My first seize!

[Deluge1]

yea, i should check out a few engine shops. I do have 3 270 top ends in a box. I have read that the stock 270 has the largest transfer ports in the industry. If it was ported It would no doubt really get with the program.

That's for sure! How much room do they have to work with? I read that the RCMK's are pretty much ported from the factory, and there's not much room to play with.

 

[Deluge1]

Now I know this may sound sorta mickey mouse. What could be done to dress up the imperfections on the crankcase- Enco out of Fernely Nevada has Assorted sizes of granet surface plates- If a guy was careful with the silicon carbide sandpaper on the plate -- Yea, a small surface plate would be very useful for lots of things-

He could probably get it done at a machine shop, as well. But then again, it could cost as much as getting a new case.

 

[jeffp83]

The f-270 is a good little engine. it will really rev to the moon on the pavement even with a 4wd xb. But-- it lacks enough power -torque to pull the xb as fast as it should in loose dirt-grass. It does not have enough oomp to rev enough to get up on the pipe -jet-pro rear mount-xb. This is in conditions that drag the car down- grass-mud-loose dirt.

That's what I'm worried about, that it wouldn't have enough power to get the MT with it's big tires up to the speed that this 28.5 could. I run on short grass mostly.

I have read that the stock 270 has the largest transfer ports in the industry. If it was ported It would no doubt really get with the program.

Found these on a french baja forum comparing the Zenoah G270 to the CY F270, indeed there is a pretty big difference in the transfer ports.

Zenoah G270



CY F270



Zenoah G270 again



CY F270 again

 

[jeffp83]

That's for sure! How much room do they have to work with? I read that the RCMK's are pretty much ported from the factory, and there's not much room to play with.

The RCMK engines have a bit of a different design on the transfer ports than the Zen or CY's as well as scavenge ports already done (is that what they are called?) on the exhaust side transfers. Wonder how much power they make in stock form, a 28.5 4-bolt top end is priced reasonably at $135.

 

[jeffp83]

The crank case could be off. I've seen it happen. Lay a straight edge on it, that should tell you if they're not flush.4 bolt engines are nice. I have a 4 bolt Zen in my 5T. Very reliable.

I checked it out deluge, the crankcase is the problem. The two case halves are misaligned on the top surface where the base gasket and cylinder sit. There is quite a few thousands of an in difference on the one side of the case on the exhaust side. The other side looked a little better. No wonder none of these gaskets are sealing.

 

[Guest]

The RCMK engines have a bit of a different design on the transfer ports than the Zen or CY's Wonder how much power they make in stock form, a 28.5 4-bolt top end is priced reasonably at $135.

I believe they are about the same as a ported CY or Zen. There is not of room for improvement.

 

[jeffp83]

Oh ok. I remember seeing a post from Dan I think? at OBR saying they could get more power out of a Zenoah than they could of an RCMK. Gizmo (gmm racing) says the plating on the RCMK's are better than even Zenoah's. Might be the engine to go with

 

[Guest]

They both will support their own products of course. I have read that the plating on the CY holds up better then the Zen also.

 

[jeffp83]

Yeah, this is true..

 

[Guest]

You really can't go wrong with either.

 

[jeffp83]

For sure... i'll probably just hold out until next spring/summer. Winter time will be upon us soon

 

[Guest]

For sure... i'll probably just hold out until next spring/summer. Winter time will be upon us soon

That's what I've been waiting for!

 

[jeffp83]

Hehehe I bet!

 

[Deluge1]

That's what I'm worried about, that it wouldn't have enough power to get the MT with it's big tires up to the speed that this 28.5 could. I run on short grass mostly.Found these on a french baja forum comparing the Zenoah G270 to the CY F270, indeed there is a pretty big difference in the transfer ports.

Zenoah G270



CY F270



Zenoah G270 again



CY F270 again

Yeah, those ports are pretty big.

 

[Deluge1]

The RCMK engines have a bit of a different design on the transfer ports than the Zen or CY's as well as scavenge ports already done (is that what they are called?) on the exhaust side transfers. Wonder how much power they make in stock form, a 28.5 4-bolt top end is priced reasonably at $135.

Yep. I've looked at the RCMK cylinders. They're different. I've seen some vids of guys porting these type of cylinders, and if I remember correctly, they really didn't do much. Basically rounded out a lot of edges.

 

[Deluge1]

I checked it out deluge, the crankcase is the problem. The two case halves are misaligned on the top surface where the base gasket and cylinder sit. There is quite a few thousands of an in difference on the one side of the case on the exhaust side. The other side looked a little better. No wonder none of these gaskets are sealing.

Bummer! Time for a new case. Or a new engine!

 

[Deluge1]

Oh ok. I remember seeing a post from Dan I think? at OBR saying they could get more power out of a Zenoah than they could of an RCMK. Gizmo (gmm racing) says the plating on the RCMK's are better than even Zenoah's. Might be the engine to go with

That's funny. I wonder if OBR has even attempted to port an RCMK?

 

[Deluge1]

They both will support their own products of course. I have read that the plating on the CY holds up better then the Zen also.

And I think that's ridiculous. They should be trying to pull out as much as they can, from all of these engines. Instead of letting their ego's get in the way.

Ah, the old CY vs. Zen plating debate. It's a lot like the Spektrum vs. Futaba debate. Always turns into a flame war.

 

[Trip]

I came in a little late with this, but when sealing crank case halves or heads to cc, try Yamabond. It's amazing poop and it can be found at any Yamaha dealer. Coat both sides of a Zen gasket and slap it together, even if the cases don't line up I bet it would still seal. I've been using it on everything for about 20 yrs.

 

[Guest]

And I think that's ridiculous. They should be trying to pull out as much as they can, from all of these engines. Instead of letting their ego's get in the way.Ah, the old CY vs. Zen plating debate. It's a lot like the Spektrum vs. Futaba debate. Always turns into a flame war.

That's the damn truth! I completely agree!