PhilB676

Recently had my #s matching 327, 300hp w carb motor rebuilt. After installation the motor was running hot (190+) and fan clutch (Hayden 2741) wasn't kicking on. Contacted fan clutch manf and we've determined my fan clutch, water pump and 7 blade fan are from an early c3 (based on size and bolt pattern). Clutch Manf said it might turn on at 195, but I'm not willing to let the new motor get that hot.

The fan has two possible bolt patterns. Machinist went through water pump on rebuild and said was fine. This pump actually has 'made in the usa' casted on it.

Radiator is a new Dewitt aluminum direct fit (4100 btu).

Any suggestions on if I should just replace all three? If so, where would you buy it from? Any other thoughts?

bcwaller

190+ is not really hot. If the car runs at a stable temperature of 195, then it runs at that temperature. You didn't say what thermostat you have. Might it be a 195? My cars usually run at or close to thermostat temperature, unless there is a problem with the system.

When testing mine, I would idle the car in the hot sun with a wall in front to cut air flow for 15 minutes. It got warmer than thermostat temperature (180), but never went over 205 so I knew it was solid. But at cruise speed the temperature drops quickly to 180 and sits there solidly no matter what the outside conditions.

If you have a 180 thermostat, and the temperature rises over 190 while cruising, then you may have an issue to look into. But with a new radiator and a stock 327/300 you should be rock solid at your thermostat temperature unless it is really hot and humid and you are idling with no good airflow.

leif.anderson93

You state that you recently had the motor rebuilt. Couple of things...was the block boiled and all residue removed from the water jackets? Was the block bored? 190*-195* is a long way from running hot, especially for a freshly rebuilt engine. What are you using as a measuring tool for the temp...the dash gauge or an IR gun held appox 4" from the thermostat housing? What is the ambient temperature and humidity? I understand your trepidation with a new motor, but the temp your car is running is nothing to worry about.
P.S. Read this in its' entirety
http://www.lbfun.com/warehouse/tech_...em/cooling.pdf

Mr D.

You say motor was running hot (190+). Plus what?

Have you put a IR gun on this to verify temps? Does car boil over or puke out the overflow?

PhilB676

Thank you both for quick responses. I'm worried that the temp didn't settle after driving the car and it was a cool evening last night in Chicago. First Drive with the new motor. The temp went up and stayed at 180 (180 thermo) nice and quick. Everything I stopped at a red light it climbed 5 degrees. When it creeped past 190 then 195 I didn't hear the fan kick on so I pulled over, opened the hood, used an IR thermo gun and also measured 195 on the intake just right of the housing. I drove it home (near a forest preserve...cooler air) and it lowered to 190 when I pulled in the gatage but shot up to 195 within 1 min before I turned it off.

The motor was rebuilt by a true v8 veteran. He took the motor whole, rebuilt, dynod and gave me an excellent warrantee provided the motor isnt run hot (hence my fear).

Thanks again for your messages....When it rains...it pours..after I posted my original message the machine shop called me and said to change out my fan and fan clutch...which I will order tonight and keep those interested posted. If it's successful, I'll share the part numbers. He also suggested I move the front plate from the middle to the side (or off completely). He agreed that the dewitt radiator I have (from this forums heavy recomendations) is the best to use.

SWCDuke

Emission controlled engines have 195 degree stats and the fan clutches are tuned to tighten at a higher radiator exit air temp. Some can be tuned to a lower temperature. This has been discussed many times.

Notwithstanding the above, there is no harm in letting it run in the 190-210 range other than an increased possibility of vapor lock/percolation, and higher engine temps also increase the propensity for detonation. That's what emission controlled engines typically run at, and the early ones have the same basic engine components as earlier non-emission controlled engines.

The normal operating range for sixties vintage engines with 180 stats is 180-230 and at 230 you still have 35 degrees boilover margin with a 50/50 ethylene glycol/water mix and a 15 psi cap.

Even with a sixties vintage fan clutch setup that's tuned for a 180 stat and all cooling system components in good operating condition, temperatures over 180 in stop and go traffic or a freeway jam-up when it's over 80 ambient are normal.

The thermostat and fan are designed to maintain 180 as the LOWEST system temperature during normal operation; 230 in extreme conditions is okay and it won't hurt the engine as long as you shut it down if it boils over, and that shouldn't happen until 265 with the proper coolant and a 15 psi cap that actually holds 15 psi.

Duke

PhilB676

Thanks Duke. Your responses are always appreciative and eye opening. I didn't think of it like that (modern car temps).

jdk971

i believe johnz or someone mentioned clocking the new fan clutches. i believe turning the
spring one half turn counter clockwise. i could be wrong on the direction of turn. jim

SWCDuke

Here's an article on how to adjust the fan clutch to tighten at a lower radiator exit air temperature.

Duke

JohnZ

Good little article on the clutch calibration procedure, but it still never says exactly what direction to turn the spring on the Eaton clutch - it's CCW (counter-clockwise). The new Schwitzer reproduction clutch from K&B is already correctly calibrated.