jimcork1

I have a 72 454 and wanted to check some temps.

In town 190 F
Interstate at 60 (if you believe this speed) 200
Interstate at 75+ 210 and climbs to 215. I have elec fan and turn on the temp drops to 210 and remains stable.

If you have a big block and have numbers please reply. Please don't get these temps confused with the small block. This is a biggie. :auto:

zwede

I have a modified 454... becool radiator. Edelbrock aluminum w-pump. Spal fans. It sits solidly at 180F on the freeway no matter what speed. In town temps creep up to 200F where the fans turn on and it drops back to 180F within 2-3 minutes and the fans turn off.

You should not heat up on the freeway. There's more than enough airflow at those speeds. Have you checked your vacuum and mechanical advance? You should have 48-52 degrees on the freeway. Not enough advance or too much will make it run hot. Also, it may be running lean.

MEAN72

I have a 72 LS-5 454 big block. MIne runs about 190 degres all the time. It will depend on your thermostat of course but BB are well recognized as overheaters. Your highway temps seem a little high You should be able to hold the intown temperature on the interstate also. As long as they stay in the range your running now your probably okay.

I started having problems with my cooling only after I cammed it and changed the timing. It would creep up on 80 degree days until it overheated. After several feeble attempts to correct the problem, including new radiators, I finally had a radiator built with 20% more capacity. It now runs 190 degree all the time regardless of temperaturee, hills or how I flog it. No problem, even on a 100 degree day.

Good luck. Big Blocks rule! :jester :D :hurray: :hurray:

72ls5fla

Mine are exactly the same as yours .....

As best I can tell, very normal as per guy at Chevy dealership (been there since 1967). Very reputable !!

Bill

Turbo-Jet

once a thermostat is open, it has no effect on an engine's operating temp

also BB overheating stories are more myth than fact. big engines make more heat, but a well maintained stock system can handle it just fine.

:cheers:

Action Vette

1st check that you have the chin spolier installed this will make a big difference on your temp at hwy speeds


[Modified by Action Vette, 12:37 PM 4/18/2004]

norvalwilhelm

I have a large aluminum rad and twin 16 inch electric fans. I like my temperature at 190. On the expressways both my fans are off and the temp runs at the 190, in light traffic I run a single fan and the temp holds. In stop and go I run both fans and again the temp never creeps to the 200.
Bigblocks do not need to overheat but a single electric fan would not work for me all the time. I do need 2.
This is just a shot of the front fan. There is one behind also but on the opposite side and down low.

Twin_Turbo

like norval says, a good radiator will help a lot. I don't have a bbc but I do have a large enough radiator (dual pass 4 core)

MEAN72

When my car was new and stock I didn't have an overheating problem - true. The story goes (i.e.the myth) that when the 1968 BB was being designed, Zora Arkus-Duntav knew there was an overheating problem with the BB in the new body style. Unfortunately, he became very ill and was hospitalized just about that time and before he could resolve the problem. The car went past the time in the schedule when it could be fixed completely before he was able to returned to work. The 1968 went into production with only a partial fix and the problem was never completely solved, therfore, the BBs are left with an inherent overeating problem in the C3 that is okay under normal and new conditions (i.e. well maintained stock system) but shows up under extreme conditions and/or old age. At least this is the urban legend: BBs overheat because Zora got sick :jester

zwede

I read an interview with Duntov made in '71. One of the car mags did some top speed testing and found that if you ran the big-blocks over 140 mph for an extended period of time they would overheat. They asked Duntov why and he said the problem was the fan shroud. At high speeds the fan is a restriction and prevents enough air from going through the radiator. The solution was to put flaps in the shroud that open when a lot of air is pushed through the radiator, bypassing the fan.

He said he had the prototype on the shelf but the bean counters vetoed it.

Now the Spal dual 11" have these flaps in the shroud and I haven't noticed any highway heat problems. Not that I go 140 all that much, but even running on a road course it didn't heat up.

jimcork1

Thanks to all for the info. One other question. My 72 454 has the liscense plate up front. I am concerned this is blocking the airflow. Should this be removed? Thanks again.. :auto: :steering: :flag

Ironcross

also BB overheating stories are more myth than fact. big engines make more heat, but a well maintained stock system can handle it just fine.

:iagree: :cheers: :thumbs:

zwede

Yes, it will cool better without the license plate. Some states require front plates, so check before you do this. That said, Texas requires front plates but I've never had a problem without one.

matchframe

Along these same lines, would a Gen V or Gen VI big block run cooler than a Gen IV big block because of the larger water jackets?
Or would the temps be about the same?

Just Curious.

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