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Cooling system changes for high rpm use.

Electric pump and pump/fan controller installed and tried two days with hard driving with studded rally tires on a frozen lake. Worked excellent. Engine ran a little cold on highway driving in sub freezing temperatures. The controller will run the pump in pulsed mode until the set temperature is reached, but without the thermostat this was to much cooling. Davies Craig recommended to install the thermostat and drill two 5 mm holes in it to avoid pump cavitation when engine is warming up. This will not be necessary during the winter.

Next is a all aluminium radiator and a air valve connection on the expansion tank to run a 30 PSI pre pressurised cooling system. This will raise the boiling point of pure de-mineralised water to 250 deg F.
 
I don't have cooling problems but I still worry about the freeze plugs. I choose to go with a high capacity aluminum radiator that keeps the engine happy under load in the heat. But, because of various issues I haven't done any high RPM tuning of my engine yet or done really any high RPM driving. I would go with an electric pump if there were a quality set-up available that enabled variable pump speed related to engine temp requirements. Seems like this would be a good way to speed engine warm-up as well by keeping pump off until coolant was warm.

Briliant! ide buy one.
 
Water is the ultimate coolant, it has far better heat capacity and conductivity than antifreeze, so pure water will perform better. By running a pressurized system the boiling point of water will rise and local boiling will not be as likely.
 
My dad used to have a v8 with 500 horsepower.....never had a freeze plug come out.

Sorry buddy, but 500crank out of a V8 is nothing, we're in Michigan, you should know this. . . not to mention it has no bearings whatsoever when it comes to Volvos.

This'll be a bit long, but give it a read.

I'm surprised nobody has mentioned this before, but the problem might be the saving grace pressure release cap that keeps being brought up over and over.

We've already established the following:
The two most likely causes of freeze plug blowouts are block vibrations, and localized pressure pockets.
When water is under pressure, the boiling point rises, as with any liquid.

Now, take your motor, operating at 10psi coolant pressure. Now floor it, build a bunch of boost, and a TON of heat. Now, find that one itty bitty spot where coolant creates a circulating current in the head/block instead of flowing to that radiatior. That water/coolant/mix of whatever you like in just a second or two can easily shoot up an extra hundred degrees or so. . . Sweet, no biggie, we have antifreeze, wetter, and system pressure to keep it from boiling. . .

Now, that pressure valve releases. This isn't some fancy valve, a little plastic doohicky with a spring. It might let the system hit 11psi, open and close right back up at 9psi. But what if it's just a little plastic doohicky that sticks open for ten seconds? Now you've lost nearly all cooling system pressure, and suddenly the boiling point of that extra-hot spot of water is suddenly twenty degrees too low?

BOOM! Flash boil, and now you've got a few ounces of water/antifreeze flashed into steam. If someone wants to do the math we could figure out what sort of localized pressure that'd create. . . the water sure isn't moving out of the way fast enough. . .

Given a large enough pocket of heat, you could easily see several hundred pounds of pressure when there was no more then ten half a second before.
 
Along with drilling holes in my head where the gasket had some, but it did not, I just got done doing this.


Here are some pics showing my water bypass from the head, and the passengers block. All plumbed to a 12v solenoid on the pass frame rail and then to the suction side of the pump via the old water cooled turbo location.

you can the stainless tube snake from the rear most head port.

IMG_20110308_214519.jpg


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and poken from the block dumping by the power steering pump.

IMG_20110308_214626.jpg


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and onto the solenoid. Its controlled via the ecu and will meet an RPM and Boost critieria (something like 3000rpm and 10psi) to open and releive block pressure for a very short period of time.

IMG_20110308_214839.jpg
 
I tried both Volvo pulleys on the stock balancer. The larger one still popped the plugs, so I made a pulley from a sbc that was 1 inch larger in diamter. Worked out to be close to 1800rpm slower at redline. But my idle cooler suffered, horribly. Once it warmed up, the logs showed like 1 degree drop in temp about every minute, and theres a pretty badass fan on it. So during this mini rebuild I reistalled the larger of the Volvo pulleys but wanted to relief the block pressure we talked about on page one.

So to ebay I went and found a 30.00, brass, 12v, 3/8 solenoid valve. Found the 2 ports....not sure if the head will help as much as the one really close to the waterpump outlet under the header. and origially was going to dump into the thermostat housing....but since I have a non watercooled turbo I still had the suction port on the lower hose. And since I was having troubles fitting/making look decent the valve under the intake, it was a natural fit on the pasengers frame rail.

My EMS has programmable outputs, but I bet a simple hobbs switch would work too.

And scottyd, one of them led's on my dash is for this mod too. lower right corner I have a blue led that will come on to at least tell me the relay has been triggered.
 
Hm. Interesting. So the holes you added in the head. Are these like the steam holes seen in some of the 8v heads? What diameter?
 
good idea, but would it have been easier to just use one of the freeze plugs as a port? like a screw in plug, drill/tap that and send that to the solenoid. well that's what i was thinking a while back, and if you really wanted to find which was the worst plug, and how much the mod changed it you could tap all of them and measure the pressure on each before and after the bypass. but that's just some crazy **** i think up from time to time, usually not practical
 
Qwkswde......I did the group a mod way back in the first page I think. But I did not add the extra holes along the exhaust side......just drilled the blind holes on the head...but present in the block and gasket. That's where my gasket was starting to fail. I drilled a 3/16 hole......I think there was 3 of them....front drivers side and 2 along the back by njumber 4.

Olov.....would take some time to figure which plug had the pressure. When mine failed the first time....I lost the rear 2 on exhaust and forward on the intake side. There were 3 others that were flush with the block and not even with the chamfer. You have a good idea about tapping the block....but from what I'm seeing...the bores are very close to the plugs so you'd almost need to start the hole...the cut the die up and finish tapping. And with my engine installed....a bit more work than what I wanted. And the valve is only 3/8 pipe.....any larger and the solenoids get huge.
 
Qwkswde......I did the group a mod way back in the first page I think. But I did not add the extra holes along the exhaust side......just drilled the blind holes on the head...but present in the block and gasket. That's where my gasket was starting to fail. I drilled a 3/16 hole......I think there was 3 of them....front drivers side and 2 along the back by njumber 4.

Olov.....would take some time to figure which plug had the pressure. When mine failed the first time....I lost the rear 2 on exhaust and forward on the intake side. There were 3 others that were flush with the block and not even with the chamfer. You have a good idea about tapping the block....but from what I'm seeing...the bores are very close to the plugs so you'd almost need to start the hole...the cut the die up and finish tapping. And with my engine installed....a bit more work than what I wanted. And the valve is only 3/8 pipe.....any larger and the solenoids get huge.
or make freeze plugs with a hose connection in the middle of it, and weld em in.
 
Has anybody tried using an auxiliary electric water pump? Various turbo cars use them, Focus RS etc, they're available from Bosch with magnetic drive and 19mm hose connections. I'm toying with the idea of plumbing one into the heater hose outlet and wiring it into the fan control so it only works when the engine gets hot and increase flow through the head.
 
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