I recently finished a 5 year project.

455 rebuilt by a guy out in Yucca Valley at Full Race Supply. aluminum heads. Alum edelbrock intake. Holley Sniper Quadrajet. Holley sniper hyperspark Timing control.

Transmission built by Dana Snif out in Orange Country.

basically I spared no expense on known vendors who SHOULD have built them right. RIGHT? Lets assume so?

Running a Champion Cooling four core Alumn radiator. Checked my return line to see if it is getting sucked closed. Looks good. Also ran a few hot and cool cycles after break in to make sure no air pockets. Checked all the heater lines to make sure full of fluid.

I have a oem shroud and 7 blade fan. Water pump is the one Autozone had on their system for 1970 with A/C

running 12 degrees initial timing and 34 WOT and 38-40 cruise. the system adjusts timing on its own.

At cruise and highway I can get down to 185 degrees (or less) no problem. It cools really well. IN TRAFFIC it overheats. I was above 230. I think I saw 240. I put it into park and reved it high and temp came down right Away back to 220 then I put in Drive again and drove and came down more

this happened twice. Once in traffic and once in a drive thru.

when I got home i put in park and watched the temp rise and rise till I was at 230. I read on here maybe to try lowering the timing so I told the Sniper to try 8 in idle.

i do not know of this is my Sniper, my cooling system or my 2004r acting up. I have BowTieOverdrive cooling lines running to the Transmission cooler on side of Radiator. I have verified that my Tranmission is full of fluid. I am running 50/50 Antifreeze coolant

what is weird is it cools and runs fine while moving but gets SO hot at idle!

should I be running Electric fans AND a Transmission cooler?

 

 

You went the wrong direction with the timing - you need to INCREASE the initial to help cooling. Retarding the timing will make the engine run hotter. Also, if you have a vacuum advance canister, connect it to full manifold vacuum instead or ported vacuum to assist cooling.

edit: Sounds as if the computer controls the timing so no vacuum canister. I can't help you with that, only to say my engine runs cooler with full manifold vacuum advance, so I guess try to replicate that.

 

Lean fuel mixtures can cause temps to rise. Poor air flow at idle and slow speeds is probably whats causing your issue. Are you running a clutch on your fan? Is the fan too far in to the shroud, should be half in and half out. Put your timing back to where it was as thats not your issue.

 

After letting it cool a few hours I went for a ride. Stayed at 180/183 degrees on a nice 70 degree evening. so cooling at drive is good.


Fan is about halfway inside the shroud. I am running a Clutch fan. The clutch is NEW from Autozone. But i dont feel a lot of air it idle. I feel a breeze but not much. I also dont HEAR a loud noise from fan until i rev high. Could I have a bad clutch?

i will tell the Computer to advance timing to 15 at idle and see of that helps and get back to you all.

 

the Sniper controls fuel mix. So what should Idle be at? I can make it anything. Left it at default.

 

OH. Almost forgot. I run a 16 pound radiator cap.

 

Your fan clutch should pull a lot of air at idle, and loosen up the higher the rpm gets. Sounds like you have a deflective fan clutch

Adding an auxillary trans cooler is a good idea, wont change your engine temps, but your trans will like it.

 

If you can't hear the fan clutch roar when it engages it's suspect. Also- make sure the fan is mounted to pull air THRU the radiator. Not unknown to have the fan mounted backwards and pushing air back into it.

Radiator air dam, side seals, all that in place? Also- was this engine overbored?

 

i have the side air dams but not sure where they go. I do not see Any gaps. Maybe they make more sense with a thiner radiator? I have the V shaped under side one that goes from bumper to the radiator Installed.

can someone post a photo of which direction the fan blade should point? I do feel the slight breeze going away from radiator toward the block

 

Are you using an air-fuel ratio meter for tuning?

 

no I have an O2 sensor.

 

So what is monitoring the O2 sensor signal?

 

the Holley Sniper displays the fuel mix ratio on the fly and uses timing and fuel spray rate and idle to manage the engine. The actual Instantaneous ratio is displayed on the handheld monitor. So if I say make it 14:1 at Idle it will adjust things to make that happen. I can change the goal up and down for Idle, Cruise and WOT.

 

Are the rubber seals in place on the sides of the core support?

Are you running a high flow thermostat?

The fan should be at least 50% inside the shroud?

I would place a bet that the thermostatic fan clutch is bad - not moving enough air at lower speeds.

 

Ok so I changed the Idle to 15. I put it in gear with foot on break like I am stuck in traffic and A/c turned on high to simulate what happened when I was overheated in traffic and at the drive through. I have no gone for a ride yet but let it idle.

it slowly got up to 185 and then the thermostat opened and then went down below 180. The idle is at 15-17 fluctuating and idle mix is 13.5 goal and it stays between 13.2-13.5 fluctuating.

changing timing higher for idle in gear with foot on brake seems to Be keeping temp much better!!! I will go for a ride in a bit to test it out in traffic.

thanks guys!

 

Mounting the fan backwards will reduce its efficiency, but it does not reverse the flow of air.

 

Still getting hot at idle in drive BUT not as fast or as high. I set it at 17 degrees at Idle. How high can I go before its bad?

i also see where the radiator strips go. Headed to OPGI to get them!

 

15 at idle may still be low. w my HEI an vac advance i have intial at 14° and vac advance to manifold so it probably pulls in another 10 ish making 25° at idle. How does the holley system compensate for vac advance or does it just run a number at an rpm ?

 

Similar here, with 18º initial, plus 10º vacuum canister connected to full manifold vacuum.

 

I have the Holley Hyperspark Distributor so no vacuum can. The EFI figures out the curve. I tell it three things. 1. idle timing 2. WOT and 3. Max cruise The timing table optimizes from there.

so I could add some more timing? I went up to 17 and in idle in drive stuck on The 57 and 60 in CAli it didnt get over 220. Much better.

 

is that fairly stock? I think my Cam is w30 spec so think 28 idle is ok?

 

I went to OPGI in Long Beach and they had the rubber radiator seals. Added them.

gonna try bumping up to 24-25 tomorrow for idle and see how it does

 

Just an update. Since raising the idle timing I have not seen the temp get above 200. It does rise slowly when idling or stopped in traffic or a drive thru but not like it did before.