valve seat drop - Parso post

[07commander]

wow so glad i own a crd I'm running a murchison 2.5" lift 265/70/17, roof rack with all the bits and spare tyre and i towed a trailer with a 4wd on from S/A back to melbourne sitting on a 100 and the temp only moved off 90* going up hill the highest it got was 103* up a long hill but it came down real quick.

[Parso]

@James i'll certainly be watching your progress on this with keen eyes as I'll likely follow suit if you find it works well. I might drop the fan temps a whole bunch more when the car's back together and see how that goes.

I dropped the disassembled short block and heads off to the engine builder on Friday and hopefully should have that back as a short block in 2-3 weeks time. In the mean time i'm slowly amassing a pile of parts to go into the car (and one hell of a bill too )

One setback was a bunch of hoses I ordered from the states ended up being unavailable as they cant access export parts for RHD vehicles. As such i'll make make some franken hoses for the heater supply and return and just make do with the old power steering hoses.

[Parso]

Well a quick update with what I've gotten done so far. I've replaced the radiator with the alloy eBay unit that was posted in the internet finds thread. Quality of it actually looked pretty reasonable and the fitment was reasonable however it did require some filing of the mounts for the condenser and power steering cooler however I was expecting this may be the case. Against my better judgement I didn't get it pressure tested as it looked pretty reasonable, so hopefully it doesn't give me any surprises there. My old radiator was probably about 1/3 clogged with mud from previous off-road expeditions so if nothing else i'm expecting a good improvement just from the increased airflow the radiator should have.

I added a 10" thermo fan in front of the condenser on the passenger side. Only a 10" because i'm running an aftermarket engine oil cooler that is mounted infront of the condenser on the other side so space was limited. This is wired into a Davies Craig 0444 thermostat and i'll have that all powered on a circuit that comes on with the ignition and then has a time delay after shutdown. I'll also wire on the same time delay circuit a Davies Craig EBP23 that will run in the heater core line to help promote the circulation of coolant after shutdown. I haven't been able to find a cooling circuit diagram but from memory the heater supply line comes from the vicinity of the water pump outlet and returns to the block? Either way I figure it'll promote the circulation of coolant somewhere in the motor hence might help temperature stability post shutdown. I've also wired in an over-ride to the hydraulic fan solenoid so I can manually trigger this at desire.

The plethora of items from the states has started arriving and boy are there lots of bits. All new seals for everything, all new sensors, mounts, bolts, pumps, lifters, pushrods, etc etc etc etc etc etc Needless to say i've probably gone overboard but when i'm done with it, it'll pretty much be a new motor. The only hoses I couldn't unfortunately get were the RHD specific ones which i'll just have to re-use. On the upside i'll have a nice swag of spare parts

Hopefully I get the motor back either late this week or sometime next week. Then the fun of putting it all back together can begin!

At some point i'll try to remember to take photos but no promises as I tend to get task focused and just get stuck into things!

[ren0vator]

That's the way Parso
Get into it
Hope it all comes together for you

[07commander]

wow sounds like you have got it sorted, nothing better than a box of parts to get and the countless hours and cut up knuckles.

I ordered $600 worth of bushes and links etc, for my commander a couple of weeks before i had my accident, it has been sitting there for 4 months now i was hoping that i would have a jeep that would handle like brand new, so don't go hurting your self.

[Parso]

Block is back from the engine builders!

Now the task of putting it all back together begins. I was hoping to have it all done this weekend however of the many parcels that have arrived on my doorstep two important ones have gone AWOL now for over a week... Unfortunately these contain my lifters and MDS solenoids so that'll hold up progress potentially for a while.

That said it'll give me time to be my pedantic self and clean, assemble and get everything exactly how i want it to be.

Now i've had a good look at the motor I am confident my plans for the coolant circulation pump will work well. Looking at how coolant flows through the motor having an aux pump in the heater line will circulate coolant throughout the block and heads so hopefully that should prevent any future issues by keeping stable temperatures post shutdown. I'll be interested to monitor the coolant temperatures after shutdown with the pump running as the factory sender is at the top front of the block. This is after the coolant has passed around the cylinder walls, up through the head and then back into the block to get spat out the front of the timing chain cover just by the thermostat so in theory it measures the coolant at it's hottest.

I'll also be interested (although unrelated to the valve seat drop) to monitor oil temperatures. I've purchased a Redarc G52-POT and will have the pressure sensor in the spare port above the factory oil temp sender and i'll weld a bung into the sump to monitor oil sump temperature. The Hemi doesn't have a water/oil heat exchanger to moderate oil temperature (hence why i run an aftermarket oil/air cooler) so i'll be interested to see how hot the oil gets as i've read these run rather hot. Intention is to eventually use the third sensor pickup of the Redarc gauge to monitor my oil temperatures post oil cooler which should give me a good idea of oil temps going to the bearings and the efficiency of the oil cooler. Yup, i tend to go overboard and i love having numbers to look at. It's just how i roll

[Redemptioner]

Originally Posted by JamesLaugesen

That’s a myth.
It can sort-of be true in some scenarios with some setups where the higher flow and/or pressure causes turbulence or pushes coolant through a bypass or radiator overflow.
Lower pressure also lowers the RPM the pump cavitates, which also happens when RPM is too fast (if a mechanical pump is over-driven for example.).

But just circulating coolant faster doesn’t reduce cooling on its own, since there’s more “passes” so to speak.

You were close, increasing the pressure means the coolant will boil at a higher temp but it will also increase the cavitation and make it happen at a lower water speed, it will also reduce the rate of thermal exchange as well as the thermal capacity of the coolant (will absorb the heat slower and absorb less of it when under pressure).

If you want maximum heat exchange you want the liquid not to be under pressure (not able to do with standard coolant) and you want the flow as fast as possible (without causing cavitation). People who make the comments about the coolant needing more dwell time (spending more time in radiator or engine) have no idea what they are talking about. The thermal absorption properties of the coolant drops off extremely fast as it absorbs heat, but as the heat comes up in the coolant it gets better and better at shedding the heat. The coolant stops being efficient at absorbing heat out of the engine within split seconds of being exposed to the cylinder sidewalls and the high heat, this is why you want to turn it over as much as possible. The same goes for when it hits the radiator, it is only efficient at dropping the heat out while there is a big difference between air temp and coolant temp and the coolant sheds the heat far faster than it absorbed it, the radiator has much more exposure to heat exchange than the motor so it needs less time in the radiator than the engine to rid itself of the heat.

The thermostat is there to prevent the coolant loosing too much heat before entering the engine again by reducing flow, if you take it out you will run into problems with the engine being too cool, not too hot.