What is normal water temperature for a 455 engine with A/C engaged?

I think you don't have a problem. Just drive it and watch it. If it stays below 230 degrees, I wouldn't freak out.

When it has good airflow, it should go pretty quickly to a normal temp. If it persists in scaring you, AND you are certain the timing is dialed in, a large tube two row aluminum radiator might help.

 

Thanks Max, i'am not scared.

I'm sure it will be just fine.
My original question, what is the normal operating temperature of a 1970 Buick 455 engine with A/C engaged on a 90+ degree day at a stop light or at an idle in stop and go traffic?

That's all I wanted to know.
Seems my question got expanded a bit. Thank you for the help and advise. VET

 

210 degrees? Factory used 195 degree thermostats...

 

Thank you, appreciate your technical information.

So, it appears, if my temp gage is reading 220* and the shop says it's reading 10* to high, this means i'am right at 210*.

 

It's hardly an absurd idea to think that a cooling system is a closed loop control system. It's designed to maintain a regulated set point. Which is controlled by the thermostat (the definition of a thermostat is "...a device that automatically regulates temperature...") and thermodynamics. To think otherwise demonstrates a lack of understanding. If temps can't be regulated within a few degrees of the thermostat rating, there is not enough cooling capacity, period. On a cold day, what do water temps run at? Right on the thermostat rating, its opening and closing as it is designed to while regulating water temp. If temps creep much above that, the cooling system is inadequate. Imagine a radiator the size of a barn door (impractical but an example). Once warmed up, the water temps will always run at the same number as on a freezing cold day with a system that has poor cooling capacity. So why should it be any different on a hot day? With an adequate radiator, it shouldn't be. Mine ran within 5 degrees of the t-stat, AC on in the summer, idling etc. It didn't initially, but I fixed it til it did. So the t-stat regulated water temps within a few degrees just like the engineers who designed it intended to.

 

This shows a lack of understanding of thermodynamics. "Delta" means a difference or differential. "Highest" Delta means the greatest difference, so in that case means the coolant temperature is high and ambient temperatures are low, not when both are highest.

The most heat is transferred from the radiator when the coolant temperatures are HIGHest and ambient temperatures are LOWest

 

My flaw was not stating this "So, much more heat is rejected into the atmosphere from the radiator when the ambient temp and the coolant temp are at their highest.)

as I was intending to convey as: "So, much more heat is rejected into the atmosphere from the radiator when the ambient temp and the coolant temp are at their highest Delta."

I was implying it, but failed to say it correctly.

The bottom line is the thermostat has nothing to do with controlling the heay above the thermostat rating. Nothing at all. The thermostat only can control cooling by closing at a temp of the rating of the thermostat. It cannot facilitate any more cooling above its rating.

You are correct that "enough cooling capacity" is the key.

And all the things I mentioned in the system support that.

You can have your "barn door" radiator, but if all the other components are either incorrect, or missing, you can still have issues cooling.

If you think I do not understand, then explain to me how a thermostat controls the cooling above the rating of a full open thermostat. Or how the a (say 195F) thermostat cause the hotter than 195F coolant to become cool enough to cause the thermostat to begin closing? (or "control" higher temp)
And maintain "to 5 degrees above the rating of the thermostat.

 

WoW guys, I didn't mean to cause a riff here!!!

My original question, what is the normal operating temperature of a 1970 Buick 455 engine with A/C engaged on a 90+ degree day at a stop light or at an idle in stop and go traffic? That's all I wanted to know!!!!

I don't need a thermodynamics class.

According to my 1970 Buick Owner's Manual,
(1) The Buick factory installed a 190-degree thermostat. I have installed a 160-degree thermostat.
(2) On my build sheet. Buick 455 (mine that is) came with a HD radiator. Which I have and is "Brand New".
(3) Came with an 18-inch diameter fan blade and shroud. That is still in place.
(4) Cooling system with A/C, 19.5 Qts. This is still the case.
(5) Has a "Brand New" Thermostatic HD Fan clutch.
(6) The water and crank shaft pulleys are correct and original to the Buick.


My Buick was fully Restored by one of the "Best" Restorers on this forum.

Here are some of the reasons "WHY" I'm have abnormal high-water temperatures.
(1) Engine has been bored out .030.
(2) Engine has been ported.
(3) High performance pistons have replaced factory originals.
(4) High performance camshaft.
(5) QJet tuned to high performance standards.

I understand these performance modifications can cause increased cylinder pressures. Which in turn, cause more internal heat.

Good reasons why I have higher water temperatures.

I have done everything to cure this problem, I was expecting to hear positive results today by the shop but that didn't happen today due to
the shop's heavy workload (75 classic cars they are working on).

Back to my original question: What is the normal operating temperature of a 1970 Buick 455 engine with A/C engaged on a 90+ degree day at a stop light or at an idle in stop and go traffic? That's all I wanted to know!!!! Maybe this is impossible to get an answer on?

Sorry guys, I didn't want to start a heated issue here. I have enough heat in my engine. LOL VET (Navy)

 

VET, what you describe is a completely different situation from a pure stock motor. A modifed motor makes more power which translates to making more heat. So any answer needs to consider what kind of motor it is. But it's still a good question. What temp should a modified motor run at for maximum power?

 

The discussion is worthwhile as it clarifies the basic concepts and how the system works.

Scot is completely correct of course. If all of your cooling system is working and sufficient, the system should maintain temp close to (a bit above) the thermostats rating.

Whether your radiator/waterpump/fan/clutch are "new" or not, and who installed them means little to nothing in my opinion.

 

Yes Larry, that helps a lot.
The only thing I screwed up is NOT buying the 2-row aluminum radiator with 1 1/4" tubes. I had asked Jim Wease (unfortunately, after I purchased a new brass/copper radiator) what I should be using for a total cooling system.

That said, I should be able to get away with the brass/cooper radiator because my engine is just a little more powerful that a factory Stage 1 engine.

I believe, where the high-water heat came from is when the previous owner decided to install high performance pistons.
This also caused donation issues. The shop has been able to cure this issue with an MSD ignition system and carburetor tuning. and spark plug change.

Hopefully, tomorrow I will here good news

Question for you Larry: I read this from one of your posts. Most Buick V8's run best at WOT, with a total timing of 30-36*, all in at 2500 RPM, or less.
Currently I have my Total Timing: 33* @3200 RPM. How much difference will it make to reset my total timing to 2500 rpm??
Does this have any effect on High or Low engine temperatures?
My Buick is a Street driven car only. But I do go WOT at various times.
I've had discussions with you before on this forum, I appreciate all your technical knowledge and advise. Keep it coming. VET

 

Walter, I agree, when I started my post, I guess I didn't spell out that there are some engine performance mods.
Although, in really, it's not much more than a stock Stage 1. One of the reasons why I liked this GS 455.

The big mystery is, how much have the Kenny Bell pistons really added? If any.
As Larry told me, I would have to remove the heads and do some measuring, something I really don't want to do because I already have a ton of
money wrapped-up into this Buick.

This is what I've been told re these pistons. They're in the hole .045 deep. The head gaskets recommended for these pistons is .041 thick.
This is a total depth of .086 deep, also another factor, this piston design has valve reliefs of 23cc's. This engine has never been decked.

It appears (using a CR calculator) that I have somewhere around 9.39 to 1 CR. That's far from the 10.1 or 10.5 to 1 CR for the GS and Stage 1 engines. So, I would think, I'm NOT that performance modified over a Stage 1 engine.

I could install .025 think head gaskets (I think this is correct for a Stage 1 engine) to get the pistons up higher but that is only get me .070, still below the deck. I don't even have a Squish band. I understand, a good squish dimension is .040.

Maybe someone could explain to me, how Buick managed to get CR's of 10.1 & 10.5 to 1 with dish pistons?

I can understand how one can get a good squish, the piston does have a flat surface (small as it is) going against the combustion chamber. VET

 

The advertised compression ratio is based on the theoretical zero tolerance design of the engine block and all parts. We now know that deck height is quite high compared to those ideal numbers. What tolerances did they build to? I do not know.

Buick themselves tested '67 430 engines for durability on a dyno. How many, we'll never know. While advertised at 10.25:1 static compression ratio, the measurements show what we know now...lower numbers.

I can dig up the Buick engineering test results, the 430 they tested measured mid 9's for static compression. So, what we saw on perfect paper isn't necessarily what we got.

Devon

 

Glad you asked about vacuum advance. To help cure the detonation issue, one of the things that my mechanic did was to install an Adjustable vacuum canister. I have to say, I've never seen one before, but it works great.

Larry, just so you know where I'm coming from and my lack of experience. The last time I rebuilt engines, was in 1969 and 1970 while I was in the Navy.
That would make me at the time, 20 & 21 years old. After I got out of the Navy (23 yrs old). I started on a job career (Tool & Die & Machinist) and started a family. Along the way, I took a job with the CIA that sent me overseas numerous times (lived there too) and into the Iraq war in 1991.

This put a major damper on my love of working on and building muscle cars for myself. Not to mention, I wasn't making a lot of money to start-off.

Now that I'm 74, I have a lot of catching up to do, so I'm way behind the learning curve.

The 2 muscle cars I had built, I never had any high-water temperature problems. Also, the good old days of high leaded octane gasoline was very easy to build a hot rod car. My last car was 56 Chevy Belair that I built a 327 with somewhere around 400 HP. In the county in lived.
I could beat almost all the BB cars. I loved this car. I called it the Big Block killer. Mouse motor rules.

When it comes to BB Buicks, they are nowhere like a Chevy engine. The first time I saw the oil pump intergraded with the timing chain cover, that blew me away.

Curious question for you: Do you happen to know what the Valve angle is on Buick 455 Iron heads?
I think, TA makes their Alum heads with a 14-degree angle, which is super good.
I can't find this info on the cast iron 455 heads. VET

 

Here is the 430 engine test report. See PDF page 15, Engine Test Log Sheet A. Note compression ratios all over the nines.

Devon

 

Obviously the t-stat cannot reject heat to the air, only open and close in response to changing water temps. As stated, the other components handle the cooling. But properly designed, the system is meant to accomplish set-point regulation, and maintain a water temp determined by the t-stat plus thermodynamics.

Looking at an example, on a 0 deg day, the tstat is initially closed until the water starts to warm when the tstat starts to open, near it's temp rating. Water flows to the radiator where it is quickly cooled and returns to the t-stat, which closes in response to this sub freezing water. This cycle repeats until steady state is reached. So yes while it sets a minimum temp, it is opening and closing attempting to regulate temperature. So it is a feedback control system, just like the float system in a toilet tank, which regulates water level. And the result is that temps are maintained within some amount near the tstat rating. It's what the designers intended.

Without sufficient capacity, temps rise above what was intended. So in a way, this feedback control set-point regulation has lost the ability to regulate as intended.

But it doesn't have to be. With a super effective radiator that has an overabundance of cooling capacity it can and will maintain a consistent water temp (within reason) largely determined by the t-stat rating, even on a 110 deg day.

 

That is amazing. Seeing that Motor Trend tested a Buick Stage 1 in the 1/4 mile turning an et of 13.38. That's fast for 1970.

In 1970, I built a 327 using TRW pistons rated at 11 1/4 to 1 CR. It developed somewhere in the 400+ HP range.
Solid lifter, Duntov 30/30 cam.
Offenhauser Low Profile Tunnel Ram manifold.
Headman headers.
Accel ignition.
T-10 4-speed. Shifted in the 6,500 to 6,700 range.
I could beat almost all the big block Chevy's, Fords and Mopars (never ran a Hemi).

Never saw a Stage 1 but most likely couldn't beat one.

How is it, these Buicks are SOOO fast? Where is all that Torque coming from??? VET

 

Devon, wow, CR's is all over the place. Amazing, never though it would be that much. Not exactly a Swiss watch. lol

Now I can see why when you blue-print an engine, you can get a lot more HP out of it.

I noticed Buick runs the engine on a 50-hour break-in. Let's see, the camshafts only require a 20-minute break-in. Is that correct.