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Old 04-05-2024, 06:06 AM
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Originally Posted by Glowgeek
Very nice Aidan, thanks for the vid! A little close to that tree?......we have special trees here that will reach out and snatch our planes out of the air if we get very close.

Ireland IS beautiful, I very much enjoyed my stay there. Some of the lynx courses were very tough there and in Scotland.
Thanks Glowgeek for your kind comments. Yes, too true, the trees are always there to be watched out for. Believe it or not there's a few things I've never done in my 60 years on this planet and playing golf is one of them. I live in a small country town with two golf courses and another just 6 miles down the road.
Old 04-05-2024, 06:09 AM
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Less time golfing, more time flying.
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Old 04-05-2024, 06:15 AM
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Originally Posted by Glowgeek
Less time golfing, more time flying.
Maybe one day I might hit a golf ball, but for the meantime the flying comes first. Lol
Old 04-05-2024, 07:09 AM
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Originally Posted by Jim Branaum
Easier and cheaper to not polish the rod. And it looks to me like they moved the oil pick up hole from the rod to bearing web to the bearing carrier area. Might be interesting to mic the thickness of the rod journal as it appears to be thicker in the newer version.

Not a machinist but I used to build up engines from junkyard salvage.
Thanks Jim, the bearing portions of the rods are same width, the beam part is wider on the later/right. one, it's also a cruder finish.
Old 04-05-2024, 07:57 AM
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Default FA 150 (stamped "E")

Deleted the pics with measurements. I just realized that the seller didn't know what he was selling. I supposedly bought 2 150's but the one with no label is a 180! 36mm bore.

I'll have to tear down the other engine and send new pics.

Last edited by Glowgeek; 04-05-2024 at 08:06 AM.
Old 04-05-2024, 10:45 AM
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Personally, I would replace that prettier, "early" connecting rod with the beefier updated rod, just as Saito did!
That oil hole is perfectly wrong, both as an oil feedpoint and the location being in a high stress location.
Old 04-05-2024, 05:17 PM
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Four nice NIB Saito singles for sale. The 150S GK has silver rocker covers and no stamp on the lug. A high compression version for certain!

https://www.rcgroups.com/forums/show...-NEW-%21%21%21

Last edited by Glowgeek; 04-05-2024 at 05:35 PM.
Old 04-06-2024, 03:13 AM
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Current offering, at 58 bucks replacing the factory rod is not happening.

The current offering is more polished than the rod on the right. The left rod is a proven component, so it's staying.

Saito 100 rod, woops, wrong 100.

Saito 82 rod
From engine to engine, almost none of the Saito rods are the same.
Old 04-06-2024, 04:03 AM
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Originally Posted by Jesse Open
Personally, I would replace that prettier, "early" connecting rod with the beefier updated rod, just as Saito did!
That oil hole is perfectly wrong, both as an oil feedpoint and the location being in a high stress location.

The location is ok imo, as long as there is only one oil feed hole, deburred, and it's opposite the compressive load side of the journal. Rods rarely fail under compressive loads unless undersized. Most rod failures occur under tensile loads at TDC of the exhaust stroke.
Old 04-06-2024, 09:55 AM
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Dave, I have numbers for the 150. Will upload when this site cooperates.
Old 04-06-2024, 09:59 AM
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Originally Posted by Glowgeek
The location is ok imo, as long as there is only one oil feed hole, deburred, and it's opposite the compressive load side of the journal. Rods rarely fail under compressive loads unless undersized. Most rod failures occur under tensile loads at TDC of the exhaust stroke.
Yes, that part applies to the compessive vs tensile load carrying ability of the rod beam.
The con rod loading is still largest during the compressive load during the power stroke.
That oil hole is smack in the area of many rod failures.
As I said earlier , It is also smack in the wrong place for hydrodynamic oiling on the journal.

It seems Saito agreed and made appropriate changes.


Last edited by Jesse Open; 04-06-2024 at 10:34 AM. Reason: Added pic of OS bronze rod
Old 04-06-2024, 10:01 AM
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Default FA-150 (Stamped "B") on the lug

Here ya go, Dave. Let's compare numbers between your high compression 150 and my later version.

My piston is flat topped with valve reliefs
Back plate has one nipple boss
Height-wise, the combustion chamber goes straight across from the left and right edges of the two valves. (Not recessed)










Last edited by Glowgeek; 04-06-2024 at 10:04 AM.
Old 04-06-2024, 06:43 PM
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you know, I had a Zinger 9x4. my god, it was lighter than air.
Old 04-06-2024, 06:45 PM
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Originally Posted by Jesse Open
Yes, that part applies to the compessive vs tensile load carrying ability of the rod beam.
The con rod loading is still largest during the compressive load during the power stroke.
That oil hole is smack in the area of many rod failures.
As I said earlier , It is also smack in the wrong place for hydrodynamic oiling on the journal.

It seems Saito agreed and made appropriate changes.
What is that, one of those under engineered weak OS twin brass or aluminum rods?

Could be as you say OR.....Who's to say the bottom of the rod didn't stretch first, distorting beyond it's metalurgical elasticity, losing oil pressure, overheating and then beating the bottom of the journal off of the beam? That's the most common sequence in connecting rod big end failures according to experts in fatigue analysis. I'm not one of those experts.....I'm also not a prophet.
Old 04-06-2024, 07:24 PM
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Lonnie,
That oil hole is in the wrong place to support proper hydrodynamic oiling for the crankpin journal.
I am in agreement with the improvements Saito experts made over the early version. Also noteworthy; they did not go back to that location.
Not a prophet, I just doubt they will.

The rod is an O.S.160 Gemini bronze rod.
It and it's mate were replaced over 20 years ago with a pair of aluminum rods. Still runs fine to this day. Despite whacking the conrod, the crankpin had no signs of lube failure.Likewise the bearing surfaces of the rod. The engine was running a too small prop and the rod let go in a high speed dive.

Last edited by Jesse Open; 04-06-2024 at 07:36 PM.
Old 04-06-2024, 07:25 PM
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Looking in my junk that is mostly picked up from swap meets I found a Saito 80 with a broken cam housing. This 80 is the original high compression version with the hump on the piston. This engine was a mess. I started to look to see if I had another cam housing.

I had a box of 120 parts and that cam housing is much larger.

Next I looked at a FA-50 cam housing and it looks the same as the FA-80 cam housing. I even fit the FA-80 cam in the FA50 housing with no problem.

Here is where I get confused. The FA-80 cam housing is SAI6533B. The FA-50 is SAI5033A.

What is the difference between the two cam housings?


Old 04-06-2024, 07:38 PM
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Measure the distance from the pin centerlines to the flanges on both.
IIRC they are different.
Old 04-06-2024, 07:42 PM
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Yep, probably took only a split second to frag once the big end distorted. Near instantaneous heat generated.

I often thought about how amusing it would be to underprop a medium case OS to see whether the valves float or the big end frags first. I have an OS fs70S that would serve as a good martyr.
Old 04-06-2024, 08:07 PM
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Not likely a lube failure. The RPM limit is impaired by the added mass of the bronze rod.
The bronze bearings are more tolerant of oiling issues than the aluminum versions. They are also stronger.
The forces at turn around rise sharply with the increased weight of the bronze rod. The aluminum rods often make noise quite a while before they let go.
Old 04-06-2024, 08:35 PM
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Gary, you are correct on the cam housing. After measuring I can see the pin location is different.
Old 04-07-2024, 02:53 AM
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Originally Posted by modeltronics
Gary, you are correct on the cam housing. After measuring I can see the pin location is different.
Pete, the 65, 80 & 91S share the same case size. I have a spare camgear housing for a 91S in good shape. What's the distance from the bottom of the camgear pin hole to the bottom of the camgear housing on your junkyard 80?

Last edited by Glowgeek; 04-07-2024 at 05:12 AM.
Old 04-07-2024, 03:14 AM
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A victim of rust.

This 56 is now a beautiful black and shiny.

Old 04-07-2024, 07:05 AM
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Lonnie
It looks like the 91 and the 80 use the same part number cam housing. I'm interested in the spare you have.
Old 04-08-2024, 01:52 AM
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Default Wy8e comments on 150S vs. 150

Dave, I stumbled on this thread this morning. In post #12 Jim reveals an interesting bit of info! Looks like I now have one more measurement to take!

Saito 150S & 150H whats the difference?



Deck Height on my 150 (stamped "B")

Last edited by Glowgeek; 04-08-2024 at 08:05 AM.
Old 04-08-2024, 07:37 PM
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What about the cylinder?

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