heating up - Chevelle Tech
Heating & Cooling Heating, cooling and air conditioning Sponsored by:Cold-Case Aluminum Radiators

LinkBack Thread Tools Search this Thread Display Modes
post #1 of 9 (permalink) Old Apr 19th, 14, 8:47 PM Thread Starter
Senior Tech Team
Larry Joe
Join Date: Jan 2007
Location: tulsa okla
Posts: 1,043
heating up

On a 66 BB does the retard on distributor have anything to do with it running down the road hot. My electric fan does not seem to bring it back down. I have aluminum radiator with a vintage aire and I have not used the air as I have not been able to dive it in summer since I took copper radiator out along with ford flex fan. Its been downhill. Even used a chin spoiler

blubu is offline  
Sponsored Links
post #2 of 9 (permalink) Old Apr 20th, 14, 12:54 AM
Senior Tech Team
Join Date: Nov 2006
Location: Houston north side
Posts: 1,448
Re: heating up

Retarded timing can contribute to any engine running hot.
What kind of fan setup are you running now?

1966 Chevelle 300 2dr Sedan
385, Flat Top Hypers, Performer RPM, S.M.I. 750 Q-Jet, 72cc Dart Platinum 200cc runners, U.D. Harold 223/233 112 LSA Cam, 700-R4, PS, Manual Disc Brakes, AC, Hedman headers with 2-1/2" exhaust.

1946 Studebaker Coupe- street gasser finally underway!
TXCR13 is offline  
post #3 of 9 (permalink) Old Apr 24th, 14, 2:02 AM
Team Member
Join Date: Jun 2002
Location: N.Y.
Posts: 11,306
Re: heating up

Originally Posted by blubu View Post
On a 66 BB does the retard on distributor have anything to do with it running down the road hot. My electric fan does not seem to bring it back down. I have aluminum radiator with a vintage aire and I have not used the air as I have not been able to dive it in summer since I took copper radiator out along with ford flex fan. Its been downhill. Even used a chin spoiler

" My electric fan does not seem to bring it back down. I have aluminum radiator , I have not been able to dive it in summer since I took copper radiator out along with ford flex fan. Its been downhill. Even used a chin spoiler "

FYI,you answered your own question when you said you removed the std rad and fan and then went to an al rad with elec fans and the motor ran hotter after doing that.

In your case the elec fans are the biggest issue , i see it every summer here in t/c as a problem with brand new al rads with elec fans having motors running hotter because the elec fans arent powerfull enough to move ample cool air thru the thicker radiator cores in hi perf al and hd cooling copper/brass rads too .

But a lrg gm clutch fan used for ac or hd cooling apps with a HD thermal fan clutch and v8 motor powering it blows most elec fan setups away when it comes to moving/sucking cool air thru thicker/more dense radiator cores used in hi perf al rads and or HD cooling 4 row ols school copper/brass rads .

But the thermal clutch fan also disenguages when motor isnt hot enough to require additonal cooloing which save power & inc mpg,fna lcuthc only locks up when motor/rad is hot enough to require more cooling.

Then when the motor cools back down after getting back up to cruise speed after 2-3 mins the fan clutch disengauges rerduing drag on motor untill things heat back up again.

But todays cars/motors with using thinner 1 or 2 row al rads with smaller tubes too running mostly dual elec fan setups that are specifically designed for todays cars/motors do just fine as we all know because they'elec fans are designed to do so in that app with much much thinner cored AL rads where elec fans do just fine cooling much smaller motors on avg too.

The best fix to your problem is to read my post (COOLING-101) RIGHT HERE IN THE HEATING/COOLING SECTION.

I have had many guys here in team chevelle with motors running too hot with elec fans install & do all the things i rec in my cooling-101 post without going for a new radiator getting 20-25 deg reduction in temp on avg and in some cases 30-40 deg reduction in temp vs the elec fans while retaining/using the same radiator in almost all cases with many testimonials from your fellow t/c members i have on file to back that up.

My rec upgraded/tweaked gm clutch fan setup keeps old school sbc/motors at 180 deg + - 5 deg at cruise and bit higher in traffic. (Thats talking in head temp/not intake temp that typically reads 10-15 deg lower on avg in warmer summer temps)

So chk it out anf follow what i say and your cooling woes will be a thing of the past " if you do everything/all i suggest " becuase its a team effort that gets the job done collectively so if you dont do all/everything as i suggest you will likely end up with a reduction on cooling efficinecy and not the great cooling i state that system provides when setup properly/fully as is suggest.

Good luck.


1969 CHEVELLE SS396,ORIGINAL #'S MATCH,GOT IN 1978,(In 2001 rblt/bored original 396 .030 to 402)/M20/12BOLT/3:31'S
2002 MAXIMA (DAILY DRIVER/1 owner,GOT 3/2013 w-44k miles)
2009 HD ELECTRAGLIDE CLASSIC ULTRA (GOT 11/14 W-9,700 miles)
SWHEATON is offline  
post #4 of 9 (permalink) Old Apr 24th, 14, 11:48 AM
Lifetime Premium Member
Join Date: Jan 2006
Location: Mountain View CA
Posts: 3,379
Re: heating up

If done correctly electric cooling is FAR better than the clutch approach.

I too have data and a real car with a high HP engine that is used on the track, in road racing, in which the clutch will fail and belts will wear out due to being run at high rpm for extended periods.
Thus I use a properly done electric system as do all moderen car manufacturers.

If you want your car to be stock the clutch is the way to go. It is also a lot less money. The worst way is to buy a cheap Electric fan kit, save your money and go stock.

My car is here:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
bikeron is offline  
post #5 of 9 (permalink) Old Apr 26th, 14, 3:44 PM
Team Member
Join Date: Jun 2002
Location: N.Y.
Posts: 11,306
Re: heating up

" If done correctly electric cooling is FAR better than the clutch approach. "

Ok,to set the record staright the only reason i am posting this is because the above staement is not correct by a long shot and i dont want to see people that dont have the experience to know better be led down the $$$/path to having thier motors run much hotter then they should due to elec fan setups that can handle the heat.

His above statement about elec cooling fans being FAr better then the clutch apporach isnt correct IN A REAL WORLD SETTING/APPLICATION when used on our old school classic chevelles running old school sbc/bbc motors with hi perf aftermarket al rads or hd cooling 4 row std type copper/brass rads.

And dont forget the clutch fan setup disengauges when motor not hot enough to require additional cooling which also aids in mpg and reduces drag on motor ,elec fans load the alt more when additonal cooling is required when also loads the motor.

So with that in mind both the elec fans and thermal fan clutch setup put additonal load/drag on the motor when additonal cooling is required and then reduce drag (clutch fan disenguages and or elec fan turn off) when motr has cooled back down reducung load on motors so its mostly a wash in that dept.

Ok,Bikeron,You may have test data under controlled test cond that shows elec fans seem to be more efficient. But i have 1st hand point of use testimnials from team chevelle member after team chevelle memer that were running elec & al rad setups by mult mfgs all getting same basic results which was thier motors consistantly running way too hot esp in stop/go traffic in 210-220-230 range even when wired right with higher output alts installed to ensure consistant/max elec cooling fan rpm/outputieved too.

Here goes,read the file i pasted below and you will see how in your fellw team chevelle member words how aftermarket elec fans are not the best choice by far for your avg old school chevelle .

But todays cars designed to use elec cooling fans with much thinner core (by 50-60% or more!) AL rads is a totally diff situatation/application which we all know works well.

But aftermarket elec fans dont work well not moving as much air thru thicker rad cores for max cooloijng in traffic on hot days when used on hi perf al rads or hd cooling 4 row rads that have very thick dence rad core vs a v8 engine powering a lrg gm 7 bblade clutch fan used for Ac or HD cooling thats got plenty of fan blade pitch along with a HD thermal fan clutch & proper matching fan shroud with airgap between shroud & rad core sealed that blows all but a few elec fan setups away weather they be a dual or lrg single aftermarket elec fan setup.

Here are the testimonials many of which were issues with elec fans having motors running way too hot esp in traffic where they got 20-25 deg temp reduction on avg (some 30-40deg ) post installing my rec upgraded tweaked cooling system with most people retianing the same radiator too!

I go by rersults not just mfgs test data and the FACT IS from your own t/c memebers in thier own words (along with my 42+yr exp wrenching these cars too) is time after that that the cooling system setup i rec with my suggested upgrades & tweaks litterally blows away every single aftermaket elec fan setup people dumped for my rec setup which the testimonial prove hand down not including all the times i have done the same elec fan to my rec upgraded & tweaked cooling swap on other peoples cars i was working on too.

Note,had to break up the testimonials into mult posts here because file was too lfg for 1 post.

================================================== ============

This testament below shows his motor was running up to 230deg with elec fans and then 220deg with a flex fan. Then his motor temp was reduced by 40+ deg to 185-190deg tops in 85 deg temps with a 772 clutch fan and HD hayden 2747 fan clutch along with other suggestion i made too .

Thats a solid 35 - 40+ deg reduction in engine temp depending on if compairing to elec or flex fan setup which is a significant temp reduction post following nmy rec setup.

I have been busy these couple of weeks after I did the upgrade, so I havent had a chance to
take her out again on a warm day.
I do plan on bringing her to work on friday, it is suppose to be in the low 80's on friday. So I will test her out then.

Just for anyone following this thread, I am giving you a little run down of what I been doing.
I been battling the hot temps on my Chevelle for a few years now. I had the flex-a-lite electric fans with a Mr. Gasket HP 160 t-stat. On warm days, she will get up in the 210-220 while cruising, on stop and go traffic there would be times she would hit the 230-240 mark in traffic. When this would happen I would just pull over and let her cool a bit. The I dumped the electric fans, and went with a 6 blade flex fan I had laying around, and thru on the stock 70 shroud. Temps got a little better, but would still hit the 210-220 mark on stop and go traffic.

A few weeks ago, I just pretty much had it, I just couldnt get good cool running temps on her that I would honestly not even drive her around in late spring, summer or fall. Only winter and early spring.

Well after posting my problem on here, Scott suggested a few things. Which I tried and so far I can say it has been succesfull.
1st I dumped the 6 blade flex fan, went with the stock 7 blade 772 fan, I also purchased the Hayden 2747 HD clutch, but kept the Mr Gasket 160 t-stat. I also switched from the 70 shroud to a 71 shroud (which the 71 covers the whole radiator, which the 70 does not). Temps got better, took her out on an 80+ temp day and in stop and go traffic. Temps where about 185-190 on 85+ outside temp with stop and go traffic.

I was very pleased with this. though now I changed the Mr. Gasket 160 t-stat and went with a standard autozone 160 t-stat Scott rec, I also drilled 2 extra holes in it.

Now this friday, I will take her out again, on 80+ outside temps and in stop an go traffic. now i will see what she will do with the standard autozone t-stat. Which i think it will do better than the Mr. Gasked HP one. After I installed the standard 160* t-stat i did take her out on a quick spin, and she never hit the 165 mark. but then again, it wasnt hot that day, it was in the mid 70's.
I hope all this info will help any fellow TC member with the similar problem I had.
Once I take her out on a hot day, I will report my findings.

Thanks Scott for all the help, and thanks everyone else that had thier .02 in it
Followup from the original poster for his above post when he tested the autozone duralst 15356 160 stat vs a hi flow mr gasket 160 deg stat.

I did take the Chevelle out on friday to work, and hit stop and go traffic on the way home, though outside temps werent as warm as I expected. Outside temps where high 70's, maybe like around 78-80 outside, BUT the good news was that even on stop and go traffic for a good 45 min stretch, she never hit 185. She was steady for the whole time in traffic at around 180, climbed to 185 when traffic started to pick up, but then she dropped to about 175-180 all the way home.

Thanks again for the great advice. I would definately say the standard autozone 160 t-stat beat out the Mr. Gasket HP 160 t-stat.
Jul 5th, 11, 10:32 AM mad70ss Tech Team Join Date: Sep 2006 Location: Corona, CA Posts: 685

Re: Help on 70 BB overheating issues....**UPDATE**
Ok, here is an update on my Chevelle....
Took her out this past friday, brought her in to work. After work, on the way home, outside temps were in the 90's. Hit about a good 30-40 min of stop and go traffic. In 90 deg heat she got up as high as 190. Did not go higher than 190. Driving down the freeway with no traffic, she was doing 175-180.

WOW!! What a difference, before with the elec and or flex fan, she would be doing 210 easy and forget about being stuck in traffic.

I am very pleased with the new set up (7 Blade fan, clutch, 71 shroud and 160 autozone t-stat)....
thanks again Scott.....Now I can get to enjoy her on the summer __________________ _____________________________________ Ralphy Corona, CA "MAD70SS" 1970 Chevelle SS http://i103.photobucket.com/albums/m...kers064-vi.jpg 1996 Chevy Silverado Z71 1996 Impala SS (SOLD)
In summary this case from the above testimony showed his motor went from running up to 230 deg in traffic with elec fans and up to 220deg in traffic with a flex fan to running 175-180 deg on avg with my rec cooling system/motor tune setup.
================================================== ==========
Here's another example (pasted below) of going from a dual elec fan seup that was running as hot as 220 in traffic to a gm 772 fan/2747 hayden HD clutch fan/and stock type fan shroud reduced temps by approx 40 deg.

With an AC Condenser on my Chevelle and the trans cooler pressed up against the radiator the (12" dual puller Flexalite) dual electric fans I had just wasn't enough air flow at idle and low speed. Temps crept to 205 and kept rising in traffic to 220 on a 90 degree day.

So replaced the dual electric fan setup with a '71-'72 28" stock type 2 piece fan shroud, installed the gm 772 fan i already had, and a HD Hayden Fan Clutch (2747 ).
Was hoping I didn't have a bad radiator.

It was about 85 degrees yesterday, took the chevelle for a ride and tried to heat her up. Highest the motor saw in 85+ deg temp temp was 179 at cruise & when sitting in traffic it actually went down to the high 160's.

I would call it a 40 degree drop in idling temperature.

I do have a brand new Dual Fan setup in the box, but that is where that will sit.
================================================== =========
Feb 3rd, 12, 1:06 AM jm209modesto josh Join Date: Feb 2012 Location: modesto ca Posts: 3
over heating
Hi,i have a 67 chevelle 468ci engine i recently upgraded from a stock radiator,mech fan,mech w-pump to an aluminum also electric fan and now my car now runs hot. it doesnt get hot right away after driving for about 30-45 minutes it starts creeping up. it never got hot when i had mechanical water pump mechanical fan and a stock radiator..

1969 CHEVELLE SS396,ORIGINAL #'S MATCH,GOT IN 1978,(In 2001 rblt/bored original 396 .030 to 402)/M20/12BOLT/3:31'S
2002 MAXIMA (DAILY DRIVER/1 owner,GOT 3/2013 w-44k miles)
2009 HD ELECTRAGLIDE CLASSIC ULTRA (GOT 11/14 W-9,700 miles)
SWHEATON is offline  
post #6 of 9 (permalink) Old Apr 26th, 14, 3:45 PM
Team Member
Join Date: Jun 2002
Location: N.Y.
Posts: 11,306
Re: heating up



================================================= ===============
Took the car out today for a cruise. It seemed to be running a bit warm. It was about 86 degrees today, but the motor was running about 220. In the winter months it get up to about 210 and stays there. I noticed this last summer, and at times it would creep over 220 when at a stop light. I am running stock 4 core radiator with 50/50 antifreeze, and a 180 thermostat. Is there a better coolant mixture that may help with this? Living in Colorado the summers get a bit warm.

Today, 12:03 AM MikeSS Lifetime Premium Member Join Date: Jan 2005 Location: Aurora, CO Posts: 229
Re: Car running a bit warm
I just finished up the mods to the car to correct the heat issues. I had initially been running about 210 degrees just driving around town.Sitting at a light, or in stop and go traffic, the temp would rise to 220ish. This was all with an incorrect 4 core rad and a 180 thermostat.

Scott Wheaton made a few recommendations, and I put them into place.

Here is what I did.
-Replaced the fan clutch, with a Hayden HD 2747. That mod alone dropped the temp to just under the 210 mark. -Replaced the radiator with a stock style 4 core (manual trans) -Installed a 160 degree thermostat -Replaced the old coolant with a 30% coolant, and a 70% distilled water mixture

Drove the car and the temp while cruising is about 176 deg. At a stop light, sitting for about 4 min, it crept up to about 185 deg. Overall this reduced the operating temp about 20-25 deg total.

Thanks for all the help Scott. __________________ MikeSS 70 SS TC Member #5479

Here's a couple examples!

I have a 71 Chevelle with a 496 built pretty tough and having trouble keeping cool. Went from 4 core radiator with single electric fan to a 2 core 1 inch tube aluminum radiator with dual 14 inch fans and when running on the highway on hot day running around 215 to 218.I had a 50/50 mix of water and antifreeze, but water out of a hose with a 180 thermostat. I have 4:11 in rear end and running about 2500 rpms at 55 to 60 mph. If I run faster than 2500 I will creep up to 220 and thats when I pull over to cool off.

SWHEATON posted many threads about how to cool these BB down. I wasn't on board because aluminum rad and dual fans come on that should do it without problems right NOT!

Well many posted how well it worked doing what SWHEATON suggested.

I decided to drink the Koolaid. It worked better than I expected. Here is what I did:
I kept the aluminum radiator and changed the mix to the 70/30 distilled water and straight antifreeze. Changed the thermostat to the autozone 160 and drilled the 2 holes. I ran the car this way with no change. Decided to go all the way. Pulled the electric fans and shroud and replaced with a 772 7 blade fan with the hayden 2747 clutch and orginal shroud.

Here is what happened: went for a drive in 90 to 95 degree weather and to my suprise I ran about 190 to 195 average on the highway at 2500 rpms. Took it up to 3000 rpms and stayed about the same. Ran up to 4000 to 4500 for couple of min ran about 185. I did creep up to about 197 for brief time but never went over 200. Got into town and ran about 185. Plan to go on a drive on a hotter day above 95 deg to see what happened but so far

SWHEATON I am a believer now Thanks for helping with cooling my BB down. JP
Another followup in extreem temp on this same motor/car! _
Well here is my update on a hot 98 day and 2nd trip after changing everything Scott suggested.

Today I went to a car show and it got up to 98 degrees today. On my way to the car show I ran average of 185 on highway doing 3000 rpms and when I got off the highway and pulled up to register I was 178. On my way home at the hottest part of the day I averaged 190.
This car used to run as high as 220 deg at 3k rpm cruise speed in similar temps but now avg
185 deg (35 deg cooler!) in same cond!
I have to give credit again to Scott because I have been fighting this cooling problem for over a year and was afraid to drive my car too far of fear of overheating and when I did drive I had to take back roads to keep my rpms down so that I wouldn't overheat. This sucked because you spend so much on these cars and its a bummer to have problems like this that you have to question to go somewhere with overheating in that back of your mind.

Thanks to Scott ready to drive and go anywhere!
Of all the things I have lost, my mind is the thing I miss the most!
jpextreme View Public Profile Send a private message to jpextreme Find all posts by jpextreme Add jpextreme to Your Contacts
#2 Jul 10th, 12, 10:29 AM 1971ss454Elco Tech Team Marc Join Date: Nov 2008 Location: california Posts: 969
Re: Overheating! SWHEATON Thanks for the help!
Scott helped me as well on our 71 SS 454 which used to run 225-230 degrees.
We now run 175-180 degrees on 100 degree day weather here in cali right now WITH A/C on no less.
Stock appearing LS5 with A/C, TH400 and 4:11 rear.
Alumitech replacement rad, stock shroud, HD clutch w/stock type fan.
Timing correct, carb tuned, foam tape used to seal shroad to radiator and radiator to support. All new hoses from pacecarJeff.
Marc S

================================================== ==========
My '70 started running hot (210 and climbing) with a big block conversion...usually on hotter days, for sure in traffic. I went with Scott's (SWHEATON) advise: '71 Fan shroud - full radiator coverage A-Zone 160 thermostat HD fan clutch Summit HI-Flo Pump. Now, In 95 degree heat it tops out at 190 degrees MAX!...cruises at 170-175 all day.
================================================== ======


Bellow is the testimonial from a t/c memeber:
I like threads that have some type of closure to them, so here is the update.
After pulling the thermostat, I was driving around in 90+ weather and thought I had my temp issue fixed, then on a drive of stop and go in in 90+ degrees outside, it started to get hot.
So, I followed Scotts suggestions and purchased the 2747 Hayden fan clutch, and it bolted right on my short shaft water pump no problem. I added a radiator spacer in my car to put the radiator where it would be with a big block, essentially moving it a bit farther away from the fan, so it would be situated in the shroud perfectly. Since I wasn't going for stock, I found and installed a shroud from a 68 impala, which covers the entire core of my radiator. I also found a 7 blade thermal clutch fan at a junk yard that would fir in the shroud... I believe it is an 18" fan. I threw it all together, put the 160 degree thermostat back in and just got back from an hour long spirited drive in 93 degree weather.
Temps didn't even hit 190. They moved from about 183-186. As stated earlier, my temp sensor is in my intake manifold as the correct 461 heads from 65 don't have provisions for the sensor, but with nothing else changed, I just decreased my overall temp from my dual electric fan setup that would climb to 225+ in traffic, to maxing at 186 in the same conditions.
Thank you so much Scott for the help with this, and I hope this can help someone down the road.
Long story short, is it possible to make dual electric fans cool a SBC or BBC? Probably, but you will spend MUCH more money doing it. MY stuff was middle of the line and my SBC was mild and the $400 shroud/electric fan setup i was running couldn't hold a candle to the cooling of my $3 7 blade GM clutch fan fan with $50 fan clutch, and stock shroud (cost $40). I wouldn't have been a believer, but this concludes my case study.
My/Scott's responce :
WOW,thats a solid 35-40 deg reduction in temps over elec fan setup showing once again the tweaked gm clutch fan setyup i rec blows the avg dual elec fan setup away.

1969 CHEVELLE SS396,ORIGINAL #'S MATCH,GOT IN 1978,(In 2001 rblt/bored original 396 .030 to 402)/M20/12BOLT/3:31'S
2002 MAXIMA (DAILY DRIVER/1 owner,GOT 3/2013 w-44k miles)
2009 HD ELECTRAGLIDE CLASSIC ULTRA (GOT 11/14 W-9,700 miles)
SWHEATON is offline  
post #7 of 9 (permalink) Old Apr 26th, 14, 3:46 PM
Team Member
Join Date: Jun 2002
Location: N.Y.
Posts: 11,306
Re: heating up



================================================== =========
Well I just wanted to give an update on the fan issue. I finally located a GM 19 inch clutch fan off a 72 chevelle that was a factory ac car. It made a noticable difference in how much better it cools epsecially when at a stop vs the flat 6 blade I was using. It has the curved blades just like the 772 my buddy has on his big block vs the flat 6 blade non GM clutch fan I was using.
My setup that was running too hot was a 3 row aluminum radiator, 71 shroud ,non GM flatter 6 blade cooling fan,std duty fan clutch,180 stat,HD water pump that was running up to 195deg at cruise and 220-230 with AC on especially when sitting in traffic idling .
Then i added a 19 inch GM curved blade clutch fan in place of the flatter 6 blade non gm fan, added a hayden 2747 HD thermostatic fan clutch in place of the std duty fan clutch, added an autozone 160 stat with one relief hole drilled in place of 180 stat.
Anyhow, it went from reading 220-230 deg to now around 200 to 205 when testing it at a dead stop (sitting idling) for over 15 minutes with the ac running. (Thats a 25-30 deg temp drop idling with AC on!)
I would say I'm now doing 180deg when cruising (15 deg temp drop at cruise) and 195 after stop n go driving (30+ deg temp drop in traffic) vs the 195 deg at cruise and 220-230 deg in traffic with AC it used to run before adding the upgrade parts SWheaton suggested.
I definitely have the best setup now for cooling compared to flex fan and dual electric fans I have used in the past.
Thanks to all who helped with advice and tips!
================================================== === __________________ SCOTT 1969 CHEVELLE SS396/4SPD/M20/12BOLT/3:31'S ORIGINAL #'S MATCH/OWNED SINCE 1978. 1977 KAWASAKI KZ1000 (ORIGINAL OWNER) 1976 KAWASAKI KZ900 2006 YAMAHA 1700 ROADSTAR SILVERADO ================================================== =====

May 29th, 13, 8:54 PM
70 nialator
Lifetime Premium Member
Darren Join Date: Mar 2004
Location: Omaha, NE
Posts: 1,061

Low dollar, BIG cooling
Just thought I’d share some of my experiences and pics all in one place with part numbers and a little how to……. I’d also like to thank everyone here that helped me along the way. Before: 3 hole top plate, copper core radiator.. with electric fans taken from an LT1 Camaro. Temps exceeded 220 often. After: 4 hole top plate, Aluminum radiator and the things below…. I couldn’t get it to 190 no matter how hard I flogged it, 102 outside temp. Parts list: • 4 Hole chrome top plate Ebay = 20.00 • 19 inch XT1 -7 blade fan - U pull it = 10.00 • Hayden 2747 HD clutch = 49.99 • Murray 433322 -29 in wide, 18 inch tall Aluminum radiator (specs on their website are jacked up, trust me it drops right in) I paid = 140.00, Listed at 159.00 right now. • Shroud 1971 BB (one piece) from Summit OPG-00T218R = 59.95 • Upper hose Gates 21204 15.00 • Lower hose 21324 lower 12.00
* 160 stat Total 307.00, rounding up. I gained a brand new free flowing aluminum radiator & car that I can’t get to run over 190 with it being 102 outside.

================================================== ===== Had it with electronic fans! ------------------------------------



1) Is there an alternative available from summit racing to the GM 772 fan? Flex-a-lite, Derale etc have 6-blade clutch fans but no 7-blade ones like the 772. At present, using a pair of electric fans on my car with a 10.5 :1 BBC 468. 4000 stall. Heats up at cruising speeds and cools down at idle or when stopped in traffic. Ignition timing and jetting are fine. The water pump is a SW heavy duty unit. May be the fans are impeding the airflow required while moving or is the radiator (3-core copper radiator) capacity less than required?

2) Thanks for the prompt and detailed response everyone! She can idle in traffic for a long time with the gauge indicating 170-180 degrees......with the two electric fans switched on. Shoots up to 220+ after 15-20 minutes of cruising and short bursts of speed. Returns to 170F in a few minutes when I stop on the side of the road. The 3-core radiator is in very good shape. Running a pretty weak mix of 25/75 coolant and water. Hoses are fine with the internal spring in the lower hose intact. Already using a EMP/Stewart 160 deg stat. No under-driven pulleys either. Picked up a 7-blade full-size chevy fan from a friend who has recently converted to an after market radiator and fan set-up. Have ordered a Hayden 2747 clutch as suggested by SWHEATON. Will definitely post the before and after temps difference once the fan swap is completed.

3) Finally, installed the 772 fan, Hayden clutch and a fresh mix of coolant and water. Idle temperatures are 175 - 185 degrees. Bit warmer than the earlier 170F. BUT, the best part is that it never goes above 195 when cruising or flogging the engine! That is a 25 degree drop. Maybe more because I never let the temp go above 220 - 225 before. The only concern is the regular shifting at 7000 rpm and a lot of weight hanging off the water pump Thanks for the advice SWHEATON and all who contributed.

4) Finally installed the Autozone 15356/160 hi flow stat. It now runs 170 - 175F at idle and 185 - 190F at cruise which is a solid 5-10 degree reduction compared to the Stewart EMP 160 stat i was running.
5) My responce to the temp reduction his motor got post doing my rec clutch fan upgrade & his rpm concern w-clutch fan rpm too.

Well you said it used to run 220-225 deg at times (esp when hammering it) with dual elec fans and now its running 180 + - few deg at idle and max of 195 deg even when flogging it and got a 25 deg temp reduction.

Well you did better then you thought in the temp reduction dept and didnt give the upgraded clutch fan setup its full recognition!/LOL!!!

My math says has your motor going from a max of 225 deg when at cruise and or flogging it hard with duel elec fans to a max of 195 deg when flogging it or when at cruise with a clutch fan setup with my rec upgrades a solid 30deg temp reduction!

As for clutch fan RPM ,thats not n issue here because even with the fan clutch fully locked up for max cooling the clutch fan turns approx 75% of total w-pump pulley rpm at that time. So for example,6k engine rpm with your clutch fan setup maybe roughly 4,600-4,800rpm if the motor is hot enough at the time to be fully locked up when you hammer it. But if the motors not hot enough at the time you hammer it the fan clutch isnt fully locked up calling for more cooling and in that case the fan rpm is a lot less like maybe 2500rpm or so at that time. Also,gm used the same clutch fan setup on L78 & LS6 bbc's & DZ & LT1 sbc's all with solid lifter cams and motors that could turn easily 6k-6,300rpm or so and the clutch fans GM used werent an issue on those motors/cars.

Now if your motor turned maybe 7k rpm or more then you would have to translate your motors w-pump rpm for fan rpm with fan clutch fulley locked up so you could then figure out exactly what max clutch fan rpm is with your motor ennsure you dont push it too far to point of failure.

================================================== ======================================


Gents, I have been dealing with an over-heating issue on my 70' 454 AC Turbo 440, 4 core brass radiator, Chevelle for some time now.

After reading many of these threads, I got a 772 fan and the Hayden 2747 (if I remember that number correctly) Heavy Duty Clutch Fan that was recommended.

I put that set up on my car and BAM!!! with the AC kickin', driving in stop and start traffic for an hour, the car never hit 200, whereas it was previously IMPOSSIBLE to run the AC and traffic was avoided at all costs. It always "left its mark" when I parked, but not now.

Now there's not a drop on the street. Soooo, I can swear by the 7 blade clutch fan HD fan clutch formula.

================================================== =======================================
Quote: Originally Posted by 70 nialator Take it easy Scotty, no one’s flaming you.. Matter of fact, I did everything you recommended. Just because I like the look of something doesn't mean we don’t love you

Didnt take it that way.
I didn't think i was being flamed for what i had posted earlier in your thread,i said that because of what i just posted showing example after example of cars/motors at variuos perf lvls from our fellow t/c members in thier own words where the aftermarket AL rad & elec fans they installed resulted in thier motors running too hot at times.
But when the only thing they did was switch to a GM clutch fan setup with my rec tweaks (that are key to max cooling with gm's clutch fan setup) along with also using a stock type HD cooling 4 row cooper/brass rad (1 person in testimonials retained thier Alumitech rad which worked great with my rec tweaked gm clutch fan cooling system) and after doing that it reduced thier engine temp 25-30deg on avg and in a couple cases reduced temp by 35-40 deg.
That shows just how versitle that cooling system setup truely is being able to satisfy/efficiently cool lower perf or stock setups to high perf old school sbc/bbc motored chevelle in mult/diff type applications.
And another thing i can say about this is every time i have been confronted with a GM car with cooling issues (chevelle/camaro/nova) where motors running too hot with a quality AL rad like Alumitech or Dewitts or even a std 4 row copper brass rad that were running elec fans over many yrs working on thes cars with heating up issues with no relief no matter what they tried every time the owners were fedup enough to allow me to remove the elec fans and install my rec tweaked gm clutch fan setup WALLA !!!!!!!!!!!!!!!!
They instantly got a 25-30 deg temp reduction in 85-90 deg outside temps and in a few cases a 35-40 deg temp reduction and again,i get that result every time i i replaced the elec fans with my tweaked gm clutch fan setup .
And in most cases that included them retaining thier current radiator weather it be a quality ALumitech or Dewitt type AL rad or a HD cooling 4 row rad.
One more important thing to note on this subject.
9 0f 10 guys running elec fans with AL rad have temp sender in the intake that in warmer temps like above 70-75 deg typically reads 10-15deg lower then the in head temps which is what i go by when posting the temp my bbc motor runs in 90 deg outside temps.
GM engineers knew what they were doing back then when they chose to run temp sender in head for the majortity(not all) of thier motors.
It makes sence to me because monitoring in head temp is much closer to the combustion chamber & main internal coolant passages where its critical to know what temps doing vs way up on top of the motor in the intake thats too far away to know what going on on a hot day.
Thats why i retain/still use the stock in head temp location for best temp monitoring.
For example,on a 90 deg day where intake temp in a sstreet perf bbc may be maxing out at 190deg @ cruise and 205 in traffic many people would think that just fine,right!!!
NOT good at all IMHO,thats becuase that suposedly acceptable intake temp would really = an in head temp (where gm chose best to moonitor temp in those old school motors) of 200-205 deg @ cruise and 215-220 in traffic which sucks for an old school non emmissions 40 yr old bbc or sbc street perf motor.
I know 1st hand from owning/working on/driving these cars the 42yrs i have been working on them that those motor run much better at approx 180 deg + - few deg vs 200-220 deg range talking in head temps and not intake temps.
When i get the motors running 30+ deg cooler in hotter 85-90 deg outside temps with my rec clutch fan setup the old school sbc/bbc motors have considerably better throttle responce,can feel they retain more power,valvetrain is quieter esp HYD,motor is less prone to detonation esp on todays pump fuel.
Running 30+ deg cooler also allows the old school motors to run a bit more timing for more power if the setup can benefit from it ,oil pressure is approx 5-8lbs higher,sometimes people have reported to me that even thier in car/cabin temp was a bit lower too,along with the reduced temps reducing or totally eliminating hot start issues in a few cases and even stoped some run on/diesling issues post shutdown too.
Again,i am talking old school 40 yr old sbc/bbc motors and not the much newer EFI/ECU emmissions controled small or BB chevy motors designed to run much hotter at 200-220 deg all day long for emmissions reasons.
Yes back in 60's/70s gm did run 190-195 deg f stats along with moring vac adv from full int vac all the time to ported vac for no timing at idle ,but that wasnt to help perf which it hurt.
GM ran the 190-195 stats and no vac adv at idle (that retarded timing approx 15-20 deg) which collectively together increased engine/exhust temps which in turn reduced certain exhaust emmissions along with installing the air/smog pump ex injection setups too.
So thats why gm ran the hot 190-195 stats back in the day which wasnt at all to increase perf ,it actually reduced dirveability and perf which you can experience 1st hand as soon as you hit the thtottle while driving an old school sbc/bbc motor thats running 190-200+ deg on avg on a hot soggy 85-90 deg summer afternoon vs running much cooler at 180 deg + - a couple deg in the same 85-90deg cond.
End of story!!/LOL!!!

1969 CHEVELLE SS396,ORIGINAL #'S MATCH,GOT IN 1978,(In 2001 rblt/bored original 396 .030 to 402)/M20/12BOLT/3:31'S
2002 MAXIMA (DAILY DRIVER/1 owner,GOT 3/2013 w-44k miles)
2009 HD ELECTRAGLIDE CLASSIC ULTRA (GOT 11/14 W-9,700 miles)
SWHEATON is offline  
post #8 of 9 (permalink) Old Apr 26th, 14, 5:33 PM
Tech Team
Join Date: Jun 2009
Location: Home
Posts: 252
Chevelle 1969 is offline  
post #9 of 9 (permalink) Old Apr 26th, 14, 9:16 PM
Lifetime Premium Member
Join Date: Aug 2008
Location: Central Alabama
Posts: 4,263
Re: heating up

TC # 5401
67 Project SS Clone

Owning a Chevelle project is like having a giant-size piggy bank that you keep pouring money into....but you can't get it back out.
pnugene is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:


Old Thread Warning
This Thread is more than 2050 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome