For ST .46 Experts

Does the head on this one look correct?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3143486584

Thanks.

I just looked at mine and it does look the same only mine isn't black anodized. Mine has the same (approx. 1/8" gap) between the case and the head.

I bought a used CL Tigre with a Black head a couple of years ago. Haven't done anything with it and not sure if it is a rework or somebody just anodized the head for grins.

I guess I am one of there experts so here goes. The head is not stock on the outside. The fins have been shaved to 1/8" and rounder on the edge. Also some material has been removed from the lower outside egde of the head to lower weight. This area is on the bottom of the head outside the compression surface.I did these mods for years but I have never seen a black one. Many people did these mods and hemied the head when they were droping the sleeve. The pictured motor looks like a NIB st/46.
Ed Ruane
I looked at the picture again and the sleeve is not dropped.
Ed

It might be a Randy Smith head. If the picture showed the top I could tell you for certin. The plug is offset from center. The head works great.

I looked at that engine also but lost interest when the price got so high. I could buy three OS LA 46'S or one of Len's Magnum/ASP SSW 53's and have change left over.

Seeing what this one sold for, I think that it's time to fire up the old time machine, go back to an appropriate time and buy a bunch at full bore retail.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3143486584

It would definitely help the old retirement fund.

>Seeing what this one sold for, I think that it's time to
>fire up the old time machine, go back to an appropriate time
>and buy a bunch at full bore retail.
>
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3143486584
>
>It would definitely help the old retirement fund.

No kidding! Last one I bought was for $75 brand new. $200+ is way too much to pay for an ST46 if your only goal is getting a stunt motor for flying. Collectors, that might be another story, but with the after-market head, then even this seems a little suspect.

Here is another point to consider when buying a motor this old.Many of these old NIB st46 motors have froze wrist pins. They have sat so long that the wrist pin have become part of the piston.Two years ago some friends bought NIB st46 motors and they didn't run well. They new I used to rework them so they gave them to me to look at. Three motors had the ring frozen to the piston.Yes I know all the tricks for getting out frozen or stuck wrist pins.The wrist pin could not be driven out with a hammer.Frozen solid.Many people selling these motors on ebay will say runs great and has great compression,but the motor will run but the rod will wear out fast and it will be low on power.If you want a st46 buy it from a friend or someone who does rebuilding and can tell you it's a good motor.That motor on ebay was a early single ring and that was the best of the series.Like Brett says go buy a modern stunt motor or two for that price.
Ed Ruane

>Ed Ruane was saying: ...That motor on ebay was a early single ring and that
>was the best of the series.

Although I don't recall actually seeing one of them made that way, G. Aldrich always told me that the earliest G21-46 had a straight bypass, and THAT one was the best of them in his opinion (also, he would say that it was much more economical on fuel mileage - which was a minor complaint I had about mine). The one with the odd head in the auction had the flared bypass shape just like the 46's that I've used & still have.

.
Kiwi

>>Ed Ruane was saying: ...That motor on ebay was a early single ring and that
>>was the best of the series.
>
>Although I don't recall seeing them made that way, G.
>Aldrich always told me that the earliest G21-46 had a
>straight bypass, and THAT one was the best of them (also, he
>would say that it was much more economical on fuel mielage).
> The one with the odd head in the auction had the flared
>bypass shape just like the 46's that I have.
>

With all due respect to George, the bypass shape is close to irrelevant. The one and only thing that really matters about ST46's is having a good ring. The earlier rings were indeed better/harder and seated in better, and lasted forever. The late run rings (after about 1980) were far too soft, wore out in a heartbeat (as little as 20-30 flights for the power to fall off noticably), and never really sealed. I have taken the magic "0315" rings (early production packages only had the last 4 digits of the part number, instead of the later production rings that had the entire part #), put them in a last-run (1982 or so) motors, and instantly they came to life.

The only other weak point is the head gasket. After a while. particularly when you got them from R/Cers, the gasket compresses and gets too thin, thus raising the compression. If you have a good ring, and it starts sputtering or cutting off in flight, replace the head gasket with a brand new one, and it will run properly again.

The rest of it - "porkchop" vs. "stuffer" cranks,"thick" vs. "thin" liner, "hemi" vs. "button", and on and on, is just re-arranging deck chairs on the Titanic unless you had a good ring, and once you had a good ring, you could do just about anything to the motor and it would respond well.

>Here is another point to consider when buying a motor this
>old.Many of these old NIB st46 motors have froze wrist
>pins. They have sat so long that the wrist pin have become
>part of the piston.Two years ago some friends bought NIB
>st46 motors and they didn't run well. They new I used to
>rework them so they gave them to me to look at. Three motors
>had the ring frozen to the piston.Yes I know all the tricks
>for getting out frozen or stuck wrist pins.The wrist pin
>could not be driven out with a hammer.Frozen solid.Many
>people selling these motors on ebay will say runs great and
>has great compression,but the motor will run but the rod
>will wear out fast and it will be low on power.If you want a
>st46 buy it from a friend or someone who does rebuilding and
>can tell you it's a good motor.That motor on ebay was a
>early single ring and that was the best of the series.Like
>Brett says go buy a modern stunt motor or two for that
>price.
>Ed Ruane
Just looked at a few that I have managed to acquire over the years. Two early ones without muffler mounting lugs have single rings as do two with lugs but a third with lugs has two rings. How many variations are there and are all the parts interghangeable as a couple of mine are a bit tatty!
thanks

No kidding! Last one I bought was for $75 brand new.
>$200+ is way too much to pay for an ST46 if your only goal
>is getting a stunt motor for flying. Collectors, that might
>be another story, but with the after-market head, then even
>this seems a little suspect.
>
>
> Brett

Yes. The going price on ebay and private sales for a NIB one usually is in the $125-175 range.

$223.86 is all the money in the world for a ST46.

Here is one thing I would do to all St/46 motors. Take the head fins down to 3/32 in. depth.The stock head runs to cold. I have run no fins at all when I lived in Florida and the never overheated.The old OS max 35s had the same problem. Through the head gasket away and remove .060 from the head combustion chamber. Stock it's .160 in. thick. do not hemi it. I have four liners in my parts and there are three different timings on the intakes. The very old double ring thin sleeve ST40-46 narrow intake had a smaller intake in the sleeve and it was timed a little bit different. The early single ring motors had the wide dust cover and the one Brett is talking about had the narrow dust cover. Never put a new ring in the motor unless you know how to test it for hardness.A good ring will last 500-700 runs.Also the banded cranks had vibration problems.I have one 46 that went 1500 runs before I put a ring in it.That motor took me fifteen years to put that many runs on it and I used it last Saturday at the Noarfolk Rapids flyin.Billy and Al pushed the motors real hard and had a lot of ring problems. I would guess they had to much airplane for the motor.It's not super powerfull it just runs great in a 50 oz 620 sq inch plane. A Juno is allmost to big for it,but I am trying it one more time. I should have my Juno done in a week and I will post a picture of it.
Ed Ruane