Broken Wings

My Feedback: (20)

The little 40A came in the mail today. Here it is next to a AX.35....

Any Pre-Run-In tips? [sm=thumbup.gif]

w8ye

My Feedback: (16)

I like to run the first tank as rich as I can to flush the junk out of the engine. After that I try to work on getting the needles set well enugh to get it in the air. After playing with the low speed needle I back off the high speed needle from peak a little.

In the air, I don't run full throttle but a sec or two until it gets some time on it. As it limbers up, I have to touch up the needles a little.

The 40 should do pretty well with a 11 X 6 from the beginning.

Rudolph Hart

Exactly what jim says above to run one in..

Pre-run-in tips?? i'm sure there are plenty of answers here.Mine is make sure you bolt it down properly.Don't rush it or you may have an unauthorised first flight while still in the shed,just like i did,it's exciting

Hobbsy

My Feedback: (102)

PU, there can only be about two reasons for having a vague HighSpeed needle, either the LowSpeed needle is too lean or the prop is too large. The rocker arm adjustment will have little to no effect on the needle settings. If the LS needle is set too lean it renders the HS needle ineffective. Its an easy fix, back the LS needle out about 1/2 turn, set HS needle at absolute peak, then set LS needle for best transition, sometimes the best transition setting will not give the slowest idle.

John, that little Saito .40 is a piece of cake to break in and in fact will act very much like it doesn't need any break in. You'll be surprised at its "big engine" sound

blw

My Feedback: (3)

This will be a nice running engine once you get it tuned. I like the sound of them when they are full throttle.

Rudolph Hart

Hi dave was reading a thread in the tacho readings forum 'wow saito 220' and lots of good info mixed in.What did you end up doing with your one?

tacx

My Feedback: (1)

Hey Everyone,

Glad to be a new member. Got a question. I had to install a new cam gear in my 220. It seemed to go into place OK, with the crank at TDC and the timing mark at 6 O'clock, but I was wondering if there is a way to check it now that the engine is all together?

Thanks

Tom

w8ye

My Feedback: (16)

Yes,

With the valve covers off

Turn the crankshaft to Top Dead Center but not on the compression stroke.

The point where both valves are open the same amount sould be about 5 degrees before top dead center. One valve will be closing and the other opening.

tacx

My Feedback: (1)

w8ye, Thanks.

As I had mentioned in an earlier post, I had to replace the cam gear because the old one had lost 4 teeth. The engine seemed to be running OK in flight when it just quit, at which time I discovered the missing teeth problem. After replacing the cam gear I checked the valve clearence and was shocked to find both gaps to be way to large. I thought maybe the adjusting screws and jam nuts would not be tight, but they were both tight. The gaps were close to 1/16th inch? With that large of a valve gap I am surprised the engine even ran. Could these large valve gaps have caused the cam to have teeth stripped off? Just curious because I would like to figure out why the cam lost teeth.

Thanks

Tom

mike early

It would have to be kick-backs.

w8ye

My Feedback: (16)

The large valve gaps most likely contributed to the broken teeth.

Also this brings up the probability that your cam followers may be worn?

The cam follower wear is easy to spot as there is usually pitting and or uneven wear associated with the problem.

You can also put them next to each other and one is likely more worn than the other

The bottom wear surface should be smooth across and slightly rounded on the edges.

Hobbsy

My Feedback: (102)

It is just sitting on my work bench, I no longer have a plane for it. Maybe somedays I'll be able to get another Cessna 182 for it.

Hobbsy

My Feedback: (102)

Jim, this is the best I could determine when the valves are open the same amount during the overlap period.

w8ye

My Feedback: (16)

That's the way it should look

Konrad

Guys,
I just got back from a visit back home. I took the opportunity to look into some of my engine storage crates (the good engines) and found this Saito 1.30. I have some questions. When and on what models did Saito start to use aluminum valve seats in the small bore heads? As Saito free pours (not pressure injected or centrifugally forced) the aluminum the cylinder are prone to pockets of porosity. If the aluminum valve seat cuts into one of these pockets of porosity The valve will never seal. I know that all my big bore heads had aluminum seat from the 1.20 through the 300. All mine, not all Saito big bores

I've heard that Saito now casts the valve covers out of plastic. If this is so when did this cost saving feature start? All my Saitos still have aluminum valve covers.

And last how does the performance of this 1.30 twin compare to comparable Saito of today?

Note;
The cylinders close ups are of the 1.30 cylinder. The one is showing massive porosity in the exhaust port (the valve still seals). The other photo shows that the 1.30 cylinder uses aluminum valve seats. Also notice that one of the dual glow plug treads uses a brass insert.

Edited: To add note.

Hobbsy

My Feedback: (102)

Konrad, I think that one guy made the errant statement about the rocker covers being plastic and was soon corrected. No one seems to have issues with the valve seats.

w8ye

My Feedback: (16)

Konrad,

You need to look at your engines some more?

Konrad

I wasn't making an issue over the fact that the valve seats are aluminum (I like the aluminum seat for heat transfer). My concern is, if you see porosity in the head that one needs to test that there is none across the valve seat. By the way Saito has been very good about warranty coverage should one get an engine that has porosity across a valve seat. What I'd like to know is what models have this potential issue. One of my big head 1.20s and GK1.50s had these issues. The 1.30 and both 300 did not.

Attached is a photo showing that the big head has an aluminum valve pocket, and therefore per Saito's standard practice it would have an aluminum valve seat (note the small brass valve guide). This is as far as I was willing to take apart my 1983/84 big head 1.20. I also learned that Saito has changed the valve pocket since the days of the big head. I'll draw up a sketch showing what I found (I like the older pocket design a lot better).

I just finished reading the sticky note about Saito engines. Can anybody confirm that the AAC cylinders actually have chrome seats? I looked at a few ABC cylinders and can say that they are in fact aluminum valve seats for the big head 1.20 and GK 1.50.

All the best.

P.S.
Anybody have any performance data or personal experience with the little 1.30 twin?

Edit: To add second hopefully larger photo to show detail. Note the inlet valve is showing some light surface rust from not being run for 20 years

Broken Wings

My Feedback: (20)

Could it be that you're thinking about a model for one of these engines? Its been over a decade...

Konrad

Why, what am I missing?

All the best,
Konrad

Konrad

Good lord no. There is no need to contaminate a good new model with slime! [X(]

I'm just interested in learning about what I have and sharing what I know.

All the best,

Konrad

P.S.
BW,
the issue isn't what I think or am thinking to do. But rather Saito engines in this thread. Please keep it on topic!

Broken Wings

My Feedback: (20)

"I'm just interested in learning about what I have and sharing what I know. The issue isn't what I think or am thinking to do."


If you say so..............

Rudolph Hart

You might be missing the sound of them running?

Konrad

How would looking closer have any relevance to sound?

What I'm looking for is knowledge.

The sights, sound, tastes and smells of our toy engines has been lost to me for decades. Now the sight and sounds of a prop out running any other prop on less input power, that is a sight to behold! That is why I now fly electrics with thermal efficiencies for the motor being from 60% to 92%. Slime power [X(] can't hold a candle to this with its max thermal efficiencies being around 20% , more like 8%! [X(] Now I did give slime power 2 decades of my life trying to get the most from them and I had some success. It is time to put away the toys of ones youth and grab some real power, or more precisely embrace a new power source.

FYI;
"Slime power" is a self-deprecating term we engine guys use to describe glow ignition engines.

All the best,

Konrad

P.S.
Guys,
Keep it about engines not my flying habits!

Konrad

While on the subject of Saito valve seats here are some of my finding I published on the other site. I have to thank a guy named "I Tobor" (Hobbsy? here) for getting me to look at this. We were have a discussion about chromed valve seats.

The report starts here:
Here is a crude drawing of what I saw under the Scanning electron Microscope (SEM). Please note I’m not a metallurgist nor did I do an extensive study. When I looked at the 2 heads in the SEM all I wanted to learn was; is there plating in the large bore Saito valve seat, there isn’t. I did not take any digital photos nor did I save (write) any of the spectrum plots. As I didn’t want any records that could be traced to this project.

The conclusion is that there is no chrome plating in the valve seat. The spectrum did show chrome, but the SEM operator said it was to be expected as it was noise (electron bounce) from having to look down inside the chrome cylinder bore. He did show me some microscopic particles imbedded in the seat that came from the cylinder wear (neat stuff).

The angles are approximations as I did not do any cross sectioning of the head.

The aluminum grain structure is horrible as there are a lot of oxides and voids in the matrix. Again I’m no metallurgist this is from what the SEM operator was telling and showing me.

Just to be clear it would be very difficult to plate the valve seat, as one would need to have a very accurate masking process for both the zinc strike and chrome plating process. Also as chrome does not lie down evenly the seat would need to be ground to finish size.
I can tell you that looking at the tool marks the valve seat is cut by a shaped cutter not a grinding wheel.
One last point if the Saito did chrome the valve seat I’m sure they would advertise it, as it would be a heck of an achievement.
I would have to say I see no benefit to a chrome seat as I would think it prone the thermal shock and would dis-bond in a hurry. Also the plating would impede thermal transfer from the valve to the head.
Again the heads I looked at, a used big head Saito 120 and a new Saito 150 both of an ABC construction do NOT have chrome plating in the valve seat. The seat is cut directly into the aluminum head with a shaped cutter.

Please note the very small raised seat (approximately 0.006 x 0.040””) any attempt to lap the seat will most likely remove this feature. Loss of this feature will result in less flow across the valve seat at low valve lifts. I strongly recommend one do NOT lap the seat to the valve. If you must lap the seat I would use an abrasive close to that of tooth past (as just a cleaner).

All the best,

Konrad