Saito 90 ts Twin temperature
06-06-2010, 12:34 PM
#26
RE: Saito 90 ts Twin temperature
Something I have noticed about the Saito exhaust pipes.
On the ones with the pressure tap, whoever is brazing the pressure tap in is extending the tap all the way into the exhaust pipe until it bottoms out and then brazing it in place. This plugs up that exhaust pipe or at least severly restricts it.
This could effect the way the cylinder runs that has the pressure tap pipe on it?
On the ones with the pressure tap, whoever is brazing the pressure tap in is extending the tap all the way into the exhaust pipe until it bottoms out and then brazing it in place. This plugs up that exhaust pipe or at least severly restricts it.
This could effect the way the cylinder runs that has the pressure tap pipe on it?
06-06-2010, 01:32 PM
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RE: Saito 90 ts Twin temperature
ORIGINAL: w8ye
Something I have noticed about the Saito exhaust pipes.
On the ones with the pressure tap, whoever is brazing the pressure tap in is extending the tap all the way into the exhaust pipe until it bottoms out and then brazing it in place. This plugs up that exhaust pipe or at least severly restricts it.
This could effect the way the cylinder runs that has the pressure tap pipe on it?
Something I have noticed about the Saito exhaust pipes.
On the ones with the pressure tap, whoever is brazing the pressure tap in is extending the tap all the way into the exhaust pipe until it bottoms out and then brazing it in place. This plugs up that exhaust pipe or at least severly restricts it.
This could effect the way the cylinder runs that has the pressure tap pipe on it?
Good point, w8ye. I have the pressure tap pipe on the rt hand cyl. I could try moving it to the left to see if it makes a difference.
Kimhoff- your right about that. My OS 160 twin rarely drops a cylinder. In fact, I don't use an OB glow driver for it.
06-06-2010, 06:03 PM
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RE: Saito 90 ts Twin temperature
I had already swapped over the exhaust- made no difference.
Also tried the turbo muffler exhaust - no difference.
How did the maiden flight go?
Also tried the turbo muffler exhaust - no difference.
How did the maiden flight go?
06-06-2010, 09:57 PM
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RE: Saito 90 ts Twin temperature
ORIGINAL: yachty
I had already swapped over the exhaust- made no difference.
Also tried the turbo muffler exhaust - no difference.
How did the maiden flight go?
I had already swapped over the exhaust- made no difference.
Also tried the turbo muffler exhaust - no difference.
How did the maiden flight go?
The engine performed admirably, no flame-outs and it flew the Cessna very "scale-like", as they say.
It was very windy, with strong gusts, but we managed to get 2 flights in. I was just about to fly again with the lights hooked up, and it started to rain. Me thinks this one is a keeper!
J.
06-08-2010, 05:21 AM
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RE: Saito 90 ts Twin temperature
Just an update
I posted the engine back to the US yesterday (Monday). It should be delivered to Horizon on Thursday.
So far they are very helpfull, so i will let everyone know the outcome as it develops in the hope it may help someone else.
Steve
I posted the engine back to the US yesterday (Monday). It should be delivered to Horizon on Thursday.
So far they are very helpfull, so i will let everyone know the outcome as it develops in the hope it may help someone else.
Steve
06-19-2010, 11:34 AM
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RE: Saito 90 ts Twin temperature
Steve,
I look forward to hearing what they do with your engine.
Meanwhile, I've been flying the Cessna w/ 90TS, with good success. Started w/ 13 X6 prop, then 13 X 8, and I think best prop for plane/engine combo is 14 X 6.
The engine is becoming more and more reliable at low idle, without glow assist on. The midrange is a little rough yet, and I may try to tweak the low needle some, but I'm happy with it's performance overall, and confident it will get better w/ more run time. So far, I have close to 4 hrs. on it.
[youtube]http://www.youtube.com/watch?v=GmQvQtRyHos[/youtube]
I look forward to hearing what they do with your engine.
Meanwhile, I've been flying the Cessna w/ 90TS, with good success. Started w/ 13 X6 prop, then 13 X 8, and I think best prop for plane/engine combo is 14 X 6.
The engine is becoming more and more reliable at low idle, without glow assist on. The midrange is a little rough yet, and I may try to tweak the low needle some, but I'm happy with it's performance overall, and confident it will get better w/ more run time. So far, I have close to 4 hrs. on it.
[youtube]http://www.youtube.com/watch?v=GmQvQtRyHos[/youtube]
06-19-2010, 04:31 PM
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RE: Saito 90 ts Twin temperature
Jai,
The plane looks and sounds great!
I reckon you will have a great time with it.
The engine is with horizon at the moment and a tech is looking at it.
Should hear this week.
Steve
The plane looks and sounds great!
I reckon you will have a great time with it.
The engine is with horizon at the moment and a tech is looking at it.
Should hear this week.
Steve
06-23-2010, 03:55 PM
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RE: Saito 90 ts Twin temperature
A update on my engine.
I spoke to Horizon today, The noise i had was the bearing at the camshaft. When they opened the engine there were balls everywhere.
So that takes care of why i had noise, just a faulty bearing they said.
They also cant get to the bottom of why rhe RHS cylinder is running cold, they have swapped the carby twice and even a new piston and ring.
I has got them completely stumped. Exept that it is running very rich on that cylinder. That i new already. Why they dont quite know and will send it back to Saito.
Horizon are going to send a replacement to me however they are out of stock and wont be another month before they arrive. Oh well!
Ive got nothing but praise for Horizon in the way they handled the claim, and the proffesional way they dealt with me personally. I have heard only good things about Horizon it is a credit to the company and employees.
Lets hope the new one works better
Steve
06-29-2010, 02:16 AM
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RE: Saito 90 ts Twin temperature
I might be going mad ! I hope not. But the 90ts only has a single camshaft, with 2 lobes, one for inlet and one for exhaust. If thats right then only one of the cylinders pushrods can only be at the top of the lobe at a time?
Again if thats right then there is a slight timing difference as to when the intake valve would open for each cylinder.
Therefore if both valve tappets were set with exactly the same gap then one cylinder would be rich compared to the other?
Does this make logical sense?
I realise that the time that both would be open is the same . however the piston would be on a slightly different part of its stroke and could cause one to induct more fuel.
Im just trying to make sense as to why one would be richer than the other.
Regards
06-29-2010, 04:51 PM
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RE: Saito 90 ts Twin temperature
Thanks W8we,
Im just trying to work out how the engine works.
Maybe if i you could tell me if im right if i number each statement.
1. The inlet valves for each cylinder open at different times.
2. Then each cylinder would have use of the carby at different times
3. The valve open time is what meters the ammount of fuel to each cylinder - depends on ammount of lash.
The reason i ask is i dont have a total understanding of how engines work, also horizon were unable to fix the cause of one cylinder running very rich.
Ther have been several issues with others that have had the same problem. I have not been able to track them down though.
It would be nice to get an understanding as to what is happening here as it may help others in the future should it happen again.
Noone has been able to offer any technical reason as to what it may be, all just say they are sweet engines. Mine didnt run sweet and the repairers were unable to find out why.
I realise i will get a new engine but that doesnt cure my curiosity as to what may cause it.
Regards
Steve
Im just trying to work out how the engine works.
Maybe if i you could tell me if im right if i number each statement.
1. The inlet valves for each cylinder open at different times.
2. Then each cylinder would have use of the carby at different times
3. The valve open time is what meters the ammount of fuel to each cylinder - depends on ammount of lash.
The reason i ask is i dont have a total understanding of how engines work, also horizon were unable to fix the cause of one cylinder running very rich.
Ther have been several issues with others that have had the same problem. I have not been able to track them down though.
It would be nice to get an understanding as to what is happening here as it may help others in the future should it happen again.
Noone has been able to offer any technical reason as to what it may be, all just say they are sweet engines. Mine didnt run sweet and the repairers were unable to find out why.
I realise i will get a new engine but that doesnt cure my curiosity as to what may cause it.
Regards
Steve
06-29-2010, 07:52 PM
#42
RE: Saito 90 ts Twin temperature
First of all, on this twin, you get a power impulse every time the prop goes around but the cylinder firing alternates. The cam turns half the speed of the crankshaft so the cam lobes are aligned on the left cylinder one revolution and the right cylinder the next revolution. Except for any difference in valve clearance, the valves will open the same amount and for the same duration.
ORIGINAL: yachty
Thanks W8we,
Im just trying to work out how the engine works.
Maybe if i you could tell me if im right if i number each statement.
1. The inlet valves for each cylinder open at different times. The valves opening alternates from one cylinder to the other each revolution because the cam rotates at half the speed of the engine.
2. Then each cylinder would have use of the carby at different times You are correct, one revolution it is the left cylinder and the next revolution iot is the right cylinder.
3. The valve open time is what meters the ammount of fuel to each cylinder - depends on ammount of lash. This is correct
The reason i ask is i dont have a total understanding of how engines work, also horizon were unable to fix the cause of one cylinder running very rich.
Ther have been several issues with others that have had the same problem. I have not been able to track them down though.
It would be nice to get an understanding as to what is happening here as it may help others in the future should it happen again.
Noone has been able to offer any technical reason as to what it may be, all just say they are sweet engines. Mine didnt run sweet and the repairers were unable to find out why.
I realise i will get a new engine but that doesnt cure my curiosity as to what may cause it.
Regards
Steve
Thanks W8we,
Im just trying to work out how the engine works.
Maybe if i you could tell me if im right if i number each statement.
1. The inlet valves for each cylinder open at different times. The valves opening alternates from one cylinder to the other each revolution because the cam rotates at half the speed of the engine.
2. Then each cylinder would have use of the carby at different times You are correct, one revolution it is the left cylinder and the next revolution iot is the right cylinder.
3. The valve open time is what meters the ammount of fuel to each cylinder - depends on ammount of lash. This is correct
The reason i ask is i dont have a total understanding of how engines work, also horizon were unable to fix the cause of one cylinder running very rich.
Ther have been several issues with others that have had the same problem. I have not been able to track them down though.
It would be nice to get an understanding as to what is happening here as it may help others in the future should it happen again.
Noone has been able to offer any technical reason as to what it may be, all just say they are sweet engines. Mine didnt run sweet and the repairers were unable to find out why.
I realise i will get a new engine but that doesnt cure my curiosity as to what may cause it.
Regards
Steve
06-30-2010, 01:26 AM
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RE: Saito 90 ts Twin temperature
Thanks w8ye,
I really appreciate your help in helping me understandi how the engine works.
So am i right that this is a Boxer type engine, but if i understand you correctly thenwhen both pistons are nearing TDC, only one cylinder is on the compression stroke and about to fire while the other one is completing the exhaust stroke and is ready for the induction stroke?
Regards
Steve
I really appreciate your help in helping me understandi how the engine works.
So am i right that this is a Boxer type engine, but if i understand you correctly thenwhen both pistons are nearing TDC, only one cylinder is on the compression stroke and about to fire while the other one is completing the exhaust stroke and is ready for the induction stroke?
Regards
Steve
06-30-2010, 04:07 AM
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RE: Saito 90 ts Twin temperature
w8ye,
Now ive started to get it!
Given all this then the problems with the engine could have been a lean (air leak on the intake manifold) cylinder,as the needle valve would only be adjusted in until it started to run on it. And the other one left running very rich. Or incorrect valve lash?
The bearing failure on the camshaft could indicate poor lubrication down there! (from being lean)
I know all this is irrelevant now, but its good to know for another time.
Thanks again for your patience and help.
Now ive started to get it!
Given all this then the problems with the engine could have been a lean (air leak on the intake manifold) cylinder,as the needle valve would only be adjusted in until it started to run on it. And the other one left running very rich. Or incorrect valve lash?
The bearing failure on the camshaft could indicate poor lubrication down there! (from being lean)
I know all this is irrelevant now, but its good to know for another time.
Thanks again for your patience and help.
06-30-2010, 07:18 PM
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RE: Saito 90 ts Twin temperature
I have a Saito 90TS that would drop a cylinder when doing rolls. I added a Cline regulator and the problem went away. However the port cylinder ring broke, the chrome plating peeled and I sent the engine back to Horizon for service. They replaced the bad piston, ring and cylinder with a good used set. BTW, my engine would spin a APC 14x6 @ 9000 rpm on 10% nitro.
07-30-2010, 08:54 AM
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RE: Saito 90 ts Twin temperature
hi Guys,
Well im not so sure now about Horizon hobby support any more. The story goes on
They received my engine 10th June
On the 15th June iwas told they would send me my new engine on the 19th July.
On the 20th July they said it would be 27th July
On the 25th July they said Early August
On the 29th July they said middle August
On the 30th July they now say MIDSEPTEMBER!
That means waiting over 3 months for a warranty on my brand new engine even if it arrives when they say- which i doubt!
I have made many phone calls from Australia as they do not keep me informed, which is both expensive and inconvenient as i have to ring at 2.30am. I have tried email but they ignore them.
What would you do or expect under these circumstances,?
Steve
Well im not so sure now about Horizon hobby support any more. The story goes on
They received my engine 10th June
On the 15th June iwas told they would send me my new engine on the 19th July.
On the 20th July they said it would be 27th July
On the 25th July they said Early August
On the 29th July they said middle August
On the 30th July they now say MIDSEPTEMBER!
That means waiting over 3 months for a warranty on my brand new engine even if it arrives when they say- which i doubt!
I have made many phone calls from Australia as they do not keep me informed, which is both expensive and inconvenient as i have to ring at 2.30am. I have tried email but they ignore them.
What would you do or expect under these circumstances,?
Steve
