i have a 69 camaro with a 396bb. i just added a aluminum radiator from summit and a trans cooler.replaced the old thermestate.with a 180 still having problems keeping it cool.im at 190-200 when driving but as soon as i idle for ten minuets or so.it starts to claim 220-240. start driving again and it starts to go down.to around 210- what temp is normal.for this car. also i plan to replace the clutch fan for a flex-a-lite fan tomorrow.any help would be greatly appreciated.i also live in las vegas where are temp eture is in the triple digits.thanks

YOur cruising temps seen fine and how accurate are your temperature gauge and where is the sender? YOU HAVE to do some calibrating here to use these as barometers for determining your real temperature.

Secondly, your idle problem is definitely airflow. I would recommend the Derale Heavy Duty series #17XXX only .... see here http://www.derale.com/hdflexfans.shtml whereas it will outperform any clutch fan easily. IT's not noisy either. Pick the largest fan that will work 17/18" and make sure your shroud is aligned at least so the fan is half way in. 2/3 is optimum. Order a couple of 1" spacers to assure proper alignment.

Good luck and report back. Also check out my signature line for more cooling help.

Do the fan blades sit inside your fan shroud? If not, that may be what is causing you to overheat while you are sitting still at idle. The air is not being pulled through the radiator engine compartment as efficiently as it would with the "tunnel" effect of the fan shroud.

Along with not enough air flow not enough initial timing can cause the engine to run warmer too at idle... Need to be careful as advancing initial timing also advances total. If your manifold vacuum is is on a ported source moving it to a manifold source can help this.

Basically if your car runs cool above 40 mph, yet over heats at idle the radiator and thermostat are doing their job. Your problem is with the clutch fan and the radiator shroud.

Do you have the correct big block shroud (two inches wider than the small block one. Are the fan blade tips one inch or more inside the trailing edge of the shroud. Do you have a seven blade (not five) thermostatically controlled fan. And is that clutch still good (loose as a goose cold, but fixed when hot).

If the blades of the fan are uncovered (not in the shroud tunnel area) then the air can fly off the end of the fan blade reducing the overall diameter of your fan by a third. If you have a five bladed fan instead of the seven, then you are giving up 29% of your available fan capacity. Finally all things mechanical wear out. The old style viscous coupling should be replaced with a thermostatically controlled unit (bimetal strip on front of clutch). If you have a thermostatic clutch; the fan clutch has to lock up the fan blade when it is hot (you shouldn't be able to turn it by hand), yet release the blade when cold in the morning (you should be able to rotate it without a lot of effort). Finally is your fan belt tight enough? Is it glazed and cracked? It may need to be replaced as well.

Larger Dave

i added the flex fan 7 blade w/2'' spacer have a 5'' shoud only half circle. blades are 1'' inside the shoud.still running 210-230 getting very frustrated. dont know what else to do.the guy at a local checkers auto part store siad thats normal for a hot rodded 396bb. im starting to think i should just sell.sence i cant enjoy the car.also i think the timmings off sence it boggles when i turn it off

Flex fans are next to useless; because there is no energy savings in using one. It takes the same horsepower to turn one when it is flexing as when it isn't. Second you have to have a full shroud (top and bottom) or it is useless. The shroud resists the air flying off the end of the blade by physically constraining it.

With only half a shroud, you have built only half a prison, made up of only two walls; and you are asking your prisoners to stay in jail. Now you seem surprised that some have escaped?

Your parts counter guy may cheerfully sell you those parts but he isn't doing you any favors. Maybe the parts guy wants to buy your car, and is hoping if you're frustrated enough the price will drop.

If your timing is off, fix it. If it is too retarded the engine will run hot. If it is too advanced it will get into detonation and destroy the engine. We are looking for a "Goldie Locks" solution here, of "just right". Your combination of parts determines what it should be, and each engine likes a different amount, so I can not tell you what the "just right" amount of timing is.

As far as what I think you mean when you say " it boggles"; I assume you are describing dieseling. As the name implies you have converted your Otto cycle engine to a Diesel cycle engine if only temporarily by having too much throttle tip in on your idle adjustment (uncovering the enrichment slots in your carb) combined with a high operating temperature (usually caused by an inefficient cooling system, running too lean, with retarded spark). I think if you get a handle on your cooling issues things will improve.


Larger Dave

thanks for all your help.i think im just going to take a few weeks off.and try not to think about it

thanks for all your help.i think im just going to take a few weeks off.and try not to think about it
Tony
Dont give up yet
there are alot of good post here ... timming should be advanced as much as you can get away with ... this will help things run better .. as one member posted .
I am a big fan of electric fans ... they pull alot of cfm while at idle ...there sensor opperated so they know when to do there job ... takes all the worry out of things when your sitting in traffic watching the temp gage .. so you can enjoy your ride ... .

Are you useing a long water pump or short .
if short you may be able to use a Spal twin 11 in fan setup 2800 cfm
or if long water pump a 16 inch Spal 2370 cfm
check this link
http://www.chevellecooling.com/m3_view_item.html

https://secure.wf-api.com/www.chevellecooling.com/46.html?psid=aMZiIDm.pcKk6nEX5M8d&sm=8856
Don

Tony,

Not sure what setup you have but you really should get your timing straight first then move on from there.

I had the same problems with my 427 some time ago.. Ran great on the highway but if I got stuck in traffic on a hot summer day I was in trouble.. I was running a stock rad, flex fan with no shroud. Here's what I changed:

Griffin Aluminum Rad. with stock BB Shroud and 7 blade fan. Now my temp doesn't see anything north of 180 either while driving or at idle.

Thanks, Joe

first i just want to say thanks to everyone.i started working on the idle today with a friend .started just fine and didnt diesel when i turned it off.didnt drive it around town.not till i get the bottom half of the shroud.i advanced the timming just a little till.when i shift from park to reverse or to drive. it wouldnt shift hard.so far so good any more suggestions.and how do i know how mush i can advance the timming.with out screwing up .thanks again

Stick with it, trust me during the past year I have overcome many obstacles and after finally driving it today for the first time in over a year it made it all worthwhile... :)

first i just want to say thanks to everyone.i started working on the idle today with a friend .started just fine and didnt diesel when i turned it off.didnt drive it around town.not till i get the bottom half of the shroud.i advanced the timming just a little till.when i shift from park to reverse or to drive. it wouldnt shift hard.so far so good any more suggestions.and how do i know how mush i can advance the timming.with out screwing up .thanks again

there are some post in here on running hot and timing issues .
i think the statment was 38 degrees total advance
i would say advance till she pings on hard aceleration the back her off a few degrees
you will find nice crisp launches and aceleration .
do a search on over heating in this section .

Tony,
The guys have givin you what you need, now you just have to do it.

You'll need either a degreed balancer, timing tape, or dialback timing light to check your total timing. When you increase the initial, total will also increase, and you'll need to recurve your distributor to get the total back where it belongs once you've determined the correct initial timing.

IMHO initial should be as high as possible. At least 12 degrees, I run 18. Play with it and drive it (gently) until it's as happy as it will be at part throttle and idle. Too much advance yeilds an engine that doesn't want to turn over when hot, or pings duing part throttle, low rpm acceleration.

Connect your vacaum advance to a full manifold source. You can verify this simply by putting your finger on the port with the engine idling. If it sucks on your finger, it's the one you want.

Increasing the initial will increase the idle rpm. Lower the idle rpm back to normal, use a vacaum guage to peak the idle mixture screws.

Once your initial is set, check your total timing. If it's more than 36 degrees, you need to get a recurve kit for your distributor that includes one or more limiter bushings. FVor a street car, you want 36 in at 3000 rpm or so. Do NOT drive the car hard until you've dealt with this, no matter how good it feels.

Richardson makes a high flow thermostat, It is also sold with a Mr. Gasket label. Your can recognize it by the round "can" on the bottom, you can't see the spring. Get one.

The flex-a-lite fans are crap. I use the Derale as suggested by Jackstands. It moves enough air to blow the hood off the car. As suggested by Dave, a 7 blade clutch fan is also a good choice.

"most" of your problem is timing/tuning related.

As others have said, and as JohnZ has written about ( may want to do a search- it is a great read!) running a Dist with an active vacuum advance is your friend on the street. At idle, you run more advance and get all of the benifits that come with it, including a cooler engine. When the engine is under load, the vacuum advance unloads, and the result is retarded timing and a reduced likelyhood of "pinging". I used to run without one, but am now conviced it is of great value on a street car.

Good luck!

Rob

i have a 69 camaro with a 396bb. i just added a aluminum radiator from summit and a trans cooler.replaced the old thermestate.with a 180 still having problems keeping it cool.im at 190-200 when driving but as soon as i idle for ten minuets or so.it starts to claim 220-240. start driving again and it starts to go down.to around 210- what temp is normal.for this car. also i plan to replace the clutch fan for a flex-a-lite fan tomorrow.any help would be greatly appreciated.i also live in las vegas where are temp eture is in the triple digits.thanks

I dont know how to link to another thread, so here are some of JohnZ's comments:

<snipped>

What about the Harry high-school non-vacuum advance polished billet "whizbang" distributors you see in the Summit and Jeg's catalogs? They're JUNK on a street-driven car, but some people keep buying them because they're "race car" parts, so they must be "good for my car" - they're NOT. "Race cars" run at wide-open throttle, rich mixture, full load, and high rpm all the time, so they don't need a system (vacuum advance) to deal with the full range of driving conditions encountered in street operation. Anyone driving a street-driven car without manifold-connected vacuum advance is sacrificing idle cooling, throttle response, engine efficiency, and fuel economy, probably because they don't understand what vacuum advance is, how it works, and what it's for - there are lots of long-time experienced "mechanics" who don't understand the principles and operation of vacuum advance either, so they're not alone.

Vacuum advance calibrations are different between stock engines and modified engines, especially if you have a lot of cam and have relatively low manifold vacuum at idle. Most stock vacuum advance cans aren’t fully-deployed until they see about 15” Hg. Manifold vacuum, so those cans don’t work very well on a modified engine; with less than 15” Hg. at a rough idle, the stock can will “dither” in and out in response to the rapidly-changing manifold vacuum, constantly varying the amount of vacuum advance, which creates an unstable idle. Modified engines with more cam that generate less than 15” Hg. of vacuum at idle need a vacuum advance can that’s fully-deployed at least 1”, preferably 2” of vacuum less than idle vacuum level so idle advance is solid and stable; the Echlin #VC-1810 advance can (about $10 at NAPA) provides the same amount of advance as the stock can (15 degrees), but is fully-deployed at only 8” of vacuum, so there is no variation in idle timing even with a stout cam.

For peak engine performance, driveability, idle cooling and efficiency in a street-driven car, you need vacuum advance, connected to full manifold vacuum. Absolutely. Positively. Don't ask Summit or Jeg's about it – they don’t understand it, they're on commission, and they want to sell "race car" parts.


__________________
JohnZ
CRG
'69 Z/28 Fathom Green

----------------------------------------------------------------------

Tony,
The guys have givin you what you need, now you just have to do it.

You'll need either a degreed balancer, timing tape, or dialback timing light to check your total timing. When you increase the initial, total will also increase, and you'll need to recurve your distributor to get the total back where it belongs once you've determined the correct initial timing.

IMHO initial should be as high as possible. At least 12 degrees, I run 18. Play with it and drive it (gently) until it's as happy as it will be at part throttle and idle. Too much advance yeilds an engine that doesn't want to turn over when hot, or pings duing part throttle, low rpm acceleration.

Connect your vacaum advance to a full manifold source. You can verify this simply by putting your finger on the port with the engine idling. If it sucks on your finger, it's the one you want.

Increasing the initial will increase the idle rpm. Lower the idle rpm back to normal, use a vacaum guage to peak the idle mixture screws.

Once your initial is set, check your total timing. If it's more than 36 degrees, you need to get a recurve kit for your distributor that includes one or more limiter bushings. FVor a street car, you want 36 in at 3000 rpm or so. Do NOT drive the car hard until you've dealt with this, no matter how good it feels.

Richardson makes a high flow thermostat, It is also sold with a Mr. Gasket label. Your can recognize it by the round "can" on the bottom, you can't see the spring. Get one.

The flex-a-lite fans are crap. I use the Derale as suggested by Jackstands. It moves enough air to blow the hood off the car. As suggested by Dave, a 7 blade clutch fan is also a good choice.

"most" of your problem is timing/tuning related.
Jim
You are the man in my book...there are many overheat conditions in this section they could all take a lesson or two from you .
check out the post

http://www.camaros.net/forums/showthread.php?t=84767

he could use some advice .
Don

lmao, Don.... I'm leaving that one alone, a car that won't cool at speed is weird. You and Jackstands can handle it!

hey,guys just added the other half of the shroud top and bottom .drove it around town for 30min stayed at 190-200 even at idle.so just to be safe when i got home i left it running on park for about 10min.it climbed to 220 so i drove it down the block and it went back down to 190 in couple of minuets.im pretty happy now.what do you guys think.

I think you made some good progress, and you got her into the safe zone.

I also think that if you didn't at least look at the tuning issues we mentioned that there could be more gains to be had including better performance and driveability.

hey guys just folowing up.i advansed the timing.idrove it all day long yesterday never went over 200.stayed between 190-200 i just want to say thanks to everyone who helped.

hey guys just folowing up.i advansed the timing.idrove it all day long yesterday never went over 200.stayed between 190-200 i just want to say thanks to everyone who helped.

That is great news. There is some great Info out there, but sometimes it just seems too simple to be true, but hey- every now and then we get lucky!

Cheers -

Rob

but hey- every now and then we get lucky!

Don't know that it's luck tho. There are a great many people here with lots of knowledge, experience, and willingness to help out.

I'd have to say that as long as the poster tries the things suggested, follows up, and provides requested info, nearly every problem brought to this board gets fixed.

Luck has nothing to do with it, lol...

I know...when I said "lucky" I was thinking the same thing. It is not to often we as humans really get lucky- whatever that is. However, with a systematic approach to problems and solutions, and a willingness to work through them with a definable goal in mind...well that can make all of the difference between success and failure. This case was a nice little study pointing towards that conclusion!

Cheers-

Rob

The real "lucky" part was when each of us found this little corner of the web... 20 years ago, could you ever imagine being able to draw on the knowledge and experience of maybe 2500 hard core car guys on any given day!

And that doesn't even consider the friends we make here, which for me is by far the best part.

I purchased Be Cools 1,000 HP kit for my car, at our local cruise a couple weeks ago I never got over 180 degrees...it was 90+ degrees outside....The night before that I ran 11.30 @121mph at the drag strip. It wasnt cheap but it solved all of my cooling issues.

Good job Tony!