Rx79394

like the title says what do you start to tune first and when you do do that what are you looking for?

mickeymouse23

My Feedback: (1)

This might be a little long winded but, when you tune a rc car engine you need a temp gun to get acurate readings from the head this is a start. Allways start with the top end needle. Get the car running and make some hot laps, about ten and check your temp on the head. Make sure you stay off to the side of the glow plug. For good engine life your shooting for a temp aof about 220 degrees. Now keep in mind that if you are running with the body off shoot for 190-200 degrees with it off as the body will add about 10 degrees to the head. If the head temp is lower then that turn the top needle in a little bit and repeat until you get a good head temp. Remember little adjustments about the width of a flat tip screew driver at a time. Usually this takes about one tank full to get right. Ocasionally check the head temp though out the day to keep the temp in check. Now for the low end, The low end is a little more trickey to do, start the car and let it sit on the bench at idle. If it loads up and dies within a few seconds you are to rich.turn the low end needle in a little and try again until you get a steedy idle. REMEMBER little adjustments at a time. If you need more help let me know. also this is for a 15 size engine for 1/10 cars. A little more history about the car/engine would help and what kind it is.

Polar_Bus

I agree with most of your claims EXCEPT your described methods of "targeting" temps. Targeting a specific temp when tuning is not the correct way to tune. A nitro engine has MANY variables from day to day running, and temps can and will vary widely. I tune for max performance and rpm's, then I richen my HSN 1/8 turn for "safe" running. You always want temps above 230F for normal hard running (anything less is not considered "up to temp" and can result in a "cold seizure"). You also don't want to exceed temps of 290F, thats getting too hot, and breaks down the lubrication qualities inside your engine. So basically anything between 240F and 280F is acceptable, which is what most engine manufactures suggest.

MassiveMods

yeah i agree , nice description mickey Mouse but yeah dont go chasing temps .. Just go for good performance , happy engine that runs and has a good feel about it.. Back in 81 when i started playing with nitro engines we never used temp guns... and our engines lasted aaaages.. here is how i like to tune, many ways to do, it heres mine

Fill tank
Run car round track till you get to 2/3 tank full
Adjust Idle first
run two more laps strat to tune HSN
Then tune LSN

I was tought this by a very experienced tuner and it feels good, i like the way my car runs with this tune.. Hope this helps !

MassiveMods !

Polar_Bus

You always tune the HSN FIRST. The HSN adjusts the TOTAL volume of fuel being introduced into the engine. The LSN adjusts a portion of the HSN's volume of fuel. So when you change the HSN setting, you are technically changing the LSN setting also.

ThunderbirdJunkie

My Feedback: (3)

I never ever EVER temp my engines, and they always last 6+ gallons.

I tune the HSN first, then the LSN, fatten up the HSN a little bit, and keep runnin.

Just keep it under 300 degrees and you'll be fine.

Fuelman

My Feedback: (6)

Like Massive said, with this to add to it.

For an initial tune on a fresh engine, start it up and lean out high speed needle from the factory settings so it is running clean, make some laps to warm it up good. Do not run it too lean and do not run it too rich, crisp and clean, not too lean

Now for a seasoned engine (has more than two or three tanks through it), Fire it up and get it to operating temps with a hot lap or two then adjust the high speed needle till it will not pick up any more power. If you have leaned too much it will sag a little at wide open throttle. Once you get maximum performance, richen the needle just a bit till the performance is still there but it is a little further away from lean.
Now we set the low speed needle for crisp off-idle response and crisp acceleration up to about half to 2/3 throttle. If low speed needle is too rich, it will take a while to clean out and not sound smooth. If it is too lean, it will bog or sag somewhere off idle and feel like it is trying to catch its breath. never try setting lsn or hsn with a cold engine, it must be at operating temp.

No where did I mention use of a temp gun, it is simply not needed. If you want to ruin your engine, start chasing the needles for some magical number. And most importantly do not let any of your friends tell you what temp you should be running at. Just run it where it will be happy and it will last a long time.

Let the flames begin.

Philster

Agree w/ everyone who said, Hi then Lo. And remember to adjust the idle LAST. Otherwise you'll be chasing the low speed setting trying to compensate for a low- or high-idle speed.

If it is tuned well on the Hi and Lo, you can now see if the clutch is engaging at idle. If it is, and you have done your tuning right, you can decrease the idle a little bit. If the clutch isn't engaging at idle, and the engine doesn't stall, you are good to go. If it stalls at idle or when breaking, but you are good on the Hi and Lo, go ahead an increase the idle.

Unfortunately, just about everyone I know doesn't do this and they hate to have their trucks/cars come to a stop. They either stall, or have really high idles (and they wear down their clutches).

bentgear

Guess somebody needs to add a little disagreement to all the above. Sometimes, when the engine is new, it is benificial to adjust the low speed needle leaner first, just so you can keep the thing running long enuff to adjust the high speed needle. Not trying to make a big adjustment either, just so the engine will accelerate and return to idle without falling flat on its face without bogging from being too rich.

I have seen several enignes life cut short because somebody tried to use the high speed needle adjustment when a little tweek of the low speed to begin with would have cured the problem.

Ed M.

Fuelman

My Feedback: (6)

The part that is beneficial is starting it up and getting it to a moderate speed so the engine warms up to operating temps. The throttle position that is necessary for this to happen is in the mid range, (above the affect of the low speed needle settings). So, I stand on the fact that if one is to get proper tuning on a fresh engine, you need to start with the high speed needle and get it running clean and hot (proper operating temps) then as you throttle down after it is hot, your adjustments on the low speed needle would be better.
The method you describe would be for someone that breaks in an engine by sitting and idling or slow speed way too rich and never gets the engine fast or hot enough to be running where the high speed needle is effective, a great way to shorten the life of an ABC type engine.

bentgear

Fuelman, I totally agree with you, but, for some doing a break in in a limited area part of the time you are coming back to idle. They get very frustrated, very quickly and start leaning out the high end till it runs when they let off to turn around. Now what do you suppose is happening to the engine during this process? All that would have been needed would be tweak the low speed needle slightly so that it stays running.

And for the second part, way back when I did use a rich process, I richened up the low speed needle till it would die with the glo igniter still on it, then leaned it just a little. Man what a difference years of knowledge makes. I think some manufacturers still recommend a rich low idle break in because they are scared of what the consumer will do if asked to bring the engine up to temp. Yes, it can cause conrod damage, it does cause much premature wear to the pinch area, but the consumer is still able to get 2 to 4 gallons of fuel thru it before needing a rebuild for the most part, so they are happy.

Ed M.

Fuelman

My Feedback: (6)

I see what you're getting at Ed, taking into consideration what you mention, then yes adjust the low speed as well. The important thing is to keep the thing running crisp and clean all around, even during break in.

It is amazing how many times I've walked into the store of one of my fuel customers and seen a frustrated car guy (or gal) complaining that the engine does not run good anymore and that the first thing the hobby shop owner does is tell them they are only designed to run 2 to 4 gallons. I usually instruct the frustrated person to get the sleeve and piston/ rod set, put it together and I'll hang around to show him how to break it in. Shop owners hate when I have done this, because I am right and they know it and all they can see is losing sales of replacement parts.

Did you know that I can get 100 gallons through an ABC airplane engine between rebuilds. On smaller airplane engines I can get 400 hours. It is not uncommon to see 10 to 20 gallons through one of my car engines. the key is properly breaking in and running and maintenance. The average car engine will not last 100 gallons or 400 hours simply because of the dust and grit that always end up in them and they are running at twice or more the rpm's of airplane engines, they use half the oil and they are overcooled!!!!!!

Rx79394

ok well I have been trying to tune my car thanks everyone for the replies but I haven't been able to get it up to speed because it will bog down really bad so does that mean I have to richen lean it out? or what? Thanks alor fuelman and other ppl u have been a big help!!

turnell

i would say richen it up if it is bogging down then cutting out, if it sounds like it is a burbling bog then lean it out, you'll know the difference.

..........TURNELL..........

bozla

After runnning 5 or 6 laps or so how does it sound? If the revs aren't stable on idling then you know its running too hot, which means too lean, so richen it up a little and try again. It can be tempting to run too lean because you can get a lot more power out of it, but you will be sacrificing engine life.

Rx79394

ok well I have got it to a good point right now but it seems that no matter what I do it just revs up all the way automatically with out me pressing down the gas and it won't go down unless if I slam on the brakes but when it is in the neutral poisition it just keeps going up with the revs and I will press the gas and it won't go to any higher RPM's so I think it just goes straight to maxx and stays there until I press the breaks.

snowbl!nd

Have you checked for air leaks etc?

Rx79394

no but this is all new so I am almost sure it has none.

snowbl!nd

Usually an erratic idle is the result of a lean low-end, but if you've tried richening it and it hasn't made any difference i'd suggest an air leak.

Rx79394

ok I will try to richen up the low end.

EG1

Some good info in this thread. I have always used what is now called the "fantom" method and had amazing luck with my engines. Then I ordered 2 STS 28's and decided, ah what the heck I'll try the manufacturer manual break-in just to see how things go for the first one. What a huge mistake, ended up having what I think was a cold lock-up. Luckily STS sent me a brand new engine and needless to say I'm back to my old ways and holy poop is it going ALOT better. The engine sounded and ran so bad trying to do that slow/super rich break-in that I really started to get nervous and BAM shot motor.

Get the damn car/truck on the ground and run it just like these guys are saying to! I was lucky that STS backed me up after I sent them the engine back.

Rx79394

yea well I think I got the hang of it now. Ran it yesterday and ended up breaking a front axle. HAHA. Thanks everyone!

noximus

ok..i just read this post...and my probs arent the same...but in fact simular..

ok when i initially got the engine, i ran it to what the manual states...such as just run it in its original setting for three tanks...after the three tanks..the engine started to idle at high RPM's, so i lowered the idle..then i noticed when i hit the throttle, it wasnt responsive on the hgih end, so i leaned out the high end...and then when i ran the motor, as i went full throttle and released...i had a blubbering noise...which i think made it sound like it was too lean (low end?) but when i turned the low end counter clockwise (rich) the noise went away...

now what i just did, seems like the total ooposite of what most of you guys do (which i WISH i knew what i just read a looonnggg time ago)...lol so now i feel like i am in deep trouble to even get my motor back where its suppose to be...if you guys have any tips on setting my motor back to its neutral setting...to (in theory) be back to a setting to where i can adjust it properly that would be fantastic, or better yet, hand me some tips on how to get it just right..i have the .26 power factory engine that came with my LSP. any info will be greatly appreciated!

EG1

The pinch test will work fine for getting the low-speed in the ballpark. For the high end just get the engine up to temp and make some 3 second wide open bursts, then richen the high speed(clockwise) by 1/8th increments and do another burst repeat and if the engine gets smoother you'll know your going the right way, if not go in the opposite direction. DO NOT get frustrated and start making 1/2 turn adjustments because you will be chasing the tune until you throw the engine off a bridge.

Check your plug and if you haven't already done so take the backplate and carb(pinch bolt also) off and seal the engine up w/ sensor safe RTV and let it cure for 24 hours.

bozla

It would be wise to change the plug after breaking it in too.