I've done ALL of the cooling tricks and am still running 210. Any ideas?
 

My thread regarding the rebuild was getting pretty long, so I started a new one.

I rebuilt the engine again. I did the 421 mod, plugging the front two holes and drilling the other one.

Cast impeller water pump, with clearanced divider plate.

I had my heater core bypassed, but replaced it during the rebuild and am now using it.

I have all the AC baffles in place.

The engine is running hotter than ever. It was doing 210 tonight with just light driving.

I'm looking for ANY ideas. You can read my build specs below.

I do need to re-check my timing. I think I may need to advance it a bit more.

Thank you in advance.

My specs are below:

1967 Firebird Convertible

Engine: 1970 455 Block, bored .060
Bore: 4.2109, Stroke: 4.21

Crank: Pontiac factory crank, ground .010 on rods and mains

Pistons: Sealed Power forged pistons

Rods: RPM International forged rods

Heads: 1971 400 Heads, Code 96
Mildly Ported, Stainless Steel Valves, Dual Springs
96cc, Valves 2.11/1.77
Comp Cams roller rockers, Ratio: 1.52

Compression Ratio: 9.53:1

Intake: Edelbrock Performer, dual plane, port matched

Lifters: Summit Racing Hydraulic

Cam: Summit 2802

Carb: Holley 0-3310S 750cfm 4-bbl with manual choke. Using ½” carb spacer.

Rear End: 3.73 Gear ratio

Rear Tires: 216-65-15

Accessories: Power Steering, Power Brakes

Ignition: Performance Distributors HEI

Radiator: Aluminum 4 core, big block, with Mark 8 electric fan

Thermostat: Balanced 180 with extra holes drilled in it.

Water Pump: Cast impeller with clearanced divider plate

Transmission: 700R4

Torque Converter: Unknown

Exhaust: Hedman Headers, Dual 3” exhaust with H pipe

Oil: Rotella T 15W-40 + a bottle of Comp Cams 159 additive.

I had similar results and this is what I did. First I purchased a cheap manual style temp guage kit from local auto parts store. I hooked it up on the crossover near the autometer sensor. The spikes I was seeing with the electric auto meter guage was not seen on the other guage. I pulled the autometer sensor and used a different type of sealant on the threads. This took care of the spikes. It was still trying to over heat during moderate speeds. I have the 4 core alum radiator as well. If I done it again, I would go with the 2 core. To make the 4 core work, you need to get the 7 blade flex a lite flex fan or a stock 7 blade flex fan. The stock ones are hard to find. I believe the part number was 1818. It is very very quiet and pulls lots of air. I think the fan clutch set up stops pulling air too soon and free wheels before the car gets enough frontal air to properly cool. This is what worked for me. If you look at the flex a lite web site, it specifically says that this fan is designed for the four core radiators. I personally like the clutch arrangement, but with this car and radiator it does not work well enough. I could likely add some sort of air deflector in the front, but like the look as is. Good luck.

Not lean at cruise rpm?
What is light driving?
What would it do during an extended idle?
The bottom hose is not collapsing?
Fan operates correctly, moves needed cfm of air.
Does you car run a shroud?

1970 455 .060 over will be fairly high compression. What kind of fuel are you using? Use at least 93 octane if available.

try a different size water pump pulley, might need to speed up coolant flow, might need to slow it down

All I know is ... fire car up driveway... your tune is your tune.

let it idle up to operating temperature. idle temperature should be at or right around thermostat. so ok, yours probably will go up 20 + F past the thermostat temperature.

leave it idle for 30 mins or maybe hour, not sure what your temperature outside is? Maybe it is super hot there?

point being you are replicating sitting in traffic.

so once you've had enough beers sitting out there letting it idle... go in the car.

rev it up to 1500 rpm, if after 5 mins (or less) it drops +20 F then you have a flow problem

As cliff said, you can run 160F thermostat and that will buy you more time but if there is a problem with cooling system you are just masking it...

Some people run a higher idle, some people run a different water pump that spins faster at the RPM then run ( TUNE )..

Some people find a different pulley and start with that.

the mods to the stock water pump divider plate that come with stock water pumps is a good mod.. as featured in older PY news letter.

I would look at pulley sizes. 8" crank pulley and a 6 1/2" water pump pulley.

Rich

i'll beat screaming chief to the punch and ask you How many eyebrows your pistons have. Hope you don't say "8"!

if they look like this you might have found your overheating cause (this is from ebay so may disappear in a few weeks): http://i.ebayimg.com/00/s/NTAwWDUwMA..._id=8800005007

Here ya go!;)

In all of this you have never mentioned how your motor runs?
What is the motors hot cranking compression and how much vacuum are you idling at?
If your stated temps readings are correct and your timing is at least 32 and your primary jetting is in the ball park then low cranking compression will tell you that your cam is in retarded which would be my guess at your issue with coolant temps!

Have any pictures of the fan and shroud?

Speaking of timing... In an earlier thread I mentioned having an overheating issue when my vacuum advance was connected to a "partial" ported vacuum, which was not giving me enough advance at cruise speed. Make sure your advance is connected to a port that is providing full vacuum at cruise. Just something else to consider.

Once found the electric fans turning backwards. Wired wrong.

I bought one of those laser temperature guns. When they first came out, I could not affford one. I bought mine @ NAPA about 4 years ago, $59.95. You can find them all over for that price now, it takes the guess work out of engine temps, etc...

One of the dipsticks at my old job installed a long block in a 92 Chevrolet van. The intakes gaskets on those can only be installed one way. He had the gaskets installed so no coolant would circulate to the thermostat, essentially blocking all coolant flow. Boss checked w/ the thermal gun, told him to take the intake off...........asked him what he was thinking when he installed the gaskets.....drum roll..........I installed the new gaskets just like the old ones were..........we couldn't stop laughing......:D...sure ya did...

4 core aluminum radiator ?

Piddled around with mine for years....on a whim I replaced my high buck aluminum radiator and put in a 2 row 1.25 inch tube Griffin...wha la .....no more 200++ temps....two different engines, same cool results....in fact, it cools so well,I was able to get rid of all my "heavy duty" cooling garbage (fans, clutch etc....).....running standard duty fan,clutch and shroud...damn thing cools well!

It is 84 degrees outside. Just had it running for about an hour. Idling, resetting timing and going for a spirited test drive. During the long idle, it stayed under 210, perhaps 205. During the test drive, it got up to about 212 max and then came back down to about 205 when I let it idle again for awhile.

The electric fan has an integrated shroud.

My timing is set at 36 total, but I need to bring that down. I could hear pinging when I got on it. I also switched the vacuum advance to full manifold instead of ported.

I have a Thermocap on the radiator and it is showing about 180-190. Before the cam swap, the fan would hold the radiator at 160 all day.

The engine runs good, but I think I liked the old cam better than the new one.

Will a 7 blade clutch fan really work better than the Mark 8 fan?

When you say Mark 8, are you talking Lincoln Mark 8 ? Is this a 2 speed fan ? I have a 2 speed Taurus fan running on the high side and it is the greatest fan I've ever used, cheap too.

When you degreed the cam where did you set the Intake Center Line?

Yes, the Lincoln Mark 8 fan.

I don't know how to degree a cam. I installed it straight up, with the dots at 6 and 12.

[QUOTE=General Z;5204300]Yes, the Lincoln Mark 8 fan.

I don't know how to degree a cam. I installed it straight up, with the dots at 6 and 12.[/QUOTE]

Well, there you go! It could be installed retarded and it will never perform correctly like that. You can not troubleshoot something if you don't know what you have to start with.

Hello All

What type of car are you working on??

Look under your car, see if there is a spoiler/air dam directly under the RADIATOR.

If your car is what they call a BOTTOM BREATHER, the Spoiler/Air Dam is VERY, VERY, IMPORTANT. Its job is to cause a high pressure area that allows the air to be directed up and thru the radiator, the low pressure area behind the air dam causes the air from the radiator to return back under the car.

I worked in a Pontiac Dealership in the 80's, one of the Mechanics was pulling his hair out trying to get a 84 Firebird to cool, tried everything, replaced everything, finally re-installed the MISSING Air Dam, EVERYTHING WAS COOL after that.

Hope this helps,

Good Luck,

Dusty

It is a 67 Firebird convertible. I have all of the air dams and AC baffles in place.

General,did you go to bakers yesterday?

Is 205 a bad temp to run with these Pontiac's? I heard 180 is the best all around temp, I thought the stock temp gauge had these cars at 210F?

Call Precision automotive, Talk to LARRY, MAN IS A GENIOUS!! he will find a solution.

Integrated shroud?
That means it only pulls air directly in front of the blades versus pulling air across the whole surface area of the radiator?

Have you tried putting the thermostat in a pot of water and putting it on the stove with a thermometer and watching it as it gets hot. It might not be opening when it should.

Like I posted before retarded cam issue!
I would go in and advance the cam 4 degrees. new timing chains give up a degree or 2 at high revs anyway and at lower revs the additional cylinder pressure will get the EXH out of the motor much better, as I would bet my bottom dollar that this is your problem at this point due to what you said in your posting about not having a temp issue with the other cam!
Also so too many fan blades can make for a hot running motor when traveling down the road at more than 40 mph, as they block air flow from getting thru the radiator at a time when the motor does not even need a fan,

I had the same result. Got a 2 row aluminum with 1.25" tubes also. No more temps over 190.

When I bought my car, it consistently ran 200+ temps that would creep up to 210-215 on hot days. I tried adjusting the clearance between the stamped water pump impeller and divider plate which did nothing. It wasn't until I replaced the missing air dam, core support seals and added a 2 row aluminum radiator with 1.25 tubes that my heat issues went away. I am still running the water pump with a stamped impeller, and I just removed my seven blade clutch fan over the weekend and replaced it with a smaller 6 blade flex fan. Still no water temps over 190 degrees.

indymanjoe: No, I almost never go to Baker's. It is one of those things, where it is so close, I take it for granted and never go.

David Jones: The fan is HUGE. It covers the entire radiator and then some. It is actually about an inch taller than the radiator, so I made a cover for the bottom of the fan, so that the fan isn't pulling air from anywhere but through the radiator.

bluebandit: I think I tried that. I think I'm also going to try a different thermostat just to see. I have one too that I ripped the guts out of, so it is just a disc for a slight restriction.

craigs69: You're saying that the 2 row, is better than the 4 row I have now?

Thanks guys.

Honestly, I don't know if the 2 row is any better than the 4 row. I replaced my old original 3 core Harrison with the 2 row aluminum radiator, added the front air dam and installed the core support seals all at the same time when I redid the car in 2012. I am not really sure if any one of those items solved the heat problem or if it was all of them together.

I agree you may want to take a closer look at the radiator...As radiators age, they lose flow capacity and cooling capacity.

I had two different GTOs with overheating problems... same scenario as you - screw around with a bunch of BS... nothing made any major difference. In one GTO, I replaced radiator with a Rodney red aluminum. Problem gone... could cruise on a 90 degree day with A/C on - no problem.

On the second, I recored radiator with a high performance core (denser fins per inch). Again, dramatic improvement - end of cooling problems.

p.s. - A 2 row aluminum radiator has more cooling capacity than a four row brass radiator as aluminum dissipates heat that much better.

The radiator is probably 2-3 years old and probably has under 1000 miles on it. It is the Champion 4 core, big block. Maybe I need something better than Champion, like Griffin or Rodney red.

Except, I have a thermocap on my radiator and the same car, same engine, same fan, same radiator, the fan used to keep the radiator at 160 all day, regardless of how how the coolant temp sensor on the engine got. Not the case now.

Getting confused. Is this right?

With no major changes to the cooling system...

• The engine ran cool with the low compression heads before the rebuild.
• The engine ran hot after rebuild with the XE cam and heads swapped to 96's, but with low compression on one cylinder due to a ring problem.
• The engine runs very hot after installing the 2802 and fixing the rings on the low compression cylinder.
• You lost a bunch of bottom end torque with the 2802 compared to the XE.

Seems like something is just wrong somewhere. Suggest another compression test to make sure that all of the cylinders are OK now. The numbers should also help confirm that the cam is installed correctly and you are building compression.

That is all pretty much correct. Thanks

You didn't loose any bottom end power with the cam swap. I've built 10 to 1 compression 400 engines with unported heads that outran 9.5 to 1 compression 455's with the XE262 cam in them!

The tiny XE262 cam is so small that it simply has the big 455 making ALL of it's power right off idle, so they "feel" snappy because of this fact, but in reality dont make very good mid-range and top end power in those engines.

Even using the larger 60919 (RAIV clone) cam in a 455 with at least 9.5 to 1 compression will make enough low end grunt to pull the end out of a ditch! With some high ratio rocker arms and Rhoad's lifters on that cam you get a power curve flat as Kansas, with peak power up near 5500-5600rpm's.

The 2802 woln't quite do all that, but it will make over 500ft lbs torque across most of the loaded rpm range in a 455 engine with mid 9 to 1 compression. If you are way down on power, running hot, overheating, pinging, and not overly impressed with the cam swap, there is a fundamental problem with the basic set-up, most likely cam timing if I had to take a guess at it......Cliff

Thanks Cliff.

install a Lincoln Mark VIII electric fan. I did on my 67 and took care of all cooling issues period.

That is what I have Nickv

Generaly speaking running hot in stop and go driving is normally a fan or air flow problem.
Overheating while cruising would be restricted radiator or poor coolant flow for one reason or another.

I would run manifold vacuum to the hei.
Has the Mechanical advance curve been checked.

I would Degree the cam and start from there.Adding anything or changing stuff is a bandaid or crutch.First things first,degree the cam and KNOW its done right.

Right on. I'm just debating buying, borrowing, renting, the kit and learning the skill on this fresh engine that I can't afford to screw up, or paying a shop to do it.

There is alot of folks here who will point you in the right direction.Start to finish.And yes,do this yourself and learn.

3'73's, unknown converter. those can do it

also cams with too much overlap.

whats your gas milage?

Do you have any pictures of the water pump impeller and plates you put in?

Update:

I haven't degreed the cam, but I did do a few other things.

1. I changed the total timing to 32 instead of the 36 I had it at.

2. I pulled the 180 balanced thermostat that was in it and instead used a standard thermostat with the guts ripped out of it, so it's just a restrictor disc.

3. I removed my 13 lb. thermocap and put a new 16 lb standard cap on the radiator.

4. I added a bottle of purple ice.

I have 16 inches of vacuum at the lowest idle I can get. I like the car a lot better with the vacuum advance on manifold vacuum. I didn't have the time to do a compression test.

I went for a long drive. Prior to this, the engine was only broken in and had about 10 miles on it. While driving on normal roads and on the freeway, the car ran at 190. Heck, on the freeway, it was down to 180. I drove about 30 miles. When I got off the freeway, I kept an eye on the coolant temp. It never went over 202. I even pulled over and sat in one spot idling, with the car in gear and it never went over 202. I put my foot into it a few times and I like the cam better than I initially did. I still say my 99 Z28 would kill this car though.

That being said, the ambient temps were 15-20 degrees colder than they were the other day, so I won't go so far as to say anything is fixed.

I'm probably still going to find someone local with a cam degree kit and the experience with it to help me degree the cam.

Old Goat 67, the water pump has a cast impeller. I don't have pics though. The divider plate is the factory one I think.

There are many badly shaped cast impellers out there!

Here is a good one. NOS.

I believe my impeller looks like the one in your picture and my clearance may be even tighter. I had the plate basically touching without a gasket.