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10-29-2003, 08:33 AM | #1 |
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Aluminum head question
Is there a difference in operating temperatures between cast iron heads and aluminum? I rebuilt a 454 for a 70 Monte Carlo and it's running about 210 compared to the 190 before the rebuild. I also installed a BeCool radiator, electric fans, Edelbrock water pump and March pullies. Everything seems to be fine just a difference in temp. I called and talked to March and asked about the pullies because the crank pully is a smaller diameter than the stock one and I was wondering if the coolant was passing through the system faster than the radiator could cool it down. They told me that the aluminun heads will run hotter than cast and that was probably the reason for the temp increase. Any truth to this?
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10-29-2003, 08:41 AM | #2 |
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pic
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10-29-2003, 08:50 AM | #3 |
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There are some other variables to consider. Did you raise compression? How much time have you run the new motor?
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10-29-2003, 10:28 AM | #4 |
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A couple of questions that I have are:
Did you have to change the sensor? How are the electric fans controlled, temp switch? If you put a smaller drive pulley on the crank then, the accessories would run slower. Jim |
10-29-2003, 10:55 AM | #5 |
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Thanks for the replies. The compression is 10.5:1. There is about 3 1/2 hours on the new motor. The first fan is controlled by a switch and the second comes on when the temp gets to 180 degrees. When running and staning still the motor will climb to 230 or more pretty fast and even with the fans and an additional fan as shown in the pic it will not go below 210 degrees. The other fan is an industrial blower and blows like a dang hurricane. We've done a compression and leakdown test and everything seems to be ok. Just gets really hot. Also we just had water in the radiator. No coolant.
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10-29-2003, 11:06 AM | #6 |
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Try the easy stuff first. Maybe install another new 160 degree thermostat and see what happens.
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10-29-2003, 11:52 AM | #7 |
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When my ZZ502 was installed it ran about the same temp as the original iron headed small block, however, I used a BeCool module that included the same parts you listed as well the aluminum water pump. Only one sensor was used to trigger the fans and it was 180 however the thermostat was a 190...kinda dumb. So I replaced the thermostat with a 160 and the fans hardly ever kick on unless I am sitting in traffic. The motor has roughly 500 miles on it but is 9.6-1.
Nice monte by the way....
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10-29-2003, 12:24 PM | #8 |
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like someone said, the smaller crank pulley underdrives your accesories, so your water pump is now spinning slower than with a stock sized pulley. so at idle your not getting alot of coolant flow. i have billet march pully's also and i was concerned when i noticed the crank pulley was much smaller than stock. but i havne't had any problems yet.
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10-29-2003, 01:34 PM | #9 |
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I 'd put some more time on the motor if it only has 3 hours. It is still wearing itself together and that extra friction causes them to run a little warmer for a period of time. If time doesn't help then move on to some other possibilities. I assume that you bumped up compression since you are at 10.5:1. This could also cause you to be running a bit warmer.
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10-29-2003, 05:21 PM | #10 |
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Horsepower=Heat The more horsepower you have the more heat you have to deal with. You will never get that combo to run 180 idleing on a warm day. Most hopped up big blocks I've ever delt with like to run 210-220. That is not overheating. My advice would be to dump the electric fans and and put a real fan on that monster.
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10-29-2003, 06:28 PM | #11 |
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Aluminum absorbs heat much easier than iron. The heads are now absorbing more heat from the combustion chamber than before. The coolant is seeing more heat as a result.
My Mustang increased 10 degrees in temp when I installed Edelbrock aluminum heads. Absolutely no other changes. Never had a problem, just had to get used to seeing the guage read higher.
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10-29-2003, 06:49 PM | #12 |
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Aluminum also dissipates heat much faster. Everything else being equal, compared to an iron head, aluminum heads run cooler. This is why you can usually get away with running a point higher on compression without getting detonation.
Tx Firefighter, were the combustion chambers smaller on the Edelbrocks. I know that they are on the BBC's - thus, increasing compression ratio and increasing heat.
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68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women" Last edited by breeh; 10-29-2003 at 06:52 PM. |
10-29-2003, 07:11 PM | #13 |
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don't run that thing to lean....LEAN = HOT....
ALSO USE A MSD DIST.. PUT IN THE WEIGHT SWING OUT LIMITERS AND GET MORE BOTTOM END TIMING=== THIS WILL GIVE YOU COOLER EXHAUST TEMP..... BETTER FIGURE OUT WHATS UP... ENGINE WILL RUN HOTTER W/HOOD ON also better get a trans cooler on the return line to the trans.... what size carb. u got...should be 850 cfm Last edited by rage'nrat638; 10-29-2003 at 07:24 PM. |
10-29-2003, 08:11 PM | #14 | |
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Quote:
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10-29-2003, 08:25 PM | #15 |
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Thanks for all the help!! Here's a little more info. I'm running a 160 thermostat. I have a complete MSD ignition system. We've played with the timing and haven't noticed any changes in temp. It's running a 825 cfm Mighty Demon. It has a seperate tranny cooler and dosent run through the radiator.
I knew it would run a little hotter since the motor isn't anywhere near stock anymore but I didn't expect about 40 degrees hotter. |
10-29-2003, 08:34 PM | #16 |
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put those swing out limiters in...
what range plugs u running |
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