First Generation Firebird

temp readings

Posted By: Firebob

temp readings - 06/29/19 04:01 PM

So I finally go t the bird out with the new electric fan installed. First day it was probably 90-100 deg out. And she ran about 204. The next day I drove to work and home in commuter traffic. Temp out was about 75 in stop and go for half an hour. Ran up to about 207. I was noticing the original temp gauge was reading 215-220 but I tend to believe the temp signal coming from the digital readout on the FI display. I'm not really happy with it yet. I'd like to get it down under 200 no matter what. If I can do that I think I'll be satisfied. I'm going to replace the 160 thermostat with a 190 today and see if that slows the coolant flow any. I don't expect a change but it's worth a try. Won't cost me anything. Kind of tough because the temps are rarely that hot around here and then I have to find the time for testing when it is. It's a process. I'm starting to think the trick might be to somehow evacuate the under hood heat.
Posted By: Gus68

Re: temp readings - 06/29/19 05:22 PM

Originally Posted by Firebob
So I finally go t the bird out with the new electric fan installed. First day it was probably 90-100 deg out. And she ran about 204. The next day I drove to work and home in commuter traffic. Temp out was about 75 in stop and go for half an hour. Ran up to about 207. I was noticing the original temp gauge was reading 215-220 but I tend to believe the temp signal coming from the digital readout on the FI display. I'm not really happy with it yet. I'd like to get it down under 200 no matter what. If I can do that I think I'll be satisfied. I'm going to replace the 160 thermostat with a 190 today and see if that slows the coolant flow any. I don't expect a change but it's worth a try. Won't cost me anything. Kind of tough because the temps are rarely that hot around here and then I have to find the time for testing when it is. It's a process. I'm starting to think the trick might be to somehow evacuate the under hood heat.

Hi Robert,
Good luck with the testing. As you may recall I'm not a big electric fan ... "FAN". lol It's not because I don't think they work, it's because I hate the way they sound. I just sold my 454 motor home. It has the largest electric fan made by man. And does it suck. I wish I had video taped that fan. Turn on the A/C or anything that generates heat and that thing comes on. It would appear by watching the temp gauge, it is keeping the engine cool. If you get a chance, video taped the sound of your engine with it running. Maybe the electric fans are quiet now. The electric fan in my motor home is 1988 technology.

Summer heat in Alberta is much like San Fran, just less no. of days a year.

Have a look at this thread in regards to the 68 Firebird flex fan specially designed for 68 400 engines. This is information right out of the sales book (I have the original book).

68 Firebird High performance Flex Fans

I put a cheap after market flex fan on my old Firebird coupe. It was amazing in how much cooler my engine was and the "no noise" it made. You couldn't touch the hood with my 4 blade fan and the car would not restart, if I stalled, until the engine cooled down.

I have attached some pics of a cheap flex fan. Works well, FB flex fan works even better. They look pretty cool as well. You rev up the the engine and the fan turns into a disc. It flattens because you don't require a fan to evacuate the heat from the rad once the car is moving fast enough, the air passing through the rad freely from you front grille supplies ample cooling air. So no performance hit (no hp lost to turning a big fan at higher revs and engine runs cooler. I did not have filler panels installed back then either.

I did some more research on the T-stats. When you start a cold engine the t-stat closes so the heating up of the engine components can be controlled. Like your vac controlled components they sense heat. Like your choke, air clearer pre heat etc. So if your in an environment where it takes some time to get the engine to operating temperature (cold environments), you want a T-stat. Otherwise it does nothing to cool the engine. In fact, 190 stats are "winter" stats and 160's are "summer" stats. You want 190's for winter to help keep the cabin warm in the winter. Ever drive one of these cars in -30? I been to the Rockies in the winter with mine.

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Posted By: Firebob

Re: temp readings - 06/29/19 10:21 PM

I have been through so many different fans . From flex fans to clutch fans to elect fans and back again. One of my issues is I have been through as many engine configurations too so what works with one, not so much with the next. Of course the next one is bigger and more powerful than the last so I end up starting over. This two speed Taurus fan set up is not really that noisey but I definitely feel the drag when it comes on( which I don't care for). It was an experiment. You never know till you try. It's fine under normal conditions, like all the rest, but I'm looking for something that flat out works no matter what, 80degrees out cruising or 110 degrees out stop and go.

A flex fan that flattens out at speed sounds fine but then I have to wonder how much air flow a flattened fan will block through the radiator.

I still have a few things to consider. I'm thinking underhood heat might have a lot to do with lowering stop and go/slow moving temps. I'm seriously considering installing some type of air X traction system to remove the trapped hot air. I know those Doug's headers introduce an awful lot of heat to the engine compartment. It's not that much of a strech to believe that if I could reduce that heat that coolant temps would come down as well. Also in the mix is possibly going from the 4 core brass to a big alum radiator.

Like I said, it a process and since no two cars are alike it can feel like a solitary journey sometimes.
Posted By: salmon38

Re: temp readings - 06/30/19 03:36 PM

I have another point against flex fans: there is the possibility of metal fatigue.

I threw an OEM flex fan blade on my old Mustang once. Besides the terrible vibration that sends you back home immediately, I was lucky that it did not take out a radiator hose or some else that was vital.
Posted By: Bartbird

Re: temp readings - 06/30/19 03:44 PM

On any car but especially Pontiacs you have to use the radiator shroud and the fan has to be 1/2 in and 1/2 out, a fan in front of a radiator is just going to spin air, it isn't going to pull it through the radiator without a shroud, if you have all this and still run that hot something is wrong, the engine has an issue or the water pump, Pontiac 400 should run 180-190 period
Posted By: Firebob

Re: temp readings - 07/01/19 04:04 AM

Well Bart that's a pretty firm statement but the reality is every car/motor is different. It would be great to say if you have this then that should be but since I'm dealing with a cammed up 462ci with 10.7:1CR at about 520hp with full length headers and a tiny engine compartment in stop and go traffic on a day when it's 100+ degrees outside...all absolutes kind of go out of the window. Pontiac really didn't design for this so factory stuff just doesn't seem to cut it anymore. Time to get creative with some out of the box thinking.
Posted By: Dr. Drivability

Re: temp readings - 07/01/19 01:08 PM

Are you headers ceramic coated inside and out Bob?
Posted By: Bluebird428

Re: temp readings - 07/01/19 02:36 PM

Great pics Gus. I had my 69 GTO stuck on the shoulder slope of highway 22 south west of calgary in a snowstorm. Looked amazingly like your pic.
Reminds me of why I moved to Pender Island, February 1989, 90 degrees F difference in temp from the prairies to Victoria.

My electric fans make a heck of lot of noise and irritates me all to H.. The car had the rad, fans and shroud in when I bought it so I just left them there. Getting 200+ degrees one day due to the temp switch in the crossover failing, causing the fans not to ground and thus not turn on was reason enough to hate any aftermarket changes in the cooling system. Took me an hour to scrounge up some speaker wire from a guy passing by in order to ground the fans and get the car home.

If, I didn't have the electric fans and if, I had an over-heating issue I would try the flex fan. I think the stock fan on a stock engine should be enough to keep the temp where they belong. but like Bob says, factory equipment is for factory engines.

I'm not in agreement with the thought that slowing the flow of water through the rad will cool it more. That's why we try to get the divider plate as close to the impeller in the pump, to move the fluid. These are closed systems, once the coolant heats up enough to expel the air out or push the excess coolant into the recovery can, if installed, it should be all coolant and pressurised. Since it is a closed, sealed system there is always a full radiator and as long as the air passing through the radiator is cooler than the fluid in the radiator, heat will exchange. The rad must be full with no air to operate at peak efficiency, that's why some people put recovery cans in their system. Energy, heat, will transfer from the coolant to the air. It's not like waving ones fingers through the flame of a candle and not burning them. If slowing the flow in the radiator would cool the water more then slowing the flow in the engine would heat the water more in the water jacket.

The unfortunate thing about the way the heat exchanger system is set up is the vast amount of heated air that is propelled through the rad, over the hot engine and all around the cockpit of the car. That and the extremely hot headers can get the temps in the car to an unbearable state. But for the most part it works, my interior overheats while the engine coolant is 190F.
Posted By: Firebob

Re: temp readings - 07/02/19 02:57 AM

The headers are " as made" Doug's ceramic coated. And as good as the company makes them, they are production pieces so I'd guess the coating is there for appearance more than functionality. My gues would be they are not coated inside. But I really don't know.

I would guess that with outside temps at 100+ and add in the heat generated just from normal operation, then factor in the heat coming off the headers in a small confined environment under the hood with very little evacuation and I'd bet that you could cook a roast in short order under there in stop and go. Maybe it silly to believe I can have my coolant circulate at 190 degrees when the air surrounding the block is 250 or more.

There is some truth that more heat is generated with higher pressure. Heck I've seen water boil with no heat added. But that's a different field altogether.
Posted By: Gus68

Re: temp readings - 07/02/19 03:05 AM

Originally Posted by salmon38
I have another point against flex fans: there is the possibility of metal fatigue.

I threw an OEM flex fan blade on my old Mustang once. Besides the terrible vibration that sends you back home immediately, I was lucky that it did not take out a radiator hose or some else that was vital.

Sounds like mental fatigue. Those blades are stainless steel. Your 4 blade is pot metal or the crap they make rebar out of. Vibrations, I guess if you bend it and then put it on a Ford...what was the point of that? lol

All I'm saying is it's 4 bolts and you get instant results, good or bad.
Posted By: Gus68

Re: temp readings - 07/02/19 03:18 AM

I tied to pull out the car with a long heavy rope. I got a lot of spring from the rope but it would not come out of the ditch.
The AMA truck driver told me the secret: always attach the rope to the downward side of the car in the ditch. Also, pull vehicle should be attached to center hitch ball. By pulling it on the downward side it effectively pulls the car out of the ditch whereas the other side the rope just pulls it thru the ditch never coming out of ditch.

One day I came across 3-4WD trucks. One in the ditch and two trying to pull him out without success. The owner of the stuck truck is besides himself in laughter. I told him, :you think that's funny watch this. Hookup that first chain to my hitch and your truck on the downward side and I will pull it out with 2WD truck. He hooked it up, and I pulled it out. Then I found out why the boys in the trucks were working so hard. He promised them a 18 round of golf at the Nicolas Pro golf resort down the street. Needless to say, daddy got the bacon today!! lol
Posted By: Firebob

Re: temp readings - 07/02/19 03:48 AM

Mental fatigue. Lol. I guess working on a ford could be described like that. My son had one of his fan tips put a nice slice through his mustang hood one day. A new fan and some duct tape and that ford kept rocking until it was sold.
Posted By: Bluebird428

Re: temp readings - 07/02/19 01:16 PM

Well Bob, the hotter the air is going through the radiator the less heat transfer for sure. But as long as there is some difference in the air temp and the water temp there will be heat transfer. If the air was hotter than the water it would be heating the water and cooling the air.

By the sound of things you and I have have similar builds, 464 CID, 10.5 CR, larger camshaft, aluminium heads, similar HP, my headers are Doug Thorley's, we should be making about the same heat. While driving down into the Dinosaur Valley at Drumheller the outside air temp was 110F, it was even hotter on the valley floor where we had to do stop and go, my temp didn't go past 195F. Keep trying, you'll get yours set up eventually. Maybe the whole system needs to be changed out rather than trying one part at a time?

What about your timing? Do you have a lot of initial? I've found nothing puts heat into a cooling system at idle like a low initial advance. Even changing the vacuum advance from stepped to full manifold can lower the temps.

I took the case of beer I had in the trunk and put it on the shoulder next to the GTO, a pickup truck, with three guys in it, stopped and helped push the car out. I went to the gas station in Claresholm and had some big-ol mud terrains put on the back. Never got stuck in the snow again. That was my only car and I drove it 12 months a year.
Posted By: Gus68

Re: temp readings - 07/02/19 02:49 PM

Look something like this?

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Posted By: uconn86hgiv

Re: temp readings - 07/02/19 02:51 PM

Funny... my stock 350 never overheats! All the oil leaking evaporates and acts like perspiration... which of course is a cooling process. :-)
Posted By: Bluebird428

Re: temp readings - 07/02/19 07:10 PM

Something to be said for the total loss oil cooling system for sure.

Yes the same shape case but I'm sure mine was Calgary Export Lager, my friends called it buffalo piss but they never turned one down. It was made by the Calgary Brewing and Malting company, started in 1892 by A. E.Cross, one of the Big Four along with Patrick Burns, George Lane and A. J. McLean who started the Calgary Stampede. Back then everyone drank one of the three Alberta breweries beers, Calgary, Edmonton and Sicks house of lethbridge who started Old Style Pilsner in 1926.

Sorry, got side tracked on one of my favorite subjects, beer.

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Posted By: Firebob

Re: temp readings - 07/03/19 01:13 PM

So what's your setup Al? What radiator and what fans/shroud?
Posted By: Bluebird428

Re: temp readings - 07/03/19 06:04 PM

It's an aluminium radiator with a built to fit shroud attached that holds the fans. Tha fans are Spal, I think they are 11", I can look up the CFM if you like. There is a sticker on the top of the shroud "universal parts". I did have to replace the radiator when I got a small hole in the original. A guy here on the island tried to TIG weld the hole but failed, he can cut a beer can in half and TIG it back together but couldn't fix the rad. I should have tried to solder it with an aluminium solder flex rod. I think the replacement I got, which is the same as the one that was on the car, was a northern rad radiator. I bought my replacement at the Glitter Zone parts store .I can look up all that if you want the part numbers of everything.

The fans came on with the ignition when I bought the car but now I have the fans powered through two spal solenoids and switched with a spal thermo switch in the crossover. After the hour trying to find some wire to get home when the switch failed, I also have a toggle under the dash to turn on the solenoids and run the fans.

I'll post some pics.

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Posted By: Bluebird428

Re: temp readings - 07/03/19 06:07 PM

Hmm said four attachments but only showed three.

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Posted By: uconn86hgiv

Re: temp readings - 07/03/19 06:46 PM

It may run hot but it sure looks cool!

I still think if you spread a little grease and oil around that thing it would run cooler! It's way too clean! You were looking for "out of the box thinking" but I guess that isn't gonna help?

I know his was mentioned before but is your car just putting out more heat than it should as opposed to not cooling as well as it should? Have you checked the timing etc? Maybe wrap the headers?
Posted By: Bluebird428

Re: temp readings - 07/03/19 07:18 PM

Uconn, those pics are of Bluebirds car not Firebobs.
This one runs at 190F until the OAT reachers over 100 and it has to do stop and go traffic. then it may go up to 195.
Your right about the timing, that's one thing that can cause overheating at idle.
Posted By: Dr. Drivability

Re: temp readings - 07/03/19 08:46 PM

Al, do you have that bottom baffle? I noticed it was missing from the car.
Posted By: Gus68

Re: temp readings - 07/03/19 10:05 PM

Originally Posted by Bluebird428
Hmm said four attachments but only showed three.

It does present itself nicely. But does it suck? lol I agree, that missing lower pan may help you quite a bit. It should keep the air focused at going thru the rad instead of dumping out on the ground.

I think your electric fan setup would work better with one big fan as opposed to 2 smaller ones. At least 25% of your rad is not covered by fan. There are fins over the open areas of the rad making it even more difficult for the rad to breathe.

We used to take a piece of square cardboard, cut out the circle for the fan and place over the front of the rad. The entire rad would be covered with cardboard except the circle. It would not overheat, but it would raise the temperature of the water in the rad IN WINTER. That might be your winter setup. Can you get a bigger fan? My fan on my 454 is enormous.

What's the cfm of your fans?
Posted By: Firebob

Re: temp readings - 07/03/19 10:47 PM

Al, I saw that exact same setup on Northerns webpage yesterday. If I buying a new setup I may end up with a similar arrangement.
I run 14 degrees at idle, 38@2k and 34@WOT. Do you think I would be better off trying another 10 degrees at idle?
Posted By: Bluebird428

Re: temp readings - 07/03/19 10:52 PM

Four only three - I posted four pics but when I came back on line there were only three, thinking out loud, four now.
The louvers in the shroud seem to let all the air that is needed go through the rad when the fans are off at highway speeds, breathes OK.
Bottom baffle? I noticed some screw/bolt holes under there in what I would call the valance panel.
I'll take some pics of what's under there.
Posted By: Firebob

Re: temp readings - 07/04/19 12:43 AM

One fan or two fans? I think two because you can wire them to come on or go off separately when needed. Wish I could find a 17" elect fan with two speeds. Best of both worlds. Think I'll mess with the timing tomorrow and see if it makes any difference that I can live with. I'll make a trip to the wrecking yard as well tomorrow and see if anything looks like it would be a better fit than the one I have.
Posted By: Gus68

Re: temp readings - 07/04/19 08:00 AM

Summit has some fans:

Electric Fan, Puller, Flex-Wave, Single, 16 in. Diameter, 3,000 cfm, Black, 18.50 amps

AFCO Racing Electric Fan and Aluminum Shroud Kits 80255-F-SB-N

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Posted By: Bluebird428

Re: temp readings - 07/04/19 12:20 PM

I think we were talking about your timing a year or two ago, yours ran best with a total of about 36?
I set my total to 28 as that's where I got the most power and torque, then I adjusted the initial to about 16-19 by altering the low side of the slots in the plates. I wasn't running a vacuum advance with the stump puller cam and the hydraulic rollers. Since then I put in a bigger solid roller, and swapped over to Crower solid lifters and their roller rockers. I know have the initial set to 16 degrees and I connected the vacuum can to manifold for a idle advance of 28 degrees. Runs smoother and cooler than without the vacuum connected, which I like, I'm done with the lopey idle at red lights and the temp needle creeping up.

I was getting some pinging at part throttle pulls, while I still had enough vacuum to advance to timing. I modified the vacuum can to release all advance at 8 inches of vacuum. That still gives me vacuum advance for cruise and idle but drops the vacuum advance when the engine is pulling harder. My car idles with about 11-13 inches now.

Why not increase the idle timing by hooking the vacuum can to manifold, just to see if it drops the temps any, or if it's already connected to the vacuum port add another six degrees at idle and test the temps? That would be a lot cheaper than buying a new cooling system you may not need. If more advance doesn't help with the high heat you can change it back, if it does help with the temps you can work on the curve to get the high rpm timing where you want but still keep the higher advance at idle.

Took some pics under the front of the car, wish I didn't the frame looks kind ugly under there, is there supposed to be a baffle under there that I don't have? If so, anyone have a pic of what it looks like?

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Posted By: Bluebird428

Re: temp readings - 07/04/19 12:42 PM

Fans are spal 11" low profile. I see northern has a set with five bladed fans that draw about a third more air. These ones work for me but if I was buying new I would most likely get the most CFM I could stand to listen to. Not that one can hear them while driving but can while it's warming up in the morning and cooling off after a days run.
Posted By: Bartbird

Re: temp readings - 07/04/19 01:39 PM

I think the louvers in the back around the fans should go, they serve no purpose except to look cool and allow air to flow there instead of through the radiator fins, air has mass and like water and electricity will always take the path of LEAST resistance, when your fans come on they would pull air through the louvers easier than through the fins drastically cutting cfm .

Before temps rise while driving air will go through the fans, the louvers aren't needed for that, they cause a problem.
Posted By: Dr. Drivability

Re: temp readings - 07/04/19 04:17 PM

Here ya go!

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Posted By: Firebob

Re: temp readings - 07/05/19 12:24 AM

I'm out testing right now. In about 95degrees outside temp. Been in a parking lot moving a few feet every now and then. 15 minutes in and temp just hit 212. I changed my idle timing to 19d g before I started playing the test. 17 minutes@213. 18min@216. Just changed it to 22 degrees@ idle. 20mins in and just went 216. MAT,F( manifold air temp)@143deg. 23minin@215. 24min in down to 212. 25 mins,209.27mins, 204. Just bumped the idle timing to 24. MAT,F 140. 32 mins down to 201. 33 minutes 199. MAT,F 138. KPA running about 68. Ok so 40 mins in and I'm at 198-199. I think I can live with that. If I come across a 16 or 17" fan in a good shroud that pulls at least the same cfms I may change it out but till something drastic happens I think I'm good to go.
Posted By: Firebob

Re: temp readings - 07/05/19 04:14 AM

I must say I'm surprised at the results of my testing today. I really didn't think that increasing the idle timing would make that much of a difference in running temps at stop and go but today proved it. Anyways it was a good day today. I feel I learned something and was able to find a solution to a bothersome issue. It may not be the fix for everybody but it seems to have alleviated my overheating issue. I feel like I can drive the car anywhere in any weather and not have to worry about it.
Like I said, a really good day.
Posted By: Gus68

Re: temp readings - 07/05/19 02:56 PM

Not sure what you have there. You pushed a lever one way then the
other. I say lever and not timing because timing
is probably not heating the car higher or lower, it’s the side
affect. When you alter timing does the flow
rate increase/decrease? Does the idle speed increase?
We know that when the flow increases, the heat loss
increases and therefore your temp inside engine
is reduced.

If it works that good but do get same results with
an increase in idle speed?

Cars with A/C have the idle speed stepped up
with a vac switch to help cool engine during idle.

I optimize my timing for max torque. If I advance
it more the engine will ping. OR is there a way
to alter timing at idle but not affect advance

One other thing, I would include ambient temp
reading, RPMs and start test at the same benchmark temp.
Posted By: Bluebird428

Re: temp readings - 07/05/19 03:16 PM

Bart, I drive that car in 110F outside air temp in stop and go traffic and the engine cooling system stays below 195F. With an outside air temp below 100F the car runs at 190F or lower. It's obvious, to me at least, the louvers are not impeding flow of air through the radiator. I suppose I could tape the louvers closed and test the running temps, but I see no reason to screw around with a system that works so well.

Dr. D, Thanks for posting those pics, I'll have to hunt for one. I see in the parts index on Vikki's site it's called 'baffle, valance panel to sheet metal'. Now, where to find one on or near Pender Island. Fifty year old parts a getting hard to find.

Bob, Good to hear the temps are dropping somewhat. I think there are two reasons the car will run cooler with maore advance.
Efficiency, getting the charge to light off at the moment in crank travel which gets the charge to peak pressure at the optimum position of the piston on the power stroke, say around 15 degrees ATDC. At idle when the throttle plates are almost completely closed, and vacuum is up the charge is a slow burn. With a low charge mass lower cylinder compression pressure occurs. The lower pressure results in a slow burn. In order to get the idle charge to peak pressure at the correct time in crank rotation, the plug has to fire sooner. One may need 35 degrees or so to get the charge to light at the appropriate time. If you've timed your car with the vacuum advance can disconnected then re connected the can to manifold you would most likely experience a jump in idle rpm when the vacuum can is connected. That would cause you to lower the idle speed screw, resulting in less fuel entering the system at idle and a more efficient idle.
Getting the idle timing as high as needed to light the charge at the optimum moment can lead to difficulties lowering the advance to appropriate levels at cruise and WOT conditions. Using the manifold pressure to operate the advance can is one way to help control the advance for different operating conditions. Having a programmable ignition box can be very helpful. Whatever method of control, the more efficiently the engine runs the less heat one will get as a by product.

The other reason is when the charge is lit off later in the cycle the charge may still be burning as it leaves the exhaust port. That can transfer a lot of heat into the head around the port, into the cooling liquid and into the exhaust. If you were to back off your idle advance then let the car idle for a few minutes and take a temp reading of the headers near the head, then advance the idle timing and let it run for the same amount of time, I'm quite positive your exhaust temps would be lower with the higher advance. Just changing from stepped to manifold vacuum advance will change the temps.

Your valve timing can also change the time in rotation pressure peaks. Sometimes with different profiles and lobe centerlines it become necessary to change the install position. A more aggressive camshaft may result in the need for even more spark advance. What are the timing events of the camshaft you have in your engin now?

When I rebuilt mine I had it idling in the garage, the temps were getting uncomfortably high. I moved the vacuum hose from stepped to manifold and the temps dropped right away.

Just my opinion of course, I'm not an expert.
Posted By: Bluebird428

Re: temp readings - 07/05/19 03:50 PM

Yes one can alter the timing at idle and still not affect the timing you want for max torque. One way is to use manifold vacuum on the advance can. That will result in more timing at idle then using stepped, but when you open it up to WOT the vacuum disappears and the timing will drop to what you have the mechanical advance plus initial set to.
Another way is to set the total timing to what you need for max torque with no ping, then adjust the distributor plate to not allow the idle advance to drop down below the number you want at idle. I set my curve to get my total advance at 28 as that is where my highest torque came in. I then welded the distributor plate slots on the LOW side to keep the advance higher at idle speed. I then set the timing to 28 degrees at 3200 RPM, the point at which the mechanical advance was full in, tightened the distributor clamp and let the car idle. The result is 19 initial at idle and 28 total from 3200 rpm al the way to 7000 RPM. I then connected the vacuum can for an additional advance at idle that is controlled by engine vacuum. More advance at cruise and idle and no vacuum advance at WOT.
Posted By: Firebob

Re: temp readings - 07/05/19 03:53 PM

Ok so just to remind you guys I have the Sniper EFI installed and the billet dist. My timing and idle speed ( and everything else) is controlled by the computer. I have the ability to adjust the timing on the fly using the handheld display inside the car. Meaning, while I was sitting in that parking lot yesterday I was able try one advance setting for awhile till the temp settled in and then change the timing and sit for a few minutes to see what that did to the temps. I even was screwing around with the timing while I was driving home on the freeway. When the timing is reset the idle speed does not change because the computer keeps the rpms at whatever value I have entered. It constantly adjusts everything to the set points I have entered in the computer.
I wish I had had an outside thermometer so I could know exactly what it was during my test but I think it was in the mid 90 to 100 degrees. My wife didn't think it was that hot but then she wasn't sitting in that parking lot with me for 45 minutes yesterday either. I know my inside manifold air temps( the temp of the hot air being sucked in) went to 140 when the coolant temp was at 215 and went down to around 120 after it came down to 200. I assume it means underhood air temp came down with the timing adjustment telling me that probably not as much burning fuel was exiting the exhaust ports.

So I can say there's no doubt that changing only the timing settings is what made the difference in idle temps yesterday.

By the way, I got on the freeway and the temp held right at 194 till I got over the hill into some cooler air. It went to 188 and stayed rock steady till I got home. It was about 70degrees out.
Posted By: Bluebird428

Re: temp readings - 07/05/19 03:54 PM


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Posted By: Gus68

Re: temp readings - 07/05/19 03:58 PM

Forgot about that...yah you got an exel testing setup.
Posted By: Bluebird428

Re: temp readings - 07/05/19 04:11 PM

That sounds like it's a lot easier than me taking out my distributor, dismantling it, welding, filing, then reinstalling and testing time after time until I got it where I wanted it.
Posted By: Firebob

Re: temp readings - 07/05/19 06:05 PM

One other thing I should mention is the only real change I made to the cooling system between last year when the temp went to 243 and I overheated in Reno is the change from a stock shroud and a 7 blade fan to the Taurus 15" elect fan and shroud. The outside temp was probably 5-10 degrees hotter last year as well but it's a pretty good testament to the ability of this elect fan to keep temps under control, at least in my case.
Say what you will but it does seem to work better than the factory setup for my situation. I probably have $200 tied up in parts and that includes $150 for a 140a powermaster alt. To power everything.
Posted By: Bluebird428

Re: temp readings - 07/06/19 03:32 PM

$150, I wish. They are $315 at Lordco in Sidney.

Once the best initial and mechanical advance has been determined and set, one method of testing and calibrating a distributor for optimum vacuum advance at cruise, with a carburetor equipped engine, is to use a good vacuum gauge and a vacuum pump. One connects the vacuum gauge to the manifold port on the carburetor and runs the hose into the cabin so it can be read while the car is being driven on the test section of highway. Next a vacuum pump, with an accurate gauge attached, is connected to the distributor vacuum advance can and that hose is also run into the cabin. A driver and a recorder is needed, along with a five to ten mile stretch of flat highway.

The car is driven at the desired cruise speed, 50, 60, 70 MPH whatever the owner determines the car would normally cruise at. The recorder then slowly activates the vacuum pump until the vacuum advance is activated and the car starts to speed up. The manifold vacuum and the reading of the gauge on the pump is recorded. To keep the car at the test speed the throttle will have to be closed somewhat which in turn will result in a higher manifold vacuum. Once the test speed is re-established the recorder adds an inch of vacuum to the pump, the driver keeps the car at the test speed and the manifold vacuum is recorded. The pump and manifold vacuum is recorded for every step applied to the advance with the pump. As the advance builds the throttle is closed more resulting in more vacuum and less fuel air charge going through the carburetor, resulting in a more economical cruise, all the while maintaining the desired test speed. After the maximum manifold vacuum is reached the car is taken back to the garage and with the use of a timing light and the vacuum pump the actual timing numbers are recorded for every point of vacuum that was supplied by the pump during the test.

The vacuum advance can then be calibrated to give the amount of advance that was obtained which resulted in the highest manifold vacuum at the test rpm.

That test would take almost no time if one had a way to adjust the timing while driving like Firebob does with his fuel injection system. One could also adjust the timing on the fly to a point that gives the best air/fuel ratio if an A/F gauge was installed in the car.

Do those Sniper systems even have a throttle blade or is it port injected?
Posted By: Firebob

Re: temp readings - 07/06/19 05:23 PM

It's a throttle body injection so, yes, it has blades. And the AFR is also adjusted by the ECU to whatever values you have entered into the program. I think I have it at 14@idle/13.5@cruise/12.5@ WOT. Another nice thing is it will adjust to changes in air pressure too. So now when I go from sea level over Donner Pass( 7300 ft) and 5500ft in downtown Reno I don't notice that lack of hp I did when running my old qjet.

I'm not saying everybody should get one but it does making adjustments much more convenient. Gas mileage still sucks but what're you going to do?
Posted By: Bluebird428

Re: temp readings - 07/06/19 10:28 PM

Well I had a brain malfunction and put in a TKO 600. Big overdrive and get about 26 MPG. I get 14 driving around the island. Could buy a lot of gas with the money I spent on that swap. Oh well, business was good back then and I thought I could afford it. OK not really but I talked myself into it.
Posted By: Gus68

Re: temp readings - 07/11/19 05:20 PM

I had conversations with my tranny builder in regards to over drive. Here is a copy of the email thread. Some of you may understand it better than I.


Wed, May 9, 2018, 2:22 PM

Hi Steve,

If I wanted to have overdrive on my 65 Pontiac, should I buy a new tranny with overdrive or rebuild my TH400 and add new overdrive unit to existing tranny?



Wed, May 9, 2018, 6:17 PM

to me

Far superior to go with a 700R4 then doing a TH400 with OD. The problem is overheating and terrible fuel economy, because you do not have a lock up with OD. I’ve seen a lot of people that are angry going the TH400 & OD route.

Do you want to do a TH700R4?


Brian <283>

Wed, May 9, 2018, 6:26 PM

to Steve
It's my driver so it would make sense to get overdrive. I have a 3.08 rear end on her. Should we get a core and rebuild one so you
can beef it up and put in shift kit and stall? How should we go?



Thu, May 10, 2018, 1:21 PM

to me

Brian 3.08 x OD gives you a ratio 2.15 which is too low unless you drive at 100mph all the time. A 350 lock up would give you a better combo. How tall are your tires in inches?
Brian <283>

Thu, May 10, 2018, 1:32 PM

to Steve
Not sure I understand. That normally would have a stock 2.56 or 2.73 rear end diff. 3.08 will have higher rpm at 70mph than 2.56. Idea is to reduce the rpm when we go into OD correct?

15" rims, have not decided on what tire size is. It's a wagon so it won't be too tall.


Brian <283>

Fri, Jan 18, 9:13 AM

to Steve
Hi Steve,
I would like to figure out weather to go the OD route for my Catalina. My brother-in-law purchased a 65 Pariseenen /wo a tranny. He could take my TH004 and rebuild it. I could get you to rebuild a OD tranny for my Catalina. What would I need to purchase? What is a 350 lockup?


Mon, Jan 21, 8:46 AM

to me

With 3.08 :: 1 gears in the diff you can’t use OD at all. Your engine rpm at 60 mph would be 1600 rpm. Most gas engines barely make power down that low. You could use the 700 R4 if you change your gears to 3.42, 3.73, 4.11, 4.56, 4.88, 5.12 or 5.30. TH350C are very hard to find.
Brian <283>

Mon, Jan 21, 6:58 PM

to Steve
Ok, I think I have it now. I have a TriPwr battleship so we go with 200-4R? The 700R4 is for engines /w computer correct?
Think I will go with 3.42 or 3.73 gears in the diff.
We can use the TH400 you have now for my son-in-law's 65 Pontiac Paris.

Does his make sense?


Tue, Jan 22, 7:59 AM

to me

No, 700 R4 & 200 4R have almost no computer control. The computer control was for the lock up (TCC) on some models 1985 and up for both transmissions. The 700 R4 has bigger planetaries and can take more abuse.

700 R4 gear ratios:

1st à 3.06 to 1

2nd à 1.62 to 1

3rd à 1 to 1

4th à .69 to 1

200 4R gear ratios:

1st à 2.74 to 1

2nd à 1.57 to 1

3rd à 1 to 1

4th à .71 to 1

If you drive fast, 70 mph & faster, than I would do the 700 R4 & change your gears, other wise stick with the TH400.


to steve

Let's take the easy route. Rebuild it like the 68 Firebird TH004 you did.
Shift kit again. Is there an extra cost to enable
the tranny to have a 2400 stall? I realize I need 2400 torque converter but
is there anything to add to the tranny rebuild side? Cost? I will let you
start anytime you ready. Take your time
Posted By: Bluebird428

Re: temp readings - 07/17/19 01:53 PM

What about your water pump pulley? The post by Ramair68 reminded me of the change I made.

My 428 had a pulley from a six cylinder when I bought it. I looked good with the long snout and polished stainless bolts with no fan, but I couldn't get it to quite line up with the other pulleys. It had a fan spacer between the pump and the pulley, i tried a few different spacers but no luck. I found the correct pulley but it is 8" dia. I searched for a smaller and found one about 5" dia. The smaller pulley spins at 1.6 times the rpm of the larger pulley which, theoretically, moves more water. The stock 68 water pump pulleys for a standard car and power steering car is 8". The stock water pump pulley for AC equipped cars is 5-11/16". That alone would result in an increase in water pump rpm from 914 to 1286 at an idle of 1000rpm. But the AC equipped cars also had the crank pulley increased from 7-5/16" dia. to 8" dia. That increases the rpm of the water pump to 1407 rpm at the same engine idle rpm of 1000, theoretically, with no belt slippage. A 40% increase in water movement could help with cooling when sitting at a red light.
Posted By: Firebob

Re: temp readings - 07/18/19 03:13 AM

I'm already running the big crank and undersized a WP pulley setup that came on the AC cars.
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