After years or searching the Unicorn of Monster Trucks is finally mine! And....

[tudordewolf]

The history of attempts to make sub-cubic-inch gasoline engines is fascinating, fraught with products that struggle to get past the proof of concept/early market phase.

The 15cc Octane is just about .92ci, and seems to run fairly well.

There's the 4-stroke Toyan S100G, with .21ci of displacement. There's also a gasoline conversion for their 2-cylinder inline, might be a fun build.

The Dynamite .31 XXL, mentioned by @WVNed

I know it's slightly beyond the scope of the discussion to mention airplane engines, but there's also the SH GF6 (.37) and GF9, (.55), notable for using gas-activated glow plugs instead of spark ignition. OS has made plugs for that purpose, too. The Turnigy TP10 is a 10cc (.61) gas engine, maybe it has modding potential for surface use.

 

[rceverywhere]

Wow lucky find! I've been looking for one, and yes very rare. Was even thinking to buy the parts loose to swap my green body savage flux xl that came out. It's the left over frame body and tranny housing hpi dumped instead of fixing the issues. There was alot of hype forvthev1/8th scale gas after the hit of the 1/5th, but I think people where expecting too much from them and got turned off by the issues. To bad, I wanted one but couldn't at the time available

 

[Chubaka]

Wow lucky find! I've been looking for one, and yes very rare. Was even thinking to buy the parts loose to swap my green body savage flux xl that came out. It's the left over frame body and tranny housing hpi dumped instead of fixing the issues. There was alot of hype forvthev1/8th scale gas after the hit of the 1/5th, but I think people where expecting too much from them and got turned off by the issues. To bad, I wanted one but couldn't at the time available

There are some on ebay. $4, 5, 600.

 

[rceverywhere]

Realy! Last I checked I found just engine and ignition box 550$ maybe cause I'm in Canada, I'll check .com to see

 

[Chubaka]

Realy! Last I checked I found just engine and ignition box 550$ maybe cause I'm in Canada, I'll check .com to see

I stand corrected. 3 or 4 weeks ago they were there. I was looking up savvy xl parts.

 

[rceverywhere]

I stand corrected. 3 or 4 weeks ago they were there. I was looking up savvy xl parts.

I don't check often enough to catch them I guess, need to put lots of effort into it, no matter what your goals

 

[janxon1022]

Finally an owner of the HPI Savage Octane!
But wait, there's more!
Its brand new, never seen fuel.

Hey guys, I have been after this truck for a long time, never thought I'd own one, let alone in a brand new condition.
I am aware this is one of the biggest RC let downs out there, but also a lot of people have got it working perfect with a bit of patience and TLC.
Apparently, a common mistake was thinking that the engine can be broken in with only a few tanks of fuel, when it really needs about 20 or more.
As always, I love challenging projects, so this fit right in.

Kind of just want to leave it as a shelf queen, but the temptation to fire it up is high!

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Very nice Savage collection my man.

 

[rceverywhere]

Found some info on big squid rc, black pipe is v1, aluminum pipe v2, and the engines where pre broken in
Ignition module was moved and a heat sink added

 

[WVNed]

Yes
Mine was pre broken.

 

[gandalfnz]

The history of attempts to make sub-cubic-inch gasoline engines is fascinating, fraught with products that struggle to get past the proof of concept/early market phase.

The 15cc Octane is just about .92ci, and seems to run fairly well.

There's the 4-stroke Toyan S100G, with .21ci of displacement. There's also a gasoline conversion for their 2-cylinder inline, might be a fun build.

The Dynamite .31 XXL, mentioned by @WVNed

I know it's slightly beyond the scope of the discussion to mention airplane engines, but there's also the SH GF6 (.37) and GF9, (.55), notable for using gas-activated glow plugs instead of spark ignition. OS has made plugs for that purpose, too. The Turnigy TP10 is a 10cc (.61) gas engine, maybe it has modding potential for surface use.

Your technical input and knowledge is always appreciated mate!
Out of my scope I guess modding wise, and there's a serious lack of time on my side, not sure why I even keeping buying more cars.

Ran the first tank in the Octane today, it went without a hitch, very rich/groggy, and loud as f.....
So far so good.

Found some info on big squid rc, black pipe is v1, aluminum pipe v2, and the engines where pre broken in
Ignition module was moved and a heat sink added

Do you mean that the engine is already broken in? Really?
Could you please link that info for me?
I think that info might be false, as I am pretty sure mine is V1 (nothing was relocated) and it has chrome exhaust pipe.

I had issues with the steering servo randomly twitching when the car runs, I then separated the RX antenna and ignition module a bit more, and now it seems to be OK.
Ignition box is still inside the battery compartment, I did not move it outside.

Yes
Mine was pre broken.

Pre broken in models or V2 was never released to the public as far as I know?

 

[WVNed]

Mine was broken out of the box and would not start. An inspection revealed piston damage.

Thus it was pre broken.

 

[rceverywhere]

Your technical input and knowledge is always appreciated mate!
Out of my scope I guess modding wise, and there's a serious lack of time on my side, not sure why I even keeping buying more cars.

Ran the first tank in the Octane today, it went without a hitch, very rich/groggy, and loud as f.....
So far so good.

Do you mean that the engine is already broken in? Really?
Could you please link that info for me?
I think that info might be false, as I am pretty sure mine is V1 (nothing was relocated) and it has chrome exhaust pipe.

I had issues with the steering servo randomly twitching when the car runs, I then separated the RX antenna and ignition module a bit more, and now it seems to be OK.
Ignition box is still inside the battery compartment, I did not move it outside.


Pre broken in models or V2 was never released to the public as far as I know?

https://www.bigsquidrc.com/3-updated-savages-being-shown-by-hpi/

 

[gandalfnz]

Third tank completed today.
One issue, it was leaking oil at the exhaust, where it meets the engine block.
I have applied high temp gasket maker silicone, so that should be fixed.
Runs really well so far, fingers crossed it stays that way.

 

[gandalfnz]

5 tanks completed, I have leaned it just a tad. No issues so far. Very sluggish.

 

[gandalfnz]

Hi Guys

Just another update

So far the truck has had 10 tanks trough it.
Replaced 1 fouled spark plug, which is normal, since it was running pig rich.
I had to adjust the second shift point, because it was not shifting, actually its quite weird, its like those gearboxes seize in a way, when sitting idle for too long.
Even after lowering the 2nd gear shift point, it was shifting every 7th WOT, which I found odd. Then all of a sudden started shifting every time.
I remember I had the same problem with my XL 5.9

Very happy with the truck, hopefully it stays that way.
Its rather quick in second gear, I will have to adjust the third later on.

Oh, and I have also been leaning the HSN by 1/36 of a turn after each tank, after the 5th tank of fuel.
I think I almost have it dialed in good, but since I have no experience with turning a walbro/petrol its going to take a while to get to know how to tune perfect.

I thinking that tuning is more or less the same as for Nitro, adjust HSN until nice and crisp at top end, then adjust LSN for good take off.
Is there anyone here who has experience with walbro tuning?

Thanks

 

[cbaker65]

Hi Guys

Just another update

So far the truck has had 10 tanks trough it.
Replaced 1 fouled spark plug, which is normal, since it was running pig rich.
I had to adjust the second shift point, because it was not shifting, actually its quite weird, its like those gearboxes seize in a way, when sitting idle for too long.
Even after lowering the 2nd gear shift point, it was shift every 7th WOT, which I found odd. Then all of a sudden started shifting every time.
I remember I had the same problem with my XL 5.9

Very happy with the truck, hopefully it stays that way.
Its rather quick in second gear, I will have to adjust the third later on.

Oh, and I have also been leaning the HSN by 1/36 of a turn after each tank, after the 5th tank of fuel.
I think I almost have it dialed in good, but since I have no experience with turning a walbro/petrol its going to take a while to get to know how to tune perfect.

I thinking that tuning is more or less the same as for Nitro, adjust HSN until nice and crisp at top end, then adjust LSN for good take off.
Is there anyone here who has experience with walbro tuning?

Thanks

Yea me ,experience with Walbro & Zama carbs ,single & 2 needle!

On 2 stroke gas ,H needle should only be turned until the highest note sound is heard from the carbs
factory setting ,once the highest note is achieved ,you should not lean anymore as it is taking away fuel
an oil!

The L needle should be adjusted when the butterfly is all the way closed with the idle set screw at its
neutral position ,an adjust the idle with the L needle to keep it running at idle when the butterfly is closed ,then from there you can
lean or fine tune for snappier take off!
It doesn't take too much turns of either needle ,per say ,just a width of a screw driver blade in increments!..

 

[gandalfnz]

Yea me ,experience with Walbro & Zama carbs ,single & 2 needle!

On 2 stroke gas ,H needle should only be turned until the highest note sound is heard from the carbs
factory setting ,once the highest note is achieved ,you should not lean anymore as it is taking away fuel
an oil!

The L needle should be adjusted when the butterfly is all the way closed with the idle set screw at its
neutral position ,an adjust the idle with the L needle to keep it running at idle when the butterfly is closed ,then from there you can
lean or fine tune for snappier take off!
It doesn't take too much turns of either needle ,per say ,just a width of a screw driver blade in increments!..

Ah mate, you just answered my biggest doubt, and that's the idle screw/butterfly and LSN relation.
I was wondering, why is the butterfly always kept fully closed, and what should be the factory idle gap, and why no-one ever mentions when they tune about adjusting the idle with the idle screw.

When you say "highest note" for HSN, do you mean as soon as it stops 4 stroking, because I can still hear it 4 stroke when pull the trigger all the way?

Thanks a lot!!!

 

[cbaker65]

Ah mate, you just answered my biggest doubt, and that's the idle screw/butterfly and LSN relation.
I was wondering, why is the butterfly always kept fully closed, and what should be the factory idle gap, and why no-one ever mentions when they tune about adjust the idle with the idle screw.

When you say "highest note" for HSN, do you mean as soon as it stops 4 stroking, because I can still hear it 4 stroke when pull the trigger all the way?

Thanks a lot!!!

I would say if full WOT an the engine wants to start cutting out ,then it is too lean an starving of fuel!
If you still hear a 4 stroke sound ,then it may can still be leaned until the 4 stroke sound dissipates in
which that is what I meant ,once a high note is heard off the 4 stroke sound ,it is a balance that
can only be achieved by ear!
Once that high note hits an the engine maintains that high note ,no further leaning should be done!..

An you are correct on that 4 stroke sound ,it has a very distinctive sound ,an a engine can hover back & fourth
from 4 stroke to high note sound ,that tells you that the H needle tune is very close an only needs a touch!..

 

[gandalfnz]

I would say if full WOT an the engine wants to start cutting out ,then it is too lean an starving of fuel!
If you still hear a 4 stroke sound ,then it may can still be leaned until the 4 stroke sound dissipates in
which that is what I meant ,once a high note is heard off the 4 stroke sound ,it is a balance that
can only be achieved by ear!
Once that high note hits an the engine maintains that high note ,no further leaning should be done!..

An you are correct on that 4 stroke sound ,it has a very distinctive sound ,an a engine can hover back & fourth
from 4 stroke to high note sound ,that tells you that the H needle tune is very close an only needs a touch!..

Thanks so much from advising on this.

The plan is ( I read this on some other forum and I think it make sense), full throttle and keep it there for a few secs while leaning the HSN at the same time and listening for that high note peak you are talking about. That will be HSN tune completed.

Then for LSN, while coming off WOT, when you reach that mid-low RPM, 4 stroking can be heard again, keep leaning LSN until 4 stroking when slowly coming off WOT is gone.

This is my plan of attack.


Thanks!

 

[cbaker65]

Thanks so much from advising on this.

The plan is ( I read this on some other forum and I think it make sense), full throttle and keep it there for a few secs while leaning the HSN at the same time and listening for that high note peak you are talking about. That will be HSN tune completed.

Then for LSN, while coming off WOT, when you reach that mid-low RPM, 4 stroking can be heard again, keep leaning LSN until 4 stroking when slowly coming off WOT is gone.

This is my plan of attack.


Thanks!

I've only adjusted LSN from idle to quick throttle response to just get it out of boggyness!