The technical adventures of Dr_C

jon andersson · Nov 8, 2014

With bigger temperature difference, delta T, more heat is transferred. Therefor parallel should be more effective as the delta T will be bigger and over a larger surface. So two parallel warmer radiators should do more work than two in serial as the downstream radiator contains already cooled down liquid.

Flow direction should be warm in on top and cold out at the bottom. That way the temperature of the water will not work against the circulation pump as colder water want to move down.

Dr_C · Nov 8, 2014

jon andersson said:
With bigger temperature difference, delta T, more heat is transferred. Therefor parallel should be more effective as the delta T will be bigger and over a larger surface. So two parallel warmer radiators should do more work than two in serial as the downstream radiator contains already cooled down liquid.

Flow direction should be warm in on top and cold out at the bottom. That way the temperature of the water will not work against the circulation pump as colder water want to move down.

Without a doubt, I would prefer a parallel connection! What about how the flow divides between the coolers? The path with lowest resistance will get more flow than the other. Any problem with that?

zaga · Nov 8, 2014

Hi

With a Y conection on top and bottom, you should be fine.

You're right, but differences shouldn't be noticeable, the best you can do is to try to recreate same conditions, the best you can, in both paths.

ZAGA

Dr_C · Nov 9, 2014

Hm. Something like this, with the coolant temp sensor incorporated?

zaga · Nov 10, 2014

Yeap
Looks cool

It looks like you will have to cut the pipe of the radiator

As much as you have room to do it, the idea is to have same conditions from the Y to the radiator (length / corners), so the conditions would be as much as possible the same.

ZAGA

Dr_C · Nov 10, 2014

zaga said:
Yeap
Looks cool

It looks like you will have to cut the pipe of the radiator

As much as you have room to do it, the idea is to have same conditions from the Y to the radiator (length / corners), so the conditions would be as much as possible the same.

ZAGA

Yes, that tube had to go. I have welded a short stub there instead. As both outlet and inlet on the engine is on the left side, it's not easy making equal pressure drop across both radiators. I'll just put a plastic strap around the hose as flow control, right Bushie?

jon andersson · Nov 10, 2014

I'm wondering if it's so important that it must be equal to both sides..? If one get more water, higher flow, to one side maybe the pressure increases on that side due to temperature difference and friction? And the side with less flow get more time to cool the liquid down which should in theory give less pressure as the colder liquid get heavier.
Also as they get mixed at the outlets I think the temperature difference from a perfect system isnt that big.

I would do it as good as I could but wouldnt waste too much time on it.

zaga · Nov 10, 2014

Right on !
Cheers

Dr_C · Nov 15, 2014

So, the inlet to the coolers is done with a y-piece and the left cooler's lower tank, will collect the outlet from both coolers before it returns to the pump.

Any ideas on the necessity of an expansion tank, where to connect it and the filler neck?

bushmechanic · Nov 15, 2014

I think you have it right in that last pic Dr_C .. overflow straight into the crank vacuum

if its only required for scroteneering a non functional one would do it ?

zaga · Nov 17, 2014

Hi

Were do you have the radiator cap ? Can't find it

Why don't you make another Y on the bottom were you have the rubber hose ? that would be the most equal between sides.

ZAGA

Dr_C · Nov 17, 2014

zaga said:
Hi

Were do you have the radiator cap ? Can't find it

Why don't you make another Y on the bottom were you have the rubber hose ? that would be the most equal between sides.

ZAGA

No, I was asking you guys if you had any bright ideas on the necessity of an expansion vessel, where to connect it and where to place the filler neck!

If the return flow from both coolers gather in the same tank, that will be close enough for me.

johnyberg · Nov 19, 2014

Dr_C i guess the linear outside has the same dimensions with the OEM, the bore is safe to oversized at 102mm??? What's your opinion?

Dr_C · Nov 20, 2014

johnyberg said:
Dr_C i guess the linear outside has the same dimensions with the OEM, the bore is safe to oversized at 102mm??? What's your opinion?

Hm. I have limited experience with std bikes and "normal" use, so I might not be the best person to ask about this... BUT, I think that the alu-liner is a bit weak already as it is. Bare in mind that it has limited support from the cylinder/casing where the piston to wall forces are high. If you are planning on staying below, say 65 RWHP, I think 1 mm less thick liner is doable. It might lead to higher blow-by and piston wear, but I do not think the liner will crack.

I'm using a 104 mm steel liner with some +80 RWHP at 8800 rpm, still trying to find the optimum piston clearance! Yesterday I got a liner back from "honing" with 0,12-0,13mm clearance. So, we'll see how that turns out!

johnyberg · Nov 20, 2014

Dr_C i will use steel liner for my project, 102mm inside and stock diameter outside. I think it can handle the load... 0.12-0,13 clearence is what i will use, it's a good starting point.

Dr_C · Nov 30, 2014

Am I the last one adjusting the pressure in the oil system? A 3 mm thick distance made pressure go up from about 0,8 bar to 1,5 bar. A hope that is enough to keep pressure up even after I enlarge both nozzles into my cams.

bushmechanic · Nov 30, 2014

cool Dr C

i tested the cracking pressure of my relief valve with air to be 35psi

in use it is only 25Psi, 20psi with thin oil

I have an additional 1mm diam jet feeding oil to the drive side main and a 15mm wide oil pump. the counterbalancer oiling hole in the 80mm crank is welded closed

this is with 3lbs force on the ball from a stiffer spring

not sure if that is useful information

I think with the stock spring you can't really add too much preload, bergsmlerg reckons id have to weld the hole shut

Dr_C · Dec 7, 2014

Bushie! Have you tried to run the oil pump only (with a separate motor/drill) and measure flow to different consumers?

http://open.spotify.com/track/4C2fObwevUwxhfzAq6JtcD

bushmechanic · Dec 7, 2014

ha!

no i wanted to do the drill powered oil fun park but i wanted to ride more... LOL

ive seen a video somewhere of a ktm rfs engine inside a plastic storage crate with the oil pump being run by a drill .. fantastic

Dr_C · Dec 14, 2014

The engine is slowly coming together again! I'm planning on test start during the christmas holidays!

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