Tower Hobbies 75 Engine-General Question
10-13-2007, 02:04 PM
#1
Member
Thread Starter
Join Date: Nov 2006
Location: North Las Vegas,
NV
Posts: 94
Likes: 0
Received 0 Likes
on
0 Posts
Tower Hobbies 75 Engine-General Question
Hello everyone,
I'm thinking about getting a Tower Hobbies .75 BB ABC engine and would like some input on them. Are they a decent engine?
Moderator corrected spelling in title
I'm thinking about getting a Tower Hobbies .75 BB ABC engine and would like some input on them. Are they a decent engine?
Moderator corrected spelling in title
10-13-2007, 03:11 PM
#2
Senior Member
RE: Tower Hobbies Eninges-General Question
From what I`ve read in here they seem to more than decent. The guys in this forum praising this engine made me get one myself
and I have only had two flights on it ( today) I`m looking forward to testing it fully.
and I have only had two flights on it ( today) I`m looking forward to testing it fully.
10-13-2007, 03:13 PM
#3
RE: Tower Hobbies Eninges-General Question
It's an excellent running and powerful engine, especially for the price. I have 2 of them.
Like a lot of Chinese engines, they do have lapses of quality control. One of mine had a bad carb. I never could get it set to where the mid range wasn't extremely rich. Tower did replace the carb and the new carb runs fine, as does the other engine.
The one thing you want when you are buying a low price engine is a distributor who stands behind his product. Tower/Hobby Services does that. Even when I had the bad carb, and you can find other references to the same problem is you search here on RCU, I ordered the second one because I knew I'd get that one fixed and the rep for the Tower .75 is excellent.
Like a lot of Chinese engines, they do have lapses of quality control. One of mine had a bad carb. I never could get it set to where the mid range wasn't extremely rich. Tower did replace the carb and the new carb runs fine, as does the other engine.
The one thing you want when you are buying a low price engine is a distributor who stands behind his product. Tower/Hobby Services does that. Even when I had the bad carb, and you can find other references to the same problem is you search here on RCU, I ordered the second one because I knew I'd get that one fixed and the rep for the Tower .75 is excellent.
10-13-2007, 06:07 PM
#6
Senior Member
Join Date: May 2006
Location: CAMDEN,
TN
Posts: 496
Likes: 0
Received 0 Likes
on
0 Posts
RE: Tower Hobbies Eninges-General Question
Be ready to replace the front bearing. Several have leaked. Mine is off to tower no for repair. I also have a new aftermarket set on the way that I will install if the new one leaks again.
10-14-2007, 12:06 AM
#7
RE: Tower Hobbies Eninges-General Question
ORIGINAL: brewski
Be ready to replace the front bearing. Several have leaked. Mine is off to tower no for repair. I also have a new aftermarket set on the way that I will install if the new one leaks again.
Be ready to replace the front bearing. Several have leaked. Mine is off to tower no for repair. I also have a new aftermarket set on the way that I will install if the new one leaks again.
....you would be hard pressed to find another front bearing leak failure.
FBD.
10-14-2007, 08:33 AM
#8
RE: Tower Hobbies Eninges-General Question
ORIGINAL: Flyboy Dave
....no so. If you go all the way back to when the T.H. 75's came out, until now....
....you would be hard pressed to find another front bearing leak failure.
FBD.
ORIGINAL: brewski
Be ready to replace the front bearing. Several have leaked. Mine is off to tower no for repair. I also have a new aftermarket set on the way that I will install if the new one leaks again.
Be ready to replace the front bearing. Several have leaked. Mine is off to tower no for repair. I also have a new aftermarket set on the way that I will install if the new one leaks again.
....you would be hard pressed to find another front bearing leak failure.
FBD.
10-14-2007, 12:11 PM
#10
RE: Tower Hobbies Eninges-General Question
I have one TH .75 engine that shot the front bearing twice in less than 5 gallons of fuel.
Finally replaced those bearings with aftermarket and haven't had any problems.
Never had an issue with any of the 7 other TH .75 engines I've had.
If you want to know about the TH .75, do a search. There's a TON of info on this engine. Just takes a little time to read through it all.
Finally replaced those bearings with aftermarket and haven't had any problems.
Never had an issue with any of the 7 other TH .75 engines I've had.
If you want to know about the TH .75, do a search. There's a TON of info on this engine. Just takes a little time to read through it all.
10-14-2007, 12:29 PM
#11
RE: Tower Hobbies Eninges-General Question
....it is odd to me that these bearing failures have occurred, especially on new, and
almost new engines. The front bearings are nicely shielded....and that in itself usually
provides enough added sealing at the front to provide for satisfactory operation.
Is it the bearing, or is it the clearance between the crankcase and the crankshaft in
the front rotor area ? Or is it the clearance between the outer race of the front bearing
and the crankcase at the front....or the clearance between the crankshaft and the inner
race of the front bearing at the front ?
The reason I wonder is because I ran the snot out of my first Tower .75 in a propjet,
and the engine ran pretty much wide open all the time....I certainly never babied it either.
I ran it for two years and then tore it down to check the bearings. They were in perfect
shape....in fact I put them back in to see how long they would last. They are still going
strong.
Maybe the fact that I use almost 50% castor in my fuel helps the longevity. Actually
our bearings only run at about half their rated capacity....they should last if they have
proper lubrication. Keep in mind, they are running without any heat to speak of, and
with a constant supply of fresh clean, cool oil. They should last a long time.
FBD.
almost new engines. The front bearings are nicely shielded....and that in itself usually
provides enough added sealing at the front to provide for satisfactory operation.
Is it the bearing, or is it the clearance between the crankcase and the crankshaft in
the front rotor area ? Or is it the clearance between the outer race of the front bearing
and the crankcase at the front....or the clearance between the crankshaft and the inner
race of the front bearing at the front ?
The reason I wonder is because I ran the snot out of my first Tower .75 in a propjet,
and the engine ran pretty much wide open all the time....I certainly never babied it either.
I ran it for two years and then tore it down to check the bearings. They were in perfect
shape....in fact I put them back in to see how long they would last. They are still going
strong.
Maybe the fact that I use almost 50% castor in my fuel helps the longevity. Actually
our bearings only run at about half their rated capacity....they should last if they have
proper lubrication. Keep in mind, they are running without any heat to speak of, and
with a constant supply of fresh clean, cool oil. They should last a long time.
FBD.
10-14-2007, 12:35 PM
#12
RE: Tower Hobbies 75 Engine-General Question
Dave,
what i did was to pull the prop hub off..............poured some straight castor onto the front bearing in which it took 3 applications because the castor kept penetrating into the bearing right past the shield.............then with piston closing off exhaust port fully, i blew through the carb intake.........the bubbles coming out through the castor from the front bearing looked like the local uncared for nieghborhood kid that always had one of those big ol snot bubbles coming out of his nose on one nostril or the other, sometimes both.........
so yeah, it's a lowsy fitting shield, and probably a larger than normal crank to case clearance.
what i did was to pull the prop hub off..............poured some straight castor onto the front bearing in which it took 3 applications because the castor kept penetrating into the bearing right past the shield.............then with piston closing off exhaust port fully, i blew through the carb intake.........the bubbles coming out through the castor from the front bearing looked like the local uncared for nieghborhood kid that always had one of those big ol snot bubbles coming out of his nose on one nostril or the other, sometimes both.........
so yeah, it's a lowsy fitting shield, and probably a larger than normal crank to case clearance.
10-14-2007, 04:19 PM
#13
RE: Tower Hobbies Eninges-General Question
ORIGINAL: Flyboy Dave
....it is odd to me that these bearing failures have occurred, especially on new, and
almost new engines. The front bearings are nicely shielded....and that in itself usually
provides enough added sealing at the front to provide for satisfactory operation.
Is it the bearing, or is it the clearance between the crankcase and the crankshaft in
the front rotor area ? Or is it the clearance between the outer race of the front bearing
and the crankcase at the front....or the clearance between the crankshaft and the inner
race of the front bearing at the front ?
The reason I wonder is because I ran the snot out of my first Tower .75 in a propjet,
and the engine ran pretty much wide open all the time....I certainly never babied it either.
I ran it for two years and then tore it down to check the bearings. They were in perfect
shape....in fact I put them back in to see how long they would last. They are still going
strong.
Maybe the fact that I use almost 50% castor in my fuel helps the longevity. Actually
our bearings only run at about half their rated capacity....they should last if they have
proper lubrication. Keep in mind, they are running without any heat to speak of, and
with a constant supply of fresh clean, cool oil. They should last a long time.
FBD.
....it is odd to me that these bearing failures have occurred, especially on new, and
almost new engines. The front bearings are nicely shielded....and that in itself usually
provides enough added sealing at the front to provide for satisfactory operation.
Is it the bearing, or is it the clearance between the crankcase and the crankshaft in
the front rotor area ? Or is it the clearance between the outer race of the front bearing
and the crankcase at the front....or the clearance between the crankshaft and the inner
race of the front bearing at the front ?
The reason I wonder is because I ran the snot out of my first Tower .75 in a propjet,
and the engine ran pretty much wide open all the time....I certainly never babied it either.
I ran it for two years and then tore it down to check the bearings. They were in perfect
shape....in fact I put them back in to see how long they would last. They are still going
strong.
Maybe the fact that I use almost 50% castor in my fuel helps the longevity. Actually
our bearings only run at about half their rated capacity....they should last if they have
proper lubrication. Keep in mind, they are running without any heat to speak of, and
with a constant supply of fresh clean, cool oil. They should last a long time.
FBD.
On my particular engine, I think it has to be a poor fit between the case and the stock bearing.
I can't explain it, but it seams funny to me that the same engine would shoot 2 front bearings. None of my other TH .75 engines ever had bearing troubles. I replaced the bearings in all the ones I have now. Maybe not necessary, but I just like taking engines apart.
Maybe that case just got machined out a few thousanths and it was enough to make the bearing fit poorly or slide around under heat and loads?
10-14-2007, 04:36 PM
#15
RE: Tower Hobbies Eninges-General Question
On most of my engines, the liner will slide right out. I think I only had one that was tight, but I never had any problems with it. Sold it after about 10 gallons of fuel.
10-14-2007, 06:03 PM
#16
RE: Tower Hobbies Eninges-General Question
.....that makes it real easy to take them apart without having to heat the case.
I've only had two apart. I was impressed with the quality of the cylinder. The
chromed brass was nice, the machining was perfect.
FBD.
I've only had two apart. I was impressed with the quality of the cylinder. The
chromed brass was nice, the machining was perfect.
FBD.
10-14-2007, 07:07 PM
#17
Senior Member
Join Date: May 2006
Location: CAMDEN,
TN
Posts: 496
Likes: 0
Received 0 Likes
on
0 Posts
RE: Tower Hobbies Eninges-General Question
ORIGINAL: Flyboy Dave
....no so. If you go all the way back to when the T.H. 75's came out, until now....
....you would be hard pressed to find another front bearing leak failure.
FBD.
ORIGINAL: brewski
Be ready to replace the front bearing. Several have leaked. Mine is off to tower no for repair. I also have a new aftermarket set on the way that I will install if the new one leaks again.
Be ready to replace the front bearing. Several have leaked. Mine is off to tower no for repair. I also have a new aftermarket set on the way that I will install if the new one leaks again.
....you would be hard pressed to find another front bearing leak failure.
FBD.
10-14-2007, 07:11 PM
#18
RE: Tower Hobbies 75 Engine-General Question
I just crashed with one this afternoon. First I've had it in the air. Crash was pilot error on maiden flight, not engine problems. I've heard a lot of good about this engine. The one thing I've heard to watch for is to make sure you have a good airtight seal around the carb. I used RTV around the carb before installing it and got a good seal. The engine ran great for the roughly two minutes I had it running this morning. I had previously run a full gallon through it on a test stand, then after run oil and cleaned it up and stored it for about six months. This morning, I primed it and it started on the second flip! (By hand, even!!)
Right now, though I'm looking for a replacement muffler. I don't care for the tin can sound of this one.
--
Tom
Right now, though I'm looking for a replacement muffler. I don't care for the tin can sound of this one.
--
Tom
10-14-2007, 07:17 PM
#19
RE: Tower Hobbies Eninges-General Question
....I hear 'ya brewski....I would have been tempted to fix it myself as well.
I use only the rubber shielded bearings....I have been for years. That eliminates
problems at the front of the engines.
On the left one of my OS .60 FSR's, on the right a new ASP .91 sealed from the factory.
FBD.
I use only the rubber shielded bearings....I have been for years. That eliminates
problems at the front of the engines.
On the left one of my OS .60 FSR's, on the right a new ASP .91 sealed from the factory.
FBD.
10-14-2007, 07:18 PM
#20
RE: Tower Hobbies 75 Engine-General Question
Here's one from the same company with a different sound
http://www3.towerhobbies.com/cgi-bin...?&I=LXEHA2&P=7
http://www3.towerhobbies.com/cgi-bin...?&I=LXEHA2&P=7
10-15-2007, 02:39 PM
#21
Senior Member
My Feedback: (2)
Join Date: Sep 2002
Location: Bruce,
MS
Posts: 1,516
Likes: 0
Received 0 Likes
on
0 Posts
RE: Tower Hobbies 75 Engine-General Question
It seem like everyone is interested in the Tower 75 and I wonder why. The cost of this engine is just rediciously low and the power is great. Oh yea, some report problems but overall it is a good engine with great power. It doesn't cost much more that an OS muffler. Parts for Tower engines are much more reasonably priced also and as you all know sooner or later you are going to need parts if you fly at all.
06-29-2020, 03:32 PM
#22
Old thread but I hope it gets revived....I found one of these in a collection but I need a muffler extension for my biplane. Anybody know what is the OS equivalent?
Thanks
John
Thanks
John
06-29-2020, 05:38 PM
#23
My Feedback: (1)
the OS 61 to 91 all have the same mounting spacing and bolt size. the OS 91 muffle is larger than the 61, but the 91 muffler should produce a bit more power on the Towers 75 than the 61 muffler would. you should ask on RC Groups for a muffler, I am sure some one will have one, just make sure you tell in your add that the flange must be good so it will seal well
oops, edit, BTW, if you could find an OS Carb for it you may find the 75 may be easier to tune.
Jim
Last edited by the Wasp; 06-29-2020 at 05:42 PM.
