Engine temp rises when I get to cruise speed
 

I've been trying to cool my car down a little for the past couple of months. When it's 50-60 degrees outside it's not a concern, but as we get into summer here in Jersey things really heat up. It seems that after I installed the radiator the problems started. I had a cheap Ebay aluminum P.O.S. it there last summer and I had no problems

Here's what I've done: This is a rebuilt motor with about 2000 miles on it.

Timing is advanced 7* at idle with a max advance of 18* in at 2200 rpm because of a supercharger. Running 102 octane.

I don't have the lower grille pan installed in the grille and wondered if this could be a problem.
The radiator is getting plenty of airflow.

Hoses are new, no restrictions, no collapsed hoses.

I replaced the sending unit and checked my gauge with a new gauge and it was dead on.

I installed a temp gauge directly in the pass. head and it reads very close to what the electric gauge says.

7Lb. radiator cap with overflow tank.

New Brassworks radiator (Not happy at all. This will be another post).

Changed fan from pusher to puller with shroud.

Change t-stats from 180* to 160*.

Started with 50/50 Propylene glycol and tap water.

Tried 40% Ethylene glycol/60% distilled water.

As of this morning I'm at 20% Propylene glycol and 80% tap just to see what happened.

Outside temperature is 72*
Idled in driveway with fan on for 20 minutes at 180* all good so far.
Get on the road and I watch the temp creep up, which is what I expected. Got onto the highway doing 60 MPH and temp goes to about 205. I'm ok with that but not real happy. Cruising rpm varies from 2500 to 3000 rpm in 4th or 5th gear with air/fuel ratio from 11.3 at WOT to 14.8 cruising on a flat road.
I pull off the exit to the back roads and the temp drops.
Now I'm cruising in 3rd or 4th gear going 30-40 MPH same rpm 2500-3000 and I'm at about 190*
As soon as I go past 45 MPH it starts to heat up again.
I understand motors heat up when driving, but I didn't think 20*-30* was normal.

The next thing I will try is straight reverse osmosis water and No-Rosion. (this is what No-Rosion recommends). I understand the boiling point won't be as high as with anti freeze, but with the 7 pound cap I'd be at about 235*. I could also change the cap to a 13 lb. and get the boiling point to around 250*.
This would only be for the summer.
The car sits in a heated garage and gets driven every weekend as long as there's no snow or salt on the roads

I didn't try removing the stats, but I will if that's what everyone agrees on.

Thanks,
Joe

Re: Engine temp rises when I get to cruise speed
 

Re: Engine temp rises when I get to cruise speed
 

Quote: "It seems that after I installed the radiator the problems started. I had a cheap Ebay aluminum P.O.S. it there last summer and I had no problems"


There's your answer. If you overheat at speed but not going slower,airflow is not the issue, it's radiator cooling capacity. Whatever radiator is in the car now is not exchanging heat efficiently and no amount of work-arounds will cure it.

Re: Engine temp rises when I get to cruise speed
 

The old adage is : "Overheating at idle and low speed is an air flow problem; overheating at highway speeds is a coolant flow problem".

Looks like the last couple of posters have nailed your problem.

Re: Engine temp rises when I get to cruise speed
 

Wow! I didn’t expect that. I know it’s a 3 core radiator. Could that be the problem? Should it have been a 4 core or is a tubing size problem?
Thanks everyone

Re: Engine temp rises when I get to cruise speed
 

Many years ago {the last century}I decided to replace a good working radiator in my roadster to what I expected would be a newer better core this was prior to aluminum radiators when I put the 671 blower on my flathead. Since I expected more heat from the blower combination.

For many months I chased heating issues as your experiencing. I tried modifying the water pumps removing every other fin slowing things down did not work went back to non modified pumps next I tried 160 thermosets and no thermostats and also tried washers with a 5/8 hole in the center doing all of that did not help. During all of this I continued to use the 50/50 coolant mixture emptying it and putting it back in.

One day I decided the heck with that I just put straight water and dam that day was the first time I experienced any improvement the engine now ran 10 degrees cooler that day I discovered straight water dissipates heat better than anything else! While not a solution to the problem at that point it proved one thing water is much better for what we are doing. Other than straight water nothing I did solved the problem.

This finally led me to that radiator could it be the issue? Prior to inferred temp guns the way I determined it was the radiator I put a temp sender at the water pump the 8BA passenger side pump has the fitting hole for the heater hose a perfect location for the sender now I could see what was happening. The water temp gauge at the head was reading 180 leaving the engine the test temp gauge at the pump was reading 180 entering the engine that radiator was the problem.

The solution I had a radiator built by Custom Auto Radiator CAR located in New Jersey. Now my 671 blown flathead ran nice and cool on the open road at highway speeds and also around town.

That radiator is now in my wife's flathead powered Deuce coupe with Ital blower, C-4 automatic 3/516 bore 4 1/8 stroke crankshaft in 95 degree temps on the highway 180 is as hot as it gets and round town 160 all day long. CAR would be my choice for a radiator that works. Also CAR placed the lower radiator outlets as far out as possible so there was no interference with the belts on a flathead blower combination.
Ronnieroadster

Re: Engine temp rises when I get to cruise speed
 

jrvariel48 checkout RMI-25. I use it in all my vehicles.

Re: Engine temp rises when I get to cruise speed
 

RMI-25 Website > https://www.rmi25.com/
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RMI-25 cleans your engine cooling system’s metal surfaces, then protects against cavitation erosion, electrolysis, pitting and further corrosion. RMI-25 promotes cooler operating and higher efficiency — and it does it while you drive, with no labor costs.

Re: Engine temp rises when I get to cruise speed
 

Not necessarily a core count or tubing size problem, though both of those are important. Fin count and proper fin to tube contact in the radiator construction is of great importance to heat transfer from the coolant to the air passing through. Extra tubes can't help if the fins can't shed the heat due to lack of proper contact. Of course tubes accidentally plugged during the construction of the unit can play havoc as well. A GOOD shop can pull the tanks and tell you what's wrong...that's the best bet other than replacement. As Ronnie said, water is the best at removing the heat, but neither it nor any additive can fix a malfunctioning radiator.

Re: Engine temp rises when I get to cruise speed
 

One thing to ponder is the cruise speed AFR reading. I'm not sure what carb you are running, but if it was mine, I'd richen up the primaries and see if that changes the AFR and associated temperature. I'd probably shoot for 13 to 13.5 as a cruise number (with a blower) and see what happens.

If you see that the engine runs a lot cooler, then you'll know you have more exploration as to the best AFR that provides economy as well as enough richness to cool the engine. It is a cheap and easy test!

Re: Engine temp rises when I get to cruise speed
 

If my flathead(stock 1952) overheats with no thermostats, alum rad, electric fan,
13lb cap, recovery tank. So I am going to try the new Bob Drake super water pumps in hopes of pushing more water (when the levels get low).
Any thoughts???

Re: Engine temp rises when I get to cruise speed
 

I'm not sure of your problem answer, but most overheating involves some forms of aluminum radiator's and electric fans or plugged block and cooling system.

Re: Engine temp rises when I get to cruise speed
 

Well... you can run any type of coolant you like. But ultimately it really comes down to volume of fluid. 5 gallons of circulating fluid will keep things cooler then 2 gallons.


If I hauled a 55 gallon barrel of water next to my car piped to my engine, I'd guess it'd take a long time to heat up.


I don't know your radiator situation aluminum or steel, or what is correct...

Re: Engine temp rises when I get to cruise speed
 

As a hotrodder I would say. Chuck the interior and spare tire and put in a large rad.

Re: Engine temp rises when I get to cruise speed
 

Brilliant stuff. I ran a bottle in with my regular water coolant mix for 3 years, then did a full service recently including changing the coolant. I was amazed how clean it was when I opened the radiator tap. This stuff is hard to get in NZ but I hunted another 250ml botte down and put in in with the refill. It works like it says. The stuff is is biodergadible too.

GB

Re: Engine temp rises when I get to cruise speed
 

Being this is a rebuilt motor. Why would it clogged? I'm sure casting sand was addressed. The only change is the radiator?


I don't know......


I'd suspect the very nice brassworks rad doesn't flow to all the mods you have made. Not really designed for a blower and high flow pumps maybe. I think of them as great solid originals.


One size doesn't fit all. Certainly when you are pushing the limits of a system.


.

Re: Engine temp rises when I get to cruise speed
 

I guess the one thing I'm really having trouble understanding is this:

The engine doesn't know MPH, only RPM and load basically.
So if I'm going 30 MPH at 3000 RPM or 60 MPH at 3000 RPM I don't see the difference. I would think that the air movement at 60 MPH would have a better cooling effect than at 30MPH. My A/F numbers are the same when cruising at those speeds. The only time times that changes if when I get on it or take my foot off the pedal. Thanks Ronnie

Re: Engine temp rises when I get to cruise speed
 

I'm running a Holly 4160. I can certainly try that.

Re: Engine temp rises when I get to cruise speed
 

I believe the Brassworks radiator is copper core

Re: Engine temp rises when I get to cruise speed
 

Did it lower your engine temp at all?