[1971ss454Elco]

1971 SS 454 El Camino
Fresh 71 Vintage .060 overbore 454, total timing at 38, 4 core stock type radiator,
Reverse rotation 7 blade flex(no clutch)fan, GM seprentine BB belt system, and 160 thermostat that works perfect when tested in pot of water. Factory guage(not repro) was tested and passed muster before I reassembled/installed dash, running factory BB shroud with the fan properly spaced half in half out, also using correct guage type sending unit that I stupidly wraped with teflon tape.:clonk:

Factory(Not repro) SS guage reads 230+ at idle, thermometer (mercury style) in radiator neck while running at idle with thermostat open reads 165-180.
Are the factory gauges really that far off? Could this be caused by the teflon tape affecting the grounding of sending unit? Does this engine really run that cool-I can stick my finger in neck of Rad while idling, although coolant is very very hot it dosen't scald. Thermo is open while engine running and I can see coolant circulating through neck.

 

[rkd]

Yes, factory gages can be off, or you could have an incorrect sending unit for the gage. And, yes lack of conductivity will do this.

I just got a new infrared handheld thermometer from Harbor Freight just to deal with things like this. $39 and works great.

 

[SWHEATON]

WELL YES THE FACTORY TEMP GAUGES WERE NOT THAT ACCURATE ,THATS FOR SURE . BUT IF THE TEMP SENDER IS IN STOCK LOCATION IN HEAD BY THE EX PORT THAT CAN EASILY READ 15+ DEG OR AT TIMES 20 DEG HOTTER THEN THE REST OF THE MOTOR IS SEEING AT THE SAME TIME LIKE FOR EXAMPLE TESTING COOLENT TEMP THRU FILLER NECK OF RADIATOR THAT READS 180 AND TEMP GAUGE WITH SENDER IN HEAD IS READING 195-200 AT SAME EXACT TIME WHIC I HAVE SEEN HAPPEN WITH VERIFIED NEW MECH TEMP GAUGES .

OPS,SORRY ABOUT CAPS.

Anyway,temp sender in head reads hotter because if its close proximity to exhuast manifold and ex port in head vs temp sender in the intake that will read much cooler vs when in the head so keep tat in mind too.

Also,setting the timing for total only at 38 which is a good total often leaves base timing retarded & retartded timing at idle and ower enigne speeds befor total is fully in can increase temps too.

Retarded base timing results in lost power in rpms below where full mech is in/degrades throttle responce esp off idle and also in lower rpms below where total adv is in/reduces fuel mileage wasting fuel/inreases engine temp esp at idle in traffic.

And the same goes for when not running a vac adv on the street or some of the time if running the vac adv on ported vacuum that has no vac for vac adv at idle insted of full vac all the time.

So to properly chk base timing idle the motor low like 600-650 rpms to ensure mech avd isnt partially activated when checking/setting base timing messing it up. Also need to have the vac adv unhooked & plugged when checking/setting base & total timing too.

With any kind of NON GM aftermarket perf cam look for approx 18 deg and if its less then that you need to adv it to that lvl.

But in that case if you have to adv base timing to get it to 18 you then need to recurve/reduce mech adv to approx 20 deg by 2600-2800ish rpms . Thats becasue the additonal base timing will push the total past the 38 deg your currently running .

Then 18 base + 20 deg mech = the 38 deg timing you like to run in by 2600-2800rpms.

Then for street you also need a vac adv thats fully activated at approx 2" the motors lowest idle vac with auto trans in gear which is limted to 12-14 deg max fully activated when at low oad part throttle cruise .

Run 93 fuel when trying thist street perf ig timing curve to avoid detonation.

You could try 91 fuel later if 93 doesnt detonate but be mindfull to not push it too hard when trying ower oct fuel becasue detonation can damage a motr like in worst case breain a psiton or 2 and you know what happens then,its not good.

Also ensure idle mixture is correct affect/increase idle & lower engine speed temps making them higher if it's too lean.

If runnng auto trans are you running cooler in front of the rad blocking a considerable amount of cool air from going thru the rad ? If so move it away from front of the rad and if not good airflow for trans cooler get the small thermostatic controlled elec mini fan to cool the external trans cooler when mounted in area of poor airflow.

Now for the fan,when you put your hand in front of the radiator and rev the motor do you feel air being pulled thru it and do you feel air being pulled thru when at idle too ?

If not good airflow maybe that reverse rotation system has wrong size pulleys for proper /optimal fan and water pump rotaton speeds for better/best cooling for your setup or maybe there pitch on the reverse rotation fan isnt enough to full enough thru your fairly dense 4 core rad.

Another thing is there is usually a lot of open airspace /slop in fitment between the rad and stock gm fan shroud when fan suck air thru insted of thru the rad because it will pull air from easiest source which reduces the fans ability to pull more air thru rad at idle 7 lower road speeds too.

What i did with the stock shroud on my 69 bbc was to buy adheasive backed foam weather strip from lowes and sealed all the open areas inbetween rad and shroud on both sides and some on bottom between shroud and rad support too.

Doing that also helps cooling at idle.

So check base timing and avd it to 18 deg if needed (you may need to address mech adv & total timing if you adv base timng),adj dile mix to enusre its rich enough,run vac adv to full inake vac,seal up the shroud to rad interface and maybe you can get the temp down a few deg doing those things.

Let us now what base timing was when you check it at low 600-650 rpm with vac adv unhooked & plugged and what if anything reduced the temps.

Good luck

Scott

 

[1971ss454Elco]

QUOTE- Run 93 fuel when trying thist street perf ig timing curve to avoid detonation.
-I have run 91 with no detonation at all but I currently use 93 form
Chevron

QUOTE- And the same goes for when not running a vac adv on the street or some of the time if running the vac adv on ported vacuum that has no vac for vac adv at idle insted of full vac all the time.
-I run a new MSD pro billet "ready to run" distributor.

QUOTE- Anyway,temp sender in head reads hotter because if its close proximity to exhuast manifold and ex port in head vs temp sender in the intake that will read much cooler vs when in the head so keep tat in mind too.
- I run the guage type sending unit in the intake.

QUOTE- Also ensure idle mixture is correct affect/increase idle & lower engine speed temps making them higher if it's too lean.
-I run a new Edelbrock 800 cfm performer series carb.

QUOTE- If runnng auto trans are you running cooler in front of the rad blocking a considerable amount of cool air from going thru the rad ? If so move it away from front of the rad and if not good airflow for trans cooler get the small thermostatic controlled elec mini fan to cool the external trans cooler when mounted in area of poor airflow.
-I run a TH400 with no external/additional cooler.

QUOTE- Now for the fan,when you put your hand in front of the radiator and rev the motor do you feel air being pulled thru it and do you feel air being pulled thru when at idle too ?
-I run a reverse rotation flex type fan and it "SUCKS" serious air at idle.
You can see the blades flatten out at higher RPMs albiet alot of fan noise with this type of setup.

QUOTE- If not good airflow maybe that reverse rotation system has wrong size pulleys for proper /optimal fan and water pump rotaton speeds for better/best cooling for your setup or maybe there pitch on the reverse rotation fan isnt enough to full enough thru your fairly dense 4 core rad.
-It is a complete GM BB pulley system that includes everything form an Alt and water pump to thier respective pulleys so I have to assume that they knew what they were doing in respect to pulley size.

QUOTE- Another thing is there is usually a lot of open airspace /slop in fitment between the rad and stock gm fan shroud when fan suck air thru insted of thru the rad because it will pull air from easiest source which reduces the fans ability to pull more air thru rad at idle 7 lower road speeds too.
-You are right there was a lot of slop so I trimed it to fit flush although there is that reletivly large open space near the bottom where the shroud dosent cover the rad on the driver side.

Bottom line though Scott is according to my readings from my thermometer in the neck of radiator is this engine is running at approximately 165-180 at idle on a hot day. I just cant understand why the factory guage is so far off. I will be installing a trio of gauges that include a mechanical temp guage and mechanical oil guage and volt meter.
THIS ENGINE RUNS LIKE A BAT OF HELL AND STAYS COOL IT APPEARS!
NO COMPLAINTS AT ALL -just dont understand why guage is so far off.

 

[SWHEATON]

Ok,still you need chk the base timing becasue i bet its retarded whichout you knowing it.

Also,does that dist have a vac adv for street, if that dist doesnt have one that can help lower temps.

But to ans your question,if coolent temp in filler neck is 180 deg ,the motr never seems to overheat or act like its running too hot,doesnt ping on 91 fuel which it wouldlkely do ofit were truely running 220-230 deg i would say the stock gauge is reading too high.

Maybe as a sanity chk you could go to a local rad/ac shop and ask if they have a hand help electronic laser type temp thermometer. Then you could askthem to take i minuiteto check the area where sender is locaked in the intake which they may do for free of $5.

I bet it will read much less then what gauge reads in the car since you have no signs of overheating and coolent temp in rad is only 180 when you checked it at the same time the stock temp gauge reads 220-230 .

You would think if there was a blockage of somekind in intake casuing coolent temp to be higher in intake tat the motor would be acting up in some was and that also the coolent temp n rad would be over 180 deg too,its almost got to be a funky temp gauge and or goofed up temp sending unit at this point.

You could invest $15 in an inexpensive mech type aftermarket temp gauge to see what that does,its a lot cheaper then buying a new elec temp checker for $40 which would also verify whats going on with the stock temp gauge.

Scott

 

[Schurkey]

I've seen gauges read goofy because of Teflon thread tape.

USUALLY, the threads cut through the tape enough to provide a decent ground--but not always. Lots of wraps and gentle torquing would be the most common causes of not enough ground.

I use Teflon-based paste instead of tape; and on temp sensors like this--I go very easy on the paste.

WHAT HAPPENS to the gauge when you hold a grounded jumper wire to the metal case of the sending unit? If the gauge reads more accurately--you need a better ground. If it doesn't change the gauge reading--the tape isn't the problem.

 

[1971ss454Elco]

[ WHAT HAPPENS to the gauge when you hold a grounded jumper wire to the metal case of the sending unit? If the gauge reads more accurately--you need a better ground. If it doesn't change the gauge reading--the tape isn't the problem.[/QUOTE]

AHHHH, grasshoppa a undastand, good idea I'll try that tonight with a jumper wire acting as a ground.

 

[1971ss454Elco]

Re: 454 running hot? or is it. UPDATE

Ran a ground to the sending unit and although it seemed to stabilize the reading on the factory dash guage(It used to hop around alot and not stay in one place) it still reads to hot(230+). I will update again when a I run the new mechanical guage.

 

[1966_L78]

1971 SS 454 El Camino
Fresh 71 Vintage .060 overbore 454, total timing at 38, 4 core stock type radiator,
Reverse rotation 7 blade flex(no clutch)fan, GM seprentine BB belt system.

Maybe an oversite, but are you running a reverse rotation pump? you didn't mention it, just the fan and belt system...

Is it a stock GM pump?

 

[1971ss454Elco]

Maybe an oversite, but are you running a reverse rotation pump? you didn't mention it, just the fan and belt system...

Is it a stock GM pump?

Yes it is a GM pump that came with the serpentine belt system all components are matched.

 

[SWHEATON]

Also chk grnd from temp gauge to grnd for dash to if it requires one.

Scott

 

[1971ss454Elco]

All grounds in place, I even added several where there wern't any from the factory. All guages/lights work flawlessly except the temp it appears, and after hearing several of you it seems that the GM guage is just way off. I seem to remember back in the day when I had my 70 SS454 Elco in Phx, AZ(went to UTI) it ran, at least by the guage, at 230+ idle. This current engine was built by Modesto Engine renu here in Modesto, Ca and is the best running 454 I have ever owned. I mean it fired right up at breakin and ran at 2700 RPM with no smoke, no leaks, no timing issues, no overheat, 60 PSI oil pressure, even now at idle I have 40-45 PSI oil pressure at 550-600 RPM. After about 500 or so miles I took it out and got on and off it hard to set the rings and still no smoke or abnormal oil consumtion at all at 2000 miles. For 500 miles I ran Castrol diesel oil with crane super lube but now run exclusivly(Thnx SWheaton) Spectrols 20/50 simi syn w/1800 ZDDP. This thing on his rear wheel dyno puts out 440 HP and 510Lb ft of TQ at the wheels! The new mechanical temp guage reads 180-190 so I'm happy with that. Thx for all your help and advice.

 

[SWHEATON]

Hi Marc,glad to hear you got it all sorted out & that your rblt motor/cam lifter breakin went well too.

Question,did you mount the new mech gauge temp sender on the head or intake?

Also,suggestion,you could call one of the places that restores/repairs temp gauges for cars to ask them if they can recalibrate & or fix your gauge/temp sending unit to read properly as a unit.

That way you can go back to the original gauge if you want,may be worth a tryif you dont want the aftermarket mech temp gauge in the car.

Scott

 

[1971ss454Elco]

The factory sending unit is in the intake and ironically the mechanical sending unit is in the head.

 

[SWHEATON]

Running 180-190deg with mech gauge temp sender in head that typically reads hotter due to proximityto ex port and ex manifold is doing very good esp with bbc.

Your good to go/LOL!!!!

Scott

 

[SWHEATON]

Running 180-190deg with mech gauge temp sender in head that typically reads hotter due to proximityto ex port and ex manifold is doing very good esp with bbc.

Your good to go/LOL!!!!

Scott