SH Engines PT21AO-XGB .21 Competition Off-Road Buggy Nitro Engine
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Reviews4.7 · 15 reviews
Normally shake my head at reviews where the person hasn't even used the product yet, but to anybody that buys this, check the carb boot. Mine came with a hole torn in it hiding in one of the creases. Gotta pull the throttle wide open to see it. Boot is plasticy vinyl material. Emailed SH Engines twice via their website but no response. Recommend replacing with a silicone boot like what's used on the O.S. / ProTek Samurai (PTK-2535). Installed the included extra head shim and idled 6 tanks with plenty of heat applied (240°F). Lots of pinch. Included instructions mention the out-of-box carb settings are good for first start, but mine wouldn't fire until leaning low speed 2 turns (~4 from fully turned in). (1/15/2024) Update: 4.5 gallons on the engine now and it's super solid. Replaced front bearing w/ the ProTek/O.S. (PTK-2504) at 3 gallons just to be safe, but included bearing might've been fine. Preheated every start, paired with Dynamite 053MR exhaust, 7.5mm venturi, 0.78mm idle gap (how it came out of the box), Sidewinder off-road 30%/9%. Stable idle, excellent power. Combined with the reasonably priced piston/sleeve/rod replacements, this is the sweet spot in the .21 nitro engine market for 2024. (4/19/2024) Update #2: Made it to 5.6 gallons before swapping in a new piston/sleeve as it finally started to become difficult to maintain a solid idle, although in that last run I was having clutch bearings fail so I might've been able to go a little longer, but I'm satisfied with it. Looks like this engine's been outta stock for nearly 5 months now. Hopefully they come back in one way or another.
Engine has way more power than I thought. First two takes idle, 3rd and 4th powerband starting coming in. Once engine is up in temp, it really comes alive. Engine is fast with good quality materials.
Great motor for the price. There plenty of videos on-line that have reviews on these SH motors. The shipping was fast
Just won my first 20min A-main race easy tune! Can’t beat the price!
Huge Powerhouse , Great Linear and Easy too Tune. It’s gonna definitely give those OS and FX boys a run for there Money. Don’t forget too add the head shim.
Reviewers broadly rate the SH Engines PT21AO-XGB .21 highly for its power and value, with several praising strong top-end performance, linear powerband and ease of tuning, and some noting it as a good budget option for racing or bashing. The most consistent complaint is very tight pinch out of the box, which makes first starts difficult and can wear out starter rubber wheels; reviewers commonly recommend preheating the engine and fitting the included extra head shim. One reviewer reported a carburettor boot with a tear and said emails to the seller went unanswered, and another reported a starter box alignment problem. Break-in and initial carburettor settings required patience for some owners.
- + Strong power and top-end performance
- + Good value for the price
- + Easy to tune with three-needle carburettor
- + Responsive and linear powerband
- − Very tight pinch at first start
- − Can wear out starter box rubber wheels
- − Carburettor boot reported torn and of plasticky material
- − Starter box alignment issue reported by one owner