in BC Canada.
 

I broke in this engine a week ago. It's had about 3/4 of a gallon through it. I love the top end power. I had some problems tuning it. Finally, I changed the plug from a #6 (which it came with) to a #5 and it's been behaving alot better.

I have been using the 7.0 venturi from my MR21 b01a instead of the 8.0 that it came with. Were some of my problems due to changing the venturi? Which venturi did yours come with?

I'd like to see the comparison done with an OD plug, seems to be the closest fit.

plugs
 

I am on my second gallon through a GRP with an O.S. plug. No problems. The only problem I had is that the motor wouldn't start with the GRP plug that was in it. My other buddy's GRP plug wouldn't even glow fresh out of the motor.
There are 3 of us running this setup with no issues.

If you read the "Ask Mike Truhe" forum on Neo-buggy.net he even tells you that its ok.

.

P3's are awesome.

I got 9 minutes exactly during a race with using Tilted Green 30%, OD97T, Dyn 53 pipe in a trugg. Engine was ran in last Friday for a few tanks, and then thrown on the track Saturday, so I am pretty sure I can get 10 minutes once she loosens up a bit and she is leaned down (this was on a track with a LOT of WOT also)

I've got approximately 8 tanks heat cycled through my .28. I've been breaking it down every couple of tanks to make sure everything is wearing well (which it was). So this weekend I decided to take it out for it's first bit of track time. I'm running Nitrotane 30% using an OS P-3 plug with my head shimmed at .5. I chased a tune for the first part of the morning, but I believe it was because the outside temp was rising so fast. The outside temp stabilized around noon at about 90 degrees and I was able to finally get a proper tune.
Good news first: The power delivery for a .28 is as smooth as it gets! It wasn’t overpowering and I didn't feel like it would get away from me as I opened her up. I was definitely happy with the power delivery and this is my first .28
Bad news: Take a look at the pics showing both sides of the piston. I broke it down this morning to see how everything looked and this is what I found on the exhaust port side of the piston. The cylinder is showing wear in the exact same place but I can't get a good pic of that area.
Not sure what my warranty options are here, but I hope I'm able to get the piston and cylinder replaced. It had to happen at the track this weekend because I had it taken apart Friday night and everything looked great.
Any ideas or opinions on what could have caused this?

^^ Looks like there was something foreign in there to do that :cry:

Ive got 10 litres on my .21 tuned and i cannot get it up to temp, after a 20 min final on a fast track, its hardly breaking 50C. Im running a 12% oil mix #6 plugs, maybe i have to drop the oil content a little? Ive got the thing absolutely screaming, not loading up and reading the plug and the amount of oil residue on the pipe side of the car its still very rich :weird: And every now and again (usually after "Release the cars" :flaming: ) it will flame at idle, was thinking just bump up the idle but 90% of the time it will idle all day after a warm up :weird: Its got me paranoid now :weird:

It’s hard to see in the pic, but the marks are from some type of continuous abrasion, just not sure what? The con rod still looks good and where it connects to the crankshaft is still in excellent condition.
The engine definitely runs cooler than most. I’ve heard that Truhe was running between 180 and 200. That’s consistent with the temps I was seeing this weekend on mine.

If your shimming .005, your way too tight on clearance, plus a p3 glowplug on top of that. It looks like the piston got hot at the exhaust port area and dragged on the sleeve IMO.

The shoulder is not an issue. There's plenty of clearance. That is good thinking though. Today was my first day competing with my .21 in my Losi 8 buggy. I've owned most of the major manufactures and this engine is the best of everything. I've got power that is more than enough, nine minutes of runtime in my main, and it's easy to tune. Using the os p3 and the Jammin' JP3 pipe. Also have a 6.5 carb restrictor in it now. Trying to make it easier to drive and going to the best runtime I can get. It's still very tight and I'm getting nine minutes. A few more race days should improve my runtime even more. My temp is 185 consistantly. Can't wait to get the GRP pipe in a couple weeks.

??????'s

I did not shim the head on my GRP .28
I asked drake at rev one day if i needed to he said nope just run it
I ruined a p5xs when i started nitro last year ....so i worry a little


What ya think shim it or not BYRONS gen 2 30 percent is the fuel i run

I was way off with the decimal, I appologize. I'm actually shimmed out to .5, It came stock with (1) aluminum .3 and (1) copper .1 already installed. I installed one more for a total of .5. Would what you describe above still be an issue with this clearance?

No, what you have sounds correct for 30%. I was just making sure with the clearance numbers you had.

You could be onto something regarding the P-3 plug. The only variable that changed from the time I took the engine apart on Friday night and drove it at the track on Saturday was that I changed the glow plug from a GRP #6 to an OS P-3??
It was around 90 degrees out (pretty warm), but the temp at the glow plug was consistently around 185-190.

I would check with GRP about repairing that engine. I would also not use Nitrotane for break-in. I would use a high oil/low nitro fuel first for break-in.

Does the engine need a shim added to run 30?

I guess not.

http://www.neobuggy.net/modules/newb...=ASC&start=220

Some add the shim, some don't. I have seen engines run without the added shim, but I prefer to add it on all of my engines.

It probably will be OK without the shim, but don't forget those guys get their engines for free, and aren't really concerned with week to week longevity. As long as it makes it through the main, for them it's good to go.

I just bought a GRP engine today. :nod:

This thing looks really sweet!!

awsome, now if we can just get steveja to get a decent engine:D

Yeah, I don't see that happening. Steve is a cheap @ss!!:lol:

BTW, I might need your advise and tips on breaking this thing in. Also maybe your tuning advise.

I think the losi's are going to be hard to beat this year!!:nod:

I just wrapped the head and heat cycled it two tanks on the starter box and then another two tanks putzing around my driveway. After that I ran another two tanks pretty rich at the Plex and then started to tune for power. This engine likes to run really cool so tune by power and exhaust smoke more than by temp. Opening week at the Plex the hottest my engine got was 210, steveja pulled his gotech off at 280 when I was temping mine:p I also put an O.S. P3 in mine after break-in, seems to smooth out the idle compared to the cold plug that comes with the GRP.

Matt, have ya had the chance to compare the GRP to another motor - power wise? I'm curious to see how it matches against my EB Modded V Spec. I'll be starting break in on my GRP tomorrow when the engine mounts come in. :sneaky:

And I love that sig. Ironically, I got yelled at on the driver stand this past Sunday when I was lapping a guy in the main for the 4th time. He yelled at ME to get out of the way! :lol::lol:

Guys,

I see that many of you are using the OS P3 plugs. I have also read that some of you think the P3 improves idle ?

For me in the UK P3's are probably more expensive to get than GRP/NINJA plugs,but if the motor proforms better for them, then I'll get some.

Just curious as to wether It's really worth my while trying P3's or I'm as well sticking with original plugs.......

Cheers

Rod

Screff - my initial thoughts on the GRP compared to other mills I have owned and ran recently are as follows:

Ninja B01A - GRP seems to have more top end, but the powerband is very linear just like the Ninja was

Nova 21-5kt - 21-5kt seems to hit harder low and mid range, but does not have near the top end the GRP has. The Nova is much more finicky to tune as well

Max Power M5 - the Max Power was like the Ninja B01A, except more power everywhere...the M5 and the GRP will likely be pretty close (which is great imo, as the M5 was my favorite engine I have run on the track)

I need more fuel through the GRP, as I have only raced it one day, but from what I have seen, it is reliable, stable, very smooth power, great runtimes, and should last a good while. I do not think it is the most powerful motor out there, but that is not what I need on the track

I'll have to remember to try that trick... might save me from being lapped! :lol:

I ran a stock V-spec last year and it was a great engine. The GRP, to me, seems smoother throughout the powerband. I've only have one race weekend on it but I like it so far.

.

Bread,

Thanks for that, a hotter plug usually helps iron out an idle, But to be honest mine is pretty good using the No.6 . I may try a No.5 just to see how it likes it. But I'm using Gen2 30% and the std. shimming so currently things are good as is. :nod:

If you guys are using the OS simply because of cost I'll happily continue with Ninja'

Cheers for the reply

Rod

the GRP plugs are fine, I just installed a P3 since I wanted to try a hotter plug and I had a new one left over from last year when I ran a V-spec.

Hey Guys,

Has anyone try to put the GRP on the losi buggy with the losi quick change motor mount? I just try it and it seems like the bottom of the case is to large. The case is hitting the side of the mount. So do I have to go back to the stock ones or is there a mod?

Thanks,

Roberts there is a memo on the Losi site about that. They have directions on where to grind to make it work.

That's Matt.

Hey Guys,

I have some more questions. When you open up the carb barrel all the way is the needle in the carb half way out? Why I'm asking is that my V-Spec never comes all the way out.

My needle setting are
HSN - 3 3/4 turns out
LSN - 5 1/2 turns out

Is this the factory needle settings for this motor? Also I just got done breaking my motor in on a break in stand and will hit the track Friday.

Thanks for your help.

Ed

well my grp .21 will be here monday. should be broken in by friday.

Well I popped my GRP in the new 808! I will see how it runs tomorrow in this buggy. These GRP's are quality motors, but defiantly not an RB C6BBT7 when it comes to power. My C6's will blow the doors of the GRP from bottom to top.... however the saying "slower is faster" is probably true. So I'm hoping this is a good combo for race day. Might run this at the Nationals....:)

double