Running Temps - 351W

[MustangGT 11]

Car made it home after another Hot Rod Power tour trip.  This year it was hot ... running 65MPH for a couple of hours in the high temps of the south made the temp climb on the motor.  In general I was running about 200-205 while doing highway speeds during the heat of the day.  If I had to stop and wait in traffic the temp really started to climb.  I would slip it into N and the raise RPM to 1100 or so and run heater full blast to try and keep temp in check.

 

I tried replacing the Thermostat and Water pump while on the road -- the HD water pump helped a little but it still got hot.

 

So, I am asking what temps are other running 351W seeing when going Highway speeds for an extended time. 

 

I am thinking of swapping to a 3 or 4 core radiator and/or adding an oil cooler.

 

So let the temp reportings start....

 

 

[1969_Mach1 333]

If your considering a radiator swap, I would suggest stepping up to a Griffin aluminum radiator or other high quality aluminum radiator.  The 351W in my 69 Mach 1 always ran warmer than I like.  I prefer keeping temps in the 180 deg range.  Even though I don't cruise down the highway, with a 4-row copper brass radiator the temps would continually climb in a hot day, 85+ deg outdoor temps.  A 24" wide Griffin aluminum radiator with two 1.25" wide rows of tubes made a significant difference in reducing engine temps.  Later I also added a Stewart high flow thermostat and Flow Cooler high flow water pump which further helped.  FYI, I have tried several brand high flow thermostats, they all look to be from the same manufacturer, but the Stewart brand has three additional holes and works much better in my opinion.  

[Rsmach1 71]

Loosing the 2 core is a good start, what type of fan are you running? If electric is it in front of the rad or behind? What mods have you done to the engine? How far is it bored? How much timing? There are a host of reasons that cause an engine to run warm, but going to a larger or aluminum rad is always a good idea. As 1969_Mach1 stated, Griffin makes a great rad, just keep in mind, the tune and cooling setup make a difference also.

 

Edit; If your temp issue is only when it's hot outside, I'd say it's due to the lack of efficiency in the lil 2 core rad. Also if your car was originally equipped with the 20" consider upgrading to the 24". The radiator is the one thing that I say "Bigger is always better"

[danno 128]

A few more questions... do you have factory or aftermarket AC that was on?  Has something changed?  If, for instance, you would have made a trip like this 2 years ago would you have had a problem?  I assume you also have had it cleaned, as I know a radiator with corrosion inside will not cool very well.  So a good chemical cleaning takes care of that.

[MustangGT 11]

It is a 24" inch radiator -- bought new just before power tour last year.  I am running a belt driven fan flex fan (stock from original).  The car will have Classic Auto Air.  I have everything installed but the compressor.  Motor is bored .030 over -- cam is little "better" than stock.  I don't recall timing specs off the top of my head -- but it wasn't roo radical.  Like I said going short distances around town I never notice crazy temps.  It has gotten hot during the last two (and only two) Hot Rod Power Tour runs I have done.  Running Hwy speeds turning aroud 2500-3000 RPM (depending on speed) for an hour or two keeps the temps up.  I can only expect it will be hot again next unless I 'fix' it. 

[JXL 12]

Is it possible that your bottom rad hose is collapsing when the rpms are at a constant 3000 rpm? Not closing right off but becoming restrictive.

[MustangGT 11]

I have the 'spring' in the bottom hose to stop collapse (at least that is what is supposed to do).  I have watched the hoses as I raised RPMs but haven't notice it collapsing.  The 'spring' runs almost the entire lenght of the hose.

[Rsmach1 71]

Bored engines tend to run warmer, combine that with your 2500-3000 cruising rpm and a stock 2 core rad I'm actually surprised it doesn't overheat more. Adding A/C will most likely make it worse. I would definitely recommend going to a bigger better rad. If a quality aluminum is in your budget go that route. As JXL stated, check your lower hose, but I don't believe your rad is up to the task, especially since you plan on A/C. Just curious, is this an auto or manual car, if auto what stall converter do you have.

[1969_Mach1 333]

Temps creeping up are indicative of insufficient coolant flow or undersized radiator.  Fuel mixture slightly too lean and ignition timing not advanced far enough at those cruise speeds will also cause it.  Check those things before investing in a radiator.  But ultimately, I also don't believe your radiator is large enough for your car.  Also, high compression motors will run hotter.  If your 351W has flat top pistons, like the stock 4 barrel versions did, and you are running cylinder heads with 60 cc combustion chambers like the stock 69 351W heads were. your compression ratio will be about 10.7:1.

 

What type of carburetor are you using?  What type of thermostat and water pump are you using?  At least use a high flow thermostat.  Those are relatively inexpensive.  Don't be surprised if ultimately you end up with a larger radiator, preferably aluminum.  Even at 24" wide that 2-row is small for your application. 

[MikeStang 247]

My 408 never gets above 180 on extended drives.

I have a 4 Core Aluminum radiator and a set of Cougar electric fans

[barnett468 418]

.

what is your t stat rated at?

 

exactly what fan do you have?

 

with a proper cooling system, your engine will run 185 with a 180 t stat all day long in 100 degree weather with the ac on.

 

if your rad is chinese it holds at least 25% less water than a us made one.

 

you need a bigger rad AND more air flow.

 

if you have electric the lincoln or contour fans are good but i would run a dcc fan controller.

 

i would run a high flow 180 or 185

[JXL 12]

I have the 'spring' in the bottom hose to stop collapse (at least that is what is supposed to do).  I have watched the hoses as I raised RPMs but haven't notice it collapsing.  The 'spring' runs almost the entire lenght of the hose.

I have the spring in mine as well and I seem to have no issues with it. My engine is a 351w .040 over, 10.5:1 compression with aluminum AFR 185 58cc heads. I have an aluminum stock size down flow rad with a single electric fan. At approximately 85-90 kilometres an hour (I'm Canadian haha) the engine is reving at about 2800rpm and the temp sits at about 180 degrees. Idleing around town it will go up to 190. Only once have I had it go up to 210 and that was a very humid and hot day, it was well over 100 degrees outside that day. I also have an aluminum high flow edlebrock waterpump, maybe that also helps a bit. My downflow rad is also baffled at the top so that the coolant flows all the way across evenly.

[Max Power 74]

If your temps are climbing while on the freeway, and your water pump and stat are working as designed, you have a radiator/capacity issue. Fans and shrouds have nothing to do with controlling temps as speed, they are only a way to generate airflow when you are not at speed.

 

Before going through all the gymnastics of fans, timing, bore, cam selection yada yada, get a decent radiator and re-asses where you are. You will need the decent radiator regardless of the other issues anyway.

[1969_Mach1 333]

Thanks for chiming in Max Power.  That's exactly what I was thinking.

[Max Power 74]

Thanks for chiming in Max Power.  That's exactly what I was thinking.

I have the same issues you did, and am seriously considering a Griffin or similar as well. I have to actually put more than 500 miles on the car a year to justify it though.....

[Footcutter11 23]

I like twin electric fans, and an electric water pump.  I stay within 3 deg of 175 deg.

[MustangGT 11]

Thanks for all the comments   Sounds like aluminum rad is gonna be my best bet.  I have an oil cooler sitting on the shelf but I don't think it will do enough to help me while traveling long distances at Hwy speeds.  I am going to try a different rad first before I switch to electric fans - I like the look of the belt driven fan.  Now I gotta try and catch one on sale.

[barnett468 418]

Thanks for all the comments   Sounds like aluminum rad is gonna be my best bet.  I have an oil cooler sitting on the shelf but I don't think it will do enough to help me while traveling long distances at Hwy speeds.  I am going to try a different rad first before I switch to electric fans - I like the look of the belt driven fan.  Now I gotta try and catch one on sale.

 

the only us made aluminum rads i know of are griffen, us radiator and some of the northern ones.

 

you can not get a high efficiency aluminum rad . . if you get an aluminum one, i would get one with 2 rows that are over 1" long.

 

if you have a standard rad, you can have a new, bigger core installed too.

.

[MustangGT 11]

Okay, so I have been searching ...looking at Griffen, US, Champion, Northern (plus a couple others I can't remember off the top of my head).  I am amazed at the range in prices.  I know I want inlet/outlet on passenger side (like stock) plus I need the internal tranny cooler since I don't want to install an external one.  Ideally, I would want it to mount with the stock "clamp" at the top and brackets on the bottom plus use the stock fan shroud -- for the appearance of being stock. 

 

Anyone running a setup like I describe?

[barnett468 418]

Okay, so I have been searching ...looking at Griffen, US, Champion, Northern (plus a couple others I can't remember off the top of my head).  I am amazed at the range in prices.  I know I want inlet/outlet on passenger side (like stock) plus I need the internal tranny cooler since I don't want to install an external one.  Ideally, I would want it to mount with the stock "clamp" at the top and brackets on the bottom plus use the stock fan shroud -- for the appearance of being stock. 

 

Anyone running a setup like I describe?

 

 

us radiator/cool craft are the only company i know of that make factory style rads out of aluminum . . they also make the copper ones.

[Rsmach1 71]

FYI they sell different insulators for the upper saddle to aid in installation, ie. 3core, 4core. CJPP sells them. There is a review on the 3core that someone left using them on a Griffin.

[1969_Mach1 333]

I have a griffin radiator in my 1969 Mach 1.  It's the larger radiator Griffin offers with 2-rows of 1-1/4" wide tubes.  It was snug. but it fit into the stock saddle insulators.  I did have to further slot the mounting holes for the shroud to drop it down some.

 

 

 

[MustangGT 11]

1969_Mach1 -- Do you remember the part number for that Rad?  Also, looking at the pic it apears the outlet is on the passenger side - is that right?

[1969_Mach1 333]

I bought it through Summit Racing but I don't remember the part number.  It's been a long time.  When I bought it I had to get the part number from Griffin then Summit special ordered it.  It was still less expensive than direct from Griffin.  I haven't had any issues but I change the coolant once a year and also use distilled water.  That's what Griffin recommended.  Yes, the lower radiator hose fitting is on the passenger side.

[Max Power 74]

1969 is on the passenger side, 1970 is on the driver side, IIRC. 1970 switched to a vertical tube cross flow which omproved cooling somewhat, but required a differed water pump. 1971 switched to a horizontal tube cross flow, which is even better.