RedneckRebeL

Hey guys, I'm new here. I found this site looking for some advice on my overheating issue and so far ive found nothing. First,some background on the car. I have an 89 Camaro Z28 with a 350. It has an erson street cam, holley carb, hooker long tube headers, and two 6'' electric cooling fans, one on each side of the rad. I have replaced everything on the cooling system. New pump, rad, Tstat, and I flushed the system. My problem is, when the car is at 190, it will hold till I have to stop which then it will creep to about 220. The problem is, I cannot get it to drop, it only keeps going up. I checked the air dam and its in place and my fans are direct connect to switches so I have them on right after I fire the motor and they are working. The heater is set up with a bypass which I usually use, and even when I route water to the core, I get heat, but it wont cool the car down. I had the car in a shop to do some motor work and prior to that never had a heat issue. When i took the car in with the old cam, it had a retarded timing so it idled really low, and since the new cam in, the timing is set back close to spec, but now it stalls (I have to keep the car at 1400 rpms when sitting so she wont stall out so it idles in gear at 1000. Used to idle about 950-1000 in park and like 500 to 600 in gear and ran like a champ), "surges" when im driving at lower R's (I have to keep it above 2000 to avoid surging, but I have had it surge even at 2), backfires a bit when it shuts off and is running hot. Do yall think the timing being up higher is causing all this? i never had any of these issues before and she ran GREAT, but now, not so much. Also, what temp would I be looking at for the car to run at? it used to run 195-200 constant. Im not sure how much power I'm putting out, but it is a 1\4 mile @ 13 flat. Nothing on the car is too radical for everyday use, and like I said, I never had this issue until I had the new cam in and re timed, and I used to drive the car all day stop and go, in cities and everything. This is so discouraging and stressful so any help would be great. Also, I did a head gasket test and the heads are A-OK so I can discount that. I have hear bad timing can cause surging, stalling and overheating, so before I take it to a shop, do yall think the timing is the culprit here? I think it just might since I never had these issues and I've replaced everything, and while I loved the way the car ran idled down (love the "cammed out" sound!) I dont wanna pay all the money to have my car tuned back the way it was for it to continue to overheat. Thanks yall

camaronewbie

1) there is no "spec" for setting timing on a carbed 1989 car, since there were no carbed cars in 1989. Your timing needs to be set where the motor likes it. Telling us specifically where it's set at present might help. Mine is set at about 15 BTDC - carbed motors get way different timing than computer controlled motors.

Your timing needs to be set so that, at 3000 rpms, you get as close to 34 BTDC total timing without getting detonation at WOT. Most us us start with about 10, and make a WOT run, if no spark knock, then we bump it up to 12, WOT run again. When you reach a point where you get spark knock at WOT, then come back down 1-2 degrees and lock it there. Timing tape, or dial-back timing gun helps determine what your total timing is at 3000 rpms. Then of course, you have to adjust your idle accordingly after timing changes have occurred.

2) you do have a vacuum advanced distributor right? Can't use a computer-controlled distributor with a carb.

3) 6 inch fans? I've never seen such a small fan before - are you sure you typed that correctly? Should be at least double that!

RedneckRebeL

yeah, i meant 12 and yes its a vacuum advance. msd super hei distributer. do you think the timing being so drastically higher than before would cause it to overheat like this?

Ray the Rat

iTrader: (1)

It sounds like it's running lean. The surge and the overheating could both be a symptom of that. What is the thermostat rated at? I'd run a 180 in something like that, but I'd remove it to see if it runs cooler that way. It'll take longer to warm up, but it might run cooler.

How are the fans controlled? Are they really only 6" or did your reply mean that they were 12"? If they're controlled by a temp sensor, what temp does it switch 'em on? You might want to consider an override switch and turn 'em on around 160. Again, that's how I do it and it's working...when I can get my damned V6 to run.

RedneckRebeL

Yes, they are 12 inch fans and as I said above, the fans are direct wired to switches inside the car so when I crank the car up I turn both on right after and dont turn them off until I shut the car off. When I got the car back he was having a heat issue with the car and took the Tstat out and it seemed to help a little bit, but it was also like 60 degrees outdoors and now its 85 average. With the temps now in the 80s no Tstat was making the car overheat rapidly so I put a new 180* stat in and now it gets up to temps alright and holds at 190-200 but then starts in with the heating up and not cooling back down. if you had to guess what SHOULD the car run at. My dad (who has been around old school cars his whole life) thinks it will run about like his big block chevy since I have a cam and so on, so about 220, but since it used to not go over 205 even when sitting in dead stop traffic on a highway, I think it should be around 195 constant. I am considering having it sent into a shop to have the timing played with since I dont really have the time or the tools to do it right, so do yall think that is a good shot? Like I said, I've replaced everything I can think of, and I've also considered getting a new air dam since I'm adding all this new stuff, but I'm at the point now where thats the only thing on the car that has changed since I got it back. Discounting my engine work, before timing change she ran low idle (could really hear the cam at idle) and ran good with no driving or heat issues. After timing and carb change, she runs higher idle, harder to keep it running at idle, surging at lower RPMs, slight backfire when the car gets shut off and a heat problem. I'm thinking that since I had no problems before and now all of a sudden having these problems and the timing is the only thing that has been changed on the car that could easily be my problem.

tonys91rs

iTrader: (17)

"two 6'' electric cooling fans, one on each side of the rad."

you clarified that they 12" not 6". are they turning in the right direction.?

Ray the Rat

iTrader: (1)

A timing light and a distributor wrench are cheaper than taking it to a shop. The other thing I think you have going on is a lean mixture. This will cause overheating and surging. The backfire is probably from retarded timing.

You haven't said what kind of carb you're using or what you used before. If it's a Holley, they're difficult to tune unless you know what you're doing. I prefer Edelbrock/Carters cuz they're "set it and forget it" carbs. Very easy to set up and tune.

TreeFiddy

Still - you had a shop install a new cam and they left it running like this? I'm all for doing things yourself, but having already spent the money I'd be taking it back.

Ray the Rat

iTrader: (1)

Good point. If a shop screwed it up, they otta fix it...especially if it's just a timing/mixture problem...They otta be able to set the timing and check the mixture with an Air/Fuel tester.

As an aside, this is one reason I run 2 A/F gauges in my salt flats car. I want to see what kinda mixture I'm getting outta both banks of the 406 V8. I also run an exhaust gas temperature sensor/display that shows bar graphs with the temp from each cylinder. Maybe it's overkill, but over the years, I've seen a whole buncha people lean the mixture out to get that last coupla HP and end up burning a piston or worse.

RedneckRebeL

Well the "shop" in question is an old family friend who builds race cars. He knows what he doing, but the whole idea was to try and make it run better, and with all the adjustments I've tried its now just all screwed up. The car on it before was a holley original, not sure the CFM, but it was a manual choke. Now i have a holley 650 cfm with electric choke. Would the backfire really be from retarded timing? tell me if im wrong, but doesnt a retarded timing help make the car idle lower? mine is much more advanced now then it was before the cam and cab swap and it didnt backfire before. I'm not as concerned about the surging and whatnot as of now..I'm more interested in why the car runs so damn hot. I can work on a timing issue if that is unrelated to the heat. And like I said I dont exactly have the time to mess with it since I'm working alot and in school (2nd year auto body major), thats why I came here, to get yalls input before I make a choice on what needs to be done

RedneckRebeL

heres another question. what way should my fans be blowing? I was outside messing with the car for a bit last night and noticed that the fan on the outside of the radiator is blowing air directly into the radiator but the inside fan is blowing on the motor. Is that correct or would making that inside fan blow directly onto the radiator be ideal? I have taken that fan off before and I have also felt for air when I first got the car and I dont ever remember feeling air blowing onto the motor so I kinda think it needs to be reversed, but thats just me and that instance was 2 years ago.

heat seeker

iTrader: (5)

The fans should blow on your engine, not on the radiator.......

Ray the Rat

iTrader: (1)

If the fan is between the motor and radiator it should be pulling air through the radiator. This might seem like it's blowing on the motor, but it's actually a "puller" fan. This is the way it should be done.

onefast85

no....you set the timing where it needs to be....and use the idle screw on the carb to set the idle...

RedneckRebeL

Well I hate to bump threads, but I figured I'd let yall know that I got the car into the shop and she was out of time, not much, but enough to make her run bad. they set the time, set the carb and as to the overheating...It was a lose wire. turns out the wire going to the battery was bad and it was shorting out. he guessed that it would work fine sitting but once the car was rolling the vibrating and bumps would make the fans shut off. Never even thought to look in the trunk, ha! Doesnt seem to explain why it was still running hot idling, but the car now idles like a dream and stays cool. Had it out in some heavily traffic roads and she only got up to about 205 rolling at about 35 and sitting at a few long lights and cooled down to around 195 in no time so i'm happy. The only thing I dont like is it still tries to surge a bit around 2000 RPMs, but no one notices but me so if it never did it bad like before I probably wouldnt notice it, just needs a good foot on takeoff from a stop at times and she doesnt like to idle at stop lights after while, it runs like my dads big block GMC Sprint haha. I will take having to put the car in neutral every now and again over messing with stuff. I just wanna cruise. Thanks from the bottom of my heart for all the help and input. Ya'll are a good bunch of people and I'm glad I came here, sure got me out of the discouraging times, I only with I found this site sooner.

Nbrooks1841

I have a 89 camaro I took a 305 out n put a 350 in but it's now running hot at idle. In 5 min it reaches 230 n start boiling over