Cox Engines Forum
You are not logged in! Please login or register! Guests are limited to posting in the "General Questions (Guest Posting Allowed)" section only. Becoming a member is fast, easy and FREE!


Cylinders Run Time & SPI Performance Babe_b10
Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Cox Engine of The Month
November-2019
jmcalata's

"Pee Wee .020 throttled combinated"



PAST WINNERS
CEF Traveling Engine

Win This Engine!
The Traveling Prop
Gallery


Cylinders Run Time & SPI Performance Empty
World of Aviation

Cylinders Run Time & SPI Performance

Go down

Cylinders Run Time & SPI Performance Empty Cylinders Run Time & SPI Performance

Post  Iceberg on Wed Jan 02, 2019 12:40 am

I have  .049 cylinders except the 0 cylinder never seen one. Does anyone have any actual stats that show if the SPI cylinders actually improve performance by what amount in RPM? Do any of the 0-8 cylinders last longer than others? Interested to know. What run time is reasonable? I've heard cylinder runnng life is roughly three hours?

Thanks
Iceberg
Iceberg
Iceberg
Gold Member
Gold Member

Posts : 142
Join date : 2018-11-03
Location : Bangkapi Thailand

Back to top Go down

Cylinders Run Time & SPI Performance Empty Re: Cylinders Run Time & SPI Performance

Post  balogh on Wed Jan 02, 2019 1:16 am

If kept clean and well lubricated, a COX engine will work for many hours. I read that a COX factory experiment put 400 hours on an engine that still could be started up afterwards, with an electric starter though. https://web.archive.org/web/20170410030959/http://www.mccookfieldfac.com/helpful-info/cox-engines.pdf ...see 2nd page, top right.

I have a COX TD051 with tapered bore cylinder that I counted to have run near 300 hours and still runs very fast. Remember that castor varnish that builds up on the cylinder wall of a used engine can partly make up for the wear of the mating surfaces.

In my experience SPI can add 500-1500 rpm depending on the type of cylinder and other particular conditions.
balogh
balogh
Diamond Member
Diamond Member

Posts : 2479
Join date : 2011-11-06
Age : 61
Location : Budapest Hungary

Back to top Go down

Cylinders Run Time & SPI Performance Empty Re: Cylinders Run Time & SPI Performance

Post  MBT85 on Wed Jan 02, 2019 2:19 am

I don’t want to sound silly but what is SPI Cylinder?
MBT85
MBT85
Silver Member
Silver Member

Posts : 97
Join date : 2018-11-29
Age : 34
Location : Melbourne

Back to top Go down

Cylinders Run Time & SPI Performance Empty Re: Cylinders Run Time & SPI Performance

Post  balogh on Wed Jan 02, 2019 2:25 am

SPI stands for sub- piston induction where the piston skirt bottom clears the exhaust ports when on top dead center, thus allowing a puff of extra air enter the crankcase and mix with the fresh charge that thus can also carry extra fuel in it = added engine power. On the parallel thread "SPI and free porting" you find more on this as well.
balogh
balogh
Diamond Member
Diamond Member

Posts : 2479
Join date : 2011-11-06
Age : 61
Location : Budapest Hungary

Back to top Go down

Cylinders Run Time & SPI Performance Empty Re: Cylinders Run Time & SPI Performance

Post  Sponsored content


Sponsored content


Back to top Go down

Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum