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RE: Old K&B Engines - 10/28/2004 3:40:03 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Mike:

I don't have a 4050/4070 to strip, but if you have a NIB one it wont be hurt by taking it apart, you can then compare the parts to a 4011 and tell us how much wilkl interchange.

I don't have one of the ABC 40s, only seen them. In appearance they're all but the same engine.

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

(in reply to MikeSell)
       Post #: 26

RE: Old K&B Engines - 10/29/2004 2:45:21 AM   
smedsky


 

Posts: 218
Joined: 1/14/2003
From: Kirkland, WA, USA
Status: offline 		Bill,
So far with limited knowledge, all the parts from newer .40's have interchanged with older parts. Are there any parts that I might get in trouble with. Such as rods or sleeves ect...........Paul

(in reply to William Robison)
       Post #: 27

RE: Old K&B Engines - 10/29/2004 4:18:18 AM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Paul:

From the front plate joint back, all series ringed 40 parts will interchange. The crank shafts and the front castings are different among the series, but all will interchange as an assembly.

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

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       Post #: 28

RE: Old K&B Engines - 10/31/2004 9:15:53 PM   
tucker1865


 

Posts: 435
Joined: 7/20/2004
From: HIGHLAND, CA, USA
Status: offline 		William ..Help. I have a pile of carbs and engines....A K&B 40 Torpedo with a perry carb I.D..270/O.D..433 that I believe is a 2100 perry. Will this fit the K&B 28. I have three K&B40 with large front bearing and exhaust flange to accept a screw on muffler. 4011? One has ribbed carb and two have block carb. I have two with small front bearing and thin flange with holes on side for baffle I believe, look exactly like the .40 Torpedo , one has Irvine carb with a sleeve to reduce carb inlet to fit Irvine. 8011's ? ..Two new Carbs marked as series 80 with O.D. of.530 and I.D. of .270 with aliminum sleeves to bring to .530. Fit K&B .61? Conley told me they are for a Super Tiger. I have one carb in the bag marked 8761 and according to K&B parts list is for a 4012 or is replaced by 5960. Fits 4011's ? Have a pump on the back of a K&B 61 that looks like a stack of half dollars inside back plate with a stack of quarters outside and a stack of black nickelks with inlet and outlet...A VP20...not a can type which is the VP30 that requires a perry pump carb. Has a V stamped on the top/back of the back plate. Am I correct. Is there any performance difference between 4011 and 8011. You seem to be the K&B expert so I could use your help. Id like to keep two, maybe three and have a perry, a ribbed and a block carb, dump the irvine. If the carb fits (O.D.) and the I.D. is close, will the carb work. The block carb for the .40 has an I.D. of .312 and the perry for this engine is .270 I.D., does that mean the K&B is dumping more fuel in than the perry? Thanks in advance for any comments....Dave

< Message edited by tucker1865 -- 10/31/2004 9:24:05 PM >

(in reply to William Robison)
       Post #: 29

RE: Old K&B Engines - 11/1/2004 9:37:34 AM   
MikeSell



Posts: 801
Joined: 10/26/2002
From: Flushing, MI, USA
Status: offline 		I can help on the pump. This is the standard pump installed in the K&B pump/pump carb system. It is basically a VP30. The VP20 works off vibration and looks like black plastic a little over 5/8" diameter with a mounting flange on its side and a fitting in each end. It looks the same as the VP22 which is for smoke and gas. The only visable difference is that the Glow version has aluminum fittings and the gas has brass.
Your assessments for 4011 and 8011 seem correct.
I have heard of little difference in the performance of the 8011 and 4011. They are quite a bit below average for current .40s. The sleeves have very different port widths, the exhaust outlet on the 4011 is much smaller. The loop charged design is just not as powerful as schnurle porting. If you add the pump system power jumps to well above average but those engines have a different model number.
The smaller carb throats will yield better idle and throttle response at the expense of a little top end. That is largely because of available vacuum at the intake. The larger the venturi opening the less vacuum to draw and atomize the fuel. The super large pump carb doesn't use the vaccum as much but relies on the pump to supply fuel and atomize it. When at full throttle it doesn't restrict air flow.
Modelers often play musical chairs with carbs between engines. Its not unusual to see an enya carb on a K&B or a Supertigre on a Webra. Many reviewers swap carbs when the installed carb is giving them problems, just to see if its the fault of the carb. If you do this remember that you need to adjust any carb to the engine to which it is installed.
Parts that won't interchange...The head, piston and sleeve of the 4050 & 4060 with any of the older engines unless all exchanged together.

< Message edited by MikeSell -- 11/1/2004 9:40:34 AM >

(in reply to tucker1865)
       Post #: 30

RE: Old K&B Engines - 11/1/2004 8:06:00 PM   
MikeSell



Posts: 801
Joined: 10/26/2002
From: Flushing, MI, USA
Status: offline 		I checked cost of the piston-sleeve-head to switch a 4011 to a 4050. $57.50 plus shipping seems a little too high for me to switch mine over. For less than $20 more I could buy new 4050s.
I've read some recent posts on other brands of engines that indicate that I may not want any more performance out of my 4050s. They took good solid performing engines and boosted the power by a couple of thousand rpm only to blow the connecting rods or do other damage. I am remembering some lessons learned years ago when boosting engine power. Don't exceed design perameters without checking the strength of related components. The pump and pump carb do a great job on a low performance 4011 but if the engine power is boosted 80% and the pump system is used will the power produced destroy components originally designed for the 4011s power? I guess I don't need to know.

(in reply to tucker1865)
       Post #: 31

RE: Old K&B Engines - 11/2/2004 12:33:01 AM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Mike:

That's a simple one to answer. Higher power gives higher component loads, gives higher wear rate unless the lubrication is improved to match. Synthetic oil is not an improvement.

Component loads will increase also, and it's possible to exceed bearing limits either in load or rpm. Any fatigue loads will not be eased by better lubrication, they are the absolute limit of maximum power.

Roughly speaking, a given engine has so many useful horsepower/hours in its life. If an engine has, say, 100 hp/hrs life, you can run the engine for 200 hours at 1/2 horsepower, or 20 hours at 5 hp. Granted, this is a generality, but it will give the idea.

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

(in reply to MikeSell)
       Post #: 32

RE: Old K&B Engines - 11/5/2004 5:26:43 PM   
tucker1865


 

Posts: 435
Joined: 7/20/2004
From: HIGHLAND, CA, USA
Status: offline 		William...From Your pictures above I am able to determine that the pump is a VP-30...the engine came with pump and no carb.(just plastic neck where carb was broken off). From a post on 11/11/03 (HB perry carb) you said that the carb on the left was a pump carb. My two perry carbs look like the carb on the left (screw on the block, upper left corner but without the second screw near the needle valve. If these are not pump carbs, then I would need to get the pump carb or run standard perry and get a new backplate. From the 8011/4011 question I believe that the older engines had the baffle and no muffler screws, right? I can't tell from the K&B exploded views on their website, they look the same to me. Dave

< Message edited by tucker1865 -- 11/5/2004 5:27:54 PM >

(in reply to William Robison)
       Post #: 33

RE: Old K&B Engines - 11/5/2004 6:01:32 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Dave:

All the built in pumps are operated by crankcase pressure, they are indeed the VP-30.

The Perry "Pump" carb is distinguished by the flow regulator, this is the added screw on top, near the mixture disc. The throttle bore on the pump carb is too large to give reliable suction feed, it needs the fuel fed under pressure.

You don't have to discard the pump if you don't have the pump carb, you just wont have the higher power given with the greater air flow. Almost any large bore carb can be installed when the pump is there, it doesn't have to be the Perry. The pump will work with the standard carb too.

All the ringed 40 engines have baffled pistons, the exhaust stacks on the early ones were either plain, of had holes allowing the installation of an exhaust throttle. Some of the older carbs have two arms on their throttle levers, the second arm turned the exhaust throttle.

The picture I've attached shows, in the center three shots, the exhaust stack variants. The top right shot is the U/C version 0.35 engine.

Other differences I've not mentioned are the cranks, For example the top left shows the "Stuffer" crank, it had the web hollowed on both sides of the crank pin for balance, then an alloy sleeve was shrunk on to keep the crankcase volume as small as possible. Later production had the web milled in the normal manner. Another difference in the crankcases is the bypass port. The bottom row shows the early passage on the left and center, the later production had the port milled out for freer flow, as shown on the bottom right.

The stuffer crank will work in the 8xxx engines only, the enlarged bypass case can be used with any of the ringed 40 engines. Or you can enlarge the passage in the earlier case.

And I'm still working on the response to your earlier post, but some of the answers are in this one.

Bill.

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_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

(in reply to tucker1865)
       Post #: 34

RE: Old K&B Engines - 11/5/2004 6:12:59 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Dave:

Back on the carbs. The earlier Perry carbs had no seal on the needle valve, they looked like the one on the right in that picture of the carbs. The later ones incorporated an o-ring inside the cup of the needle valve, they looked like the one on the left. The needle design change was dome on all the Perry's, it had noting to do with pump style or plain. If your Perrys don't have the flow regulator they are standard carbs regardless of the needle type.

Look at this picture again. The 6535 on the left has the original needle, the 6560 on the right has the sealed needle.

Bill.

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_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

(in reply to William Robison)
       Post #: 35

RE: Old K&B Engines - 11/5/2004 6:15:49 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Here's a better picture showing the needles.

Bill.

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_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

(in reply to William Robison)
       Post #: 36

RE: Old K&B Engines - 11/5/2004 7:21:45 PM   
tucker1865


 

Posts: 435
Joined: 7/20/2004
From: HIGHLAND, CA, USA
Status: offline 		William..We have to stop meeting like this...and I'm sorry if I'm being a pain the rear but I'm still fuzzy on the combinations. So lets layout the different scenario's. I have two K&B .61 #6550, one new and the other used. I can send the new one to Clarence Lee for porting, install a standard perry carb and the pump VP30. 2. Lee, perry carb, no pump. 3. Lee, standard carb, VP30 pump. 4. Lee, perry pump carb, VP30 pump. If I understand performance is as follows from strong to stock. 1. Lee, perry pump carb, VP30 pump
2. Lee, perry non-pump carb, VP20 pump
3. Lee, perry non pump, VP30 pump
4. Lee, std. carb, VP30 pump
5. Lee, perry non pump, no pump
6. Lee, no perry carb, no pump
7. No Lee, std. carb, no pump, basically stock Is that a fair accessment of the situation. And thanks for your patience Dave

< Message edited by tucker1865 -- 11/5/2004 7:28:50 PM >

(in reply to William Robison)
       Post #: 37

RE: Old K&B Engines - 11/5/2004 8:16:00 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Dave:

The standard ringed 61s with the standard carb, be the carb small bore Perry, the block carb, or the ribbed carb, are good "Cooking" engines, and are the least powerful variant.

Going up from there you have two ways to go. One is the pumper set, with the large bore "Pump" carb, the other is the PDP conversion done by Clarence Lee. I don't know which is the more powerful, but the PDP is louder; part of the work is enlarging the muffler ports. The PDP has a sharp "Rap" to its sound.

And of course, when the PDP is combined with the pumper parts you should have the most powerful version of all.

If you already have the engines and the Perry parts it's a practical thing to do, but if you are buying new there are other engines that will give higher performance. The K&B engines shine as sport power plants, if you want a screamer you would be better getting something else.

I accept the limitations of the K&B ringed engines, and working within the limitations, I am very pleased with them. Just remember there are others more powerful.

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

(in reply to tucker1865)