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Heng Long Abrams "Overhall and Rebuild"

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Old 07-24-2018, 10:32 AM
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Default Heng Long Abrams "Overhall and Rebuild"

For almost a year now I have been using one of my Abrams as a "test bed" for developing simple ideas towards improving top end scale speeds, cross country performance and durability. Some of these ideas were dead ends some exceeded all expectations and were then incorporated into my other tanks in one form or another. During the testing of the different improvement ideas this tank has been run hard and abused for many hours of jumping, hard turns at high speed, smash, bashing, crawling over rocks, debris, through dirt, sand, mud and snow. This experimenting with ideas turned a simple "test bed" tank into an off road monster that performers somewhere between a Baja Trophy race truck and a Jeep rock crawler. But the abuse of hard testing and running hour after hour has taken its toll on the hull, tracks, motors and some bearing to the point where they need to be completely overhauled or replaced.




Items being replaced:

The lower hull do to broken idler wheel mount and extensive forward hull glance impact scratches and rear hull gouges caused by the track slipping while testing running only one retainer ring. The scratches and gouging are more cosmetic than anything. The idler wheel mount is another story.

The HL 390 red motors are worn to the point that they no longer perform at an acceptable level and have lost a fair amount of toque. This is to be expected with brushed motors and the abuse these have seen. Given the history of good performance with these motors I will be replacing them with another new set of HL 390 motors.

Rear hull bearing and mount (all but exploded). This bearing and mount were from a HL Challenger 2 and were made to work/fit in this Abrams. No surprise one finally failed. These are being replace with new HL hull bearings made for the Abrams.

DKLM tracks. I finally worn a set out!! The rubber pads are worn down to the metal and they have lost a fair amount of their prior grip. The track, though abused beyond belief has never broken or failed. No rubber pads have been lost or ripped off. It is easy to say I will be replacing them with new DKLM Abrams track as they have proven to be worth every penny.

Suspension springs are being replaced with fresh ones as they have lost a fair amount of strength. I am also taking this opportunity to refine the suspension down travel stops as these are still the mismatched prototype testers.

Items being rebuilt:

The HL steel gearboxes are being dissembled, deep cleaned and inspected. At this point in their life they run butter smooth and have proven extremely durable so they are being kept in service.

The road wheels and suspension arms are being deep cleaned and repainted to match the new lower hulls paint tone.

I will be following up with photos of the overhaul and rebuild process soon, so check back.

Last edited by Fsttanks; 07-24-2018 at 02:39 PM.
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Old 07-24-2018, 02:25 PM
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The following photos show samples of the wear, gouges, broken parts and new replacement hull.


Lower hull set to be replaced.


Close up of broken idler wheel mount.


Lower hull scratches and deep gouges caused by rocks and concrete obstacles.


Rear lower hull with deep gouges cause by the metal tracks slipping off sprocket while running only one retainer ring during some recent testing. Also shows the remainder of the axle hull bearing support.


Worn out and damaged track pads.


New replacement hull show next to worn hull.

Last edited by Fsttanks; 07-24-2018 at 02:30 PM.
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Old 07-24-2018, 02:46 PM
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Man I wish you could have come to our modern battle this last sunday. We had a blast with fast tanks whipping around the field. My abrams did great with no failures and performed exceptionally with the 12volt ibu and red motors, though its still slower than a tamiya, i want to go up to something like a 480 motor maybe. My 5amp battery cam handle the run time just fine i think.
my only glitch was a few rocks that got sucked up above the track and got jammed above the track beteen the two return roller supports. Was kinda strange to figure out and find.
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Old 07-24-2018, 04:05 PM
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Originally Posted by RichJohnson View Post
Man I wish you could have come to our modern battle this last sunday. We had a blast with fast tanks whipping around the field. My abrams did great with no failures and performed exceptionally with the 12volt ibu and red motors, though its still slower than a tamiya, i want to go up to something like a 480 motor maybe. My 5amp battery cam handle the run time just fine i think.
my only glitch was a few rocks that got sucked up above the track and got jammed above the track beteen the two return roller supports. Was kinda strange to figure out and find.
An unforeseen event came up the night before so I could not make it down to watch. Also had to send back the IBU2U I bought as it had "issues" that could not be resolved and so I had no IR ready tank. Going to see if the OpenPanzer board is less problematic. Either way I will be there for the trials in Sept., one of the reasons I am doing this overhaul now.

Outrun by a Tamyia Abrams is surprising given 12v of power, 3:1 gears and red motors of your Abrams? That is puzzling as I have outrun Tamyia Abrams and Leopard 2s, but then I do not know your entire set up beyond the above. Was the Tamyia Abrams heavily modified? There are most likely still a few tweaks you can make to your Abrams to enhance its efficiency before going to 480s. I can PM some ideas to possibly consider that made for fair improvement in my top end (kind of keeping them under my hat for now) just let me know if you are interested.

The rock getting stuck between your return rollers is a new one. That must have been a head scratcher...

Last edited by Fsttanks; 07-24-2018 at 04:22 PM.
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Old 07-24-2018, 04:19 PM
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Yes it was for sure, only problem i had, and it was 4 rocks at onces or one that broke into 4.
the tamiyas have a switch in the turret for standard mode and then move it for ludicrous speed. Thats where they can get me.
i would like a bit more speed when i de-null my throttle and go all out for a charge.
pm me and send your phone number, or just email me from the flyer you picked up at tank fest.
im also curious to the ibu2u issues, man i have older ones but ive heard some bad stuff on the Us out now.
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Old 07-24-2018, 04:32 PM
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Originally Posted by RichJohnson View Post
Yes it was for sure, only problem i had, and it was 4 rocks at onces or one that broke into 4.
the tamiyas have a switch in the turret for standard mode and then move it for ludicrous speed. Thats where they can get me.
i would like a bit more speed when i de-null my throttle and go all out for a charge.
pm me and send your phone number, or just email me from the flyer you picked up at tank fest.
im also curious to the ibu2u issues, man i have older ones but ive heard some bad stuff on the Us out now.
PM sent to you Rich.
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Old 07-24-2018, 04:41 PM
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Huh, it hasnt arrived
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Old 07-24-2018, 04:58 PM
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Originally Posted by RichJohnson View Post
Huh, it hasnt arrived
I just sent it again.
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Old 07-26-2018, 03:40 PM
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Progress on overhaul this week. Still waiting on a few small parts and new DKLM track to arrive.


New hull with suspension down travel limiters installed and ready for parts install.



Installing modified suspension arms.



Installing clean (internally) and inspected road wheels.



Old motor and gearbox.



New motors assembled onto cleaned and inspected gearboxes.



New hull bearing support and return roller installed on hull.



New hull bearing support and return rollers installed on hull. Using M41/26 rollers mounted slightly higher to aid in additional track retention and tensioning.



Close up of new hull bearing support.



Motors and gearboxes installed in new hull. Yes, the gearbox one on the left is a mid mount not the normal high mount.



Electronics going in. Note the new cooling fan to help reduce high electronic temps that come with 9+ volts. Also added a grease/oil splash shield over the gearboxes and a metal hull support strut.

As alway your question or constructive comments are welcome.

Last edited by Fsttanks; 07-26-2018 at 03:44 PM.
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Old 08-02-2018, 02:29 PM
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Default Update on "Overhaul"

Overhaull has proceeded well and is complete. Here are the final pieces of the overhaul.

Prior to securing the hull bearing supports (seen in above post) in place I saw that the supplier of the Heng Long supports now has new Heng Long supports designed specifically for the Abrams. These supports are longer and provide better bracing for the drive shaft (see photo below tan support) so I ordered a set for use on this project.

I also decided to modify the rear sprockets by drilling out "lightening / debris evacuation holes" similar to those found on the real Abrams and many other tanks. One of the biggest issues I have is with the sand/dirt and hidden pee size pebbles found mix within. These separately don't cause to big of an issue, but when mixed and packed together tend to cause jamming issues between the sprocket and track. The new sprocket holes help with the evacuation of the sand/dirt and thus greatly reducing any jamming issues. Plus I think they add a bit tougher look to the rear section of the Abrams.

The new track is still ~10 days out so I went ahead and reinstalled the old tract. I soaked it overnight in soapy water and then pressure washed it the next day to remove any remaining small sand or dirt particles. Once that was does I summerged the track in Gun Blue which turned them a rusty dark gray which in person looks great, but does not show well in the photos below.

Once the new hull bearing supports were attached I put the sprocket and tracks back on and it was off to the test range on one very hot and dusty day (110deg). The ground temp was 133-152deg. depending on the color of sand/dirt. I mention this because this was not just a mechanical function test, but also a test for the new internal cooling fan. During the testing (45min time frame) I took several internal temp readings. With the fan o n the temp hovered around 110deg. With it off the temp quickly reached 150+. The outer hull that was exposed to the sun turned in temp readings of 123deg and the lower hull running close to the hot sand was running in the range of 130-140degs depending on the amount of power I put into the motors. Point to all this is the fan seems to work well at keeping the internal heat from roasting the electronics.

Overall testing of the new hull, new motors, new return rollers, new fan and sprocket mod s went well. The track is tight and except for one instance where I deliberately and completely buried it in sand had no de-tracking issue. Even then it was able to re-track itself with a simple backing movement. Something given the severity of the de-track it could not have done prior to the overhaul improvements. I believe the ability to re-track was due to the improved return roller and its position closer to the sprocket.

As always your constructive comments or questiosn are welcome.

Below are the photo showing the above:


On left (tan) is the new HL Abrams hull support bearing compared to the T90 bearing that was used prior.


The new hull bearing support installed. I used epoxy to secure it and give it a formed in place look.


Close up.


Heng Long metal sprockets, stock on left and modified on right.


Close up of modification installed on tank.


Close up of modification installed on tank.


Testing the sprocket modification in sand. Sand temp was 136deg.


Sand testing of sprocket modification.


Transiting from sand to rock crawling test.


Testing to ensure proper suspension performance. Note that the increased wheel travel aids in keeping the tract tension tight.


Even with badly worn track pads the DKLM tracks in combination with the modified suspension on this Abrams has good grip.


Testing the reinstall suspension. Note how the longer front road wheel down travel is acting to aid in tensioning the tract.


Testing the reinstalled suspension. Here the longer down travel on the rear road wheel is acting to aid in tensioning the tract.

Last edited by Fsttanks; 08-02-2018 at 09:49 PM.
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Old 08-02-2018, 07:33 PM
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Hi Fsttanks
Like what you're doing with this.
What size holes did you drill in the sprockets? I've done similar with some of my plastic M41 sprockets - haven't attempted the metal ones as yet - in an effort to replicate the real M41 sprockets. Think I made mine 6mm?
Where did you get the sprocket support bearings? Have been doing similar with my M41, using bog, but a pre made part looks much easier.

Mal
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Old 08-02-2018, 09:32 PM
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Originally Posted by afv aficionado View Post
Hi Fsttanks
Like what you're doing with this.
What size holes did you drill in the sprockets? I've done similar with some of my plastic M41 sprockets - haven't attempted the metal ones as yet - in an effort to replicate the real M41 sprockets. Think I made mine 6mm?
Where did you get the sprocket support bearings? Have been doing similar with my M41, using bog, but a pre made part looks much easier.

Mal
The new sprocket holes are just over 7mm and there are four hole in each. I still have room left on the sprocket to increase the holes size to 9mm. Though 7mm seems to work well. They are not perfectly at 90 deg. to each other as I “eyeballed” the drill points but most people would not notice except under close inspection. I first did this mod on my “Modernized” M41 that is running the same Abrams sprockets and metal/rubber track. The M41 was kind of an experiment that has proven to work and is easy enough to do so I added it to this overhaul project.

The new HL Abrams hull bearing supports were acquired through Aliexpress.com. Have to search “Heng Long Abrams parts” and then sift through a few pages of parts to find it. They are reasonably cheap and work as expected.

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Old 03-11-2019, 03:51 PM
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Thanks for this and your other builds and mods Fsttanks! I'm enjoying making these mods to my Abrams, have the bearing holders on order from Aliexpress and just finished the suspension arm stops mod! Still need to hit the auto store for the nylon washers. This is a lot of fun and your pictures inspire the confidence to go ahead with them. Even though I don't have your tough terrain it's good to know my M1A2 will be ready for it!
Let me ask, when you added the bolts and nylock nuts to your wheels did you sleeve the bushings with something or are the wheels running on the threads of the bolts?
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Old 03-11-2019, 11:20 PM
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Originally Posted by JREEVES View Post
Thanks for this and your other builds and mods Fsttanks! I'm enjoying making these mods to my Abrams, have the bearing holders on order from Aliexpress and just finished the suspension arm stops mod! Still need to hit the auto store for the nylon washers. This is a lot of fun and your pictures inspire the confidence to go ahead with them. Even though I don't have your tough terrain it's good to know my M1A2 will be ready for it!
Let me ask, when you added the bolts and nylock nuts to your wheels did you sleeve the bushings with something or are the wheels running on the threads of the bolts?
The wheels are riding on the suspension arm "axle" shafts (note these are metal HL arms and metal HL non bearing wheels). The screws are not in contact with the wheels. The wheels are held on with the use of small locking nuts and nylon washers attached to the screw and tightened to a snug point. It is important that the axle shafts and all nylon washers be lightly lubricated. The screw and lock nut will work without the enlarged hub modification seen on my suspension arms and on the back side of the wheels, but without this modification there will not be any reduced wheel wobble, it will just hold the wheels on tighter.

Hope this helps.

The Abrams is still running great. Shown below vvvvvv getting some air time at one of the recent "LA Tank Battle Days". I enjoy putting on a show with it, folks think I am crazy jumping it and can't believe how much of a beating this Abrams can just shake off and keep running.

Screen shot of Abrams "getting air" during drive demo at recent IR tank battle day.

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Old 03-12-2019, 02:51 AM
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Do you remember what size bolts and nuts you used? Your Abrams looks awesome!
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Old 03-12-2019, 04:46 AM
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Just now seeing this rebuild and it's pretty amazing! It's great to see that with some care and modification these tanks can take quite a beating.
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Old 03-12-2019, 09:00 AM
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Fsttanks, I wish you lived closer to me, it would be fun to have you and your tanks come up to Tankland and shake things up a bit. As it is, I'm watching what you are doing, and I'm learning. Thanks for pushing the envelope.
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Old 03-12-2019, 09:44 AM
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Originally Posted by JREEVES View Post
Do you remember what size bolts and nuts you used? Your Abrams looks awesome!
The Abrams shown has 2x18mm screws and lock nuts. They can be tight to fit as the HL metal arms are not super consistent from batch to batch. I have used slightly smaller and slightly larger diameter screws/nuts when building sets of these arms and wheels for others. I would recommend starting off with 2mm and determining the need for change from there, but whatever the size keep all the screws and nuts the same measurements.
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Old 03-12-2019, 09:45 AM
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Come down to a socal battle Pah, and youll likely see them.
Where is tankland?
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Old 03-12-2019, 11:37 AM
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Tankland is in western Colorado. It's the place where 99% of my tank pix and movies are made. It's about 13 miles NW of the RGS headquarters. The area inside the red line is Tankland.

Last edited by Pah co chu puk; 03-12-2019 at 11:56 AM. Reason: added picture of tankland
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Old 03-12-2019, 11:39 AM
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and I do get down that way in the summer to get my beach fix, so please keep me posted on your battle dates. I can bring tanks to California. I took tanks to Arizona.
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Old 03-12-2019, 01:37 PM
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You probably wantbto come to our modern battle. Back channel me your email and i will bet you on the list.
If your on facebook we post everything there. https://www.facebook.com/groups/SanDiegoRCTankBattles/
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Old 03-12-2019, 06:25 PM
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PM sent.

You can see from the Google Earth image that Tankland would be a good place for Fsttanks to kick up some dust. It would be fun to check out his high performance tanknology first hand. If I can work out the timing, it would be fun to meet you guys San Diego next summer.
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Old 03-15-2019, 04:24 PM
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Great ideas here for mods. I'm just getting back into this and dusted off my Leo last week. Got it back up and running this morning after a week.of putting it back together. Love the work on the suspension.
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