Jett 120
06-29-2010, 06:07 PM
#1
Jett 120
Does any one have some rpm numbers? i did some mods on my 120. i only ran it once because i bought it used and it needed a new rear bearing. with the stock muffler it turned a 15x10 at 9,800. I will be looking to run this engine at some higher RPM numbers now with the mods and will be in the 12,000 range on a 13x11 prop maybe more.
06-30-2010, 08:31 AM
#2
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RE: Jett 120
It will turn if you want it to 
Biggest thing you have to do is get the right muffler on it. The 12000 rpm target is at the "high" rpm range of the standard SJ-120 muffler. That likes the 9000-12000 rpm band. 10000 target.
If you have a SJ-90L muffler try with that. The engine has the torque to make it work. The regular 90L muffler works fine starting down as low as 12,500 rpm - so when unloaded in flight it should work perfectly.
Biggest thing you have to do is get the right muffler on it. The 12000 rpm target is at the "high" rpm range of the standard SJ-120 muffler. That likes the 9000-12000 rpm band. 10000 target.
If you have a SJ-90L muffler try with that. The engine has the torque to make it work. The regular 90L muffler works fine starting down as low as 12,500 rpm - so when unloaded in flight it should work perfectly.
07-02-2010, 07:27 AM
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RE: Jett 120
If I run across any more info, I will let you know...
And feel free to post your results here too. Always good as a refrence.
BTW... do you have an older Big Block 120? or is it the 120L ???
Bob
And feel free to post your results here too. Always good as a refrence.
BTW... do you have an older Big Block 120? or is it the 120L ???
Bob
07-08-2010, 10:33 AM
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RE: Jett 120
If it is cast, it is the original "bigger block" engine based off the original 95 and 105 engines (and fanjett 95 engine).
Very strong engine. One of the best Dub ever made. You will not hurt it.
(if it were a SJ-120L engine, it would be machined bar stock crankcase, only available that configuration)
Several SJ-120 engines were raced over in Australia for years in the AT-6 class (midwest at-6 was the baseline design). A few ran turbo-jet mufflers and rather custom props for the event.
(oh wow... i still have this on the website.... perhaps as a reference ... http://www.jettengineering.com/hall/at6com.html )
Very strong engine. One of the best Dub ever made. You will not hurt it.
(if it were a SJ-120L engine, it would be machined bar stock crankcase, only available that configuration)
Several SJ-120 engines were raced over in Australia for years in the AT-6 class (midwest at-6 was the baseline design). A few ran turbo-jet mufflers and rather custom props for the event.
(oh wow... i still have this on the website.... perhaps as a reference ... http://www.jettengineering.com/hall/at6com.html )
07-14-2010, 06:57 PM
#8
RE: Jett 120
I just bought one of these engines...
Are they ABC or AAC? This one has the needle on the carburetor (YEA!!) and the venturi is round and not "bathtub" shaped like the carburetor on my BSE 120.
Can you explain how these Jett Carburetors work?
I also have both 90 & 120 size mufflers.
Are they ABC or AAC? This one has the needle on the carburetor (YEA!!) and the venturi is round and not "bathtub" shaped like the carburetor on my BSE 120.Can you explain how these Jett Carburetors work?
I also have both 90 & 120 size mufflers.
07-15-2010, 12:03 AM
#11
RE: Jett 120
ORIGINAL: bob27s
If it is cast, it is the original ''bigger block'' engine based off the original 95 and 105 engines (and fanjett 95 engine).
Very strong engine. One of the best Dub ever made. You will not hurt it.
(if it were a SJ-120L engine, it would be machined bar stock crankcase, only available that configuration)
Several SJ-120 engines were raced over in Australia for years in the AT-6 class (midwest at-6 was the baseline design). A few ran turbo-jet mufflers and rather custom props for the event.
(oh wow... i still have this on the website.... perhaps as a reference ... http://www.jettengineering.com/hall/at6com.html )
If it is cast, it is the original ''bigger block'' engine based off the original 95 and 105 engines (and fanjett 95 engine).
Very strong engine. One of the best Dub ever made. You will not hurt it.
(if it were a SJ-120L engine, it would be machined bar stock crankcase, only available that configuration)
Several SJ-120 engines were raced over in Australia for years in the AT-6 class (midwest at-6 was the baseline design). A few ran turbo-jet mufflers and rather custom props for the event.
(oh wow... i still have this on the website.... perhaps as a reference ... http://www.jettengineering.com/hall/at6com.html )
08-03-2010, 09:25 PM
#13
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RE: Jett 120
ORIGINAL: Broken Wings
I just bought one of these engines... Are they ABC or AAC? This one has the needle on the carburetor (YEA!!) and the venturi is round and not ''bathtub'' shaped like the carburetor on my BSE 120.
Can you explain how these Jett Carburetors work?
I also have both 90 & 120 size mufflers.
I just bought one of these engines...
Are they ABC or AAC? This one has the needle on the carburetor (YEA!!) and the venturi is round and not ''bathtub'' shaped like the carburetor on my BSE 120.Can you explain how these Jett Carburetors work?
I also have both 90 & 120 size mufflers.
There are two needles. High speed needle is on the left, low/mid range needle is inside of the throttle arm side (Brass screw).
The carbs are nothing mysterious. Very much like the original supertigre carbs. The low/mid speed mixture is set very close by Dub before sending them out. Instructions on the website for resetting it if the low speed has been over-tweeked a bit.
Bob
