Your explanation of everything going on with these heads and why, seems absolutely accurate to me. I wonder what his typical climb and cruise CHT were.
Been following you for awhile, have some mechanical acumen, but not a shop mechanic, yet every time you talk about a Jabiru, I know it’s about their soft aluminum heads. Starting to wonder why anyone would buy one unless they had already added the cost of water cooling conversion to the equation. Enjoy your videos, wouldn’t mind a few more Kitfox videos if you could fit them in. Love the yellowjack colors (an American wasp) with the R2800.
I don't doubt the superior cooling of Rotec WC heads on a Jabiru but this video misses the root cause of the problem. The stock Jabiru heads failed because they were overheated NOT because they were air cooled! Primary cause of air cooled cylinder heads overheating is running too high a CHT! Keep CHTs within conservative Lycoming limits (380F cruise/climb, 400F for 5 minutes MTO power) and air cooled heads won't have the problems shown in this video! Why is this so difficult? 1. Poor air ducting/cylinder baffling 2. Engines mounted in STOL aircraft with low air speeds and high AOA 3. Uniformed owners/operators following Jabiru SOP and monitoring CHT via a thermocouple fitting under the sparkplug vs. a thermocouple in a dedicated CHT hole in the head (50+F degree CHT increase from CHT probe "in hole" vs under spark plug) I think the Rotec WC heads are great and I'd put them on a Jab if I had one. However, one can still get reasonable service (certainly better than 120 hours) out of any Jab air cooled heads by investing in a multi-cylinder CHT monitor (with probes in the "right place") and limiting CHTs to 400F for MTO and 380F for cruise climb. If CHTs rise past limit, reduce the rate of climb or increase fuel, it ain't rocket science.
I solved the issue by putting the finest finned heads on (my 2200) and opening the front of the cowl, the heads stopped moving, pror to the change the heads would need regular tightening and valver adjustment.. I would have loved a set of Rotec heads though.
I assume the same applies to a 2200A? I have 160 hours since new and the last static leak down was within specification. I’m considering my options when a subsequent leak down indicates leakage due to the heads. How much extra weight would the liquid head system add? Also, I’ve heard of chronic issues with coolant leaks. Is this an issue that has since been resolved, assuming it was a product issue and not just isolated to a few?
Hi there, chronic coolant leaks? How the internet distorts reality! 12 years ago from one batch of heads a few (3) had some casting porosity, the issue was identified and quickly resolved. Never been an issue since. We back our heads for the overhaul life of the engine.
Yes the same applies for the 2200. Which has left and right mirrored heads so we had to make a reverse port head for the 2200. Where as the 3300 heads are all the same.
Just been through that with my vw, was running thin wall 1641 cylinders which ran too hot for the heads. Now I've replaced them with 1600 barrels. Used the same heads but cut them down 12 thou. Your heads would work very well on high hp vw engines.
I've reported you to the ruler abuse society lol.... That's pretty serious recession. I wonder if the head bolts are too ductile? Basically Cylinder hammered in. I've considered the Jab.. This problem gone with the Gen4 engines ya? Gen4 a decent engine overall? They are mighty expensive to have that much wear at such low time.
Excellent information and I am wondering' I know they are new, but is this still a problem with the Gen 4 heads?
Aaah the gift of Jabiru that just keeps on giving
Your explanation of everything going on with these heads and why, seems absolutely accurate to me.
I wonder what his typical climb and cruise CHT were.
Been following you for awhile, have some mechanical acumen, but not a shop mechanic, yet every time you talk about a Jabiru, I know it’s about their soft aluminum heads. Starting to wonder why anyone would buy one unless they had already added the cost of water cooling conversion to the equation. Enjoy your videos, wouldn’t mind a few more Kitfox videos if you could fit them in. Love the yellowjack colors (an American wasp) with the R2800.
I don't doubt the superior cooling of Rotec WC heads on a Jabiru but this video misses the root cause of the problem. The stock Jabiru heads failed because they were overheated NOT because they were air cooled! Primary cause of air cooled cylinder heads overheating is running too high a CHT! Keep CHTs within conservative Lycoming limits (380F cruise/climb, 400F for 5 minutes MTO power) and air cooled heads won't have the problems shown in this video! Why is this so difficult?
1. Poor air ducting/cylinder baffling
2. Engines mounted in STOL aircraft with low air speeds and high AOA
3. Uniformed owners/operators following Jabiru SOP and monitoring CHT via a thermocouple fitting under the sparkplug vs. a thermocouple in a dedicated CHT hole in the head (50+F degree CHT increase from CHT probe "in hole" vs under spark plug)
I think the Rotec WC heads are great and I'd put them on a Jab if I had one. However, one can still get reasonable service (certainly better than 120 hours) out of any Jab air cooled heads by investing in a multi-cylinder CHT monitor (with probes in the "right place") and limiting CHTs to 400F for MTO and 380F for cruise climb. If CHTs rise past limit, reduce the rate of climb or increase fuel, it ain't rocket science.
What generation 3300?
I solved the issue by putting the finest finned heads on (my 2200) and opening the front of the cowl, the heads stopped moving, pror to the change the heads would need regular tightening and valver adjustment.. I would have loved a set of Rotec heads though.
who manufactures your new designed liquid cooled heads ? I'm designing new performance heads for a different engine
I assume the same applies to a 2200A? I have 160 hours since new and the last static leak down was within specification. I’m considering my options when a subsequent leak down indicates leakage due to the heads. How much extra weight would the liquid head system add? Also, I’ve heard of chronic issues with coolant leaks. Is this an issue that has since been resolved, assuming it was a product issue and not just isolated to a few?
Hi there, chronic coolant leaks? How the internet distorts reality! 12 years ago from one batch of heads a few (3) had some casting porosity, the issue was identified and quickly resolved. Never been an issue since. We back our heads for the overhaul life of the engine.
Yes the same applies for the 2200. Which has left and right mirrored heads so we had to make a reverse port head for the 2200. Where as the 3300 heads are all the same.
Just been through that with my vw, was running thin wall 1641 cylinders which ran too hot for the heads. Now I've replaced them with 1600 barrels. Used the same heads but cut them down 12 thou.
Your heads would work very well on high hp vw engines.
Is this the Gen 4 engine?
Nope
I've reported you to the ruler abuse society lol.... That's pretty serious recession. I wonder if the head bolts are too ductile? Basically Cylinder hammered in. I've considered the Jab.. This problem gone with the Gen4 engines ya? Gen4 a decent engine overall? They are mighty expensive to have that much wear at such low time.
Sounds underfuelled and undercooled to me.