MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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burner1
Gary W

(212 posts)

Registered:
09/24/2011 09:59AM

Main British Car:


Re: Engine heat in GM V-6
Posted by: burner1
Date: November 07, 2014 01:39PM

I concur with Jim on Evans coolant. I ran it in mine. It does not have the cooling capacity of a traditional 50/50 coolant mixture. In a normal system with more then adequate cooling you would never notice because the temperature is controlled by the thermostat. When the cooling capacity of the system is exceeded it begins to rise above the thermostat setting.

In mine, I could only go about 10 miles before starting to run hot. I put in an oil cooler under the front valance and I got quite a bit more mileage but still too hot after driving a while. I changed to traditional coolant and the system has since been fine.


superdave
david morris

(1 posts)

Registered:
11/08/2014 12:36PM

Main British Car:


Re: Engine heat in GM V-6
Posted by: superdave
Date: November 08, 2014 01:49PM

I had a heating issue in my 70 MGB with 3.4. I have a bigger aluminum radiator and single electric fan. The temp would be fine while moving, but would creep up every time I stopped. I ended up putting a small GT350 style hood scoop from Speedway that allowed that underhood heat to escape when I stopped and that helped a lot. Different from your issue it seems, but something to think about. Louvers would do the same thing. I liked the scoop since my hood had a ding right in the middle and it allowed me to get rid of that and use a larger air cleaner.


MGBV8
Carl Floyd
Kingsport, TN
(3727 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Engine heat in GM V-6
Posted by: MGBV8
Date: November 14, 2014 01:00PM

Don,

Just curious to see if you have tried replacing the Evans, as suggested by Jim B. & Gary. I usually go with 30/70 mix of antifreeze/water. Doesn't get as cold here in Spring & Fall and I don't drive my B in cold, nasty weather on salt covered roads. Some may need the 50/50 for the extra boil-over protection, but mine doesn't run hot.


denvermgb
Brad Carson
Aurora, Colorado
(104 posts)

Registered:
03/10/2008 12:45AM

Main British Car:
1975 MGB 350 SBC bored 0.040 over

authors avatar
Re: Engine heat in GM V-6
Posted by: denvermgb
Date: November 15, 2014 01:56PM

Don,

I know my expertise can't hold a candle to most folks' skills here, however.... Perhaps I missed something, as I am trying to see where coolant is added to your system and where you bleed the air out? On my car, I had to mount a coolant filler/thermostat housing because the rad sits lower than the engine. Brad
engine bay 001a.jpg


DonB
Don Bonar
Prairie Village, KS
(80 posts)

Registered:
09/09/2011 10:06AM

Main British Car:
1971 MG-B 95 GM 3.4 V-6

Re: Engine heat in GM V-6
Posted by: DonB
Date: November 27, 2014 10:18AM

Once again, thanks to all who offered up potential solutions on my heat issue. Some of you have also added PMs or asked specific questions. Here's a recap of what I've done so far... and future action plan when it's not 15 degrees in my garage!
Overstated.... it seems to come down to air flow, fluid capabilities, correct measurement, and a realistic "normal" heat range for a 60 degree V6.

Measurement- Installed new 180 thermostat, new Auto Meter gauge and probe, and will run a dyno test next spring on timing and lean/rich carb settings.

Fliud- Will defer on dumping the Evans collant till spring. Once we have a baseline, I'll run it both ways.

Air flow- see below... tried to turn grill opening into a "cold air box" to drive all thru rad. If necessary, will also open louvered vent holes in inner fenders to wheel openings.
Again , thanks to all. Don B.


bv6-er
Bob Wilson

(2 posts)

Registered:
02/14/2015 01:48AM

Main British Car:


Re: Engine heat in GM V-6
Posted by: bv6-er
Date: February 14, 2015 02:20AM

Overheating in these conversions is 90% related to airflow problems. Bigger, high powered (and power equals heat) engine crowding a small engine bay. Look at the space around the original little 4-banger compared to what you have done. So...is the air hitting the front of the radiator getting through it without restriction? Are the fan(s) running at the proper speed? Do you have the radiator "sealed" to the front bulkhead so that other airflow is not bypassing it, and "pressurizing" the engine bay so the radiator's backside doesn't want to allow airflow?

Heat soak is what happens once you shut off or stop moving, but your fan arrangement should partially compensate for this. My 1994 GM factory manuals for the 3.4 and 5.7 engines state that the PCM will cause the cooling fan(s) to switch on at low speed at 220F and high speed at about 240F. That was what GM's engineers designed, so they did not consider those to be alarming temperatures. Toss the boutique coolant and go back to standard Ethylene Glycol (Prestone green/yellow) or DexCool at a 50/50 mix. If your cooling system is up to snuff, install the GM recommended 92C thermostat. And run 5W30 synthetic oil.

I have a 240 Volvo and see guys on that BB complaining occasionally about overheating. First question to them is "did you remove the splash shield under the engine?" Answer is often "yes". They don't understand that the clever Swedes put that there not only to keep water out of the alternator, but to increase airflow through the rad by preventing air at highway speeds from washing up behind the front bumper/airdam and pressurizing the engine bay. So airflow through there is extremely important to cooling efficiency....(to state the obvious).

Drilling a little hole in the thermostat flange is a way to bleed off any trapped air and let it get to the upper portions of the rad. 99% of the time it makes no difference,as the opening of the thermostat will do this anyway.



Edited 1 time(s). Last edit at 02/14/2015 02:30AM by bv6-er.


MGBV8
Carl Floyd
Kingsport, TN
(3727 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Engine heat in GM V-6
Posted by: MGBV8
Date: February 14, 2015 10:08AM

Since I don't require the extreme protection of anti-freeze, freezing or boil-over, I never use a 50/50 mix. Anti-freeze reduces the heat transfer efficiency of water. Therefore, I find that a 30/70 or even a 25/75 works for me & does a better job with engine cooling. LBC Winter drivers should stick with the 50/50, though.



bv6-er
Bob Wilson

(2 posts)

Registered:
02/14/2015 01:48AM

Main British Car:


Re: Engine heat in GM V-6
Posted by: bv6-er
Date: February 14, 2015 02:22PM

MGBV8 - fair enough if you never see cold temps. The anti-corrosion additives in antifreeze do deplete over time and if you are using a weak mix, you should consider draining it and refilling with fresh stuff more often than if you used 50/50.


BMC
Brian Mc Cullough
Forest Lake, Minnesota, USA
(380 posts)

Registered:
10/30/2007 02:27AM

Main British Car:
1980 MGB '95 3.4L 'L32' SFI V6, GM V6T5 & 3.42 Limi

authors avatar
Re: Engine heat in GM V-6
Posted by: BMC
Date: March 01, 2015 08:13PM

Hi,

Running late to the party and restating some things that have already been said but some cars such as Sunbeam Tigers, so I have read, have issues due mostly to air flow more than radiator size. I think the same holds true for any small engine bay.

Small fans, fans that are running the wrong way (blowing forward instead of with the air pressure going backwards), fans that the blades are 1" or further away from the cooling fins (no matter how good the shrouding- I question yours by appearance) and other air moving across the fins is a big portion of the issues.

The Original Fuel Injected version of this engine does run happy all the time above 220* but if you have the engine set up with a cooler thermostat, yup, it should run cooler.

Although I see many very good factory and aftermarket water temp gauges, I would say at least a third of the overheat complaints we hear about are a combination of a gauge that is not set up right or individuals who are not used to seeing the stock gauge go so far. For most gauges, this just needs an extra resistor of size 'X' in line.

My car and many that we build run stock radiators for the late model MGB. We sell a retrofit kit for the late model radiator to fit into the 1962-1976 MGB. This fits fantastic, looks stock and has no problem running hot. The biggest difference is the cooling fan used. Cheap cooling fans will allow overheating with almost no regard to how good of radiator installed in the MGB or other small engine bay car.

-BMC.


1320nut
Jerry LeMasters

(2 posts)

Registered:
08/01/2008 11:09AM

Main British Car:


Re: Engine heat in GM V-6
Posted by: 1320nut
Date: March 19, 2015 10:28PM

Just A Thought, Did You Check To See, If You Had A Counter Clockwise Water Pump Or Clockwise. I May Have Missed That Topic Here??


Charles
Charles Long
McDonald, TN
(177 posts)

Registered:
09/15/2013 08:54AM

Main British Car:
1966 MGB V6 1994 Camaro 3.4L 60V6

authors avatar
Re: Engine heat in GM V-6
Posted by: Charles
Date: March 22, 2015 10:05PM

Bob B, We met in CS. I am running 3.4V6 like yours, 66 B no hood lovers and FI. 195 degree thermostat, stock water pump, 50/50 mix coolant. I put a wireless grill therm. sensor under the hood with the display unit on the console, went for a slow speed trip in traffic. Engine temp gauge shows between 195-220. At 220 fans come ON, then OFF at about 195-200. Engine area shows between 170-185, when the fans come temp will rise to 190-195 then start to cool down. When I shut engine off and watch the temp. it will go to about 195-200 for a short time then start to drop.
Like Bob W. and Brian Mc wrote, GM don't consider 220 hot on this engine. When setting at idle my engine bay temp seldom goes over 175, my ambient is about 70, granted it has not gotten hot, but it will, I will check again later.
I have reset my fan control to ON at 220 and OFF at 200. I would rather be ahead on the temps than to try to catch-up.
charles


burner1
Gary W

(212 posts)

Registered:
09/24/2011 09:59AM

Main British Car:


Re: Engine heat in GM V-6
Posted by: burner1
Date: March 26, 2015 01:58PM

When I put my 3.4l in my car, it ran hot. 10 miles or so I had to stop. I had the Evans like I said. I did 2 things. First I swapped out the Evans. I imediatly got 20-30 miles but was still getting too hot.

One thing I noticed was the water temp would come up and stabalize like it should with the thermostat. Then the oil temp would come up...and it would keep on going. The oil temp would then pull the water temp.

I then put in a small oil cooler under the front valance and have had stable water and oil temps ever since:


http://www.rc-tech.net/MGB/cooler.jpg


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Engine heat in GM V-6
Posted by: BlownMGB-V8
Date: March 27, 2015 11:43AM

Great tip Gary. One thing the factory did better than most of us is to keep tabs on the engine oil temps and the OEM oil cooler was there for good reasons. The piston takes as much heat as the head (nearly) and almost all of that heat goes into the oil. To get to the coolant it then has to migrate back through the block. American engines have for many decades used exactly that approach but the more efficient method is to cool the oil.

Jim


burner1
Gary W

(212 posts)

Registered:
09/24/2011 09:59AM

Main British Car:


Re: Engine heat in GM V-6
Posted by: burner1
Date: March 27, 2015 01:47PM

When I put the cooler under the front valance, I did not know how well it would work since it was not in dirrect airflow. I was suprised how well it did work.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Engine heat in GM V-6
Posted by: BlownMGB-V8
Date: March 27, 2015 03:17PM

Usually the oil is significantly hotter than the engine coolant, sometimes quite a lot hotter. That means the cooler will be just that much more efficient.

Jim



burner1
Gary W

(212 posts)

Registered:
09/24/2011 09:59AM

Main British Car:


Re: Engine heat in GM V-6
Posted by: burner1
Date: March 27, 2015 03:44PM

I also think the air is rolling around the valance getting more airflow then one might expect.


mansep2
Paul Mansell

(2 posts)

Registered:
03/22/2015 11:21PM

Main British Car:


Re: Engine heat in GM V-6
Posted by: mansep2
Date: March 27, 2015 09:43PM

Good idea Gary so where on the engine does the oil lines run from to and from the oil cooler


burner1
Gary W

(212 posts)

Registered:
09/24/2011 09:59AM

Main British Car:


Re: Engine heat in GM V-6
Posted by: burner1
Date: March 28, 2015 12:37PM

I have a remote filter adapter on the block. I put the remote filter inside the front fender well:

http://www.rc-tech.net/cars2/mg2/remote1.jpg



I used to have it in the engine bay but moved it when I cleaned some things up in the engine bay. You can see it on the right on one of the picutres before I did more work in the engine bay:

http://www.rc-tech.net/cars2/mg2/cleanup/before.jpg


It just looks better with it in the well:


http://www.rc-tech.net/cars2/mg2/gal/CAI.jpg


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Engine heat in GM V-6
Posted by: BlownMGB-V8
Date: March 28, 2015 01:26PM

Not only that, it's less mess when you do a filter change.

Jim


burner1
Gary W

(212 posts)

Registered:
09/24/2011 09:59AM

Main British Car:


Re: Engine heat in GM V-6
Posted by: burner1
Date: March 28, 2015 02:06PM

You know the remote filter block also gave me a good place to hook up the oil temp gauge.
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