Well Today was a really great day. Just to give a bit of background ... I've not owned a nitro anything in something near 17 years and after being given a cash value to spend on something by my employer I went a bit gaga and instantly thought "Monster Trucks" a colleague at work had just bought a WheelieKing and it sent me off on one again. So after getting my ModelSportUK vouchers in the mail I promptly bought an HPI Savage 3.5 RTR. That arrived 5 days ago and today (Saturday) was Break In day. I've never broken a nitro engine in from new so this was all new territory. Anyway, if your reading this and in the same situation I have two words for you.

WORRY & DONT ...

I've just finished my first days bashing and all was well sweet. From reading all I could find on the topic to talking with my brother (who has broken in literally hundreds of nitro engines over the years) it can all sound really complicated, time consuming and laborious. Firstly, I'm no expert on the topic which is why I wanted to write this up from a newbies point of view. The forums from HPI are fantastic, full of great people but I was continually finding references to things and thinking ... what's that mean? Eh? Why ... er ... oh! Oh NO! ... you get the picture. So I'm writing up my day from an idiots point of view!! With pictures! YAY!

I need to make some things clear. This write up is based on a Savage 3.5 with an HPI Nitro Star .21BB (3.5cc) engine and you should follow YOUR engines instructions or you could risk voiding your warranty. That said, from reading the forums and talking to people the manual I have really did neglect to mention some important things to consider. These engines are tight when they're new. I mean 38,000 rpm is not something to trifle with. If you do the calculations that means the pistons are completing cycles in milliseconds!!!! Incredible ... anyway ... lets get on with it. Here's the 21BB Manual.

Where is the flywheel? And why do i need to know? Its here ... (outlined in red!)

Right, you may have come across the acronym BDC (Bottom Dead Center) BDC means that the piston is at the very bottom of its stroke. You need to know this in order to make sure that after the first tank of fuel has been pipped through the engine that it cools down with the piston at the BOTTOM of its stroke. Once I'd put the first tank of fuel through (25% btw) I popped out the glow plug and rotated the flywheel to place the piston at the bottom position. The 'center' in BDC refers to the fact that the conrod (connecting rod between the piston head and the crackshaft) is in its center position (and fully vertical in orientation) at both TDC (Top Dead Center) and BDC. Before I'd started this engine for the first time this flywheel was unmovable, leading me to question if what I thought was the flywheel was actually the flywheel! Don't worry if yours is also 'stuck', the pull start bearing might be preventing you from moving it ...

Here's a list of the kit I took with me:

First up in my manual it said that I needed to run one tank of fuel through it without allowing the car to do anything at all. This was excruciatingly boring ... hence the Fun Factor! Woo! (click the images to open bigger versions)

Here is my Savage going through its first tank of fuel. No transmitter needed and the electronics are off. Manually set the throttle to 1/4 and let it run through the tank of fuel. To start the engine I filled the tank, popped the glow starter on it, popped the pull start, it popped into life and sat there FOR THE WHOLE tank without cutting out once ... amazing ... and certainly due to the factory settings being a very rich fuel mixture.

You can just about see the smoke coming from the exhaust in this picture. This was taken literally just after initially starting it.

This close up was supposed to show you more smoke ... ah well ...

Another shot of the Savage chomping its way through the first tank of fuel.

Woo ... only another ... what 20 mins at idle to go ... hmm ...

In this shot you can see just how much unburned fuel is pissing out of the exhaust pipe all over the box (the middle bit of the Savage shipping box btw (no fancy stands here!!!!). This sign of unburned fuel is good as the default settings for the break in are factory set and run the engine really rich in order (as I understand it) to make sure there is excess oil in the engine during this critical process. This ended up becoming quite a puddle of goo so its good to do this away from anything you care for!

Shortly after this shot the Savage had munched the first tank of fuel and had been allowed to cool for about 25 mins. As soon as the engine had stopped after this first tank had completed I used the glow wrench to remove the glow plug and make sure the piston was BDC. You should also mark the flywheel with a marker (Sharpies ahoy!) to allow easy placement of the piston in future. Some folks said that they just 'feel for it' but until you know what to feel for that is a bit of a tough call. As soon as I had placed the piston in the desired position I put the glow plug back in (you REALLY don't want to leave the glow plug out for longer than necessary ... purely to make sure no crap gets in the chamber).

After this cooling I refilled the tank and, as the manual says, I restarted the engine and slowly raised the throttle to maximum momentarily and then let it fall back to an idle. This helps clear the engine of any buildup due, again, to the rich fuel mixture. All good so far ...

.

This shot is the first one my mate Dave took as I remembered I had the camera ... was having too much fun doing ovals and figure 8's for the first time with my new truck!!

Hmm ... that's me BTW ...

OK, ALL of those pictures you've just looked at are basically part of the same process. The initial driving period. Never above 1/2 throttle ...

In fact because this Savage is still running at factory settings (i.e. REALLY RICH) trying to take it above 1/2 throttle (or even much above 1/4 really) will just flood the engine and force you to restart the engine. Over the course of the 3 tanks of fuel I used (to be on the safe side - manual says 2 tanks) I noticed the engine change its response to throttle movements A LOT. Towards the end of the second tank it was starting to feel very different. Like it was really wanting to be tuned. After each tank during this period of the break in I checked all the bolts and screws to make sure anything that was working loose was tightened back up. A few of these were loose, nowhere near falling out but they were a little loose and benefitted from this 5 min check over.

After this 'bedding in' process of driving in ovals and figure 8's we moved onto the tuning process. Unfortunately since we were both really invested in this we didn't take any shots. Not that they would tell you much though. We just went through the process as per the manual. Starting with the HSN (High Speed Needle) tuned to get the speed and acceleration setup and then idle needle next to the High Speed Needle on the carburetor. My manual says that the needle on the accelorator (the LSN - Low Speed Needle) linkage should be left alone ... so we did! Tuning was a long process and we used a good few tanks completing it with a cooling period in between. In fact its fair to say that tuning will probably be taking place for a good number of sessions over a few weeks. Weather and outside temperatures will also effect this and you'll be tweaking the engine setup a lot depending on a number of things.

Once we had done this tune up process we just had a bit of fun with the two cars. Then a wedding arrived ... eh? Yeah that's what we thought ... why are you getting married in a car park for fucks sake ... so we left ...

haha ...

we found somewhere else to have a blast though ... no photos of that either ... sorry ... too much fun to be had to bother with cameras so here are some pictures of the fall out ... :)

Damn ... my first scratch!!!!

The results ...

After taking these shots I popped the glow plug out and blobbed a few drops of After Run oil into the chamber ... pulled the pull start a few times to work it around the engine and said good night ... till tomorrow!!! :)

The main problem at the moment is the total lack of breaking power ... something that urgently needs attention!!!! (I'm going to use a small length of fuel pipe on the break/servo link arm to adjust this properly).

Its worth noting that today (Sunday) I went out again and have encoutered my first problem. No power going to the wheels anymore which leads me to suspect I have a clutch issue. I'm going to look into that and probably document that here as well in case that happens to anyone else.