SVX Engine cooling "Again & Again" - Page 12

oab_au · #**166** 10-09-2009, 12:14 AM

Quote:

Originally Posted by yt

by creating one leg longer than the other you are essentially causing less resistance in the shorter leg and we are back at step 1.

Tom

If the difference is at the block inlet, it won't affect the water pressure inside the block.
We won't be able to get both sides flowing the exact same amount, the cast water passages in the block and heads won't be the same, but does it really matter?
As long as we remove the outlet restriction so both sides can flow their own flow, that should remove that fault and allow us to come back to the high water flow, to see if that needs looking at.

If we are ever to get good track horsepower out of this engine, we need to put torque out at 6000/6500 rpm, the engine needs to run between 5000 to 8000 rpm. If we don"t, successfully cure this problem, all the engine work is wasted.

One step at a time, change one thing at a time, we will get there.

Harvey.

Trevor · #**167** 10-09-2009, 03:55 AM

Quote:

Originally Posted by oab_au

While I agree with Toms approach to use two pipes to a two inlet radiator, it may be beyond the possibility's of the average member. I agree it is best to keep using the std pump, till we find if removing the restriction will solve the problem, as most people would be using the std pump.

I think there is merit in Tony's center tap of the pipe, to remove the restriction and provide equal flow, as far as we can.

If the modded pipe was provided with a center divider to direct the flow from each side to the outlet pipe, each side would have the same resistance, and flow the same.

May not be too hard to do .

Harvey.

No positive evidence has been established, that the small difference in resistance at this last point in each circuit, is having a significant effect on flow balance.

The difference in flow within the two sides, which appears to be indicated as a result of uneven temperatures, will continue as a result of unequal restriction and distances in each side, at any point post the water pump outlet. This is the major issue, rather than a limited restriction at the final output, where flow is at minimum pressure, and therefore least affected, to be in any event balanced before the final restriction of the radiator.

There are two circuits in parallel, pressured from a single source and ending at a single outlet. The flow in each is governed by the individual total restriction in each. The existence and affect of unequal resistance bypass routes within each circuit, is important, with these constituting the opposite of a resistance.

It should be kept in mind that a limited section balance pipe, between circuits at any critical point, will balance pressure and flow. There should be terminals where one or more could be fitted, without too much strife. It is a matter of fluid mechanics, not an airy fairy mystery.

Trevor · #**168** 10-09-2009, 04:37 AM

Quote:

Originally Posted by oab_au

If the difference is at the block inlet, it won't affect the water pressure inside the block.
We won't be able to get both sides flowing the exact same amount, the cast water passages in the block and heads won't be the same, but does it really matter?
As long as we remove the outlet restriction so both sides can flow their own flow, that should remove that fault and allow us to come back to the high water flow, to see if that needs looking at.

If we are ever to get good track horsepower out of this engine, we need to put torque out at 6000/6500 rpm, the engine needs to run between 5000 to 8000 rpm. If we don"t, successfully cure this problem, all the engine work is wasted.

One step at a time, change one thing at a time, we will get there.

Harvey.

Any difference between the cast water passages within the block and heads most certainly has a critical effect, particularly as these are early in the circuit where there is maximum pressure. The suggestion that this does not really matter is beyond belief. The current paramount question, is that the flow in one head is in doubt and is causing overheating.

It is this very factor of resistance through tortuous passages which intrudes more as pressure, increases. (Due to engine RPM.) High turbulent water flow, constitutes a very poor coolant. This is scientific fact which must not be ignored.

What is more, distance in a passage comprises a definite resistance to flow/pressure. Unequal distances post water pump outlet have a definite effect on each circuit.

Yes, one step at a time, but the likely effective, the simple, the most economic, first.

Trevor · #**169** 10-09-2009, 04:54 AM

Quote:

Originally Posted by dynomatt

Remember the old cars with something called a fan clutch? They operated the mechanical radiator cooling fan on a hydraulic disc such that when it achieved a certain load (or rpm), it couldn't spin any faster...this sounds like something we should try with the water pump...above certain RPM's it becomes a fixed speed.

We can do this with electric pumps, but not with the mechanical one.

If this is the case, why have the people who have dabbled with electric pumps (I can think of a handful), not been able to achieve a solution?

I've procured a BMW water electric water pump in an effort to solve some of this.

Cheers,
Matt

Interesting Matt, best news here so far.

I believe that experiments with electric pumps to date have been based on and limited towards the need to increase pressure/flow, whereas the the opposite has been the problem. You will have the ideal set up to experiment in this regard. I certainly hope you proceed as planned.

What you require is a speed controller for the pump. A set up delivering pulsed DC to the motor is not hard to arrange. Try a googly ---- DC motor speed control circuit, or building a DC motor speed control circuit, with the object of obtaining some hobby electronic info. There is plenty out there. If you draw a blank, get back to me via PM with full specs on the motor you have on hand.

All the very best with your project, Trevor.

Trevor · #**170** 10-09-2009, 05:11 AM

Quote:

Originally Posted by yt

add a third small hole to each side... Open up a block and you will see why.

Tom, will you please expend on this point as it appears very applicable and should be given some air.

Quote:

Also, remember making them equal on top means they are unequal as a system. it would be best to run both pipes on the RH side of the engine. The coolant has to flow into the block farther on the RH side so the make it as equal as possbile having a shorter exit would essential try to balance the two halves out. Tom

The distance in respect of each circuit is an interesting fact, which has not previously been addressed. Ford obviously had this in mind years ago, with their twin pump and twin pipe set up on the old flat head V8.

Keep the ideas coming, Trevor.

RallyBob · #**171** 10-09-2009, 09:28 AM

Quote:

Originally Posted by oab_au

If we are ever to get good track horsepower out of this engine, we need to put torque out at 6000/6500 rpm, the engine needs to run between 5000 to 8000 rpm. If we don"t, successfully cure this problem, all the engine work is wasted.

One concern I have is that the standard cooling system has proven to be substandard for even a bone-stock engine that is run continuously hard (6500 rpm max).

Even if the inherent flaws are cured for that standard engine, will it be enough for 300+ whp and 8500 rpms N/A, or 500+ whp and 7000 rpms w/forced induction and sustained loads that might be seen in off road desert racing and road racing. After all, more power = more heat.

SilverSpear · #**172** 10-09-2009, 01:16 PM

Well 12 pages of theories and still nothing applied. I think the only way to do this is through Tony's method. Water flowmeter, a temperature meter and begin the journey of trial and error in modding the cooling system.

Keeping with the speculations without this will lead to more pages, more confusion and more arguing. We need to test.

Tony any luck wtih the flowmeter? What is the cheapest you were able to find so far?

yt · #**173** 10-09-2009, 05:21 PM

Take this to heart when thinking about the radiator's efficiency.

A stock engine can run at 5000 RPM all day with a stock radiator and never get too hot.

My supercharged car making an estimated 350wheel horse runs all day without ever getting too hot with a PWR radiator

So double the wheel horsepower of the engine without revving it out to 6k+ RPM and you will see that double the power generates more heat. This heat is not too much for the radiator to cool to proper levels.

So to put the radiator out of our minds, we are stuck with the rest of the engine. It will take step by step investigation and modification to actually find and address the root cause. Now, Tony has been a huge help in testing the modified stock water manifold and has brought back results telling us it is not enough. Jack and Bob have also done quite a few things to their engine, which has helped but never fixed the issue at hand. I am going to list a couple things below which have been tried but have not proven any great results

- Electric Water Pump
- Modified Water Manifold
- Aluminum radiator
- Modified Thermostat
- Water Wetter

Lets work from here with all this in mind to address it logically. I will try my best to get the custom manifold done soon but I cannot make promises on a time frame yet.

TOm

Dessertrunner · #**174** 10-09-2009, 05:29 PM

Still not there with flow meter but this is heading in a simlar direction I want to ask everone a question. That maens I want everyone to just say yes they agree or no they don't. Don't debate the issue just agree or don't agree.

The Question do we all agree that,
The flow in the Left Head is LESS then the Right Head and I submit as evidence the higher discharge coolent temp on the left head.
Remember the answer is to be Agree or Don't Agree. When everyone answers I will explain why I ask the question.
Tony