XRAY - Model racing cars

Just completed the final touches last night on the buggy - had to redo the shocks since I didn't pay attention to the holes in the pistons....oops.

Adjusted my starter box for the new setup, got the heat gun out and went to work on the new engine (O.S. V-Spec).

After preheating the engine I spent the better part of an hour trying to get it to turn over. Flooded it the first few times then leaned things out a little and after struggling with the piston constantly locking up I finally got things to start.

Spent another hour struggling to keep the engine going.

Finally stopped with about a 1/2 tank through the engine, a large amount of wear on my starter flywheel, some sore hands from disengaging the piston every time it stuck, and having to recharge my starter box once.

Back to work tonight - hopefully with more luck.

ANY TIPS????

Thanks

when i broke in my spec it locked up a couple times as well. i first took the plug out then put some ARO in there. then when you go to start it leave the plug a little loose and heat that motor up w/ a heat gun to 200deg. have the piston on the bottom. when it starts tighten up the plug. the spec is really rich and you need to lean it out so it will run on the ground. do a idle take first. just PM me if you have any trouble and ill help you.

keep heating with heat gun until it easily turns over. Make sure the flywheel is at bottom dead center(moves freely). Put the car on the box and push down just enough to get the starter box to spin. Let it spin up to full speed then push the car down engaging your start. Like Zman said just loosen the plug a crack or one half turn and it will start. If you played with the needles to much, just go back to default settings. It tellos you in the manuel of the vspec what they are. It should atleast start at the default settings. After it starts tighten the glow plug up. If you do these steps I gaurantee you will be sucsecfull. Just remember to heat the crancase of where the sleeve sits and not the head. Just be carefull not to melt any plastic, as that would *** :-) ***. My first time I wasn't cafefull and I melted the air filter sponge, SO BE CAREFUL!

Welcome to 1/8th scale.

Pre-lube your engine properly. I used wd40 in my xb8. Spray it pretty good. Take the plug out and spray in there some too. Shake out the excess. Turn the flywheel back and forth 20 or so times to move it all around internally. This prevents it getting stuck for the most part when you attempt to turn it over. Make sure your plug is fresh and that your using good 20-30% fuel. Take off the fuel tube to the pipe and blow into it, this will get the fuel into the carb. And put a drop into carb too. Also make sure your shims are correct in the engine and that your clutch bell spins freely and not binding on the shoes. Throw a charged Ni on it and it should turn right over. Once it's started keep the Ni on it for a few minutes, may even have to leave it on or it will cut out on ya. I always turn mine out 4 1/2 turns and run a tank thru it each 1/4 turn til I'm 2 1/2 out than smaller adjustments to 2 - 2 1/4 out. Lo-end flush is a good starting point also. Also get a temp gun, there about $80-90 or you can use the spit test. If it bubbles off way too hot but you shouldn't see those temps till your ready to race. That's the way I do it. Good luck!!

~B

Don't use WD-40 in your engine if it has any epoxy in the crank. Most of the new P5's have an epoxy filled crank and the WD-40 will soften it and possibly loosen it.

Just pre-heat, get it to start and run it slowly but surely at about 200F.
Don't be afraid to rev it a bit, run it for a few minutes, let it cool down at BDC and start over again.
After a few tanks, slowly lean it out as the engine loosens up.
Just keep at it and break that bronco

@1PHATXB8
As for putting wd40 in an engine, not such a good idea!
It can mess with your o-rings and if you have an epoxy filled crank, will corrode the epoxy.
If you want to pre-lube the engine, use plain castor oil or afterrun oil.

Well went back to work on breaking in the engine last night. Man I can't wait to see how this car runs

I added the extra shim that came with the engine, grabbed a new battery for the glow igniter, fully charged the starter box, and dialed in the engine settings.

Applied heat from the heat gun to both the head and crankcase this time - lined everything up and within a few minutes vrooom got things going. No problems this time when I was at idle, ran through the entire tank at idle blipping the throttle every so often. The temperature stayed nice and steady at 195 the whole time. Restarted it a few times with no sticking issues this time around. Man does this thing have some power potential.

Oh yeah my dog learned not to put his nose on the engine

Thanks for the advice - hitting the track today for some easy laps...

Basically, that's what i said. i leaned it and it started to lose power (not enough fuel = starving = less power). I'm not a Pro or anything ( I Wish I Was!!:lol:), but i have been in Nitro racing for aroung 10 years, so i know how to lean or richen an engine. (not to mention i'm a mechanic). I went IN on the needle. The only way to make a scew go IN is by turning it clockwise (unless it's a reverse rotating screw, but we don't have those in carbs)
Leaning the low end too much DOES hurt the performance, from what i have expierenced. IMO


I think i just leaned it too much. Just a little mistake on my part.

It was a crazy day at the track today, i was helping a new racer, it kept raining, and we were running back and forth in and out of the rain, so i never really got a chance to get a decent practice to fine-tune the carb.
i'm sure Giorgi50 was correct. I was just a little surprised by it cause it has been running perfect for months (low end), and i havn't had to make one adjustment to it, then all of a sudden it was wromg. I'm also gonna check the o-rings on the needle screw to make sure they are not worn, and the needle is not vibrating out.

Thanks for the advice.