Jabiru - Liquid Cooled Heads

[Vev]

I called into Rotec yesterday and took a look at their Liquid Cooled heads … very impressive

 

According to the guys at Rotec they said if they can get this to work as well as they hope it will fix any potential over heating or detonation problems in the Jab engine for good.

 

The guys started up their 6 cylinder test engine for me and ran it to demonstrate the effectiveness of the cooling. What struck me instantly was how much quieter it ran, I presume the water jackets around the head must dampen some of the over head engine noise.

 

After a short warm up the engine was loaded up to cruise power and then a full power over about a 30 min period… the CHT, oil and water temp remained well within in the green the whole time. In fact the oil temp may have been a little low in my view and might require some consideration around reducing the oil cooling.

 

Despite the current test radiator being probably bigger than required for operational in-flight use, there was very little air flow over the radiator, owing to its position of being mounted at the back of the engine on the test stand. It seemed reasonably logical to me that a smaller radiator mounted inside the cowl will be quite adequate.

 

They had an electric water pump fitted, which the Rotec guys said will have a thermo switch fitted, this will be good for start up on a cold engine to preserve battery power for turn over. I think I would also prefer a manual over ride on/off switch as a back up and to control power consumption at start up even on a hot engine.

 

The guys said they would look at a 4 cylinder version soon, as the exhausts ports on the 4 cylinder are 180 deg different to the 6 cylinder on 2 pots and needs a new head shape.

 

The rocker chest is based on the earlier narrow thick fined head, which should take all of the rocker configuration be it sold tappets or hydraulic lifters type. The new hollow push rods over head gear should fit too, but I think only just… personally, I would have preferred they had used the latest wider rocker chest configuration as I think this was an improvement and it takes all of the rocker configurations easily.

 

The aluminium material used is much more substantial and head crush from head bolt over torque shouldn’t be an issue … nearly all the Jab heads I have seen have some crush around the head/barrel interface, which I have presumed a combination of soft material and too much head bolt torque.

 

The guys at Rotec said they will be working with a few selected people to test the heads and see how they perform under operational conditions.

 

I guess time will tell but it does look quite promising.

 

Cheers

 

Jack

 

 

[Guest Michael Coates]

Good news.... lets hope they get it sorted out and to market !

 

 

[biggles5128]

Interesting to read your post Vev. I am very keen to find out from other users what they think of the Rotec heads. I have not contacted Jabiru to get their slant on it for obvious reasons. To me, it appears a logical solution to a few problems with this engine.

 

Would like to hear from those with a sound mechanical back ground on what they think. The other issue is that with all new things... time will tell.

 

Danny

 

 

[Guest Michael Coates]

I am also a little disappointed I have not heard back to much information about the liquid cooled heads. As we start to head into summer I imagine it will then become an important issue again for a lot of the jabiru owners. It would be great to get some information about how they are working and what sort of hours they are getting up on the aircraft. I just love hearing about new products

 

 

[dazza 38]

HI Left Seat, there are a few Videos on youtube in regards to the Liquid cooled heads from Rotec.They appear to be very good.

 

 

[biggles5128]

Thanks Dazza, had a look at them and it does look impressive. Thanks for the reply.

 

 

[dazza 38]

Thanks Dazza, had a look at them and it does look impressive. Thanks for the reply.

NO worries mate.I hope it has helped you.