the gas.

Hi,
Instead of auto trans fluid in you gas, try Marvel Mystery Oil. In airplanes we add about 1/2 pint to the fuel. The mixture lubricates the lower part of the valve stems when it passes through ports in the head above the valves.
It definitely reduces sticking valves.
Mike

only a small amount. supposed to be about 100mm to a tank.

My bet would be on the lack of airflow at idle.

What kind of fan are you using? If it's a stock thermostatically controlled fan clutch, you need to ensure it's working OK. Hayden produces clutches and has a good troubleshooting page on their home page.

ATF will not replace lead. ATF will make things much worse, if anything at all.

mscicluna007
I don't know if you have access to old copies of Streetmachine magazine, but there was an article in the back of one issue a few months ago on a guy in Melbourne who has a kit that relocates the thermostat into a block in the lower inlet hose. There is a restrictor placed in the outlet (top) hose and a bypass hose that connects the top hose block to the bottom hose.
The overall effect is that water temp changes throughout the block are minimised and the whole engine temp is better controlled. He's had very good results on some very hi-po engines...making them quite streetable.
I'll try and find the contact details for you.

Hi Joe,

You didn't say whether your vacuum adv is ported or manifold. If you are running it ported, checkout the thread on using manifold vacuum for advance. Works for me.

jim

i have just ordered a clutchless 19 inch seven fan a week ago from the states.
that is another possibilty that i am going to try.
Was using a 17 inch six blade fan which might not be capable of cooling it enough.

OK...heres the contact details for that cooling system enhancement I was talking about.
Call John Bennett at Ecotherm - 03 9338 5311.
It'd be worth talking about your problem to him.

Wow, this threads still alive! http://forums.performanceyears.com/g...icon_smile.gif

There is no vacuum advance - just mechanical - it's a Mallary mechanical.

The car's been okay now that it's still cool outside. The car has an 825 Demon carb and an aluminum radiator with 2 1" rows. Both helped but neither fixed it.

Joe,

A mechanical advance isnt the best for the street. Check out the cooling thread about the advantages of vacuum advance and about hooking up the vacuum to manifold vacuum,

Thanks for the tip. http://forums.performanceyears.com/g...icon_smile.gif

O.K
We still had trouble with over heating at idle and i think we've finally overcome the problem.
First of all the car wasn't getting enough vaccuum advance so a crane adjustable advance unit was used. it has alot more adjustment than the standard unit allowing the car to run at about 34' at idle.
But their was still overheating and now the timing side of things was sorted we had to look at pumps and fans.
A flex A Lite 7 Blade 19.3" fan was installed along with a flowkooler water pump from Summit Racing.
Seems to have done the trick Very stable temps at about 160'
Hopefully were on top of the situation but we;ve just missed summer so we have a lot of winter testing to look forward to.
Thank you all for your help
Michael

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Leigh:
OK...heres the contact details for that cooling system enhancement I was talking about.
Call John Bennett at Ecotherm - 03 9338 5311.
It'd be worth talking about your problem to him. </div></BLOCKQUOTE>

G'day Leigh,
I ran one of John Bennetts systems for years on a WB series 11 Caprice. I ran that car for over 12 years WITHOUT any cooling fan at all. Just electric fans for the A/C. That car NEVER boiled or ran cold. When I decided to let the old girl go (450k on the speedo was too much for a daily driver), I put the car back to stock. Ran like a pig!!

I keep meaning to take a Pontiac Water Pump over to John to get his opinions on it. I'll bet he has a bit to say. That guy has been studying cooling systems for 40 years. Nice old bloke. http://forums.performanceyears.com/g...on_biggrin.gif

Here's picture of the old bypass which I pulled out of my WB.

This question about manifold vacuum being used for the advance poses one question for me. On a stock show car where things need to look completely original how do you tap into manifold vacuum????? I have had this battle with high temps since a complete frame off. Did all the other things first including flow kooler pump and tweaked the plates. Even put the factory looking Griffin rad in. Need to put this behind me....I'm staring at that temperature guage like it's a naked girl.....Need some pics of this manifold vacuum set up. preferably stock. Joe

Pretty sure stock WAS manifold vac.

George

George , This is on my Ram Air car and I have a factory formed vacuum line that runs from the front of the carb to the rear and has a small brace that attaches to the rear mounting bolt. Off this is the connection to the distributor. Could I successfully tap into the vacuum port on the rear plate of the carb that connects to the brake booster. Would this be manifold vacuum????

Yes,
You can tap into the brake booster line to pick up manifold vacuum. I have this set up on my 66 GTO. I believe 67 was the last year that manifold vacuum was used for the dist vac adv unit. The switch to ported vac adv was for better emissions.

Geoff, Maybe you missed something I wrote. My advance connects to a fitting in the front of the carb. There is a formed metal tubing that runs along the drivers side of the carb. This is not manifold vacuum. Connecting to the rear of the carb plate where the power brake connection goes is the connection I need. This will help with my temps? I'll give it a shot. Joe

The brake booster supply certainly is manifold vac. Are you sure the exixting fitting is not manifold vac?

To test, pull the line off when idling; if manifold vac, you will feel suction on the carb side. If ported you will probably feel no suction. If you gradually increase the throttle, you will start to feel suction on a ported vac line.

George

Thanks George!

George, Hooked up the setup and motor ran 180 degrees. My real test will be tomorrow when I take a trip to Pontiac Day about 35 miles away. Did notice that the choke did not let off when I tapped the gas pedal as it normaly does. Will the diferent source of vacuum change the choke settings? I did block off the tube coming off the carb.

Which choke setup do you have? The mechanical one that has a thermostatic spring in the intake manifold well, connected by a rod to the choke, or the heated one with the round choke housing connected by a tube to the manifold well? In the latter case, a vaccuum source inside the carb sucks air thru the well, where it is heated, then goes into the choke housing to heat the bimetallic spring.

Sometimes with this type, the choke housing is slightly loose from the carb body causing a air leak and not drawing enuf heated air thru the choke housing to heat it up & release the choke.

George

I have a mechanical choke stove. It worked perfect up until I switched vacuum sources. I'll report back tomorrow.Joe

Ok I had the car out to the show and had plenty of stop and go traffic. Even stoped for gas and had a 15 minute idle time and the car never got over 182 degrees. I really feel for the first time since the rebuild that this motor has run so good. I did notice like I mentioned before that the idle was a bit higher and stayed about 1200 RPM at lights and waiting periods. I'm tempted to lower the idle but feel that because of the manifold vacuum source at the distributor it's elevated some.....Thanks to this forum once again....Joe

yep, the additional vacuum advance has increased your idle speed. Crank it down a bit.

george

George, I will give the idle a couple of turns down. I will see if that affects temps any. Joe

The flowkooler pump and flexilite fan have not done the trick.
Is it possible that the headers we are running are heating up the oil filter which in turn is heating up the sump oil and slowly warming the block.
I don't have an oil temp gauge but it may be worth investing in one shortly.
Was thinking of running a remote mount oil filter and oil cooler. Has any one found this to be a concern.

Michael

Who can figure this? Drove the car to a show on Sunday. Had no traffic on the way to speak of and the temps were under 180. Upon leaving met with a slew of bumper to bumper traffic for about 45 mins. Temps were 190. Traffic cleared up and we were flying and temps went to 200+. Again got into the bumper to bumper stuff and the temps went down to 190. Started to clear and the temps climbed to 200. In bumper to bumper it seemed to run cooler???? Have a heavy duty fan clutch installed at present. Anyone get a bead on this? Joe

Michael,
Headers are not the most likely culprit. I ran log style manifolds when I first started on the path, switched to HO RA II style GTO factory headers( so damned heavy you wont believe it!) and now run Dougs Headers with a full 3 inch mandrel bent exhaust system and dynomax mufflers. The sound is incredible AND civilized. There has been no measurable difference in temp crawl or peak temps using any of these exhaust systems. The Log and HO manifolds were both routed well away from the filter housing in terms of the cit pipes.

The oil pump relocation system is an okay idea, but greatly increases the volume of the oil system, and can cause more problems than it solves. I tried it and went back to the old style filter housing when I discovered it was taking as long as 20 seconds to pressurise the entire system. An accumulator/PreOiling system would alleviate this tho. Moroso makes a good one but they are somewhat pricey, and it isnt likely to solve the overall problem. I would have the car Dynoed to see where your fuel mixture sits throughout the pull. It sounds to me like youare close to perfect on mixture in most conditions but that there is a small "hole" that allows your car to lean out in certain ranges of the rpm band. The dyno is the best way to settle that question, and in most cases an hour is right around $100, not including tune time. Just my own expensive observations.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by GTOJOE228:
Who can figure this? Drove the car to a show on Sunday. Had no traffic on the way to speak of and the temps were under 180. Upon leaving met with a slew of bumper to bumper traffic for about 45 mins. Temps were 190. Traffic cleared up and we were flying and temps went to 200+. Again got into the bumper to bumper stuff and the temps went down to 190. Started to clear and the temps climbed to 200. In bumper to bumper it seemed to run cooler???? Have a heavy duty fan clutch installed at present. Anyone get a bead on this? Joe </div></BLOCKQUOTE>

Yeh, I noticed my Firebird runs warmer at highway speeds since i removed the stock fan and installed a clutch fan. Cools fine in traffic though.