TTR EK4 S2 Project BEAST MODE

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That's awesome! I have no idea how it'll work, but awesome work!
 
Give it a go and in the meantime I'll look around for a spare
I had to make a new head as the previous owner butchered the original. First he stripped the glow plug thread and then didn't know how to remove the head. This pick is all that was left, I turn it hoping to Tig it up but it's too thin.
 

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Hi guys!
I loved this thread! I'm really an EK4 enthusiast since it was launch back in 2000.
I have 2 of them but to be honest, none of them is working as I would like.
@Nitrotrout, Your project is just amazing! Including some @sv250 tips, wow!!! I have lots of questions for you, Wish you don't mind :)
1. How did you polish the engine and Manifold?
2. I saw you enlarged the the manifold port. Did it work?
3. How did you cut the cooling head? Does it work? Whats is the temperature average there where you are? I'm asking that because I live in Brazil and here where I live, its commom to reach 86F (30C). So, it is extremily important for me that the cooling head works,
4. I saw you are using a Buku clutch. Did it work? Which of buku clutch you bougth?
5. The clutch bell worked?
6. What about the Jammin pipe?
7. Last but not least, what about the overall performance?

Thank you and congratulation for your project.
Ciro.

10530843_10153464826093161_8181797454807939792_n.jpg 600437_10153464825948161_5710616940318358619_n.jpg
 
Sorry it took so long to respond to your post, @ciroalves. I've been wrapped up with work much more than I want to.
I encourage fellow EK4 enthusiasts like yourself to check in with your photos, comments, questions.so feel free to post your stuff here anytime.
To answer your questions:

1. I don't think the engine had much mileage on it so it cleaned up like new with degreaser and some hand scrubbing.
I sanded the top of the cooling head and header with 800 and 1500 grit sandpapers, then hand polished with Aluminum Polish.

2. Until recently, I haven't had a stock .70 engine to compare to so the verdict is still out performance wise.
I'm putting the finishing touches on a stock EK4 restoration so I'll be able to better see any gains.
One things for certain, it has a loud ,raspy idle similar to a two stroke dirt bike that's really bad@ss.

3. I used a hacksaw to cut the cooling head. Then I filed down the burrs smooth, and I used several grits of sandpaper
finishing with a 1500 grit paper, then polished. Seems to be working well so far but I wouldn't recommend cutting the head
unless its absolutely necessary. These engines are notorious for overheating (with the helicopter head) so the massive cooling head is beneficial.
The only reason I cut down the head was because it was sticking up much higher than the body's roof line.
As fate would have it, this thing back flipped on its lid several times so I'm glad I did it.
Summertime temps here in Northern California can range from 70F to 105F, similar to your weather I'm guessing.
If you're having tuning/cooling issues try using a helicopter/ airplane fuel with a high oil and nitro content. I'm currently
using VP Fuel with a 20% oil 20% nitro mix.

4. The Buku clutch seems to be holding up well so far. I haven't opened it up to check for carnage as of yet. The thing I like about
the Buku clutch is the adjustability. I'm using the big block clutch kit #2000ABK-34

5. If memory serves, I used a Losi 14t clutch bell part #Losi Clutch Bell 14T # LOSA9117. So far so
good.
6. Love the Jammin JP-1 for this engine. Its made for bottom end torque which is what these engines are all about.
The stock pipe is junk and could have something to do with your performance issues if that's what you're using.
Whatever pipe you choose be sure its a low end torque pipe.

7. Performance wise, I'm happy with it, It's loud as all get out, it wheelies and backflips on command but I wont know what the true performance
gains are (if any) until I get my other EK4 running. Then I get some true comparisons.

Thanks for checking out my thread! Feel free to post more pics of your EK4's here if you like..:thumbs-up:
 
Hi all
Just found this thread after doing some searching to see if there was any interest in the EK4 anymore.
Well I guess there is still some. Nice to read.
I have one that I bought brand new in from auto haus rc in 2003. I run it it only sometimes.
Let's put it this way it has a gallon of fuel though it in the who,e time I've owned it
Took it out the other day after sitting for 4 years and it fired right up.
I forgot how much power this damn thing has. The low end is just downright unruly. I love it!

Anyhow here is a pic of it







image.jpeg


One more.

I made a lot of pieces for this truck but I still have every single original piece for it as well as the box instructions sales receipt lol
 

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First things first, welcome to RCNT, @COPO .
That's one bad motor scooter you have there. Glad to hear you're still running it.
That MSJ cooling head you have is pretty rare these days and worth a good chunk of change if you ever decided to sell it as you probably know.
Original box and instruction manuals are also very collectible these days
I like the piggy back shocks, it gives your truck a mean aggressive look.
Your body mounts appear to be custom made as well as the lower shock mounts. Very nice. How about the wheels, Tamiya maybe?
 
First things first, welcome to RCNT, @COPO .
That's one bad motor scooter you have there. Glad to hear you're still running it.
That MSJ cooling head you have is pretty rare these days and worth a good chunk of change if you ever decided to sell it as you probably know.
Original box and instruction manuals are also very collectible these days
I like the piggy back shocks, it gives your truck a mean aggressive look.
Your body mounts appear to be custom made as well as the lower shock mounts. Very nice. How about the wheels, Tamiya maybe?
Well thank you there nitrotrout.
The wheels are ofna dominator wheels. Much lighter than the factory ones.
The quad shock set up was all customize by me as well as all the other mounts you see.
 

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The ek4 was sold in 2 versions V1 and V2.
I have the V2 version. It came with a tall round cylinder head but the MSJ is better at cooling. V1 came with a flat head and had lots of problems because if it.
Same for the starter clutch. I have a MSJ. Factory one was weak. The factory starter clutch and head I have wrapped up and put away. They have never been used.
This is the biggest baddest nitro truck ever and I'm glad I own a piece of history.

I also have a mint only driven once Ofna titan twin. It's awesome just for its size alone and another great piece of history.
Highly doubt we will ever see a twin nitro monster truck again. Just my opinion
 
You're right about the two versions. My project was a V1 with the flat helicopter cooling head and dysfunctional header.
The return nipple was drilled directly over the exhaust stinger on the V1 creating tuning issues.
The pipe was revised on the v2 with a screw plugging the initial nipple hole and the return hole was moved back.
There was also an issue with the clutch assembly on the v1 I'm guessing, My v2 has a clutch setup completely different than the v1.
ek4 v2.jpg


The MSJ parts are really difficult to find these days. I was fortunate to buy a v2 on ebay that already had the MSJ cooling head and starter backplate
A couple years ago on ebay I found a complete TTR EK4 upgrade kit unopened, it came complete with every red ERGAL aluminum part offered for this truck.
So I got in a bidding war with some guy and I tapped out at $400.00 bucks.
 
You're right about the two versions. My project was a V1 with the flat helicopter cooling head and dysfunctional header.
The return nipple was drilled directly over the exhaust stinger on the V1 creating tuning issues.
The pipe was revised on the v2 with a screw plugging the initial nipple hole and the return hole was moved back.
There was also an issue with the clutch assembly on the v1 I'm guessing, My v2 has a clutch setup completely different than the v1.
View attachment 17767

The MSJ parts are really difficult to find these days. I was fortunate to buy a v2 on ebay that already had the MSJ cooling head and starter backplate
A couple years ago on ebay I found a complete TTR EK4 upgrade kit unopened, it came complete with every red ERGAL aluminum part offered for this truck.
So I got in a bidding war with some guy and I tapped out at $400.00 bucks.


Congrats Nitrotrout on your rebuild. Just awesome. I have an original EK4 bought new with many MSJ upgrades(including that big purple head you spoke of) I dont think it has a dozen tanks run through it. I kept having issues with the clutch locking up. Last time it did, I put it on the shelf and bought a 1/5 th scale GT2, which also now sits on shelf being too big to drive; unless a lowes parking lot is handy.(and then security would run me off, and that was on sunday after closing). It has a zenoah 230 with modified head. it made so much power, it just spun the tires. That was over 10 yrs ago. I'm not sure what the problem is with the EK4. I can't even turn the motor over. I hope that big motor is ok. I look at both daily passing them on the shelf collecting dust. One day I would like to call you when I am ready to get back to the EK4. It was so much fun when it did run. Anyway thank you for the new inspiration.
 
Hopefully this thread will bring out more EK4 owners of past.
There use to be a website call midmad that was dedicated to the EK4. It is now defunct.
 

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Welcome to RCNT, @twintec99 I'd love to see some pics of your EK4 if you have some handy. Does your rig have the composite shoes like these
ek4clutchshoes.jpg


or the steel shoes like illustrated in post #90 ?
 
I will clean it up and take some pics. I must have just put the msj upgrades on rt before motor locked, as they look brand new. Probably original clutch it has been so long, but has MSJ flywheel, head, rear diff, and starter housing on rear of motor. At the time I bought the EK4, shop recommended those items. A few years later I remember some florida shop via phone telling me I needed to spend 250 to fix clutch issue, but I never got to it. I also owned a Tmaxx that was under powered in comparison. I sold the Tmaxx. I'm sure they have more power now with electric motors and lithium batteries. I am in the middle of a housing project, so not much time for EK4 rt now.
 
Welcome to RCNT, @twintec99 I'd love to see some pics of your EK4 if you have some handy. Does your rig have the composite shoes like these
View attachment 17774

or the steel shoes like illustrated in post #90 ?
I'm guessing those new parts you posted are no longer available?
I have the sliding set up on my V2. Even though the shoes are still in good shape, I'm going to make some out of clutch material I have.
I made this set out of phenolic. Didn't work. Too slippery.
 

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Welcome to RCNT, @twintec99 I'd love to see some pics of your EK4 if you have some handy. Does your rig have the composite shoes like these
View attachment 17774

or the steel shoes like illustrated in post #90 ?
So after tearing the motor down because I just had to know if the motor was OK, I do have the revised clutch like yours. Not sure why my motor was stuck...bearing looked all gunked up. I baked it at 300 and got the piston up to 250. It came loose. I cleaned it up and used Mobil one to lube piston and crank. Did they come out with a better bearing that I should have before putting it all back together? I did not want to force the rod off.

I pulled on it with needle nose and it really was not cooperating. What is your method for getting rod off crankshaft.Maybe I needed to use more force. There did not seem to be any give like smaller engines have. So I hit pause. Motor spins fine now and piston looks brand new. Been sitting for 10 yrs though. So new bearing might be best while torn down. There is really nothing online about this motor.
 

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So after tearing the motor down because I just had to know if the motor was OK, I do have the revised clutch like yours. Not sure why my motor was stuck...bearing looked all gunked up. I baked it at 300 and got the piston up to 250. It came loose. I cleaned it up and used Mobil one to lube piston and crank. Did they come out with a better bearing that I should have before putting it all back together? I did not want to force the rod off.

I pulled on it with needle nose and it really was not cooperating. What is your method for getting rod off crankshaft.Maybe I needed to use more force. There did not seem to be any give like smaller engines have. So I hit pause. Motor spins fine now and piston looks brand new. Been sitting for 10 yrs though. So new bearing might be best while torn down. There is really nothing online about this motor.
Hi there
I'm wondering if the piston got stuck for a short while. Cold seizure maybe. Piston grows faster than the cylinder and the clearance tightens up to the point of interference. Then it cools and can sometimes be restarted but the piston walls are usually wrecked. Just a guess.
That engine looks beautiful.
 
So after tearing the motor down because I just had to know if the motor was OK, I do have the revised clutch like yours. Not sure why my motor was stuck...bearing looked all gunked up. I baked it at 300 and got the piston up to 250. It came loose. I cleaned it up and used Mobil one to lube piston and crank. Did they come out with a better bearing that I should have before putting it all back together? I did not want to force the rod off.

I pulled on it with needle nose and it really was not cooperating. What is your method for getting rod off crankshaft.Maybe I needed to use more force. There did not seem to be any give like smaller engines have. So I hit pause. Motor spins fine now and piston looks brand new. Been sitting for 10 yrs though. So new bearing might be best while torn down. There is really nothing online about this motor.

That piston looks like its way to far up in the pinch!
It should be about an 1/8 down into sleeve!
 
I thought it looked too high as well. Maybe something happened when the piston locked. I see no damage but with head on, when rotating motor, it feels like it could be just barely touching something. I'll take it to the experts in town that sell RC and ask their opinion. Thanks for input.
 
I thought it looked too high as well. Maybe something happened when the piston locked. I see no damage but with head on, when rotating motor, it feels like it could be just barely touching something. I'll take it to the experts in town that sell RC and ask their opinion. Thanks for input.

Once it gets beyond that pinch point ,there is no way that it would run properly & tune!
If the piston /sleeve still looks good ,an is smooth ,you can send it in an have it re-pinched
for $ 20 bucks + $ 10 for shipping ,which is well worth it it!
 
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