Avon - The Damage
Turbo Mini Forums

On the small bore, there are two large ports for the coolant to pass out of the block between cylinder 4 and the end of the block, unlike the big bore block that just has a small hole.

But the coolant has to have somewhere to go.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Since the head is the only change Id be looking at that, is the cooling in there sufficient?

I seriously doubt it!

What is wierd is that although the rad looked full, when I emptied it, not much came out.

I'm thinking that there may have been an air lock. I also haven't checked that pump yet to make sure it's pumping.

My initial thought is to utilise the heater take off and run a line from there back to the bottom hose. I may also add a small rad to this line.

Basically that end of the engine does not have enough flow through it.

It was getting hot ticking over, as if there was not enough water in actually. It was fine at Harewood in similar temps ticking over for longer periods.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

are you using the heater take off port wil ? on the head
the zddp.... upping is a bit more insurance

what fan are you using?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

No, I have the temp sensor stuck in it. We never used it in the old head. But Maybe this one just needs a bit more flow.

As I have said before though, it was fine at all events before avon, so I don't think that it is at all caused by the head design per say. But my cooling system was always on the limit and the extra power (read heat) has meant that the extra capacity it had has been absorbed. so when something is a bit wrong (low water for instance) there is no redundancy to cope, hence it gets hot.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Yes I didn't realise until earlier this year how much the fan does make a difference. I rad for 12 months with just an electric and it was boderline even at speed. I slapped a two blade on with the electric on a thermostat and it's been great. It just needed that extra flow.
You don't think the head is absorbing more heat from the turbo as it's ally?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

I agree about the fan. Running a side mount without a mechanical fan is not a good idea. I know people who have got away with it, but not on powerful engines.

I understand that the cooling of a CNC head is always an issue as you can't get the same water capacity in them as you can in a cast head. However, as I have said, it was not an issue at Harewood, so something has gone wrong.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

do you use an electric water pump ?

No, I use a mechanical pump. It was new this winter (cast type). I have inspected it and there is nothing wrong with it.

As I don't run an alternator I need to keep electrical power consumption to a minimum.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I would highly recommend using an electric pump [ we used one on the KAD engine from Corley Conversions , ie Ben Bolt - he used to be on the HSA committee ]

it pumps , if I remember correct 25L/min and draws next to no lectric 0.6amp ? , we never ran an alternator and always duel drove , no probs .

It is a huge + in being able to leave it running for a few mins after a run , preventing heat soak into the head , especially with an alloy head and marginal head gaskets !! we used to leave the fan on as well , plug a jumper battery in if your worried about draining your battery.