Engine temperature
Thread Starter
2nd Gear
Joined: Sep 2003
Posts: 2
Likes: 0
From: San Jose CA
Engine temperature
In 1998 I had to remove the 4-speed and install a Turbo 350, which works great. In July of 2001 the car was in an accident with major front end damage. The body came off, frame was repaired, along with just about everything else. New Delco Harrison radiater, all hoses, fan, fan clutch, ect.
When I got the car back in January of this year I noticed the temp would climb to 220+ on a warmer day in traffic. When the car would move again it would cool down. I also had all gauges redone so I verified the the temp, it was accurate. I checked collant level, including coolant/water mix, thermostat, timing, ect. It acted like the "new" fan clutch was not locking in so I replaced it. Same thimg. After more invetigating I found out the the thermostat on the fan clutch has 2 settings. I moved it clockwise (180 degrees), it's now better but not right. The engine has 10,000 miles on it. The only damage do to the accident was a cracked driver side exhaust manifold. The car now gets up to 195-200 degrees in slow traffic. I'm thinking maybe the fan blades may not right. I would appreciate any help.
When I got the car back in January of this year I noticed the temp would climb to 220+ on a warmer day in traffic. When the car would move again it would cool down. I also had all gauges redone so I verified the the temp, it was accurate. I checked collant level, including coolant/water mix, thermostat, timing, ect. It acted like the "new" fan clutch was not locking in so I replaced it. Same thimg. After more invetigating I found out the the thermostat on the fan clutch has 2 settings. I moved it clockwise (180 degrees), it's now better but not right. The engine has 10,000 miles on it. The only damage do to the accident was a cracked driver side exhaust manifold. The car now gets up to 195-200 degrees in slow traffic. I'm thinking maybe the fan blades may not right. I would appreciate any help.
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,264
Re: Engine temperature (LFP)
Replacing a manual with an automatic is going to load up the engine at idle, which means a lower idle speed and less manifold vacuum.
The question becomes, do you have enough total idle advance? What are the vacuum can specs and does the engine pull enough vacuum at idle (in drive)to pull the installed vacuum advance to the limit with 2" Hg. margin. A seventies vintage vacuum can that was designed for emission controlled engines is not suitable for a high performance or modified engine. Also, "ported" vacuum advance is totally unsuitable and is nearly guaranteed to cause idle overheating, so make sure the vacuum can is signalled by a full manifold vacuum source including idle conditions.
Total idle advance (idle speed in drive) should be 20-25 degrees for a medium performance engine (300HP) and 25-30 degrees for an OE SHP cam or similar aftermarket cam that pulls 14" of less manifold vacuum idling in drive with an automatic.
Duke
The question becomes, do you have enough total idle advance? What are the vacuum can specs and does the engine pull enough vacuum at idle (in drive)to pull the installed vacuum advance to the limit with 2" Hg. margin. A seventies vintage vacuum can that was designed for emission controlled engines is not suitable for a high performance or modified engine. Also, "ported" vacuum advance is totally unsuitable and is nearly guaranteed to cause idle overheating, so make sure the vacuum can is signalled by a full manifold vacuum source including idle conditions.
Total idle advance (idle speed in drive) should be 20-25 degrees for a medium performance engine (300HP) and 25-30 degrees for an OE SHP cam or similar aftermarket cam that pulls 14" of less manifold vacuum idling in drive with an automatic.
Duke
Le Mans Master
Joined: Aug 2000
Posts: 9,662
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From: Semper ubi, sub ubi
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: Engine temperature (LFP)
You didn't say what year model you had but according to my 69's owners manual "Normal" operating temp is 210 degrees. According to the Corvette Black Book later 70's C-3 were designed to run at even warmer temperatures. So there is probably nothing wrong with the temps you are seeing.
Thread Starter
2nd Gear
Joined: Sep 2003
Posts: 2
Likes: 0
From: San Jose CA
Re: Engine temperature (LFP)
More information,
The engine is the same engine with all the same settings before the
problem of running hotter when not moving. The car ran at 180 degrees moving or at idel. The only changes were the radiator, fan, fan clutch, and fan shroud. Whem I chaned the etting pn the fan clutch it was much better, but still not the same. I am thinking if there is any way of determining the correct fan by measurement. I would appreciate any input.
Thanks,
LFP
Tha
The engine is the same engine with all the same settings before the
problem of running hotter when not moving. The car ran at 180 degrees moving or at idel. The only changes were the radiator, fan, fan clutch, and fan shroud. Whem I chaned the etting pn the fan clutch it was much better, but still not the same. I am thinking if there is any way of determining the correct fan by measurement. I would appreciate any input.
Thanks,
LFP
Tha
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: Engine temperature (LFP)
How hot is it? Is it really too hot or just somewhat hotter? As for fan blade measurement, it should come within a 1/2" of the shroud, radially. The blades should project to half their depth into the shroud. The dimensions are for the greatest fan efficiency. You can check similar cars to see what is "normal". Also, check all the shrouding for proper fit. There should be no air gaps giving air an alternative route except through the radiator. The body shop may not have been as conscientious as possible. If you still end up dissatisfied, consider an electric fan set up. There are many benefits to this. First, it frees up quite a bit of engine horsepower. With a thermostatic switch, it only runs when needed. It takes a ton of weight off the water pump bearings, allowing a longer pump life. Except for the initial cost, I cannot think of a single disadvantage to an electric fan. Good luck, and...
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