408 still overheating :/

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yellow rose said:
Ok, help a blind onl man out. I don't see any pictures with a belt driven fan. I see where the OP says he had a shroud and took it off, but I see no pictures of it.

Thanks
Click to expand...

Misunderstanding, I'm talking about using an electric fan with a shroud. OP has an electric fan without the shroud and installed only covers 1/2 the radiator area. No good. He owns a mechanical fan with a shroud that should be used, IMO.
 
T56MaxTorq said:
Misunderstanding, I'm talking about using an electric fan with a shroud. OP has an electric fan without the shroud and installed only covers 1/2 the radiator area. No good. He owns a mechanical fan with a shroud that should be used, IMO.
Click to expand...


Good. I thought I was going blind!!

Thanks
 
Ok first of all i wanted to say again this pic
IMG-20170803-WA0006.jpg

is from a test drive yesterday - where i just wanted to make sure the car is cooling while DRIVING and without the hood.

I thought first i will make sure the car is not overheating while its moving and air is rammed thru the radiator but i think 210°F is still too hot??
The electric fan like you can see in the pic is just mounted like this for the test drive (figured out it pulls only about 1300cfm).
I know it will not cool my engine like this when the car is not moving.

But since i saw the engine masters episode where they test a 300hp chevy 350cui and the mechanical fan killed about 40 or 50hp i wanted to stay with electric fans.

I just ordered the electric spal fan you can see in the pic above because my old electric fan doesnt fit between the new griffin radiator and the water pump pulley.

What do you think of installing the new electric fan on one side of the radiator as a puller and the old one on the other side of the radiator as a pusher - so it should cover nearly the whole radiator??
IMG-20170803-WA0017.jpg

And do you think an engine oil cooler will helb the whole situation?
Because i could easily go from the oil filter relocation kit to the front.
 
I doubt mounting an oil cooler will help much with the water temperature. Your relocation kit being quite a chunk of aluminum should help cooling already. :)
Temperatures shouldn't be so high (210°) while driving ... like your engine should only need the help of a fan while sitting in traffic. Makes me wonder whether you have proper circulation....
 
There was A thread on fabo about the engine masters episode of the electric fan vs mech fan. It was a good read. My opinion was that the test is highly flawed since the fans tested were of different cfm output. Electric or mechanical, it takes X amount of power to turn a fan of the same cfm output. Electric has the ability to fully control the power when not necessary, and that's the real benefit. The mechanical fan they tested was heavy but I bet it moved a ton of air. An electric fan pulling 5000 cfm or more is likely gonna cost you 50+ amps.

I honestly think that a mechanical fan is the way to go, with a shroud of some kind. You can put an electric pusher on the front for extra cooling if you want, especially if it is helping cool a trans or oil cooler or both.

Oil coolers are always a good idea and easy to install but focus on getting the water to the right temp first.
 
Last edited:
1974scamp said:
Ok first of all i wanted to say again this picView attachment 1715079128
is from a test drive yesterday - where i just wanted to make sure the car is cooling while DRIVING and without the hood.

I thought first i will make sure the car is not overheating while its moving and air is rammed thru the radiator but i think 210°F is still too hot??
The electric fan like you can see in the pic is just mounted like this for the test drive (figured out it pulls only about 1300cfm).
I know it will not cool my engine like this when the car is not moving.

But since i saw the engine masters episode where they test a 300hp chevy 350cui and the mechanical fan killed about 40 or 50hp i wanted to stay with electric fans.

I just ordered the electric spal fan you can see in the pic above because my old electric fan doesnt fit between the new griffin radiator and the water pump pulley.

What do you think of installing the new electric fan on one side of the radiator as a puller and the old one on the other side of the radiator as a pusher - so it should cover nearly the whole radiator??
View attachment 1715079129
And do you think an engine oil cooler will helb the whole situation?
Because i could easily go from the oil filter relocation kit to the front.
Click to expand...



Those test results were off a bit. The most I've ever lost from a mechanical fan was 17 HP and that was some GM piece of crap. Usually a decent fan will take about 12 to drive. I've seen some clutch fans take a bit less.


Make sure you don't trick screw yourself. You'll find more HP and have a more consistent tune up if you control water temp.

You say you have a Griffin radiator. Doesn't really matter whose name is on it. What really matters is the size of it, how many cores it has, and how big the cores are.

If the radiator can handle the job (IMHO, you need a 26 inch core and 2 rows of 1.25 tubes. 1.5 tubes would be even better.

Get a Milodon high flow pump (if you don't already have it) and make damn sure the pump is turning crank speed (1:1) and driving the water pump faster won't hurt you. You need FLOW.

Also, use a mechanical fan, and get it as close to the radiator as you can. If you get the fan close enough, you won't need a shroud. We did a bunch of testing with and with out a shroud. We found ZERO on the dyno either way. At the track, the car was about .1 quicker without the shroud. Where we really found the interesting thing. At highway speeds (and higher) the set up with the shroud ran about 10* hotter than the non-shroud set up. We figure the shroud was blocking air and making the air stack up in front of the radiator.
 
yellow rose said:
Those test results were off a bit. The most I've ever lost from a mechanical fan was 17 HP and that was some GM piece of crap. Usually a decent fan will take about 12 to drive. I've seen some clutch fans take a bit less.


Make sure you don't trick screw yourself. You'll find more HP and have a more consistent tune up if you control water temp.

You say you have a Griffin radiator. Doesn't really matter whose name is on it. What really matters is the size of it, how many cores it has, and how big the cores are.

If the radiator can handle the job (IMHO, you need a 26 inch core and 2 rows of 1.25 tubes. 1.5 tubes would be even better.

Get a Milodon high flow pump (if you don't already have it) and make damn sure the pump is turning crank speed (1:1) and driving the water pump faster won't hurt you. You need FLOW.

Also, use a mechanical fan, and get it as close to the radiator as you can. If you get the fan close enough, you won't need a shroud. We did a bunch of testing with and with out a shroud. We found ZERO on the dyno either way. At the track, the car was about .1 quicker without the shroud. Where we really found the interesting thing. At highway speeds (and higher) the set up with the shroud ran about 10* hotter than the non-shroud set up. We figure the shroud was blocking air and making the air stack up in front of the radiator.
Click to expand...


Ok then i will order a fan clutch and reinstall my old fan maybe this one.
https://www.summitracing.com/int/parts/hda-2747/overview/


The radiator i have now is this one:
https://www.summitracing.com/parts/GRI-1-25222-X
I thought it should be enough.

Yes i already have a milodon high volume pump - i will order a high flow thermostat too.

I will report when i installed all this stuff!

Thanks for your help!
 
1974scamp said:
Ok first of all i wanted to say again this picView attachment 1715079128
is from a test drive yesterday - where i just wanted to make sure the car is cooling while DRIVING and without the hood.

I thought first i will make sure the car is not overheating while its moving and air is rammed thru the radiator but i think 210°F is still too hot??
The electric fan like you can see in the pic is just mounted like this for the test drive (figured out it pulls only about 1300cfm).
I know it will not cool my engine like this when the car is not moving.

But since i saw the engine masters episode where they test a 300hp chevy 350cui and the mechanical fan killed about 40 or 50hp i wanted to stay with electric fans.

I just ordered the electric spal fan you can see in the pic above because my old electric fan doesnt fit between the new griffin radiator and the water pump pulley.

What do you think of installing the new electric fan on one side of the radiator as a puller and the old one on the other side of the radiator as a pusher - so it should cover nearly the whole radiator??
View attachment 1715079129
And do you think an engine oil cooler will helb the whole situation?
Because i could easily go from the oil filter relocation kit to the front.
Click to expand...
 
I know many have stated this already,i understand the reasoning,but running belt driven fan may be a way to prove/disprove the theorys being presented. At least you will know if its an airflow issue.
 
Measure your crank pulley groove for your water pump. If your water pump pulley is larger diameter than the crank pulley, chances are that the water pump is running too slow. To fix mine it took a smaller dia pump pulley and a high flow water pump. Pump pulley is smaller than crank pulley. Yes, if the water is moving too fast the water will move through the radiator too fast to cool. I was told I was making a mistake...but it worked. New motor, clean boiled out radiator. Granted, my overheating problem was at idle only.
 
I just don't understand how a 4 gallon-ish recirculating coolant system running through a radiator could go so fast it doesn't cool down. Physics doesn't explain it to me. Because if the radiator couldn't cool the fluid solely on the fact that it's going too fast, then the same phenomenon would apply to the engine, it couldn't heat the fluid because it is moving too fast. I honestly think this is a myth. The cooling system isn't moving too fast, it just has another problem or a combination of little problems.

I do think that if you have a large water pump and the intake to that pump is in any way not large enough to move the designed amount of flow, it will cavitate. When cavitation occurres, steam is created from the pressure drop at the pump vanes and I'm sure inducing steam into the system would produce similar problems.
 
T56MaxTorq said:
I just don't understand how a 4 gallon-ish recirculating coolant system running through a radiator could go so fast it doesn't cool down. Physics doesn't explain it to me. Because if the radiator couldn't cool the fluid solely on the fact that it's going too fast, then the same phenomenon would apply to the engine, it couldn't heat the fluid because it is moving too fast. I honestly think this is a myth. The cooling system isn't moving too fast, it just has another problem or a combination of little problems.

I do think that if you have a large water pump and the intake to that pump is in any way not large enough to move the designed amount of flow, it will cavitate. When cavitation occurres, steam is created from the pressure drop at the pump vanes and I'm sure inducing steam into the system would produce similar problems.
Click to expand...
I saw it too on a water cooled heat exchanger on a new installation of one of our refrigeration systems. we pumped brackish channel water through the exchanger with no restriction on the outlet. The temp of the water at the inlet was 2 degrees colder than at the outlet. We reduced the outlet from 2" to 1 1/2" and the outlet temp rose 15 degrees and the high head pressure shutdown went away. been running like that now for 15 years.
 

74 Scamp,

IMO you need a full shroud and a "pulling" dual 12" e-fan setup. Drop the $$$ on some Spal Fans. Running no shroud will not be effective. The dual fans will cover more radiator surface.

FYI,
Marion
 
...soo finally i installed my old mechanical fan and now the engine is never overheating anymore even not in traffic on hot days!


I had fun for 2 days but now my converter is damaged :(

I had a Hughes Performance 27-25HD converter and suddenly there was really strange noise when the transmission was in gear or reverse.
Took the transmission and converter out today and there are loose parts falling around inside the converter.
Transmission oil was black and there where a lot of metal in there...

Summit said they will replace the converter or give me a credit because I am not sure if i sould install the same one again.

Wich converter would you guys recommend for my engine?
preferably one from Summit because they would pay the shipping and taxes back to europe too...

Thank you,
Laurin

IMG-20170827-WA0008.jpeg
 
1974scamp said:
...soo finally i installed my old mechanical fan and now the engine is never overheating anymore even not in traffic on hot day...

View attachment 1715086724
Click to expand...

Way to keep it simple and not fall for that band-aid lower power aftermarket electric fan stuff.

A mechanical fan with viscous clutch will cool most properly tuned motors with correctly functioning and good condition cooling systems in cars.
 
autoxcuda said:
Way to keep it simple and not fall for that band-aid lower power aftermarket electric fan stuff.

A mechanical fan with viscous clutch will cool most properly tuned motors with correctly functioning and good condition cooling systems in cars.
Click to expand...


And there is my next question:

wich clutch fans do you run, i have read some of them are good just up to 4000rpm, think that would not be enough..
 
See that BIG hole between the bottom of the radiator and the front of the K member? Air is coming right under the radiator instead of THROUGH it. On modern cars, all of that area is blocked off, PLUS there is an air dam added to redirect air through the radiator. Irrespective of which fan you run, consider plugging that big *** hole and adding a small air dam. It will do nothing but help.
 
Last edited:
1974scamp said:
And there is my next question:

wich clutch fans do you run, i have read some of them are good just up to 4000rpm, think that would not be enough..
Click to expand...

I got away with the Jag fan clutch 2765. That was before they came out with the 2947. Mine cooks fine at the track up to 5900 engine rpm.

Most normally aspirated motors have a redline way more than 4000 rpm. That number doesn't make sense.
 
autoxcuda said:
I got away with the Jag fan clutch 2765. That was before they came out with the 2947. Mine cooks fine at the track up to 5900 engine rpm.

Most normally aspirated motors have a redline way more than 4000 rpm. That number doesn't make sense.
Click to expand...
When I was running the jag type on mine it always ran in the 190-210 range in mild temps and that's with the 8 vain impeller with cavitation plate and a 180 high flow thermostat than I switched to the 2947 and temps don't go over 185. 190 in traffic on a pretty hot day.
 
1974scamp said:
And there is my next question:

wich clutch fans do you run, i have read some of them are good just up to 4000rpm, think that would not be enough..
Click to expand...
Here's another fact to mull around...at 4 k...youre moving enough air without the fan to cool the motor. Clutch fans don't need to run above those rpms, fans help at low speed and idle, after that it's all wind cooled with the vehicle speed. A good indicator of a problem is when it overheats at cruise, capacity issue or blockage..
 
67 gt said:
When I was running the jag type on mine it always ran in the 190-210 range in mild temps and that's with the 8 vain impeller with cavitation plate and a 180 high flow thermostat than I switched to the 2947 and temps don't go over 185. 190 in traffic on a pretty hot day.
Click to expand...

I have a custom fan shroud that's foam sealed to the radiator. I also have Milodon water pump with anti-cavitation plate.

I run the 5 blade 18" diameter type fan. But the blades are cut a whole 1" shorter because the top hose on those early Champion 4 row radiators was too close to the fan. So it's just a 16" fan now.

And it still cools fine.

I think the a huge factor is the block prep I did when rebuilding the motor. I meticulously picked any rust scale out of the passages, around the cylinder bores, places I could feel with long rod but couldn't see. Hot tanking a 40 year old block is NOT enough.

I also have a new hood to radiator support seal.
 
Sticking your head out the window at 80 mph ,lotsa wind. Dont open your mouth, will fart for a week.....
At tgat speed theres lots of cooling.
 
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