Strut bushings

[MadProps]

I have a genesis and it has always leaked water, I addressed all the transom hardware bolts etc but the water comes up the flex shaft, I use shrink tubing over the stuffing tube to strut joint and I found if I use a lot of grease it slows it down considerably, "unless" its a long run then it accumulates too much water again as it pushes out the grease.

frustrated today I was inspecting the strut and found some play in the strut bushings....I replaced them and the water shaft intrusion has been cut down dramatically

how often should I expect to replace strut bushings?


edit: while I have you here whats the purpose of the resistors being installed to stop the sparking when connecting 6s or more batteries to the ESC....is this causing any damage to the ESC? or is this just a geeky mod we can do

thanks for looking

[ray schrauwen]

Converting to speedmaster drilled brass bushings will last longer. I would say depending on how much you run, every season or more for lead Teflon. If they are Chinese lead Teflon then you might get a few runs between bushing changes, they are crap in most cases.

If the lead Teflon is from H&M Germany, it will last as long as the speedmaster.

[ray schrauwen]

The last question will get answers that vary between each person. For some it's safety. Over 6s people have burnt off the ends of their fingers connecting Batts.

[MadProps]

ok thanks I havent gone over 6s so I havent experienced that pleasure but clearly obvious now

and I run everyday I live on a river so that would explain the bushing wear ...also clearly obvious now:doh:
Ive upgraded everything else so I will also try that drilled bushing, Ive seen them on the OSE site thanks

[Prodrvr]

If your connectors spark whenever you plug them in, the connectors start getting pitted from the arcing and that will lead to connectivity problems and higher resistance. Use either anti spark connectors or make an anti spark jumper wire yourself.

[fweasel]

The bushing wear has many contributing factors. All is takes is a single run on an unbalanced prop to wear one significantly.

[MadProps]

The bushing wear has many contributing factors. All is takes is a single run on an unbalanced prop to wear one significantly.
thanks good to know, my props are balanced, but in my case it is excessive usage.

[CraigP]

If your connectors spark whenever you plug them in, the connectors start getting pitted from the arcing and that will lead to connectivity problems and higher resistance. Use either anti spark connectors or make an anti spark jumper wire yourself.

I wish more people would listen to this advice! Not only do you pit your connectors, you also stress the dielectrics in the capacitors badly, causing them to eventually fail. I personally use a jumper wire with a 50 ohm resistor, alligator clips on the ends... ALWAYS pre-charge large, electrolytic capacitors, Electronics 101....

[CraigP]

I have a genesis and it has always leaked water, I addressed all the transom hardware bolts etc but the water comes up the flex shaft, I use shrink tubing over the stuffing tube to strut joint and I found if I use a lot of grease it slows it down considerably, "unless" its a long run then it accumulates too much water again as it pushes out the grease.

frustrated today I was inspecting the strut and found some play in the strut bushings....I replaced them and the water shaft intrusion has been cut down dramatically

how often should I expect to replace strut bushings?


edit: while I have you here whats the purpose of the resistors being installed to stop the sparking when connecting 6s or more batteries to the ESC....is this causing any damage to the ESC? or is this just a geeky mod we can do

thanks for looking

All bushings need grease to take up the tolerance, or the bushing would run with too much friction. Grease the Bushings then check the side play, I bet they are much tighter. If it feels real loose after you bring it in, you may have to re-grease. Many use that as a sign their grease is low in the stuffing tube.

[rol243]

i used to use lead teflon bearings that were approx 1/4 inch in length and shaft fee play developed rather quickly unti a mate said to try the 1/2 inch long lead teflon bearings / bushings and these lasted alot longer , only used oil no grease as i was sick of the greasey mess coming out at the motor end of log. i have never tried the brass sleeve bushings but they do seem to be a better option than the old style teflon coated lead bush.

[Fluid]

I've used both lead/Teflon and SpeedMaster bushings for years and prefer the latter for most uses. Mine last a long time even with many race heats per year. I do use a quality 70W synthetic gear oil with EP additive - costs about $10 for a quart and has lasted me 12 years....so far.

If water is running up the cable, put a 1/2" piece of silicon tubing over the inside end of the stuffing tube so that it just bearly touches the cable. This will stop most/all of the water intrusion. Water in an FE hull is never a good idea and is preventable.


.

[CraigP]

I do like the design and concept behind the floating bushing. My problem is I run a sealed strut, with a U-cup seal on the back side, which keeps grease in and water out. So I need a static or a set bearing/bushing. I have the bushings in there now, 3 of them, with about 5/16" in between them. I pack each section with Proboat Blue, then add some 50wt oil to bring down the viscosity of the Proboat lube, which is thick! This has brought my shaft maintenance down to every 15-20 runs, and since getting into that shaft is my least favorite FE chore, this pleases me!

I checked into roller bearings and the rpm's of FE boats is beyond their specifications. The small ones are only about 12,000rpm rated.

[kfxguy]

I do like the design and concept behind the floating bushing. My problem is I run a sealed strut, with a U-cup seal on the back side, which keeps grease in and water out. So I need a static or a set bearing/bushing. I have the bushings in there now, 3 of them, with about 5/16" in between them. I pack each section with Proboat Blue, then add some 50wt oil to bring down the viscosity of the Proboat lube, which is thick! This has brought my shaft maintenance down to every 15-20 runs, and since getting into that shaft is my least favorite FE chore, this pleases me!

I checked into roller bearings and the rpm's of FE boats is beyond their specifications. The small ones are only about 12,000rpm rated.

Hey buddy, I run sealed roller in all my struts. The ones I run are rated for 60k rpm. The strut has to be machined in a lathe and a snap ring groove machined. I stack 6 bearings together. I have some genesis struts on hand if your interested in me setting one up for you. It keeps the water out too. If your interested just pm me.

[CraigP]

Hey buddy, I run sealed roller in all my struts. The ones I run are rated for 60k rpm. The strut has to be machined in a lathe and a snap ring groove machined. I stack 6 bearings together. I have some genesis struts on hand if your interested in me setting one up for you. It keeps the water out too. If your interested just pm me.

Are those Boca bearings? Do you have a P/N I could look up? Wondering how I missed those... Travis, what about unsealed bearings and let the lubrication flow thru the bearing stack, then let the lip seal stop the water and keep the grease in? My concern is the life of the bearing running as fast as we do and relying on factory grease. Are you getting long run time on those? Maybe I'm making it too hard, but it is working well. As long as those Bushings have good lube, I'm not seeing any appreciable wear.

[kfxguy]

Are those Boca bearings? Do you have a P/N I could look up? Wondering how I missed those... Travis, what about unsealed bearings and let the lubrication flow thru the bearing stack, then let the lip seal stop the water and keep the grease in? My concern is the life of the bearing running as fast as we do and relying on factory grease. Are you getting long run time on those? Maybe I'm making it too hard, but it is working well. As long as those Bushings have good lube, I'm not seeing any appreciable wear.

I do use boca or fast eddy sometimes. Whoever has a better deal. I've been using this setup for a couple years now in all my boats and all my customer builds. I've had one bearing come apart when I first started doing it. My fault. You have you chuck the flex up in a drill and spin it while having 400 grit sandpaper (crocus cloth recommended) with a little Wd40 on the paper. Move it up and down the stub and check the bearing fitment from time to time. The shaft needs to slide into the bearings but have a good fit. Think about the fact that the flex shrinks and grows so if you don't allow the slip fit for that, it will bust the bearings. I use seal on all of them. They seem to have a very long life like that. When they need changing they are not hard to change.

You could pop the seals out of all of the bearings and leave the outer seal on the outer bearing if you want to. I thought about it but I also realize that even tho not much water gets in with this setup, some will shill find its way in and get to the bearings. How will you get he moisture back out? So for now I just leave the seals on as it's been working for me that way. You do have to drill the strut in a lathe or you will not be able to drill it straight enough in a drill press or by hand. I also machine a snap ring groove as extra insurance on top of the blue loctite I use. Not to many people do this except for me because it's kinda involved to do it. I feel it's worth it because it eliminates slack, wear and greatly decreases water intrusion. The only boat I have right now that doesn't have this done is my sport Rivercat. Why? I was pressed for time trying to get it ready for its maiden run. I will be adding the bearings to it once I get it dialed in and base lined. Mark the strut. Mod it for bearings and then run it again to see if it actually goes faster. When I do, I'll start a thread with results. I'm honestly not sure it helps any, I kinda doubt it does but it keeps it nice an dry.

[CraigP]

This U-cup seal I found is keeping all the water out, and all the grease in. Seems we need to collaborate and put our ideas together. I do not want water in there! Cleaning that driveline really sucks and it's dirty... I ran about 12 good runs with the seal on it and took it apart. Not a lick of water and the grease looked like when I put it in. I would love to try the bearings and the seal, see if we can make both our setups better. I pm'd you on it... many probably think we are wasting our time, but I see less friction and less maintenance! I'll pm you my email, it's much easier than the site... Lets do it!!!

[kfxguy]

This U-cup seal I found is keeping all the water out, and all the grease in. Seems we need to collaborate and put our ideas together. I do not want water in there! Cleaning that driveline really sucks and it's dirty... I ran about 12 good runs with the seal on it and took it apart. Not a lick of water and the grease looked like when I put it in. I would love to try the bearings and the seal, see if we can make both our setups better. I pm'd you on it... many probably think we are wasting our time, but I see less friction and less maintenance! I'll pm you my email, it's much easier than the site... Lets do it!!!

What seal did you use? Part number or link?

[ray schrauwen]

Are those Boca bearings? Do you have a P/N I could look up? Wondering how I missed those... Travis, what about unsealed bearings and let the lubrication flow thru the bearing stack, then let the lip seal stop the water and keep the grease in? My concern is the life of the bearing running as fast as we do and relying on factory grease. Are you getting long run time on those? Maybe I'm making it too hard, but it is working well. As long as those Bushings have good lube, I'm not seeing any appreciable wear.

That I know of, Boca only had two roller bearings on file with 3/16" id.

I use a pair in my Cheetah.

They are not waterproof. I could be wrong about all Boca has in stock. I would love to know where these roller bearings come from.

[CraigP]

Ray, Boca has open and sealed versions. The "sealed" version is not waterproof. If there is water in your strut, then the ball bearing may not be your best bet. Jay likes the floating bushing, and for a wet setup, I agree. Sealing the strut requires machining and some figuring out. I wish Speedmaster sold a sealed version. I'd pay more not to hassle that grimy flex shaft as often!

BTW, water will just eat up Lead/Teflon bushings... If using, bring some spares! A floating bushing has much more bearing area, so it resist the bad effects of water much longer.

[CraigP]

Travis, you didn't send me your email, I'm heading out to the lake now. Here's a PDF of the concept we can kick around. Have a good time out there!

[kfxguy]

Travis, you didn't send me your email, I'm heading out to the lake now. Here's a PDF of the concept we can kick around. Have a good time out there!

I use 6 bearings because I think less than that won't hold up from the side loads

[martin]

Yes you want at least 2 ball bearings back to back at the rear of the strut to take side loads otherwise I have found a single ball bearing at the rear wears excessively. You can get away with a single ball bearing at the front of the strut.

[kfxguy]

Yes you want at least 2 ball bearings back to back at the rear of the strut to take side loads otherwise I have found a single ball bearing at the rear wears excessively. You can get away with a single ball bearing at the front of the strut.

I like overkill so I don't have to worry with it.

[ray schrauwen]

When you say roller bearings it made me think of these https://www.bocabearings.com/products/bearing-and-ball-types/needle-bearings-common-sizes?ProductType=0 I used in my Cheetah strut. I don't have enough run time on them to actually recommend them but since it was a direct fit into my large Octura strut I thought why not??? I hold them in place with the red retaining compound I got from the free bee bags every Michigan run I've gone to.
Two of these to be exact: https://www.bocabearings.com/products/sce36tn-660

I like the rubber seal on the PDF. I can machine what is required. Where do you get the rubber seals? Part number for the lazy. :tongue:

[martin]

Keep in mind if you use needle or roller bearings you must use a hardened & ground stub shaft like the ones offered by Aeromarine, as the shaft runs directly in the needles.

[martin]

I think using the term roller bearing as in some previous postings is confusing things, as they actually used single row ball bearings or ball race.

[ray schrauwen]

Keep in mind if you use needle or roller bearings you must use a hardened & ground stub shaft like the ones offered by Aeromarine, as the shaft runs directly in the needles.

My shafts are pretty hard. :banana:

We shall see how long they last. If they fail, I will go to roller bearings maybe or just shim it to Speedmaster.

[Peter A]

BTW, water will just eat up Lead/Teflon bushings...

Teflon is lubricated by water. It is the loading that wears out the bushes.

[CraigP]

When you say roller bearings it made me think of these https://www.bocabearings.com/products/bearing-and-ball-types/needle-bearings-common-sizes?ProductType=0 I used in my Cheetah strut. I don't have enough run time on them to actually recommend them but since it was a direct fit into my large Octura strut I thought why not??? I hold them in place with the red retaining compound I got from the free bee bags every Michigan run I've gone to.
Two of these to be exact: https://www.bocabearings.com/products/sce36tn-660

I like the rubber seal on the PDF. I can machine what is required. Where do you get the rubber seals? Part number for the lazy. :tongue:

U-cup Rod Seal - Source: theoringstore.com Part Number: 626-008-5747, Buna-N 70 shore U-cup

Note: requires a 5/16" counterbore. The seal is 0.065" thick, counterbore needs to be 0.060" to properly load the seal. That means the total depth on that drawing should be set to 0.160", 0.060 for the seal and 0.100" for the stop in the back. Very low friction with this type of seal. I don't have any water in my strut using it.

[CraigP]

Teflon is lubricated by water. It is the loading that wears out the bushes.

The teflon on these Bushings from OSE is a very thin veneer of teflon, bonded to the metal. I've found and others have reported that this veneer goes away very quickly. They, however, do not have sealed struts. I run 3 bushings, with a 3/8" gap in between in a Speedmaster 21 strut. I have well over 20 runs on this setup and the bushings are as tight as when I put them in. The grease stays in, so when the boat comes back in, there's no side play on the strut. Now, I have np proof that the exclusion of the water is the reason for this longevity, but the circumstantial evidence is pretty strong. When I first put the bushings in, I didn't have the seal, and the veneer was gone in the end bushing after the second run.

[ray schrauwen]

U-cup Rod Seal - Source: theoringstore.com Part Number: 626-008-5747, Buna-N 70 shore U-cup

Note: requires a 5/16" counterbore. The seal is 0.065" thick, counterbore needs to be 0.060" to properly load the seal. That means the total depth on that drawing should be set to 0.160", 0.060 for the seal and 0.100" for the stop in the back. Very low friction with this type of seal. I don't have any water in my strut using it.

Perfect, thanks! My strut is bored to 5/16" already. I only need to move bearings around etc.

[CraigP]

That drawing shows a concept to try. I don't have a press fit plug currently in mine. I fabricated a small plate to go over the back of the strut and affixed it with two, 2mm hex head screws. There are 3 holes in the picture, I broke a tap in the lower hole, so it's not used. I was trying to come up with something that was less work. If you come up with another way, please share!

[ray schrauwen]

Ok. Not possible on my strut. I'll think about it a while.

Is that originally a 1/4" strut?

[CraigP]

No, it's a 3/16" strut...

[Hydrocarbon82]

Have you guys seen anyone who's modded the TFL stinger for a Speedmaster bushing? If i'm measuring correct, the lead teflon it uses is 0.25" OD. It appears I could replace them with a 0.25" OD brass tube and use this Speedmaster stinger bushing (link) (https://www.offshoreelectrics.com/proddetail.php?prod=ros-spdsd-187).

Otherwise I'm thinking of just getting the whole 3/16" Speedmaster stinger for $40. It's 0.2" longer but I can deal with that.

[zooma]

Have you guys seen anyone who's modded the TFL stinger for a Speedmaster bushing? If i'm measuring correct, the lead teflon it uses is 0.25" OD. It appears I could replace them with a 0.25" OD brass tube and use this Speedmaster stinger bushing (link) (https://www.offshoreelectrics.com/proddetail.php?prod=ros-spdsd-187).

Otherwise I'm thinking of just getting the whole 3/16" Speedmaster stinger for $40. It's 0.2" longer but I can deal with that.

I was getting ready to post the same question. Very interested in any solutions for inserting a Speedmaster floating bushing into the TFL stinger. I have three of these in use now.

[CraigP]

Yes, you can use the floating bushing in a strut with a 0.250" ID. You can bring the stuffing tube deep into the strut, or use a smaller, separate 1/4" OD tube to fully support the floating bushing. Teflon lined Bushings will not hold up with water intrusion, regardless of other statements made. I think many of us have experienced short life of the lead/teflon bushing, or in the least, the bushing in the back of the strut.

I'm currently using 3, lead/teflon bushings with 0.30" space in between them. It's working great for me, but I'm keeping the water out! So if you run an unsealed strut, then the floating bushing will hold up the best under the water/oil/grease lubrication of an unsealed strut.

Note: if your stinger has a loose fit to the 1/4" tubing, then use some Locktite Blue to hold it in place. If it spins, it will really wear out the aluminum housing.

[Hydrocarbon82]

The TFL stinger definitely isn't sealed, there's a good 1/4" gap at the front. I'll get a speedmaster bushing need time I order then use a separate 1/4" stub tube in the stinger. I plan to flair the front so it can't slide backwards.

[CraigP]

Why not just Locktite it in? The 1/4" tube isn't supposed to turn or move...

[zooma]

Yes, you can use the floating bushing in a strut with a 0.250" ID. You can bring the stuffing tube deep into the strut, or use a smaller, separate 1/4" OD tube to fully support the floating bushing. Teflon lined Bushings will not hold up with water intrusion, regardless of other statements made. I think many of us have experienced short life of the lead/teflon bushing, or in the least, the bushing in the back of the strut.

I'm currently using 3, lead/teflon bushings with 0.30" space in between them. It's working great for me, but I'm keeping the water out! So if you run an unsealed strut, then the floating bushing will hold up the best under the water/oil/grease lubrication of an unsealed strut.

Note: if your stinger has a loose fit to the 1/4" tubing, then use some Locktite Blue to hold it in place. If it spins, it will really wear out the aluminum housing.

So, wouldn't the TFL stinger bushings have to be machined to .25 inside dia?

[Hydrocarbon82]

The TFL lead bushings are 3/16" ID x 1/4" OD, so no. It could be 6mm because I can't measure it perfectly (flush & chamfered), but most TFL struts show 6.35mm ID on various sites.

[CraigP]

My comments were based on the ID being 0.250", so if it's metric, you'll have to machine a tube or machine the stinger, depending on the measurements. It's up to each modeler to consider the exact implement to use on your boat. Seems that making/modifying parts is a big part of the hobby!

[kfxguy]

Why not just Locktite it in? The 1/4" tube isn't supposed to turn or move...

If it can't move then you can't angle the strut unless you make the screw slot in the strut bigger.....so actually it is supposed to be able to move some.

[kfxguy]

The only potential problem I see with using the floating bushing in a title strut is the aluminum isn't as hard as the Speedmaster aluminum. It's almost like the Tfl one is made of pot metal while the Speedmaster is made from billet aluminum. So I'd imagine the Tfl would wear faster. I dunno. I guess I don't have a dog in this fight because I don't use bushings anyway. I've got a couple struts to machine for bearings, if anyone is interested I could take pics as I do it.

[CraigP]

If it can't move then you can't angle the strut unless you make the screw slot in the strut bigger.....so actually it is supposed to be able to move some.

I was talking about a second piece of tubing, not the stuffing tube. I have a stinger strut on my mono, it has a fixed, brass tube in there which sets and provides a bearing surface for the floating bushing. But that tube is in there good, you'd have to drill it out to get it out.

[kfxguy]

I was talking about a second piece of tubing, not the stuffing tube. I have a stinger strut on my mono, it has a fixed, brass tube in there which sets and provides a bearing surface for the floating bushing. But that tube is in there good, you'd have to drill it out to get it out.

Gotcha. Even having a stinger and changing the angle, if the stuffing tube is fixed in it, it still has to slide a little bit. Maybe post a pic.....

[CraigP]

The boat is all together, going to run this evening, so no pic. But on my boat, the stuffing tube comes thru the hull on the outside, extending about 1/4". The stinger housing mounting bracket bolts to the back of the boat and the stuffing tube stub goes thru that. Thst leaves about 0.075" of the tube extended from the mounting bracket. The O-ring goes on that... Then the stinger housing, with its separate bearing assembly, bolts up to the hinge on the mounting bracket. This pinches the O-ring between the stinger and the mounting housing, and provides the ability to move the stinger up and down by compressing the o-ring. So the stuffing tube never penetrates the stinger. They are two, completely different sections. Some stinger setups do have the stuffing tube coming all the way in to the stinger, but I'm not a fan of that setup. I like the two separate sections, with the flex shaft starting just ahead of the O-ring position. This leaves a good, solid shaft in the stinger to work with the bearings. That's how I would use your ball bearing setup in a mono, with the ball bearing races only riding on the solid, hard prop shaft. I believe this is what you are already doing, preaching to the choir!

[Hydrocarbon82]

I just pushed out the Pursuit lead teflon bushings and they're 6.35mm OD x 4.76mm ID & 9.79mm long. That lets a 1/4" OD 0.014" wall K&S tube to slide with a little friction. The overall strut length is 78mm but the 1/4" section is 44.7mm long. The remainder is ID is 9mm. A 3/8" x 1/4" silicone or pvc tube should work great if you're looking to fill that space & seal out the bushing.

The pivot bolt is 66.5mm from the tip, so that's probably the max tube length. Here's a pic for reference:
153719