The backplate that comes with the motor is too deep for the case and grinds on the rod. It's easy to check----take the back-plate off, If you have the deep back-plate, you will be able to see were the rod is worn from grinding on the face of the back-plate---There will also be thousands of scratches on the face of backplate----the metal that comes off act's like sandpaper in your engine. O.S. needs to correct the back-plate or include a brass shim washer between the case and back-plate for this motor. No motor should have a rod that grinds on the back-plate.

I had a v-spec go in about 2 gallons because of the same problem.

Is OS recognizing the problem and replacing it?

I have sent them proof of the problem so they cant say that it anything but a manufactures defect---waiting responce-----They need to recall all those motors and send a new motor out to all that have the back-plate problem(or at the least new internals.----That would be the fair thing to do!!!

OK i'm not a fanboy of OS & i too have concerns about their lifespan BUT are you guys sure the cranks on your engines were pushed all the way through the bearings? i know tightening the flywheel should ensure this but it can happen!
plus the only reason i can think of for the backplate getting marked is the crankpin wearing!
when the crankpins wear down you will find the rod slips sideways & rubs against the backplate due to the cone like shape a worn crankpin develops! there only needs to be a slight amount of wear on the pin for this to happen & once it starts it gets rapidly worse, especially once you introduce alloy particles from the backplate into the engine [:'(]

apparently the modified versions of the OS like the "Recab" have cured this problem by hardcoating the crank which (so i've been led to believe) really extends the engines life, the cranks are also bored out bigger & have the epoxy resin stuffer too

Please let us know what they say. I have a just broken in v-spec in a box waiting on the season to start up.

Os wont do anything about it, Its a known problem with the TZ series as well.(the fix for that is a spacer on the wristpin)

well i might be able to give some feedback on this as i now have a Recab Vspec to test
we don't start racing properly over here for a while yet but once i have any finings i'll post em up

that sounds like how my last v-spec died in the end.

it had lots of fuel through it and i replaced the bearings and rod, then only got about 3 more gallons out of it. basically it had siezed the rear bearing and also distorted the the conrod where it had been rubbing against the backing plate. I wasn't sure what went wrong but i figured the conrod went and the metal particles hurt the boca bearing that i put in it. I'll have to check out my new v-spec to see if there are any differences between the two. like a different backing plate.

clone3 i can't rember did you replace the bearings in yours from new. Could it be the bearing are slightly different and hold the crank further out. My motor had enough fuel through it that it could be just be wear on the crankpin but yours was new. Mine also had now signs of rubbing until after the bearings where replaced.

That was the issue I was asking about in your other post. The OS TM and TZ's had that problem.
There is too much slop. RD Racing fixed it by installing a spacer between the piston and the rod. What that does is, it stops the rod from moving all the way over on the Journal and rubbing the back plate.

HB and JB---

We should get paid by O.S. for solving that problem!!!. Holy #%$$ I'm pissed off----
I have been racking my brain over this motor for the past 6 weeks----new bearings----new rod and pins-----new pis/sleeve----plugs--- and most important my time!!!. I've been in a winter point series for the last five weeks----95% of the time working on that motor!!! O.S. better do something about That motor and fast!!! 300.00 then you have to replace the front bearing for another 20-30 bones then you still have a motor that's grinding and spitting metal flake in the motor-------I've got one word-----------%$#$$^%@ !!!.

On the good side of things I have a RB C5BB with a 2020 pipe that will be here in the AM from ASHFORD HOBBIES.

It b seems that the OS V-Spec isn't the only OS engine to have this type of problem. I read the new issue of XRC and they did a test on a truggy in there and used the new OS .30 big block engine. It died after one gallon and the guys doing the test openly admitted there was something wrong with that engine as well. I have an older VZ .21 and a RZ .21 and i liked both of those engines. They were'nt power house engines.....but they certanly ran more than a gallon. i hope OS does some more research on their VZ-Spec engine. I also hope that they do a little more testing on their engines before they put them out on the market.


JEFFRO503

The biggest problem i have with this motor is that i love the way it drives, it just suits me. hence i have bought another one, hoping it gives me a good life. i actually got a fair bit of life out of my last one. Probably 10 gallons, with a conrod and bearing change, but if you do the sums on that it doesn't work real good vs my novarossi 421b i paid $50 dollars more for and have got 12 gallons or so out of and its still going strong (and only recently changed the rod). its a pitty the 421 just never came out of corners smooth for me.

yeah the 421 Blasts you out of the corners, its good wen there's plenty of grip but most of the time you're sideways!
the thing i like about the 421 is overtaking people down the straights
it might not be the fastest way round the track but how much fun is it to use a ballistic engine

Why type of spacer should be used on the wristpin? Copper, alloy, stainless, ect...

It sounds like OS has 4 new motors that have this problem and they don't want to do anything about it. I like my buddies V spec, but I've read too many horror stories and I went with a P5X instead.




Aluminum or copper would work. Aluminum would be best.

the memories have just inspired me to go back to the 421. even if i don't win i'll still have fun. at my local track we have to "bumps" down the straight, the 421 will hold the front of the ground (when running 7000 or above in the centre) right up until you jump on the brakes.

my track is technical and very slippery a lot of the times, so i mgiht save my new v-spec for big races and very slippery days.

p.s. i might get my self some badlands as well and just go out to kick up some dust, lol.

they are a lot of fun, i still have 421's in my MBX5 & my 777SP1
i used the SP1 after a meeting last year for the first time in a long while & it was mad! i let a couple of people drive it as they were trying to get a feel for what cars they'd be changing to for 2006, they all thought the 777 was the fastest thing they'd ever driven, of course we all know it was the 421 on the 9886 pipe that made it fast

"421 on the 9886 pipe"

I actually got this motor as a replacement to the hyper 8 port in my old hyper rtr. it was the second nitro motor i ever owned, so i guess thats probably why i have very good throttle control.

damn i'm going home this arvo and taking out the v-spec and putting the 421 back in. I hope its as good as i remeber. [8D]

LSTCraZY-

To be Honest, I really don't know what spacer if any would work. If you have the V-spec problem----send it back for a refund if you have the receipt---That's just what I did!!!

The spacer would work if the problem is the journal and rod are hitting the back plate.

There is too much space for the top of rod on wrist pin. The true problem is that the sleeve and crank align. are off. If they were correct the rod would run-true(center) without grinding on the back-plate.-------------------check the pic's----I'm done with O.S.[:@]

On the OS, check for slop on the wrist pin.


That RB will let you forget the rest! LOL

YEA and I don't have to rebuild it and put new bearing's in it and watch the thing spit out metal and replace the Piston/sleeve and rod. As soon as I get info from O.S. I will post the results!!!

dooodd.


That looks like a monster. [8D]