" 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.
FINAL FOLLOWUP UPDATE:
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.
ANOTHER EXAMPLE OF STOCK COOLING SYSTEM OUTPERFORMING AN AFTERMARKET AL RAD & ELEC FAN SEUP.
Feb 3rd, 12, 1:06 AM jm209modesto josh Join Date: Feb 2012 Location: modesto ca Posts: 3
THIS GUY WENT FROM A GM CLUTCH FAN COOLING SYSTEM THAT WAS COOLING JUST FINE TO AN AL RAD WITH ELEC FAN ,SEE THE RESULT IN HIS OWN WORDS PASTED BELOW.
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..