914

[rhtrudder]

Starting to wind a few hours up on my 914, looking at engine rebuild or replace , terrified of the cost, would it be possible to convert the 80hp 912 to a 914 by swapping all the 914 bits over , carbys airbox exhaust and turbo , worth a thought

 

 

[bones]

Starting to wind a few hours up on my 914, looking at engine rebuild or replace , terrified of the cost, would it be possible to convert the 80hp 912 to a 914 by swapping all the 914 bits over , carbys airbox exhaust and turbo , worth a thought

The motor would be the last thing that would need changing, the turbo will go before the motor.

 

 

[rhtrudder]

WE have turbo chargers on most of the engines on the farm with high hours , never given any trouble , but unsure of the life on the rotax

 

 

[Downunder]

Do 914's still have the 1500 hr tbo or was it lifted to 2000?

 

If compression, operational limits are still good and no metal in the filter, could you run it on condition?

 

Another option, if it is still in good condition, is to sell it and use that money towards a new engine.

 

I recon if you put it up for sale while still operational (so buyers could see it running) you might get some reasonable offers.

 

 

[rhtrudder]

Engine has 1400 hrs on it , compression down consistently on one cylinder over the last 200 hrs , guessing it's going past the rings , doesn't seem to be using any oil so I will keep flying it , just looking at all he options, I believe the 80 is a lot cheaper than the 115 and maybe keep the original for spares

 

 

[Downunder]

If you can aford an 80 outright, then look at the price difference between that and a new 914. 10 grand?

 

If you can sell your engine for $6 000 then you are only short $4 000 for a complete new 914.

 

 

[rhtrudder]

It's hard to see why it costs 10k to fit a turbo , doesn't look like it's that difficult

 

 

[Downunder]

Carbs are different I believe as they are pressurised in the 914.

 

I think if you used an 80 hp and swapped over the turbo parts, the inital cost would be a saving but as those parts started to fail and need rebuilding/ replacing you would lose in the long run.

 

Added to that, is the "risk" involved with over 1500 hr parts in operation. The core engine might be fine but other parts can "bring you down".

 

And in general, the world has evolved to the point where labour and parts costs make "replacement with new" a much more efficient and viable situation in the long run even taking into account interest paid on a loan.

 

I know someone who buys old cars because they are cheap. I call them pieces of sh*t.

 

He breaks down about on the side of the road about twice a year and they are always in the shop being repaired.

 

He throws money at them constantly maintaining them.

 

At the end of the day, they are still worthless POS.

 

I take out a loan and buy a new car. I plan on owning it for 10 years and write the purchase cost off against this time period.

 

It is nice and comfortable and doesn't break down. My costs are servicing and the odd set of tyres.

 

Because it is new, it is fuel efficient and safe.

 

I believe in the long run, I am far far ahead in reliability, efficiency, safety and costs......

 

 

[rhtrudder]

Still haven't given up on rebuilding my engine , heard they can last up to 3000hrs but am I bit disappointed on the compression loss

 

 

[planesmaker]

When you did the leak down where was it leaking? Exhaust or sump? Should not be difficult to rectify. What was the leak down figure?

 

Perhaps best to rectify rather than keep flying it

 

 

[rhtrudder]

First I wound the hot engine over on the starter to check what the compression looked like between the cylinders 3 at 125 last one at 110

 

Leak own test had more air coming through the tank than the other 3 , might not be a big deal to just change the rings, but only guessing

 

 

[planesmaker]

Rings are not difficult.

 

 

[bexrbetter]

Have a look down the plug hole with a scope, you can even get them for mobile phones now, see if it's a glazed bore or signs of leakage around the valves.

 

 

[rhtrudder]

I will give that a go

 

 

[rhtrudder]

Rings are not difficult.

How many hours have you got on your engine?

 

 

[planesmaker]

I only have about 200 however I have worked on many rotaxes, I doubt you will find any glazing. Not difficult to remove head and cylinder to replace rings, have a look in the maintenance manual(heavy). I really like my rotax 914 powered jab! What plane is your 914 in?

 

I have a 80 hp that I plan to install a small turbo then fit to a fox type aircraft, looking at 110-120hp.

 

 

[rhtrudder]

Engine fitted to a sabre , I'm the third owner , had 400 hrs up when I bought it, never had any issues with it, read somewhere the compression needs to be above 85 before a rebuild, if flying with one soft cylinder can that have any detrimental effect to the engine

 

 

[geoffreywh]

Please don't do that. It has to be in good working order, Pull the heads and barrels. Have a close look at the "soft" ( I would have said Fu##ed) cylinder. It'll be the rings or a valve...Not difficult.

 

 

[planesmaker]

What are the figures on a leak down test ? ?/80 psi then see what the rotax manual says is the limit.

 

Manual says max leak 25% ie 60 psi. Always perform leak down on warmed up engine.

 

 

[rhtrudder]

Thanks for the help , got to fly a mate to Griffith tomorrow so I will do the test on the hot engine and let you know,

 

 

[Downunder]

Just as a general question, can nickasil (or whatever) coated cylinders actually become glazed?

 

A friend with a motorcycle says he goes through 2 or 3 sets of rings (maybe pistons too) before the coated cylinder/ barrel gets replaced on his dirt bike.

 

I got the impression the cylinder linings are hard as f*** and the applicable rings were soft?

 

 

[rhtrudder]

Raced 2 stroke motocross bikes in enduros back in the early days , had some sort of chrome bores , only ever changed the ring and sometimes the piston, good air cleaner, the cylinder seemed to last okay

 

 

[rhtrudder]

Leak down test showed 65 lost from 80 psi , pulled the cross over pipe off definitely loosing air , so leaky inlet valve, rang wally who thought that would be the problem, should be a easy fix if comes apart.

 

 

[manna]

I have a rotax 912 ULS with 3200 hours on it I have been running in on condition for years. Complete a leak down every 100 hours, do a bore scope inspection and cut open oil filter looking for metal, and all is clean, the engine is still running without any issues. Leak down test is regular and is 76 - 77 over 80 PSI. My Engine has been run on Premium Unleaded for 90 % of its life with oil changes at 50 Hours, and spark plugs every 200 hours, unless I have run Avags in which case I change the oil at 25 Hours and spark plugs at 100 hours.

 

For my 2 cents worth, I would be looking to resolved issue with the one cylinder, particularly if it is valve blow by.

 

Cheers

 

 

[rhtrudder]

I was hoping my engine was going to last like yours , my maintenance program was similar to yours but I will be happy if this is the only trouble I have