Ouch!!! GTP Nissan engine.

Ouch. Sorry too hear that Jason.

A good dose of castor oil added to whatever fuel the previous owner was using, probably could have prevented it.

Some unscrupuluos shop owner likely sold him some high nitro, low oil fuel with no castor.

Sounds like a fun project though.

Bob

Well yes, I thought some of mine were bad! Looks as if it was run on some pure nitro with no oil at all in the mix!

mr_cox wrote:If I may believe the box. They run standard at max 23.000 Rpm! You can find pictures with data on my website at the for sale section.

This piston looks toasted!

I have a box also from when I bought one new. I doubt 23000 is sustainable in this application. I never tacked one. The oil residue was light yellow so I know that they didn't use Cruel Power (Cool Power) Maybe Byrons car fuel that was clear. Super Power fuel back in the day was clear.

Here are pictures of the final result. I am bidding on a Cox/Sanwa 2 channel to bring this back to original condition.

I missed out on a Cox GTP Nissan lexan body a while back. It seems as if 1/12 scale cars have gone the way of the dodo. Bolink was a big player as was Associated. 1/12 scale Lexan bodies are getting scarce. I picked up a 1/12 scale Bolink Porsche 969 body off of eBay and it should fit decent. It will give it a different look for sure.





New engine installed.



Jason

Are you sure you can't replace the cylinder and piston assembly? Take the cylinder off and find another with the same porting.

Admin wrote:Are you sure you can't replace the cylinder and piston assembly? Take the cylinder off and find another with the same porting.

The problem is finding a cylinder that fits the throttle ring. A sure start cylinder will work but the outer diameter is too big for the throttle ring. It uses the same cylinder and piston that was used on the later .049 medallion engines. It is precision ground to fit the throttle ring.

I had a spare set so I am good to go for this rebuild. The Cox part number for the cyl/piston is is 1477 and the throttle ring is 20467.

Here is a picture of the difference. The ground cylinder is on the left.



Jason

If anyone else has a similar problem with a throttled cylinder replacement, this might help

http://www.ebay.co.uk/itm/Cox-Surestart-049-Piston-Cylinder-throttle-custom-RC-/130461590708?pt=Radio_Control_Parts_Accessories&hash=item1e601de4b4


I have one on order, they say the throttle ring is fitted to a ground Surestart cylinder

or you could give this a try!

http://www.exmodelengines.com/product.php?productid=17765&cat=267&page=2

I keep forgetting to check EX for parts. That is the exact piston/cylinder I need. Looks like I need to order a couple sets.

Thanks,

Jason

Jason, you may want to try a cox dragonfly cylinder/throttle or its other equivalent; I forget what they are calling them in the curent sales. It apears to be the same muffler from what I have seen,but I could be all wrong too.

Jaspur_x wrote:Jason, you may want to try a cox dragonfly cylinder/throttle or its other equivalent; I forget what they are calling them in the curent sales. It apears to be the same muffler from what I have seen,but I could be all wrong too.

Is that not what he has now?

Jaspur_x wrote:Jason, you may want to try a cox dragonfly cylinder/throttle or its other equivalent; I forget what they are calling them in the curent sales. It apears to be the same muffler from what I have seen,but I could be all wrong too.

What I used on my GTP Nissan recent rebuild (dragonfly set).

I did one better than that on my Nissan years ago. Had the thing running real good,,,with no load on it,,,el-seizeo!!!. It either sucked or rattled (or both) the reed clip off of the backplate,, jamming said clip underneath the crank throw, turning the rod into a C shape, and stopping all rpms IMMEDIATELY. Piston, rod, sleeve, crankcase,,ect. Singing happily one second, the next it's trying to torque out of my hand from the seize.

I just picked up a complete Nissan awhile back, minus radio gear, but no gear ever mounted to the blocks. The guy ran the motor after he got it, then stuffed it in a box without after-run oil and never touched it again. Should be salvagable. Another project for down the road,,so to speak.

Here's a cylinder chart I put together awhile back.

https://sites.google.com/site/coxenginecollection/choosing-a-cylinder

What I used on my GTP Nissan recent rebuild (dragonfly set).

I did one better than that on my Nissan years ago. Had the thing running real good,,,with no load on it,,,el-seizeo!!!. It either sucked or rattled (or both) the reed clip off of the backplate,, jamming said clip underneath the crank throw, turning the rod into a C shape, and stopping all rpms IMMEDIATELY. Piston, rod, sleeve, crankcase,,ect. Singing happily one second, the next it's trying to torque out of my hand from the seize.

I just picked up a complete Nissan awhile back, minus radio gear, but no gear ever mounted to the blocks. The guy ran the motor after he got it, then stuffed it in a box without after-run oil and never touched it again. Should be salvagable. Another project for down the road,,so to speak.

PV,

Do any of your GTP's have the Maples exhaust? I have 2 of each type. I have to post pictures of the Maples exhaust on my other GTP. Very strange setup that recirculated exhaust gas through the engine. Did this improve low end RPM
?

Jason

No Maples here Jason, both have the Dragonfly muffler/throttle. When I raced mine back in the day for about a year, I only seen 1 other car with the Maples and that guy said that they were a pain to tune. He ended up swapping out his setup for the muffler/throttle. He was a young guy, maybe he just didn't take the time to get it right.

He offered me that whole Maples setup and I passed on it,, another one that slipped away.

Really helpful topic. I think it is the same cylinder/piston that is running in my Kyosho F1 0.49.

Jason_WI wrote:...
I tried a new piston in the cylinder from a sure start and the piston gets tight 3/16" from the top. It must have got so hot that the top of the cylinder shrunk. I do not think it can be salvaged at all.
...
Jason

If you want to get into it you can use some lapping compound and oil to lap a piston to the cylinder like if you were making a home made engine.

I have read about it, but not tried this, or have had a reason to try this yet. When I got my lathe I looked up a whole lot of different things to try (naturally making an engine was on the list)...but haven't replaced the missing chuck yet, so I can't work on small items (yet).

Phil