HPIs RcRob

Got a stock .26 Hot Bodies engine in my lightning. Running it yesterday, it appeared to be rich (ie steady smoke stream, relatively low top-end RPM), and I have it set rich to where the low speed needle is not flush with the carb body but sticking out slightly, but it got damn hot! My temp gauge is out of battery at the moment but i'd say it was around 350-375F. I'm running a #8 OS medium plug and always have, here in SoCal it's usually in the low 80s outside right now. Any advice out there to lower the temps?? Maybe just a colder plug?

HerrSavage

Don't mean to be a jerk and put a damper on your parade, but of all the engines I've had, the HB 26 was the worst. It was constantly all over the place with the tune, rich-but-hot, etc.. Probably air leaks all over the place.. I gave up on that thing pretty quickly..

HPIs RcRob

No insult taken haha I've had a new engine in mind for a while now, I very much know it's a sh1t engine but just trying to make what I have work as best as it can..

Mpower25

hey! having the same problem in a hot body .28 axial engine, in factory settings in idle is reaching tem 320F aprox , and using 20% nitro. I test for air leaks but everything is good, and the glow plug is R5 O.S

Argess

I think that Hot Bodies 26 might be the same engine as the Force 26. I had a Force 26 in my OFNA buggy, and the tune was always touchy. I found using an OS A5 glowplug (cold plug) helped keep the temps down. Using Backyard Basher fuel was a real killer for heat. I think it was the high % of oil, so I switched to Sidewinder Race fuel and it ran a lot cooler.

I also bought an extra large cooling head for it. For most engines that isn't a good answer for heating issues, but I compared the 26 to the 28, and noticed that there was a huge difference in the amount of cooling fin area on the 28, so it did appear the 26 cooling head was not sufficient.

As others have said, it's easy to set the HSN a bit too lean IF the LSN is set a bit too rich. Lean the LSN out a bit and then retune (richen) the HSN a bit. You may have to go back and forth until you're happy with it. I think I wound up with my LSN turned in from flush about 1/2 a turn. Anyway, it was somewhere between flush and 1 turn in.

I noticed my 26 would detonate at about 320degF, so you want to keep the max temp under 300degF. I check this after doing a couple of WOT runs.

As I was sticking with 20% nitro, I thought I'd experiment a bit with head shims. I added one, and the engine temp dropped drastically. Unfortunately, I was trying to hard to build up some heat, and broke the conencting rod. It wasn't all that traumatic for me as I'd run many, many gallons through it prior to this. I think of I ever got another one, I'd try playing with the shims again, as I think my engine was already on its last legs anyway, but I caution you, as mine did break when I did this. Not hot enough, so tight piston and sleeve, and then running it too hard just overloaded the old connecting rod and it let go. Adding a shim might require another break-in to be performed.

But I won't get another one. It was by far, the most touchy engine for tuning I've ever owned. For a budget engine, the 28 is better by far, as it keeps a tune better, runs cooler, and is more powerful.