Well, just had the 4 core radiator redone today and almost everyone I talked to said it should be enough to keep my setup cool. The car idle runs upto 220 in 5 mins of just sitting.
I have 2 12inch fans blowing a lot. The mech that is working on it swapped out my 190 themostat for a 160. ( I heard this is not a good thing)
I am very frustrated cause I just want to enjoy the car once or twice a week.
I dont want to waste 400ish dollars on a BeCool or Griffin and it doesnt solve the problem.
The mech that is working on the car is kinda not sure and its costing me money as he scratchs his head. So I am turning to you guys to help me out.
The motor is basiclly 330ci with a 6.71 blower.
Jon

Are the fans pullers or pushers? Also, are the fans pulling air across the entire core of the radiator or are they just mounted to the core. Auto trans, and is the trans fluid going into the cooler in the rad or is it an external cooler. What Idle RPM do you run it.
Have you driven it with the 190 stat and the new radiator?

Are the fans pullers or pushers? Also, are the fans pulling air across the entire core of the radiator or are they just mounted to the core. Auto trans, and is the trans fluid going into the cooler in the rad or is it an external cooler. What Idle RPM do you run it.
Have you driven it with the 190 stat and the new radiator?
Okay, where to start. Yes I did drive it with the 190 but the rad was clogged. So cant really tell anything. (I have owned the car for a week and drove it a total of 15 mins)
The fans pull air. There are some open spots on the radiator and there is no shroud. They are mounted to the core. Its an auto trans. It does have a trans cooler but its mounted in front of the the radiator. Right now it idles at 1000
When I drive it 60-65mph runs 3000rpm.
Jon

your 2 12" fans probably pull about 1500 CFM each (just as a guess)
and have open spots of the radiator that are not having air pulled over them

if you were to switch to a mark VIII or taurus fan, the whole radiator will be covered, and they pull more air (I read 3500 CFM for the tausus and 4000+ CFM for the Mark VIII)

Sorry to say....your mechanic doens't know squat about cooling systems if he thinks putting in a 160* thermostat will change the "overheating" conditions. First, thermostats only regulate the MINIMUM temperature your system will work at...and has absolutely nothing to do with the other end so to speak.

Also, a 160 is really too cool for any street application and can cause other problems with the oil etal.....such as not getting hot enough to evaporate all the moisture out of the crankcase etc.

While you may have dual 12" fans....we don't know the CFMs ratings of the fans. My bet is that they are less than 1000cfms each....which will NOT be enough. Do you know what kind they are ...and continuous running current or wattage? If they aren't pulling down at least 20+ amps....then they are far from what you need for a blower motor car.

If your motor will cool down when cruising at steady speeds above 40mph to the thermostat cycling point (or close) then the MarkVIII suggestion is a good one. A Taurus fan also is pretty good or a Spal Twin 11" or Derale twin 12/13" fans as well. All of these provide at least 3000cfms or more of airflow.

Another approach would be to increase the efficiency of the radiator. An Alumitech or PRC crossflow would make a HUGE difference as well. I think your reworked stock radiator is NOT enough personally depending on the hp you are making...but your geographic location dictates more radiator too.

Thanks, I learned a lot thus far being new on this site.
I ordered a MarkVIII fan for 85 dollars. It will go in on Monday. I am sure it will work better, but if I need a new rad. then I will order one. Start small and work my way up.
What is the best Stat to go with? 185, 190, 195???
I found out the amps of the fan will be fine in my car. I just rather tell the mech what I want done rather than him trying to figure stuff out.
Thanks,
Jon

Is that a new Mark VIII fan for $85?

Is that a new Mark VIII fan for $85?
Fan/shourd and motor for 85 plus 13 shipping
Ebay from a guy with 100% rating and sold a few of these fans.
18inch blades
Jon

Looks like you recieved plenty of info.
I would also go with the 190* stat.
Do the Mark fans come with any type of stat to cycle fan off/on?

Looks like you recieved plenty of info.
I would also go with the 190* stat.
Do the Mark fans come with any type of stat to cycle fan off/on?
I am going to make the tech put in a 190ish stat in. I already have a device in the car that turns the fans on and off. As well as it runs the fans when the car is turned off to cool it down for a few mins.
Jon

As Steve has stated .. he is a good man to listen to .. I just want to add to the fray .

THERMOSTATS

Probably the most misunderstood components in the cooling system
the Thermostat has nothing to do with controlling maximum engine operating temps....especially when the rest of the cooling system in NOT efficient enough to handle the BTU'S the power plant is churning out in which case it will stay open while the temp gage continues to rise
What it does it do ? At cold start ,it blocks off the flow of the coolant out of the engine until the trapped coolant reaches the thermostat rated temp ...at witch point it opens and allows coolant to begin circulating
this aids in rabid warm up which REDUCES cylinder and piston ring wear by bring the engine up to operating temp quickly .
In short only the heat transfer efficiency of the radiator and the airflow
trough the radiator determine the engines maximum operating temp.
if you have a 180 degree thermostat and your engine is operating at 220 degrees changing to a 160 thermostat will not change your operating temps you will need more radiator or a more efficient one or more air flow or both .
If your lucky enough to have the efficiency of a good cooling system
a 180 state is a good choice .. why ?O.E.M testing has proven that the rate of cylinder bore and piston and ring wear is DOUBLE the wear rate at 160 degrees then that at 180 degrees .. also 160 doesn't get the old in the pan hot enough to boil off condensed moisture and blow by contaminants which remain in suspension and accelerate the formulation of acidic sludge in your engine .

there several things that lead to a over heating condition or running hot ..,
enging timing
lean conditions
lower rad hose falure ...soft or blocking suction collapse
to many btu's for the amount of cooling efficiency of the system .
not saying your b/c 4 row is bad ...but if its not doing the job ... you may have to switch to a more efficient aluminum rad

check this link https://secure.wf-api.com/www.chevellecooling.com/46.html?psid=ZsR5nn2N31igHw7U-Wx2

Don

Don are you sure about lean conditions? Wouldn't a leaner mix burn more completely and faster thus not heating up the head than a richer mix that would burn slower and not as complete before going out the exhaust port and create more heat? Also is there a big difference with puller and pusher fans? I was thking of going with a pusher setup to have a cleaner engine compartment.

In short only the heat transfer efficiency of the radiator and the airflow
trough the radiator determine the engines maximum operating temp.

It's interesting to me that there has been no mention of water flow.

[QUOTE=onovakind67It's interesting to me that there has been no mention of water flow.[/QUOTE]

Coolant flow in a street engine has little bearing on cooling system performance; the factory water pump flow curve is more than adequate for 99% of street applications.
:beers:

THERMOSTATS

Probably the most misunderstood components in the cooling system
the Thermostat has nothing to do with controlling maximum engine operating temps....especially when the rest of the cooling system in NOT efficient enough to handle the BTU'S the power plant is churning out in which case it will stay open while the temp gage continues to rise
What it does it do ? At cold start ,it blocks off the flow of the coolant out of the engine until the trapped coolant reaches the thermostat rated temp ...at witch point it opens and allows coolant to begin circulating
this aids in rabid warm up which REDUCES cylinder and piston ring wear by bring the engine up to operating temp quickly .
In short only the heat transfer efficiency of the radiator and the airflow
trough the radiator determine the engines maximum operating temp.
if you have a 180 degree thermostat and your engine is operating at 220 degrees changing to a 160 thermostat will not change your operating temps you will need more radiator or a more efficient one or more air flow or both .
If your lucky enough to have the efficiency of a good cooling system
a 180 state is a good choice .. why ?O.E.M testing has proven that the rate of cylinder bore and piston and ring wear is DOUBLE the wear rate at 160 degrees then that at 180 degrees .. also 160 doesn't get the old in the pan hot enough to boil off condensed moisture and blow by contaminants which remain in suspension and accelerate the formulation of acidic sludge in your engine .

Excellent! :) Somehow it sounds so very familiar...... :) ;)

:beers:

Don are you sure about lean conditions? Wouldn't a leaner mix burn more completely and faster thus not heating up the head than a richer mix that would burn slower and not as complete before going out the exhaust port and create more heat? Also is there a big difference with puller and pusher fans? I was thking of going with a pusher setup to have a cleaner engine compartment.

Lean mixtures and/or retarded timing make more heat, always. Richer mixtures make less. Ever watch a top fuel or funny car spitting fuel out the zoomies? That's the only cooling system they have!

Coolant flow in a street engine has little bearing on cooling system performance; the factory water pump flow curve is more than adequate for 99% of street applications.
:beers:

How about the other 1%? I'll bet less than 1% of the SBC's around have 6-71 blowers.

How about the other 1%? I'll bet less than 1% of the SBC's around have 6-71 blowers.
Really, do you really think its that low? It seems 6.71s are pretty cheap compared to other SC applications. Procharger, Vortech, Kenne Bell, Whipple all are kind of expensive.
Mine is a street application. I like to have a fun street car. I have seen a lot of people goto the track and brake things ALOT. Not something I want to get into even if it means I am traction limited.
Jon

Lean mixtures and/or retarded timing make more heat, always. Richer mixtures make less. Ever watch a top fuel or funny car spitting fuel out the zoomies? That's the only cooling system they have!

Jim what exactly causes an engine to run hotter when its lean?

If your lucky enough to have the efficiency of a good cooling system a 180 state is a good choice .. why ?O.E.M testing has proven that the rate of cylinder bore and piston and ring wear is DOUBLE the wear rate at 160 degrees then that at 180 degrees .. also 160 doesn't get the old in the pan hot enough to boil off condensed moisture and blow by contaminants which remain in suspension and accelerate the formulation of acidic sludge in your engine.

All of the suggestions given have been excellent. However, I must disagree with the claimed pitfalls of running a 160 thermostat. I've owned my car since 1989 and have run a 160 degree thermostat for the last 15 years. The motor that was in my car when I bought it was an '80 to '85 low HP 2 bolt main 350 that I finally pulled in 1998 and gave to a friend as a rebuilable core. The only reason I pulled it was because the cam bearings were shot. They appeared to be the originals. Surely after my 9 years of daily driving, and who knows how many miles from the previous owners, it would need new pistons and an overbore? Wrong, the machine shop checked it and all it need was a hone and new rings. My friend got off cheap. Also, there was no sludge whatsoever.

My current motor was built in 1998 and was just freshened up a few months ago. It was also driven daily from 1998 through 2004 and is the same setup in my sig. When freshened up this summer it had zero wear. I had to go through it because I broke a valve spring which sent pieces into the motor. The bearings were as good as new but we did replace them. The machine shop that does my work is extremely meticulous and conservative. I had 1 roller lifter that was just starting to go bad and they insisted that the entire set be replaced.

You may also try a high volume water pump and a water wetter.

All of the suggestions given have been excellent. However, I must disagree with the claimed pitfalls of running a 160 thermostat. I've owned my car since 1989 and have run a 160 degree thermostat for the last 15 years. The motor that was in my car when I bought it was an '80 to '85 low HP 2 bolt main 350 that I finally pulled in 1998 and gave to a friend as a rebuilable core. The only reason I pulled it was because the cam bearings were shot. They appeared to be the originals. Surely after my 9 years of daily driving, and who knows how many miles from the previous owners, it would need new pistons and an overbore? Wrong, the machine shop checked it and all it need was a hone and new rings. My friend got off cheap. Also, there was no sludge whatsoever.

My current motor was built in 1998 and was just freshened up a few months ago. It was also driven daily from 1998 through 2004 and is the same setup in my sig. When freshened up this summer it had zero wear. I had to go through it because I broke a valve spring which sent pieces into the motor. The bearings were as good as new but we did replace them. The machine shop that does my work is extremely meticulous and conservative. I had 1 roller lifter that was just starting to go bad and they insisted that the entire set be replaced.

You may also try a high volume water pump and a water wetter.

You misses something, the tests the others refered to were based on engine temps not t-stat ratings. You can run a 160 deg stat and still have a cooling system that keeps the engine temps above 160. Once the stat opens the temp is controlled by how well the rest of the cooling system works. It's a given that once the stat opens it won't close until temps fall below the stats ratings.

In this day and age of big alum cores, high flow pumps and tornado like electric fans it's easy for cooling system to be over efficent. A 160 stat would not allow an engine to heat up above 160 if this were the case. A 180 stat wouldn't allow flow until 180 degs the system would cool the temps down some, the stat would close and the cycle would start over. The point being, check your gauge and if your not hitting at least 180 degs and you are running a 160 stat change it to a 180 stat. If you are running a 160 stat and your temps are running 180 know once the stat opens it never closes...

Just wondering, what caused the cam bearings to go if the rest of the engine was like brand new?

Jim what exactly causes an engine to run hotter when its lean?
First, a lean mixture is more flamable, it burns faster and hotter. I think tho, that it's really that a rich engine doesn't run as hot. A rich engine has more fuel than it can burn, the burn is slower, and the excess fuel that didn't burn carries heat out the tailpipe.
Years ago, I spent a lot of time in small airplanes. They have a manual mixture adjustment on the high speed jet. They also have a cylinder head temp guage and an exhaust gas temp guage. Normal operation is "full rich" under load, then lean it at cruise till the EGT reads 1200 degrees or so ("the book" says 1200 degrees is about a 14:1 mixture). If you work the mixture lever, you can see both the head temp and the EGT fall like a stone when rich, and climb like an eagle when you lean it out.

Just wondering, what caused the cam bearings to go if the rest of the engine was like brand new?

The engine had been bored .030" over by a previous owner, but they did not replace the cam bearings. This was done sometime back in the 80's because I bought the car in '89. Nine years later while doing a cam swap I noticed the cam bearings had worn through to the brass. The block was an '80 to '85 model which means by 1998 the cam bearings were 13 to 18 years old.

First, a lean mixture is more flamable, it burns faster and hotter. I think tho, that it's really that a rich engine doesn't run as hot. A rich engine has more fuel than it can burn, the burn is slower, and the excess fuel that didn't burn carries heat out the tailpipe.
Years ago, I spent a lot of time in small airplanes. They have a manual mixture adjustment on the high speed jet. They also have a cylinder head temp guage and an exhaust gas temp guage. Normal operation is "full rich" under load, then lean it at cruise till the EGT reads 1200 degrees or so ("the book" says 1200 degrees is about a 14:1 mixture). If you work the mixture lever, you can see both the head temp and the EGT fall like a stone when rich, and climb like an eagle when you lean it out.


Thanks Jim!

How about the other 1%? I'll bet less than 1% of the SBC's around have 6-71 blowers.

:waving: That percentage is a tad higher in my neck of the woods lol
http://i16.photobucket.com/albums/b50/s30119/Steves%20Motor/DSC01576.jpg

Does the car run cooler on the road when you have airflow through it? Look at your timing and carb mix first, it may be too lean, and its the cheepest fix. Your radiator is your main cooling component in the car, but all the components work together. Thats why when you ask these overheating questions you get 12 different answers.. good 4 core aluminum radiator, stock pump, 160 or 180 thermo (take your pick), and even your fan set up youve got now should work. Otherwise your looking ito other problems not associated with the cooling system. Let us know how the fan works out for you. Good luck.

Is your mechanic doing all this work for you.? $$$ ouch....

how long have you had this motor? has it alway ran hot.? is the blower producing too much boost.? lots of variables when you put a blower on there.

Does the car run cooler on the road when you have airflow through it? Look at your timing and carb mix first, it may be too lean, and its the cheepest fix. Your radiator is your main cooling component in the car, but all the components work together. Thats why when you ask these overheating questions you get 12 different answers.. good 4 core aluminum radiator, stock pump, 160 or 180 thermo (take your pick), and even your fan set up youve got now should work. Otherwise your looking ito other problems not associated with the cooling system. Let us know how the fan works out for you. Good luck.

Is your mechanic doing all this work for you.? $$$ ouch....

how long have you had this motor? has it alway ran hot.? is the blower producing too much boost.? lots of variables when you put a blower on there.
It runs cool when I am driving and that was with a clogged radiator. I have not driven it since it overheated. The fan came in today so I will know monday how it works.
Yes I have a mech doing all the work. Its getting old, I wish I could do some of this myself my LS1 vette cost me TONS of $$$ cause I couldnt do the work. :(
The motor was built in 89. The motor only has 5000 miles on it since then. It was in Iowa and never ran over 210 up there. The blower is 30% underdriven right now.
Jon

If its cool when running and heats up too much at idle , it leads me to believe the fans are not pulling enough.. The Mark VII fan from what I hear should do the trick.

Couple of other questions running though my brain.....
Are you sure your guage is accurate..?
Do they have a temp sensor that turns on the fans or do they run continously.?
When you say that you had a plugged radiator, ... with rust?? Your engine may also be plugged.. did you get the engine flushed.?

Oh, also.. why don't you do some of these repairs your self...?? I thought owning a 67-69 Camaro required you to get your hands dirty on the thing.....

Oh, also.. why don't you do some of these repairs your self...?? I thought owning a 67-69 Camaro required you to get your hands dirty on the thing.....
Agree. Assuming you don't mind getting your hands greasy, feel a sense of accomplishment over a job done well, are reasonably trainable and know how to read, and you actually want to, you CAN learn how to do all this stuff. We've helped MANY MANY people who barely knew what a wrench was. Hired mechanics are expensive, and there's no telling if they know more than you do about 35 year old cars with superchargers.

If its cool when running and heats up too much at idle , it leads me to believe the fans are not pulling enough.. The Mark VII fan from what I hear should do the trick.

Couple of other questions running though my brain.....
Are you sure your guage is accurate..?
Do they have a temp sensor that turns on the fans or do they run continously.?
When you say that you had a plugged radiator, ... with rust?? Your engine may also be plugged.. did you get the engine flushed.?

First off, thanks so much guys for all the help thus far.

The radiator just needed rodded out and 2 of the tanks needed fixing. I doubt it was rust the rad. shop said it was in good shape. The engine seems pretty healthly. (did not flush the engine) There is a slight exhaust leak. (That I can live with for a little bit)

I do plan on doing some of the work myself. Just like to learn some first. I changed my rad. on my Vette which is a lot more to get to.

The fans turn off when rad cools off by a thermostat that sticks into the radiator.

The guys working on my 68 has a 67 Camaro himself. Granted its not blown but if nothing else its a good start for me.

Jon

hmmm. havnt heard of turning the fan on and off with sensor in the rad. suppse it could be done but they are usually on the motor on the left or right side of the head or somewhere on the intake manifold. I would move it to one of those locations. placing it on the radiator may place it in too cool of a spot and the fans would turn on late if at all.

The other option would be to have the fan run whenever the motor is on as such as my neighbors blown potiac.

The best way to learn is to dive right in and DO IT..

Don are you sure about lean conditions? Wouldn't a leaner mix burn more completely and faster thus not heating up the head than a richer mix that would burn slower and not as complete before going out the exhaust port and create more heat? Also is there a big difference with puller and pusher fans? I was thking of going with a pusher setup to have a cleaner engine compartment.

lean mixtures tend to burn hot ....fatten things up .. fuel will help cool .. I/E
Think about why when guys running nitrous have the extra fuel selinode
when the button is pushed .. ok mabey this dosent make complete sence
but if you run fatter things will run cooler ... just dont stand behing the car
you may start caughing .

as far as pusher fans ... they dont seem to be as efficient as pullers .. so you better get the highest cfm rated one you can buy I/E 3000 cfm Spal

as far as pusher fans ... they dont seem to be as efficient as pullers .. so you better get the highest cfm rated one you can buy I/E 3000 cfm Spal

What about a shroud, I should have a shroud on the front with the fan? This would basically block most airflow except when the fan is running correct?
I suppose a larger diameter fan would be better than a smaller one even though they both have the same CFM correct?

Well, I bought the Mark VIII fan supposed to pull 4000cfm. The mech that is working on my car said I needed a larger alternator. So I bought a 100amp today. He said he needs to get custom brackets made now... Always something I guess. Didnt even try to work on my car today. :(
Looking for new Mech..as soon as I get it back. Will be trying to learn some stuff also.
Jon

It may be intimidating trying to learn and fix some of this stuff on these cars, but the best way to learn is to just try it and do it. Mistakes that you make are a valuable lesson. For the price your paying your mechanic you could be buying lots of tools and you are missing out on a lifetime of knowledge gained by having someone else do it.. Everybody at one time had a FIRST time of doing everything, pulling a motor, changing a carb, timing the car, placing new carpet in...whatever....... we are all virgins at some point.......Get yourself a couple of books, shop manuals, and read everything you can about your Camaro. After a while its not that bad, and you start to look upon it as a challenge and not a problem.

Good Luck

Mark

What about a shroud, I should have a shroud on the front with the fan? This would basically block most airflow except when the fan is running correct?
I suppose a larger diameter fan would be better than a smaller one even though they both have the same CFM correct?

he said that pullers are more efficient than pushers
and with a puller it is better to have a shroud

if you are going to use pusher (even though it is not as efficient) you should not use a shroud, because like you said you would block most of the air flow through the radiator when cruising at freeway speeds