coolant flow - (follow up to cooling diagram)

[Northern Bongolow]

i pulled one geoff,did you mean that one,sorry didnt want to appear confrontational on 2 seperate topics.

[g8dhe]

Oh right, no wasn't confrontational at all, same as the crack I'd missed the reference to it having reached the water ways.

[widdowson2008]

When I don't understand summat, I retreat to my computer and draw something (a cop out). Relieves the pain of ignorance.
...and here is the latest offering - it shows how and where I cut the head. Hope you like it.



Ady
To reply to your earlier post, I am 99% sure I know how and why air gets trapped in the head on refilling the system. Unfortunately, I need to do yet another pic to explain.

[Northern Bongolow]

come on then steve,get it on a fag packet,but do it quick.

[widdowson2008]

come on then steve,get it on a fag packet,but do it quick.

OK - give me 30 minutes

[widdowson2008]

Sorry for crudeness but I hope it explains what I'm getting at.
When filling, coolant comes in from the right hand side via the top rad hose. Because the hose dips down from the rad and then climbs up to the head, it will fill the head as shown.
However, once the coolant reaches the top of the bypass, it traps the air at the top of the head (which has now got no exit.)
Does this make any sense to you?

[Northern Bongolow]

true to a certain extent steve,but it also fills via the bottom hose,passing through the stat via the jiggle pin until the weight of water lifts the jiggle pin up into its sealing position.it also fills via the heater loop when the rad is full then filling continues via the expansion tank.
i persnally think its this filling in all dirrections which traps air.
the amount of trapped air usually found to escape when the bypass is shut(stat open fully)is approx 2 standard cups full in my method of bleeding.does this equate to the volume of the head roof??? full length.
and if it does why didnt mazda/ford fit the bleed pipe here???

[widdowson2008]

Think about it Ady. That lump of air trapped in the head (and it will ALWAYS happen after refill) can only be shifted via the radiator - no other route it can possibly take, and to do this takes a good amount of revs to make the pump shift it, don't you think.

You're about right with the 2 cupfull thing. I can get a more accurate measurement tomorrow. (You are talking about Northern cups aren't you? Not one of these daft Southern thimble things?

Question I'm asking myself is why didn't Mazda position the bypass pipe higher up at the top of the head like it is on the rad side? Gotta be a reason, even if it's only Saki.

[Northern Bongolow]

agreed steve unless your using bongonads method!! it can take some shifting,when im delivering fuel into an underground storage tank,like a petrol station,an airlock in my 4 inch delivery pipe can hold back 3 or 4 thousand litres of fuel,maybe weighing 3 tons.and thats dropping 4-6 feet all the way.

[widdowson2008]

What's the reasoning behind that then

[Northern Bongolow]

theres bound to be a tecky explanation that someone will know,(i dont) probably something to do with hydraulics.
the only way i can get it to move though is to give it an easier route to travel,instead of pushing the air through the already present liquid in the tank/pipe, i break a coupling and let it out,(bleeding)

[Northern Bongolow]

you could maybe remove the rubbish temp sender unit out of the head and replace it with one of those little thimble auto bleed things that are fitted to rads in houses nowadays, they auto close when water hits the back/inside of them.auto bleed bongo.sorted

[The Great Pretender]

you could maybe remove the rubbish temp sender unit out of the head and replace it with one of those little thimble auto bleed things that are fitted to rads in houses nowadays, they auto close when water hits the back/inside of them.auto bleed bongo.sorted

Makes sense, expecting the head to bleed down through the outlet to the rad is wishful thinking. Large bore,low speed, higher pressure will hold back any air/gas in the head.

[widdowson2008]

you could maybe remove the rubbish temp sender unit out of the head and replace it with one of those little thimble auto bleed things that are fitted to rads in houses nowadays, they auto close when water hits the back/inside of them.auto bleed bongo.sorted

Quite close to what I was thinking. Very close in fact.

[Ron Miel]

When I don't understand summat, I retreat to my computer and draw something (a cop out). Relieves the pain of ignorance.
...and here is the latest offering - it shows how and where I cut the head. Hope you like it.



Ady
To reply to your earlier post, I am 99% sure I know how and why air gets trapped in the head on refilling the system. Unfortunately, I need to do yet another pic to explain.

Picking up from PM's last night, Steve - great animation, just glad you got it down from the 65MB file per image before bunging the whole thing on here.

Have just caught up with the whole thread, BTW, having gone down the pub when my senior attention span failed to cope with the long jiggle pin saga, weeks ago Brilliant! You deserve an MBE (Master of Bongo Engineering) - hope Ian's getting the degree certificate ready.

David