SVX Engine cooling "Again & Again"

[Dessertrunner]

Looks great, becarefull with the angle in relation to the bolts as the pipe needs to go at different angle also I was working on 45mm OD

[TomsSVX]

That is not hard to make at all really. Problem is, I am still not totally confident the solution has been found in this elbow. I will continue to test my current theory with the custom water pipe.

Tom

[sicksubie]

Chris, if you want, email me that file as I have a buddy who may be able to do a production run of those elbows...

[Trevor]

Originally Posted by TomsSVX

That is not hard to make at all really. Problem is, I am still not totally confident the solution has been found in this elbow. I will continue to test my current theory with the custom water pipe.

Tom

Thank you Tom,

At long last some logic has been recorded. I have studied this thread from go to whoa and have found nothing definitive in respect of curing a cooling problem in respect of the SVX

[TomsSVX]

Problem I see thus far is this...

Right nowwe are banking on the fact that air is being introduced to the system via flash point due to a vacuum on the inlet of the pump. If this were the case, the pressure on the outlet side of the pump would drop to a near zero with the introduction of air being at this point. Water is not compressible and hence the pressure is build. Air is very compressible and if it were introduced, the system pressure would drop drastically. From what I have seen from Tony's recordings, pressure on the outlet of the pump increases with RPM at a relatively constant rate of acceleration... Not typical of a fluid system contaminated with air.

This is all my speculation on the matter and can be wholeheartedly taken purely as an opinion

Tom

[Dessertrunner]

Tom for what its worth one of my test involved a pipe from the top of the engine back into the inlet of pump and open at the top. With the standard pump cover the system failed. When I change the cover and the pipe size every thing worked perfect.
The pump system work in the following way,
Any increase in outlet size from the motor is good because it will reduce friction and therfor increase flow provided that the inlet of the pump can supply the extra flow.
Your point about the pressure going up as revs go up needs to be looked at in the context that suction also went down. The faster the revs the greater the vacum on the suction. Once the suction reachs 14.7 PSI vacum its all over and the pump stops pumping.
In short I think you should change the top pipe but you will have to do the bottom suction or you will have a cooked motor.
Tony

[Dessertrunner]

I think it would be good to give people some number related to the vacum on the pump intake and what it does to the boiling point of the coolent.
at
-2 psi coolent boils at 94 C
-4 90 C
-6 84 C
-8 77 C
-10 76 C
-12 53 C

Given the problem Steve had with his buggy running at 7,000 rpm and the high vacum numbers I have got in the tests you can see what it will do to the pump flow, remember once it boils on the intake the pump stops pumping.
I need to clarify the logic and that is if your coolent is running at 80C on the return from the radiator then the pump will lose prime at around - 6 psi. Hope this sheds some light on the issue.
Tony

[Trevor]

Originally Posted by Dessertrunner

I think it would be good to give people some number related to the vacum on the pump intake and what it does to the boiling point of the coolent.
at
-2 psi coolent boils at 94 C
-4 90 C
-6 84 C
-8 77 C
-10 76 C
-12 53 C

Given the problem Steve had with his buggy running at 7,000 rpm and the high vacum numbers I have got in the tests you can see what it will do to the pump flow, remember once it boils on the intake the pump stops pumping.
I need to clarify the logic and that is if your coolent is running at 80C on the return from the radiator then the pump will lose prime at around - 6 psi. Hope this sheds some light on the issue.
Tony

When, where and how has it been indicated, much less proven, that the SVX cooling system, when operating at a pressure of in excess of 10 PSI and closed to the atmosphere, has vacuum or a negative pressure, anywhere within the closed circuit?

[TomsSVX]

Originally Posted by Trevor

When, where and how has it been indicated, much less proven, that the SVX cooling system, when operating at a pressure of in excess of 10 PSI and closed to the atmosphere, has vacuum or a negative pressure, anywhere within the closed circuit?

Tony did it with pressure sensors a while back.

The Radiator causes a large pressure drop and then the inlet of the pump enhances it.

Tom

[Trevor]

Originally Posted by TomsSVX

Tony did it with pressure sensors a while back.

The Radiator causes a large pressure drop and then the inlet of the pump enhances it.

Tom

Tom,

Specifically ---- When, where and how has it been indicated, much less proven, that the SVX cooling system, when operating at a pressure of in excess of 10 PSI and closed to the atmosphere, has vacuum or a negative pressure, anywhere within the closed circuit?

I can find only references to a test set up which was open to the atmosphere.

[TomsSVX]

Originally Posted by Trevor

Tom,

Specifically ---- When, where and how has it been indicated, much less proven, that the SVX cooling system, when operating at a pressure of in excess of 10 PSI and closed to the atmosphere, has vacuum or a negative pressure, anywhere within the closed circuit?

I can find only references to a test set up which was open to the atmosphere.

the system is only closed until the rad cap reaches 13psi. Then it is open to the atmospher... I am with you here Trevor but I am not looking for holes in research, just taking everything with a grain of salt

Tom

[Dessertrunner]

Hate to burst your bubble Trevor but do you know what a close loop is as regards the cooling circut. You seem to have in your mind some kind of perpetual motion and it just doesn't happen that way.
The simple fact is that a closed loop cooling system that has pressure on the outlet of the pump doesn't mean that it then provides pressure to the suction, it just doesn't happen as you think.
One trial I did was with a pump only with the out let going back into the suction. Surprise, surprise there was no pressure on the outlet of the pump and no vacum on the inlet because the systen was balanced provided I used larger pipe on the thermostate cover. With the standard size outlet the pressure went up and the suction went vacum.

Before you come back and debate, as they say in the classic's "The proof is in the pudding". I have the wrungs on the board Steve's buggy now runs cool and that would have to be the only SVX engine in the world that is staying cool. So it your turn to put up the facts not words, provide postive proof and I will admit I am wrong.
Tony

[TomsSVX]

Tony, just doing a little more looking and I wonder what you have been doing in regards to the small bypass pipe on the water pump. Looking at the stock configuration, it just cycles on the LH side of the engine w/o ever cooling

Tom

[Dessertrunner]

Tom don't get me wrong I think if you can change the top pipe as you suggest it will increase the amount of coolent at high revs. As regards the back small pipes, on a race car the heater one kept the other blocked. I am working on moving the thermostate up to the top pipe and us one that when open will close the top pipes.
Tony

[TomsSVX]

Originally Posted by Dessertrunner

Tom don't get me wrong I think if you can change the top pipe as you suggest it will increase the amount of coolent at high revs. As regards the back small pipes, on a race car the heater one kept the other blocked. I am working on moving the thermostate up to the top pipe and us one that when open will close the top pipes.
Tony

I think I lost you there for a minute, are you saying you just looped them together on the pump or you still have them on??

Tom