[Formulajones]

There has been a bunch of overheating threads lately and it's all jumbled up.

I mentioned in one of them, maybe yours, that timing has to be optimized. Meaning it needs enough to be happy, including a vacuum advance that is working properly.

31 degrees won't be near enough, and vacuum advance on top of that should be adding another 10-12 degrees at light throttle cruising.

I'm not a fan of the pistons and they probably aren't favorable to good flame travel, and I don't know what your compression ratio is or the cam specs, but I'd bet 34-36 degrees would work outa little better, and then you'll want to see 44-46 degrees all in with the vacuum advance at light cruise.

If you don't have that, the engine is going to run warmer than it should no matter what you do with radiators and fans.

While the heads are off, since you are already there, I'd want to make sure they are flat too. I've had an instance where I couldn't cool an engine and found one of the heads slightly warped. Once milled all was fine.

[Formulajones]

Once that is all figured out, I'd probably do away with the electric fans myself.

I had a thread in here a couple years ago experimenting with the Cold Case radiator and dual electric fans on my fathers GTO and how those things struggled to keep the temp regulated, even after several modifications to the enclosure and using different controllers. In the end I wound up switching the car back to the stock clutch fan and shroud and dropped temps tremendously. So much so some might even say it runs cold now.

I like electric fans, and I like how they clean up the engine bay and free up horsepower, but you need a pair of pretty big electric fans that move a ton of air to get the job done. Most of the stuff out there I see people use isn't even close.

I know, you already have them and you'll probably want to stick with them, and I understand that. Would be a lot easier to sort this out with hands on.

[alanmay0]

yes using stock set up no hammering effect no noise from radiator when shut off. no over flow problems

[alanmay0]

My water pump is spinning clockwise.

[alanmay0]

nope i will go with whatever cools the best.

[alanmay0]

I did a compression test a couple of days ago. all were between 145 and 150

[alanmay0]

am i pressure testing the cooling system

[nytrainer]

As noted your understanding of the coolant flow is backwards. With your aftermarket a/c system are you still using the factory style heater hose fitting with restrictor in the passenger head?
If not There’s Too much hot coolant flow through the fitting without it and result is a larger volume of heated coolant (then what factory engineered) returning to the water pump heater inlet and mixing with the “cool” water coming from the radiator. This hot/cool coolant mix cycles directly back through the engine and eventually temperature climbs. Basically you’re diluting the cooled coolant meant to keep engine cool with hot coolant at a rate that radiator flow cannot keep up with.

[Formulajones]

Funny I just went to a car show Saturday and we were sitting in line to get in for maybe 10 minutes.

After we were parked the guy next to me was talking about how sitting there his car kept getting hotter and climbed over 200 degrees within a couple minutes so he shut it down. I just shook my head, it was only 64 degrees outside!!! This was just a stockish 350 in a really nice street rod.

I sat there and idled the whole time with a 600hp 454 and never saw over 159 degrees, dad with 724hp said he never got over 164 degrees.

So you aren't alone. It amazes me the amount of people that have these overheating cars, but it seems to be a common theme here in Arizona. It also amazes me the cars that I get in here fairly frequently that don't run a vacuum advance.

Butler is old school, and I believe we had a discussion on here where it was mentioned he's not a fan of vacuum advance. So it wouldn't surprise me if he suggested keeping your timing low.

What I find is that it's really people just don't understand how it works and don't understand how to set it up properly, so they just choose not to fool with it and think it's an unnecessary piece. That's all fine on a race car deal, but on a street car there is no reason not to have it. Without it you give up a lot of efficiency, gas mileage, and drivability. I've fixed and setup more than a few that came through here and it makes a big difference in how cool these cars will run in the heat too.

[Murf]

Originally Posted by alanmay0

yes using stock set up no hammering effect no noise from radiator when shut off. no over flow problems

Thanks for the answer. I know it must be tuff answering all these questions !

What symptoms of overheating does it have? Any chance both gauges are lying to you?

Would it be too big of PIA to hook up a “known good” mechanical gauge just to make sure your not chasing ghosts?

Hang n there!
Murf

[alanmay0]

dont understand what you mean by a restrictor. I just have the heater hose connected to a large nipple on the passenger side head i guess maybe 3/4 or 5/8 inch hose. one hose runs from the water pump to the top inlet of the heater core and then another hose runs from the lower heater core to the passenger side head. you can see the picture on one of my post here showing the hoses. I have no restrictors or restrictions that i am aware of.

[alanmay0]

that is on my list of things to do. thanks

[alanmay0]

are you talking about one of those in line restrictors that you can turn to close off the water flow to the heater core? if so i do not have one although i did have one when i first bought the car but took it off and am not running a straight heater hose.

[Formulajones]

Restrictors are generally there to slow down coolant flow to the heater core, to keep from blowing out the heater core in high rpm situations. I've never known or heard of them being there having anything to do with how the engine cools.

In fact most, if not all the cars I have here, have no restrictors in them at all and I don't have overheating problems with any of them.

[nytrainer]

Originally Posted by Formulajones

Restrictors are generally there to slow down coolant flow to the heater core, to keep from blowing out the heater core in high rpm situations. I've never known or heard of them being there having anything to do with how the engine cools.

In fact most, if not all the cars I have here, have no restrictors in them at all and I don't have overheating problems with any of them.

Well if you think about it a high flow of 240+ degree coolant (in Alan’s case) returning directly back into the pump essentially bypasses the radiator and never gets to cool through the radiator. Not an issue with a restricted flow back through the pump. Some will block off the return to the pump and install a fitting into the crossover so this large hot water flow will get through the radiator to cool.

[Formulajones]

I'm not seeing where any of that makes a difference. Whether the restriction in the heater hose nipple is there or not, it doesn't change how the coolant flows through the system, and the temperature certainly won't change.

The coolant flow, and how much it's cooled as a whole is controlled by the thermostat.

How many Pontiacs running around with aftermarket aluminum heads that just have a pipe thread nipple in there for the heater hose?

[alanmay0]

what kind of a fitting are you talking about. what cross over are you talking about. i would like to try it but i cant figure out what you are talking about.. please explain so i can try it. thanks

[Schurkey]

Originally Posted by alanmay0

I have no clue what the piston clearance is. These are the pistons that came with the car. I am not an expert on pistons. I have it rebuilt and the guy used the same pistons and did not mention anything to me about how good or bad they are so i am stuck with them.

Same block, honed (again) and pistons re-used. Not likely to be overheating due to tight piston-to-bore clearance.

Originally Posted by alanmay0

the total timing is set to 31 degrees per butler performance.

WITH or WITHOUT VACUUM ADVANCE? Do you HAVE a vacuum advance? Does it work? Ported, or manifold vacuum?

If your idea of "total timing" is initial + centrifugal + vacuum, and you've got 31 degrees, you're throwing away power, fuel economy, drivability, and there's no wonder you've got overheating.

If your "total timing" is initial + centrifugal, and you've got 31 degrees but there's no vacuum advance, you're throwing away power, fuel economy, driveability, and there's little wonder you've got overheating.

I bet that engine would wake right up with 10--15 degrees initial timing, ~35 degrees total (maybe more, with those pistons) and another 10--15 degrees of vacuum advance.

Originally Posted by alanmay0

As for the carb adjustments i started out about 3 turn out then used a tach to achieve the highest rpms and left it at that. The idle was set when he car was idling at about 600 rpms.

Could be worse. I find a vacuum gauge to be more sensitive than a tach. And I nearly always adjust the mixture needles just a touch "lean" at idle. Doesn't affect idle quality much, but dramatically cuts down on tailpipe emissions.

This still leaves the potential to be lean at cruise. But that's going to involve jets, metering rods, air bleeds...I'm not going there.

Originally Posted by alanmay0

don't know the amps per fan at the moment but they are rated at 280 CFM each. I have a separate relay for each fan. The fans come on at about 160 degrees.

Those fans are junk. That, or you're not remembering the capacity correctly. Are you sure they aren't rated for 2800 cfm, each?

The first electric-fan kit I found on Summit claims FOUR THOUSAND CFM.
https://www.summitracing.com/parts/der-16927

The two fans together pull 50 amps. Frankly, I consider that to be too small. OEM fans often need 30 amps or more per fan.

Note that the shroud has two rubber flaps that can open at higher speed.

Originally Posted by alanmay0

I have not verified the cam timing nor do i know how to do this. I'm sure when rebuilt it was set dot to dot. One member on this web site suggested setting the cam timing to 4 degrees retard due to the fact that he used this to cool a 67 GTO that he could cool no other way. What are your thoughts on this and how do i check the cam timing??

The brutally-fast, not-entirely-accurate method: (Works better on solid-lifters than hydraulic)

Remove left valve cover for 1--3--5--7.

Turn crank so that #1 cylinder is at TDC-EXHAUST.

>>>This is NOT THE SAME as most times you'd want #1 at TDC Compression (both valves totally closed.)<<<

Make sure the piston really is at TDC, and then make sure the mark on the damper aligns with "0" on the timing pointer. If the piston is all the way up, but the timing marks don't align, your damper has slipped and your ignition timing is no longer trustworthy.

With #1 at TDC-Exhaust, the camshaft will be on "overlap", both valves open very slightly, and the intake open more than the exhaust most likely. If one valve is open way more than the other, good chance the cam is mis-timed.

Getting more accurate than that requires degree wheels and dial-indicators. It'll be way more involved.

Originally Posted by alanmay0

You may be on to something with Your number 9 suggestion or comment . Attached is a picture of the way the heater water hoses run in my car. As you can see the heater hose leaving the water pump goes into the top tube of the heater core and the bottom tube then goes to the nipple on the back of the passenger side head, see S curved hose. Would having these switched cause a slow temp rise??

They're fine. Inlet at the bottom of the core, air bubbles rise to the outlet and are swept away by the coolant flow. Nothin' wrong there.

Originally Posted by alanmay0

Also what temp thermostat should I be using? a 190.

When you fix this overheating problem, I think you'll have your choice between 180 and 195. A "toy' car, in Texas...hard to argue against a 180.

Originally Posted by alanmay0

You are correct the electric fan shroud does not have flaps that open at high speed.

DITCH THAT ELECTRIC FAN SET-UP.

Fan, fan clutch, and a proper shroud.

Originally Posted by alanmay0

I will contact Butler Performance and ask about this.

I have never purchased from Butler.

I have the sense--correct or incorrect--from your posts, along with multiple other people who have street-operated engines they've bought, or bought parts from Butler based on their recommendations, that they may be able to build a decent racing engine, but their advice and recommendations for street engines are totally out-to-lunch. This is the "Street" section of the web site. Butler is not the folks I'd be going to for help. In fact, I'd go out-of-my-way to avoid 'em.

[dataway]

If it were me ... I would.

a. Make sure the timing is right.

(if that doesn't work then)

b. Return to an original style cooling system. Proper AC fan type, shroud, at least 180 thermostat, etc. Make sure you use parts for a 67 WITH AC. (you KNOW they worked originally so that removes a variable.)

(if that doesn't work)

c: You have added AC to a non-AC car You need to also make sure you are using any originally installed air control pieces ... baffles around the frame horns, seal under the radiator etc. Might have to look through a 67 Assembly manual to find them all.

Because of the cooling system mods you have made you are starting with too many variable to easily diagnose. Did the car EVER run the right temperature?

I recommending going back to a full original style AC! cooling system because that is what obviously worked on the original car from the factory. From that starting point it would be easier to diagnose any problems.

Bear in mind, you have done two things that can adversely effect cooling .... changed the original cooling system, AND added AC to a non-AC car.

With AC cars the factory went to a lot of trouble to ensure that ALL the air flowed through the radiator, that's why they used big fans, big shrouds, lots of air baffles in the core support. That's where you want to start from.

[Cliff R]

"Butler is old school, and I believe we had a discussion on here where it was mentioned he's not a fan of vacuum advance"

Per Rodney Butler last time I sent a carb down there and they called up wanting me to send bigger jets because it was too lean on the dyno when they were running in the engine:

"we don't use it".

If you are NOT using vacuum advance then you don't understand it. Last time I looked it was 2022 and we should be a LOT smarter at this point. Even so there are a butt-ton of folks stuck in the 60's that still think than putting light springs in a distributor to get ALL the timing in right off idle makes up for not having vacuum advance.

You are still MISSING a lot of timing with these mechanical advance only distributors, so loosing a LOT of combustion efficiency and you are going to have to burn a richer mixture to keep things happy.......FWIW.

As for the overheating issue here, I covered it in the last thread when I ran into the SAME thing with a 400 build decades ago. It had those POS 8 valve relief pistons on it, they were nearly .050" in the holes at TDC. That is NOT a friendly set-up when it comes to running hot/overheating.........FWIW......