# 190 product engine exhaust port height

Thanks Admin, indeed, it must be a #8..(I just found its correct description in the Cylinder identification page here on CEF)..Given the narrow exhaust, single bypass and non-SPI, this is surely not the most powerful cylinder design, but I will love it as just another genuine COX relic..I cannot wait to tach it and compare with other product engines of my fleet.

Any idea on which period of COX history it dates back to?
The COX Model Engine Handbook says on its page 11 this was used only on car engines.(The vendor says it was removed from a plane, though)

This one will work well with a Cox buggy exhaust muffler.
Single bypass port means one port per exhaust port with no boost flutes.

Some say this setup puts out more steady needle settings and will also suit a throttle sleeve.

Yes one would expect that with time passing COX was constantly trying to ramp up engine performance. This engine features the red horshoe backplate with no mesh, like the Killer Bee, i.e. it must be a relatively late model (despite the stepped cylinder with top fin unmilled for the wrench) so I wonder what may have driven COX to narrow down the exhaust port and thus reduce output a bit compared to e.g. the No 1 cylinder which must have been one of the post 1957 cylinders.

One logical explanation for the narrowed exhaust could be the non-SPI design required for the muffler in a car as 1/2A Nut suggested, but this engine is said to originate from a plane (no wonder the prop which is left hand, another puzzle...)

Wow. Learning something new each day here.
I just looked thru my dozen or so cylinders and none have ports that small.
Rarity = value!
Good accidental score Andras!
Greg

It has finally arrived from Chicago to Budapest in a record less than 10 days. A nice little, brand new engine though strange as well:



It was definitely born sometime in the 1970-s:
Stepped wall non-SPI #8 cylinder with no flat top fin for the wrench and only 1 (!) bypass port without a booster
Narrow exhaust port
3-piece piston: the ball-joint socket was swaged into the piston top as a separate item, like in all my old engines from the 60's and 70's
red horseshoe backplate with berillium star reed and circlip
enlarged neck crankcase nose

What makes it strange, is that it was said to be removed from a plane, it came with a prop and spinner,  while I understand these engines always served cars. The backplate screws were quite shiny, and were hard to remove - I replaced them with stock screws. Left hand spring starter with left-hand prop, aftermarket as well as the prop screw.

I assume this product engine, desined for cars by COX,  may have been installed by a third party seller in an airplane...

Anyways it is in mint condition and I cannot wait starting it and taching with the 5x4 Thimble Drome prop from Bernie. I also added a mesh screen to the air intake as well as a right hand starter spring, and pulled a silicone tube over the NV seal...a proven method to prevent excessive valve vibration, wear and leakage.

Does anyone know the history of genuine COX product engines built into an aftermarket planes? The vendor on ebay has a bunch of such new product engines with similar history....

I can only hope this was not a fake COX made in China...15 or so years ago I saw in a Bejing hobbyshop some COX planes made in China. Even if it was made/assembled in China I hope the engine parts are original...

One of the best buys I ever made on feebay for an unbelievable 15USD, even though I do not expect this #8 cylinder to come anywhere near in performance to other cylinders...Will tell you after I have broken it in and tached tomorrow.

If no one here can guide you to a definitive answer, I know who may have one for you.  I'm in touch with Daniel Sitter who along with Tim Dannels co-authored the Cox Model Engine Handbook and I believe he's still in touch with Tim who also wrote the American Model Engine Encyclopedia.  PM me if you would like his contact info.
Greg

Is there 1 bypass port per exhaust port?

Sig Skyray wrote:If no one here can guide you to a definitive answer, I know who may have one for you.  I'm in touch with Daniel Sitter who along with Tim Dannels co-authored the Cox Model Engine Handbook and I believe he's still in touch with Tim who also wrote the American Model Engine Encyclopedia.  PM me if you would like his contact info.
Greg

Thanks Greg, I have the Handbook but could not identify the engine, there is no example there with these attributes. I tend to believe someone may have put the engine together from genuine COX parts before buil ng inside the plane from which then the ebay vendor removed it.

1/2A Nut wrote:Is there 1 bypass port per exhaust port?

Nope; the cylinder is asymmetrical, there are 2 exhaust ports but only one bypass port. Strange, why instead of using any other existing porting COX developed this #8 design? As though they intentionaly wanted to derate the performance...

If the engine was mounted on it's side in a car and used the cox buggy muffler "since this is a non SPI cylinder" then perhaps the single bypass port was was positioned in the sweet spot when the cylinder was seated on the crank case. Looking at the cylinder which side is the transfer port with the cylinder seated?

My guess would be that the engine is just a knock-off. Assembled from odd-bod bits and pieces. The 3 piece piston was only used in the very first Babe Bees and pre-Babe Bee engines if memory serves. It would not have been installed in a stepped cylinder, only the narrow walled type. I don't believe that the Tee Dee style alloy spinner was fitted to any product engine. Most RTF planes with a spinner used a rubber or plastic spinner.
Also, I note on this engine that the backplate is inverted, with the NVA reversed to place the needle at the top. Sure looks like a home built one-off to me.

Rod.

1/2A Nut wrote:If the engine was mounted on it's side in a car and used the cox buggy muffler "since this is a non SPI cylinder" then perhaps the single bypass port was was positioned in the sweet spot when the cylinder was seated on the crank case.  Looking at the cylinder which side is the transfer port with the cylinder seated?

It is on the left, looking from the propeller side. Given the mass production of the engine parts and random pairing of the cylinders and crankcases I doubt, though, that the exact positioning of the bypass port in the sweet spot could have been repetitively ensured.

Anyways I tached the engine after a short break-in. Surprise-surprise !!!! No matter if the cylinder is a bit handicapped with non-SPI design and single bypass port, the engine revs Bernie'd 5x3 competition prop at 17,2k on a 20% nitro fuel. I tached my other reedie with a No5 (TD 051) cylinder on it 5 minutes apart for a comparison, with the same prop and fuel...it tachs only a tad better, 17,6k.

I need to profoundly review my knowledge about the performance of COX 049-s relative to the cylinder design and drop any and all prejudice regarding product engine cylinders.

Oldenginerod wrote:My guess would be that the engine is just a knock-off.  Assembled from odd-bod bits and pieces.  The 3 piece piston was only used in the very first Babe Bees and pre-Babe Bee engines if memory serves.  It would not have been installed in a stepped cylinder, only the narrow walled type.  I don't believe that the Tee Dee style alloy spinner was fitted to any product engine.  Most RTF planes with a spinner used a rubber or plastic spinner.
Also, I note on this engine that the backplate is inverted, with the NVA reversed to place the needle at the top.  Sure looks like a home built one-off to me.  

Rod.

Thanks, Rod,

even if this is just a knock-off, whoever assembled it but from genuine pieces did a job worth much more than the price I paid for it

As I sang about it up in this thread, the engine turns out to be comparable in output to a TD051-reedie combo that I have had since the 1970-s when I got it in a Super Sport Trainer.

Your are right, the 3-piece piston shows up only in my fleet of very first Bee-s and old TD 049-51 dating back to the early 1970-s. The set of old-stock parts in my such engines and this one gives me a confidence these represent the genuine COX quality - not that the later engines are of lesser quality.

The aluminum spinner is already my add-on as is the mesh-screen and the right-hand starter spring. It came as shown in the first thread, wuith a plastic spinner so your observation that it may have been assembled by a RTF airplane maker from otherwise good old parts seems to be correct.