36cc vs 29cc. Is it really a 36cc? Where is the proof other than a sticker?

[gasserbob]

Hello

I have been reading and reading and looking at endless forums and photos and am trying to figure out how to tell a 36cc motor apart from any other size cc motor beside a sticker on the side of the case.

I have a 36cc in my buggy but is it really a 36cc?

Sure the stickers say 36cc and all that jazz but where is the proof?

Anyone can slap a sticker on something and make claim.

Ive looked at the carb sizes, the side capped off plate and so on but cannot see any difference or any numbers stamped on the block or head specifying the CC's other than a sticker.

Anyone have any knowledge on the issue?

 

[Buzzsaw46]

Stroke x bore= displacement. your 36cc is a bored out, stroked copy of the Zenoah 32cc.

How's it run, I have had bad luck with Rovan engines had a 30.5 drop a wrist pin washer, and a 32cc with I think casting flash on the con rod that came off and destroyed the mill. Both engines ran good till the metal chunks came loose. I won't be buying anymore Rovan engines!

Last year I ran one of these http://shopping.netsuite.com/s.nl?c=885035&n=1&it=A&id=12593

This year I moved that mill to my back up truck and built one of these http://shopping.netsuite.com/s.nl?c=885035&n=1&it=A&id=12613 with OBR transfer covers for the main truck.

 

[gasserbob]

WOW That is very interesting.

Thanks for the link.
Those motors look really amazing with the polished aluminum case.

If my little 36cc ever fails Ill look into a DDM for sure.

I really do not have anything to compare my 36cc to.

Its on its 3rd tank of fuel and I spent about 2 hours idling the motor and cooling for proper break in.

Off the line it will kick a 1 foot tall rooster tail and shreds the grass pretty good for about 10ft or so,
Still have not completely opened her up all the way.
The exhaust is almost deafening when its close by.
Thats about all of the observations for power I have noticed at this point.

 

[Buzzsaw46]

I had to go to silenced pipes as you said the sound is deafening, much more comfortable with silenced pipes.

I did some looking and your motor has 30mm stroke and a 39mm bore, my 34cc mills have 30mm stroke and 38mm bore. Hope you have better luck than I did with the Rovan engines.

 

[gasserbob]

Ok so the 36cc should be 30mm from top to bottom of one stroke. Thanks for that information/
Im pretty sure I can figure what my stroke is by simply pulling the spark plug and watching a straw move with the piston stroke and measure how much stroke. Guess Ill pull the head in the next few days and measure the bore with a micrometer.


I took some photos of my 36cc motor and found something interesting. The side of the motor does not have the typical block off plate with screws. Instead it appears to have a plate that was cast filled or was not cut out with the cnc machine.

Ive been looking at other photos of 27.5cc motors and 30.5 cc and 36cc motors. I have not seen any 2 stroke gas motors for 1/5th scale cars or trucks that did not have a block off plate without screws for the plate.
Not sure if it matters but has peaked my interest for sure.

I just wanna know for sure I do in fact have the 36cc motor.

 

[Buzzsaw46]

That is odd that the transfer port covers are cast into the top end. My Rovan 32cc has the removable covers, the transfer port covers are unique to the larger block 32+cc zen and clones, the smaller 23-30cc motors don't have them.



Weird I just got this pic off rovans website of the 36cc and it has the removable covers. Seems odd that they would go to the trouble to have two different top ends?

 

[gasserbob]

Yes I agree.

Rovan has always been pretty good about responding to me via email. Im gonna hit them up tomorrow and see what they say.

In the mean time I'll prob pull the head and take some measurements myself.

Is it mandatory that I replace the head to case gasket once I remove the head? Can the Old head to case gasket be reused?

 

[Buzzsaw46]

Both of my Rovan motors the gaskets came apart during the tear down post mortems, so chances are a new gasket will be needed. I would bother pulling it apart though, run it as it is and enjoy it. When it dies get a Zen!

 

[gasserbob]

I appreciate that but I have to know for sure it is a 36cc because I paid a lot of extra money on the Claim that it is a 36cc.

I bought the buggy brand new.

 

[Buzzsaw46]

I here ya about the $$$.

 

[Peteolheadz100]

I myself always wondered this myself, the more cc's an engine has should equate to more power or not necessary? Or is it just the cubic centimeters of the engine?

 

[gasserbob]

huh?

 

[Buzzsaw46]

After I had two failures with the bargain mills I decided it wasn't worth it. They say there's no replacement for displacement but I had to figure in reliability also. I ran my Zenoah ESP stoker hard last summer and it survived, picked it up when DDM had it on deal of the day for $169 worth every penny! I picked up my race ported stroker at full price because I was so happy with how well the stroker ran and held up.

 

[gasserbob]

I had to pull the head to see for myself.

Took about 30 mins or so, anyhow the top of the cylinder had been etched with the number 39.
I miked the cylinder head and it looked to be spot on but the stroke was about 1.2 inches of stroke.

Still scratching my head on the Block off plate missing.

The piston already seems to have some minor scoring on the walls.
Im guessing that could have been assembly.

Otherwise for only having 3 tanks run threw the crank and connecting rod are completely saturated in oil fuel mix which is a good thing to see.
I guess since now Ill be waiting on some head gaskets and intake and exhaust gaskets im gonna smooth out the exhaust port so it has a nice even flow. Currently there is a pretty good lip from the cylinder head to the pipe. Looks like it has plenty of meat in there. Shouldnt be a problem taking a little off to get that smooth flow.

Some more photos of the cylinder.
Only today I opened her up full throttle while doing some donuts and when the power band kicked in it started to wheelie while in a donut.

Had to let off right away.

Can totally see how one of these could easily get away from someone.

Ordered a remote kill switch for this thing and just got the kit in the mail today.
A serious must have for these things.

You got the motor for 169? Thats a really good deal, Then you bought a stroker kit?

I bet that thing screams.

Have you looked into the RB innovations super charger?
I have hit them up but seems like there is a issue with the super chargers not being available, Plus im a little skeptical on how well that belt drive set up will hold up.

 

[Buzzsaw46]

The stroker Kit ddm sells is a crank case with bearing and seals installed modified for the 30mm stroked crank. A modified cylinder for the stroked crank, stroker crank, piston, wrist pin, wrist pin washers, wrist pin snap rings, and gasket set. You have to add wrist pin bearing, flywheel, complete clutch, intake manifold, carb, and ignition. Since all the additional items needed are on your current engine all I would add is the wrist pin bearing. That kit comes up on deal of the day from time to time.

When I built mine I also added an alloy intake manifold, bearing modded WT-1107 carb, and a cy lightened flywheel. Clutch parts and ignition came off the Rovan 30.5.

The RB super chargers are a joke, no way to build boost with a 2 stroke engine. The intake and exhaust ports are open at the same time. A proper pipe is a super charger in effect as the shape pulls exhaust out and the pressure wave pushes un burnt fuel and air back into the cylinder.

 

[gasserbob]

I pulled the head last night and the top of the cylinder reads 39.
Today I put it all back together but I did clean up the Head to case threads with a tap just to get the old lock tite out.

Added a kill remote kill switch for safety.

Im gonna try to find some long thread and some narrow nutts so I can stud the case.

Anyhow got it all back together and running again.
Rovan wrote me back and confirmed I do in fact have the new 36cc.
Apparently the new motors have no block off plates.

 

[Thrasher]

When you deal with cheap brands you have to have figured out that there is a reason they are cheaper. The brand name brands are not rolling around in cashflow, it's not big business. Relatively speaking. So to be cheaper, you have to cut corners. I doubt they would downright lie, tho. If it says 36, I think you can believe that. .

 

[gasserbob]

Ya

Im the guy who likes to save a buck for sure, an No worries on my little Rovan. Got the Buggy delivered to my front door just 7 days ago and Ihave been driving it every since, heck just 4 days after I got it I pulled the head and measured for myself the cylinder bore. Its a 36cc with a 39mm cylinder beyond the shadow of a doubt.

So far this little Rovan has been a blast.

Ive had my Rovan for a week now and have put at least 5 Miles on it. Ive run at least a tank of fuel a day now for 7 days in a row and shes still going stong.
I swear just pulling the head and putting it back on seems to have done something because it seems a little faster now.

Anyhow since I have owned my Rovan it seems the only people who have ever said anything negative about Rovans have been those who own any other brand besides Rovan..
I don't know, I guess I can see how someone who spent $1300 dollars on a base line 27cc 1/5th scale could be tweaked out a bit, by seeing a guy who has the exact same Buggy with a bigger engine and only paid $500 bucks.

Ehhhh what do you do?

To each his own..

 

[Buzzsaw46]

I speak from experience, I bought myself a Losi 5ive-T. The wife thought it was so cool she wanted to get one for our son, I decided to try a Rovan. Horrible decision on my part. Half a tank of fuel and the rear center shaft broke, two tanks in the clutch was gone. Shocks were super stiff, fuel tank leaked, engine mount inserts set pinion to spur mesh too tight, couldn't tighten the pinion to the clutch bell or it would cause the clutch bearings to get notchy. During this winters rebuild I found both the front and rear diff cases had issues so I replaced them with Losi parts and the Rovan ring and pinions no longer meshed so Losi diffs were ordered, it is now more Losi than Rovan and way more expensive than if I had just bought a second Losi to start with. Maybe I got a Friday afternoon build, but it was not a good experience. Top it off with two Rovan engines that didn't make it through a single season, and I have a pretty good reason for my poor view of Rovan. On the bright side I now have two TLR 5ive-T's, the sad part is the only Rovan parts left on the truck are the arms, bumpers, chassis, shock towers, and the throttle/brake linkage. Sure wish I was ticked off that I spent $1500 on the Losi instead of ticked that my $850 Rovan is now a $3000 Losi,LOL!

 

[PSH72]

I have a Rovan for 5 years now and it still runs, have I changed parts to upgrade of course like all of has done, even most hpi onwners buy upgrades.

If you save the money on buying a rovan, you can spend the rest on upgrades and have a even better baja than the original hpi.