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Any tips with the STS D30 for tuning and whatnot?

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olds97_lss

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I recently acquired a savage that has the STS D30 in it. Personally... I'm ready to just throw the engine in a drawer with my axial and forget about it.

But, I figure I might as well see what I can do to make it a little more friendly to run. It probably has about half-3/4 gallon through it including 9 tanks of a heat cycle break-in.

I was with the original owner through the break-in process and every time he ran it after that, which wasn't much.

I ran it the first time yesterday morning prior to doing anything to it just to get a feel for it. It ran pretty bad and I can see why the previous owner was really frustrated with it. If it wasn't tuned overly rich, it would lean bog and just stall for no reason while on the gas. It would also do a weird idle that wouldn't step down once the engine was warmed up. I tuned to keep it below 260F. Regardless of tune, the weird idle wouldn't go away and frequent stalls would occur when on the gas. It also didn't like to idle well at all.

So, I tore it apart yesterday afternoon and sealed it up with RTV. The carb neck, banjo fitting, backplate, carb cinch bolt, LSN threads. I also retapped the starter housing for 3mm instead of what was in it. Put it all back together and took it out today. I had much better results today, but I only had a small spot to run it in due to rain. I ran it in a 60 foot square pavilion at a park with an occasional romp across a parking lot when the rain let up.

Even though it's "better", it's still not an engine I'd give to an enemy. Power is sub-par for what I was expecting, tune is still muddy. It idles well now and no longer has the weird idle that won't drop and it opens up to WOT pretty well if I don't let it sit and idle for more than 15 seconds or so. I still had frequent stalls when on the gas, which I just have never had before. Like 2/3 throttle, then dead. No weird sound, no fluctuation, just flat out stall.

I'm running 25% fuel with an OS8 plug and an MC59 plug. The MC59 plug was the starting choice today and I ended with the OS8. The inner coils in the MC59 plug were compressed pretty bad which if I remember correctly means too much compression?

Anyway, power is weak at best from 0-1/2 throttle, stalls inexplicably and tune is muddy to keep it below 260F.

Any tips? Or should I just give it more time? I notice I can still feel a heavy mechanical pinch with the GP out, even when at temp.
 
You are on the right track. A STS 0702 pipe will help it tons.
All the newer STS .30's have way too much pinch, they usally crack the piston/rod/ crankshaft instead of actually breaking in. This was confirmed by Rick Brake at RB Mods, it is why he quit selling modded STS's. The quality is horrible
Stick with the MC-59 plugs until it breaks in then drop to the MC8.
I have a RB modded crankshaft that will make it scream if it ever breaks in right. It's yours if you want it.
Add a head shim to it to help relieve some compression, it helped on my buddy's STs which acted just like yours.
I had a good STS .30 at one point. It's needle settings were; LSN 2-3 mm out past the carb ball link.
HSN around 2 1/2 turns out from bottom.
Hope that helps.
 
Just found these guys on google.
http://nitrocountryrc.com/button-gasket-d30m-p-927.html
I added an extra copper shim to my bud's engine, it still ended up cracking the piston.
If it keeps crushing glow plugs, tear it down and look at the underside of the piston at the wrist pin. His cracked there, it still ran but kept killing plugs.
 
No problem, also forgot to mention the JP-2 pipe works even better on that engine. We put my modded .30 in a racer Aftershock with a JP-2 and it was just plain nuts.
Rick Brake suggested the JP-2 to me, and man was he ever dead on.
 
Well... in my stupid state, I found a spare head shim laying in a drawer. It was too small of course, so I lightly ground out the center until it fit.

One thing I did notice when pulling the head was that there was a lot of oil that appeared to seep out from where the sleeve and crank case meet. I've never put anything there on any engine to seal it... so I figured I'd clean it really well with DA (both the lip of the sleeve and inner area of the crank case) and put a bead of RTV around there, just enough to seal it. Probably a poor idea... but was quickly backed up with another poor idea of grinding a head shim. Although, I've ground a shim before and it worked just fine for many years.

Too bad the JP2 is a side pipe... and you can't put a exhaust deflector on it. Two bad things IMO for the savage or any other MT where you can point it at the ground.
 
That leaking at the head is sure sign the engine is defective. That's the same problem we had and could never stop. Too much damn compression, the piston and sleeve are actually too tight and for some reason they do not want to relax. Maybe put a Valium in the fuel tank???:hehe:
The RTV on the head is a horrible idea man, scrape it off. Order a fresh set of shims see if that helps. If not send it back to STS and ask for a D28M in place of it. Those are the best engines they made.
 
AND HOW!

I don't think the RTV will hurt anything. I put it around the base of the lip between the sleeve and crank case. That's where it appeared to be leaking from, near where the pin is that keys the sleeve to the crank case. Not between the head shims or that area.

Regardless, I got a HB long chassis savage with minimal use for an OFNA jammin XB1 buggy that was pretty well used. I kind of wish I had kept the engine too, XTM24.7... but I think the main reason the guy wanted to trade was because the engine was fighting him so much.

Every few years, I pick up a buggy roller for $100, like this one. So I don't think even with the engine being crap that I lost anything. Considering I cracked the seal on the STS, I doubt STS will swap it for a new one or the 28. Which is fine for me. I'll probably get a picco 28 for my aftershock and throw my LRP from it on the savage next year. Or get another LRP.

Considering that I read that I can't re-pinch the STS due to the sleeve being so thin and causing warping... it's kind of a throw away engine anyway. Just figured I'd try and get a bit of life out of it. If not, it will make a nice friend in a drawer for my Axial28 that I gave up on after a gallon of anger.
 
lol, I just pulled one of my old Axials out for my CRT Pro project. I hope it likes the CRT better than it did my Muggy. If not I have a Picco .21 3 port that runs great.
 
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