after the lack of OS support with these engines im going to say stay away from these engines. all they could say without even opening up the engine was refer to page 17 "no warranty..."

too many of these engines are having conrod problems. unfortunately for mine when the conrod went it took out a piece from the bottom of the piston then went thru the the liner.

dude for the little money more go for the mugen ninja r01. ive heard many great stories about these and ive seen them run at our track, they are really fast and seam reliable to finish races.

i will be throwing out this vz-r and getting a mugen ninja.

Dag32, I see you are in SoCal. What do you race currently and where?

I have the OS VZR and have had no problems. I run at Crystal Park and find my motor to run very well compared to the others. With a few gallons through mine, I am still on the same original rod. I purchased a new rod, but have not installed it yet. With a good setup and clean driving, you will have plenty of power with the OS.

hey guys
trying to save this engine beforee my new one arrives

i had purchased a replacement conrod for this engine before i had reliased the piston/liner was screwed/ and i noticed there are no oil holes in the rod.
so theirs a oil hole in the crank shaft to get into the rod but no oil hole for the oil to leave.

this seams strange as all the other engine ive used have oil holes.

msgsr, after viewing your post about the rod I went to check the new one I recently purchsed.... it has no oil hole either. Have not checked my motor to see if it has one or not.

what oil content is in your fuel ?

i wonder if no oil hole and low oil content is bad for these engines ??

I run no more than 30%, usually Byrons but have run Blue Thinder and Odonnel.

i meant oil content %

i only run 25% nitro in my fuel

You shouldnt have issues with 25%

I just got a MTX-4 and I like it so much I want to get a MRX-4R too. I run at Revelation but I want to make it down to Crystal Park soon... real soon!

Crystal Park is a better track for 1/8th as the back straight is longer and the motor get actually hit nice speed. I raced at Revelation last year at the Toys for Tots event, and didnt have too much fun. There was an unreal amount of traction, actually too much and I had to find some old brick fronts (luckily I had them) to get my car to work. I think I removed the rear sway bar too, and recall ripping my front belt to shreds from the traction. I have seen some 1/8 guys cut down the width of their front tires to reduce steering out there.

If I remember, I will send a PM to let you know when I plan to head out to C.P. I think you will like what you see from the OS motor.... I really like them.

The nitro sedan Nationals are at CP, check it out if you get a chance.

do you guys think modifying the conrod by putting a small oil hole thru it will be a good idea ?

You may actually weaken the conrod. Just a thought.

I ran the engine this last weekend for the first time and was happy with it's performance. With such a strong pinch on the piston and sleeve I can see how premature conrod failure could be a problem. If you have some patience with warming up the engine from a cold start it probably won't be an issue.

I'm still not tuned at 100% due to it being a new engine. Next race I'll take it too it's max and see what it really does. My fastest lap was .3 off the fastest lap of the day by a very talented, national driver. He was running the MAX Power MF modified. For the most part I never really felt like I was being out powered on the track. Maybe on a larger track it would have been more noticeable.

I agree, bad idea to drill a hole. The clearance in the fit of the crank pin and rod should be enough to keep it lubed. I cant complain, no bad experience with mine yet.

hey guys
i got the new inernals in the vzr and starte dthe break in process at the track today. 2 tanks on the starter box, 2 more tanks on the starter box heat cycling up to about 70 degrees c

today i ran another 5 tanks at the track getting close to a race tune but its still rich now. peaked a temperature at 89 degrees.

the question now is that without the plug out i can turn the flywheel around freely. i guess its ready for race tune

should there be a nip at the top dead centre when i turn the flywheel ?
im new to these .21s

During break-in, you should be getting more heat. The metals expand and contract with each heat cycle, and you should be running somewhere between 180-200 degrees. Just make sure the piston is not at TDC when it cools.

With the plug in, you should have more than a nip at TDC when the motor is cool.