69 4 blade fan orientation in shroud?

[KevinW]

So, I have been running a 6 blade clutch fan in my 69 since I swapped engines (327/210 out, 350/300 HA in).  But it has always run on the hot side. Rebuilt radiator did not fix.  Fan blades were correctly half in/half out in the shroud.

So I decided to try the 4 blade fan, to see if it changes anything.  So this is all factory parts, 69 version fan, and correct 1" 3927792 spacer. 

It surprised me to find the the fan is no longer in the shroud.  It needs 1/2" or 3/4' more spacer to get halfway into the shroud.

Was this the was it was from the factory?

ps, still running hot.

 

[bcmiller]

How long is the spacer you are using now?

I am not sure exactly what is correct, but half in/half out seems to work for most setups.

What is your timing? If too much, it can cause an engine to run hot.

[David K]

Kevin,
Can you define "running hot"? That's a subjective term and leaves a very broad interpretation.  Assuming the radiator is clean, is it a 2 row or 3? 50/50 mix? Correct accessory belts and pulleys? Timing correct?

[GMAD_Van Nuys]

According to CRG, a 1 inch fan spacer was used for the small block V-8 in 1969 with the fixed 4 blade fan, whether the vehicle had a 2 or 3 core radiator:

https://www.camaros.org/coolingsystems.shtml

As there was only one fan shroud for the small block V-8 in 1969, your set-up looks okay to me. 

Besides checking your ignition timing as previously mentioned, your thermostat could possibly not be functioning properly and not restricting the coolant flow enough for the radiator to cool the fluid.

[KevinW]

Byron, its the correct 1" 3927792 spacer as noted in the "cooling report".

David, correct factory 3 row rad (rad was re-cored in the spring). 50/50 green mix, Factory SB with PS accessories and factory style belts.   

Timing might be a bit advanced, slight ping when 200r4 locks up. Engine is a factory 350/300 HA (10.25 comp) with 488 points dist.  When I installed the engine (10 years ago), I did set the dist as best I could and limited the "all in" advance.

No sure about the thermostat, I reads 215 deg when I shot it with a IF gun. Probably a 180 deg version, should I try a 160 deg?

I hope I can get the original 327/210 engine back in the car this year, trying to break it in on a run stand currently.

I will be using the 4 blade fan setup for the 327.  I just wanted to make sure the fan is located in the correct spot since it was not in the shroud like I thought it should be. 

[boomer632]

Maybe go for a spin running commando with no t-stat and see how hot it gets.. then work backwards from there selecting a thermostat. If it gets hot without, then maybe a jacket is obstucted.

[GMAD_Van Nuys]

I would recommend that you check the timing as your 350 engine shouldn't ping.  I believe that the standard thermostat was a 195 degree unit and I wouldn't go lower than a 180 degree thermostat.  215 degree operating temperature is still within the acceptable limits.  What spark plugs are you using as the wrong plugs can cause your engine to run hot.

[David K]

Regarding timing, what is it set at with respect to idle rpm, vacuum advance unplugged? Is the carburetor correct for your application?....jet size?

[David K]

Additionally, since the IR gun only measures surface temperature, you have no idea what the internal temperature actually is. While not convenient, I suggest replacing the electric unit with an aftermarket manual temp gauge to verify--do you have a dash light or console gauges?
As you said, its always run hot. So if the 327/210 didn't.....

[KevinW]

Plugs are AC 43S, I put in 45S first, did not like those at all!

Just idiot lights, no clue if sender works.

Timing was set with vac plugged, normal procedure.  I keep having to raise idle speed, cause it does not like idling in hot weather.  No clue what it is now. Had to add an anti dieseling solenoid. I have not tuned it in a long time. Runs just fine, not counting the heat.

Carb is a numbers and dated qjet for a 69 SS 350/300 4 speed, ran rich right from Phil's shop. Opened it up and jets are stuck.  I had to replace the rods with bigger to cure the rich. No clue now, what is in there. Ran fine after that for many years, just hot IMO.

Right now car has a 200r4 (86 Monte SS) and 3:55 gears. Most of the time, engine is running below 2K.  At 65 mph I think its around 2500.  Not ideal for this engines power band, I know this.  That's why I want to get the 327 back in.


 

[x66 714]

If running hot is the issue, I would switch out that 4 blade fan & get the 7 blade, like a 772, with a thermo type fan clutch. I would also review the radiator to make sure you weren't sold a bill of good. Even though it's 3 row, what is the make-up of the 3 rows? Width of rows & fin count per inch is very important. I live in Tucson. These items are very crucial here. I just went through all this on my 440 cuda. My Camaros are stock so no problems with them.....Joe   

[GMAD_Van Nuys]

My 1970 BOSS 302 has a similar 4 blade fixed fan, original shroud & spacer, with the original radiator (rebuilt), and it does not overheat, even when I took the car to the Fabulous Fords Car Show on a day where the temperature hit the 90s.  The Mustang also has Hooker Super Competition headers, which generate more heat under the hood than the stock exhaust manifolds.  As the car is also equipped with a factory oil cooler, it does help keep the engine cooler as Ford found out that during hot temperature testing, BOSS 302s with 4.30 gears recorded oil temperatures over 300 degrees without an oil cooler.

I still believe you need to check your ignition timing.  I checked the advance on my 1979 Trans Am before I went in for emission testing and the advance had moved from the factory specification of 18 degrees at idle to 10 degrees, which would have failed the test.

[rich69rs]

I was having a similar issue with my '69 RS w/ 327/210 engine in the 2004-2009 timeframe.

I solved my problem by changing from the 4 blade fixed to 6 blade w/clutch in Aug 2009.  Since then my engine temp has not exceeded the 1st segment past the 1/4 mark on the temp gage (195-205 on the thermostat housing with an IR temperature gun).

I also sealed the gap between the top of the core support and the fan shroud to reduce air flow leakage around the radiator. (The RS core support by design appears to me to have less leakage around the radiator which inherently helps.)

My issue with the car tending to run warm in slow traffic on summer days started after the engine was rebuilt in 2004.  My issue had nothing to do with timing but resulted from increasing the compression ratio & head mod during the rebuild, that coupled with the reality that the 3 core radiator is marginal, IMHO, from the factory in the first place.

Picture shows my 327 running during break in back in 2004.  From what I can see in the picture, looks like the fan is pretty much fully covered (90%) by the shroud.

Richard

[KevinW]

I have been running for years with a 6 bladed clutch fan.  It actually really overheated with this setup last year (in stop and go show traffic and light did not come on).  But the main culprit was a cracked repro radiator cap.  Which also busted the radiator, which is why it got rebuilt.  Rebuilt by a local company who have been in business for 90 years (I think).  I have used them many times for Camaros and other cars.  I have no issue with their workmanship.

Richard, your fan spacer is NOT the stock 69 one inch version. Looks like 2 or 2.5 inch.  That is one of my main questions.  Should I ditch the number correct one and get a thicker one that puts the fan better in the shroud.

Next time I get a chance, I will re-check the tune and see if that helps.  I also have to find my other spacers.

     

[rich69rs]

" Richard, your fan spacer is NOT the stock 69 one inch version. Looks like 2 or 2.5 inch."

Not surprising - spacer was what was on the car when I got it.  I no longer have either it or the 4 bladed fan, so no opportunity to check whatever the p/n was.

One other point I forgot to mention is my distributor vacuum advance is connected to full manifold vacuum and the ported vacuum line from the carb is capped.  Something else to maybe consider if you are using ported vacuum.

From JohnZ's (John Hinkley) "Timimg 101" article: 

"Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it."

Richard