Eccentric Shaft Oil Jets Modification
02-08-2004, 05:37 PM
#1
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Join Date: Jun 2003
Location: Grand Prairie, TX
Posts: 917
Moderators, I'd like this one sticky'd if I could, please.
I was just doing this e-shaft oil jet modification for a friend of mine's motor today and realized that there's no single source of information on this. I've decided to take some pictures of the modification during its process, post my comments and personal experience on it, as well as provide links on where to purchase jets, etc.
Modification Details
This modification entails replacing the ball and spring activation of the two factory oil jets located near the rotor bearing journals on the eccentric shaft. These oil jets allow pressurized oil to enter and fill the rotor's cooling oil jacketting on the rear (opposite the gear side) to pull heat off of the rotor faces and rest of the rotor's body. From what I understand, the factory ball and spring acts as an RPM-activation for the oil jets to pass oil at 2500rpm and above (below this RPM the oil jets are not full) to pull heat off of the rotor combustion faces and body.
Purpose for this modification
For what it's worth, our rotary engines are cooled 1/3 by the oil lubrication system running throughout. The point of this modification, as best as I can see it, is to enhance the rotors' capability to remain within operating temperatures while engine loads are high and much heat is being produced. I'm not entirely certain if this is efficacious for a completely stock setup. I would personally gather that it isn't necessary for your typical "beater" or daily driver that never sees above stock power output. On the higher powered setups, such as those that see 300bhp and above or any circuit racing/aircraft (constant, high RPM) applications, I believe it's a big help.
Pro's and Con's
In my personal experience, the benefit outweighs the con. The only con that I see to applying this modification is the drop in oil pressure at and around idle. It can be significant, especially on summer days when ambient temperatures are higher, producing higher oil temperatures. The higher oil temperatures running throughout the engine will yield lower oil pressures overall. I have seen as low as 12 to 14psi at an ~800rpm idle. Idle oil pressure can be increased by the use of a higher oil pressure regulator as well as chamfering of oil passages and other modifications designed to make the pickup system more efficient (by reducing pressure drop points).
The pro, however, is substantially more oil that can be used to pull extra heat off and out of the rotor to help stave off problems with overheating (rotor body warpage, especially at the thinnest portions of the body near the side seal) and what not.
There seem to be two different "camps" concerning the viability and usefulness of this modification; you be the judge. I believe it is worthwhile for anyone looking to build or have an engine built for the purpose of high horsepower or constant, high RPM use.
Explanation and Photos
1) Closeup of the stock oil jet partially unscrewed from the eccentric shaft. Use a very large flathead screwdriver to remove these. Apply some downforce while unscrewing as they have a tendency to be firmly 'stuck' in place.
2) This is what the stock oil jet w/ ball and spring looks like freshly removed (top) and in its native components (bottom).
3) These are the two air corrector jets used to replace the ball and spring components. The inner diameter of the jets' outlets is 2.00 to 2.20mm (200's / 220's).
4) Using a *very thin* layer of JB-Weld or other high-temp metal filler, after cleaning the factory jet thoroughly, insert the air corrector jet as shown in the picture below. Let cure overnight before using. Also check to make sure that there is no obstruction of oil flow through the jet from the JB-Weld or other metal filler used.
5) Re-insert the two jets as-is while leaving the ball and spring completely out using a large flat-head screwdriver. Make sure to screw the jet in firmly. The use of Loctite or other thread locker in a thin layer may be advisable. That's it!
These Weber-style air corrector jets can be purchased anywhere that sells or manufactures carburetor jets. The type to purchase specifically are air corrector jets for DCOE, DCO, IDA, and/or IDF. I purchase mine from Weber Carbs Direct (800.871.3619.). The sizing on the air corrector jet is 200 to 220 (2mm to 2.2mm). Make sure to purchase the correct mm size! Here is a link to their website for quick purchase:
http://www.webercarbsdirect.com/inc/pdetail?v=1&pid=703
Comments and criticism (as well as pro's and con's about this modification) are welcome. Hopefully this will answer some questions and also provide a resource for those builders out there interested in going this route.
B
I was just doing this e-shaft oil jet modification for a friend of mine's motor today and realized that there's no single source of information on this. I've decided to take some pictures of the modification during its process, post my comments and personal experience on it, as well as provide links on where to purchase jets, etc.
Modification Details
This modification entails replacing the ball and spring activation of the two factory oil jets located near the rotor bearing journals on the eccentric shaft. These oil jets allow pressurized oil to enter and fill the rotor's cooling oil jacketting on the rear (opposite the gear side) to pull heat off of the rotor faces and rest of the rotor's body. From what I understand, the factory ball and spring acts as an RPM-activation for the oil jets to pass oil at 2500rpm and above (below this RPM the oil jets are not full) to pull heat off of the rotor combustion faces and body.
Purpose for this modification
For what it's worth, our rotary engines are cooled 1/3 by the oil lubrication system running throughout. The point of this modification, as best as I can see it, is to enhance the rotors' capability to remain within operating temperatures while engine loads are high and much heat is being produced. I'm not entirely certain if this is efficacious for a completely stock setup. I would personally gather that it isn't necessary for your typical "beater" or daily driver that never sees above stock power output. On the higher powered setups, such as those that see 300bhp and above or any circuit racing/aircraft (constant, high RPM) applications, I believe it's a big help.
Pro's and Con's
In my personal experience, the benefit outweighs the con. The only con that I see to applying this modification is the drop in oil pressure at and around idle. It can be significant, especially on summer days when ambient temperatures are higher, producing higher oil temperatures. The higher oil temperatures running throughout the engine will yield lower oil pressures overall. I have seen as low as 12 to 14psi at an ~800rpm idle. Idle oil pressure can be increased by the use of a higher oil pressure regulator as well as chamfering of oil passages and other modifications designed to make the pickup system more efficient (by reducing pressure drop points).
The pro, however, is substantially more oil that can be used to pull extra heat off and out of the rotor to help stave off problems with overheating (rotor body warpage, especially at the thinnest portions of the body near the side seal) and what not.
There seem to be two different "camps" concerning the viability and usefulness of this modification; you be the judge. I believe it is worthwhile for anyone looking to build or have an engine built for the purpose of high horsepower or constant, high RPM use.
Explanation and Photos
1) Closeup of the stock oil jet partially unscrewed from the eccentric shaft. Use a very large flathead screwdriver to remove these. Apply some downforce while unscrewing as they have a tendency to be firmly 'stuck' in place.
2) This is what the stock oil jet w/ ball and spring looks like freshly removed (top) and in its native components (bottom).
3) These are the two air corrector jets used to replace the ball and spring components. The inner diameter of the jets' outlets is 2.00 to 2.20mm (200's / 220's).
4) Using a *very thin* layer of JB-Weld or other high-temp metal filler, after cleaning the factory jet thoroughly, insert the air corrector jet as shown in the picture below. Let cure overnight before using. Also check to make sure that there is no obstruction of oil flow through the jet from the JB-Weld or other metal filler used.
5) Re-insert the two jets as-is while leaving the ball and spring completely out using a large flat-head screwdriver. Make sure to screw the jet in firmly. The use of Loctite or other thread locker in a thin layer may be advisable. That's it!
These Weber-style air corrector jets can be purchased anywhere that sells or manufactures carburetor jets. The type to purchase specifically are air corrector jets for DCOE, DCO, IDA, and/or IDF. I purchase mine from Weber Carbs Direct (800.871.3619.). The sizing on the air corrector jet is 200 to 220 (2mm to 2.2mm). Make sure to purchase the correct mm size! Here is a link to their website for quick purchase:
http://www.webercarbsdirect.com/inc/pdetail?v=1&pid=703
Comments and criticism (as well as pro's and con's about this modification) are welcome. Hopefully this will answer some questions and also provide a resource for those builders out there interested in going this route.
B
02-08-2004, 05:46 PM
#3
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Thread Starter
Join Date: Jun 2003
Location: Grand Prairie, TX
Posts: 917
Originally Posted by j9fd3s' date='Feb 8 2004, 03:41 PM
could you not just drill out the stock piece?
B
02-08-2004, 06:08 PM
#5
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Join Date: May 2002
Location: California
Posts: 22,465
Originally Posted by BDC' date='Feb 8 2004, 03:46 PM
The outlet on the stock jet is larger by about 1.5 to 2 times. I think just removing the ball and spring and using the jet alone would make the oil pressure at idle drop to nearly zip. That's my theory on it, atleast.
B
B
02-09-2004, 08:56 AM
#7
Member
Join Date: Jun 2003
Location: Helena, AL
Posts: 96
Very good writup BDC!
I did this modification on my motor when I built it late last year. I found it required an impact screwdriver to remove my oil jets. I sort of regret it now because it is just a daily driver and I am having oil pressure problems at/around idle. Because of this my next oil change will involve pulling the oil pan and switching to an FD main oil pressure regulator and shimming the front pressure regulator. Hopefully that will put me back up around 30psi at idle.
I did this modification on my motor when I built it late last year. I found it required an impact screwdriver to remove my oil jets. I sort of regret it now because it is just a daily driver and I am having oil pressure problems at/around idle. Because of this my next oil change will involve pulling the oil pan and switching to an FD main oil pressure regulator and shimming the front pressure regulator. Hopefully that will put me back up around 30psi at idle.
02-09-2004, 10:21 AM
#8
Senior Member
Join Date: Sep 2002
Posts: 1,089
this is a great mod. joe does this on most of the high performance motors he builds. in my experience, with a racing beat 115 psi oil pressure regulator and shimmed front press regulator, there are no real oil pressure problems associated with this mod. ive used this mod on the last 4 engines ive had built and i think its worth doing.
02-09-2004, 11:56 AM
#10
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Thread Starter
Join Date: Jun 2003
Location: Grand Prairie, TX
Posts: 917
Originally Posted by SPEED_NYC' date='Feb 9 2004, 08:21 AM
this is a great mod. joe does this on most of the high performance motors he builds. in my experience, with a racing beat 115 psi oil pressure regulator and shimmed front press regulator, there are no real oil pressure problems associated with this mod. ive used this mod on the last 4 engines ive had built and i think its worth doing.
B