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  #11  
Old 10-07-2014, 09:00 AM
chaskuss chaskuss is offline
 
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Location: SE Florida
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Originally Posted by Saville View Post
Hi Peter,

Thanks but I already had all that information. Unless I missed something, he document doesn't tell me if I can bolt an O-360 Dynafocal II onto an engine mount where an O-320 DII now hangs.

thanks
Yes, you can install an O-360 Dynafocal II engine on a Dynafocal II mount which originally had a Dynafocal II O-320. Question, do you already own this mount and engine? Or are you asking to help understand your options when choosing an engine?
Regarding the engine mounts, a Conical mount will work with any 235, 290, 320, 340 or 360 cubic inch engine with provisions for Conical mounts. The same holds true for the Dynafocal I mounts and the engines designed for them.
Regarding the Dynafocal II mounts, they were designed for aircraft with wing mounted twin engines. They have a 30 degree focal point, as opposed to the 18 degree focal point used on the Dynafocal I mounts, which are designed for single engine aircraft. If you do find a great deal on a used Dynafocal II engine, be aware that it can be converted to Dynafocal I, by Divco. The engine needs to be disassembled and the crankcases sent to Divco for this to be done. It's only cost effective if you were planning on having your crankcases overhauled. Divco's web site is linked below.

http://www.divcoinc.com/


Charlie

Last edited by chaskuss : 10-07-2014 at 09:10 AM. Reason: Added 2nd & 3rd paragraphs
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  #12  
Old 10-07-2014, 09:04 AM
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Saville Saville is offline
 
Join Date: May 2014
Location: KBVY Massachusetts
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Quote:
Originally Posted by chaskuss View Post
Yes, you can install an O-360 Dynafocal II engine on a Dynafocal II mount which originally had a Dynafocal II O-320. Question, do you already own this mount and engine? Or are you asking to help understand your options when choosing an engine?
Charlie
I'm asking this question to help understand my options when I buy an already-built RV-4.

Each -4 for sale has it's own engine/mount configuration. I may want to upgrade an O-320 to an O-360 in the future. I want to be able to look at a prospective a/c and know whether or not I can do the upgrade without modifying the mount and/or firewall.

thanks
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  #13  
Old 10-07-2014, 09:23 AM
chaskuss chaskuss is offline
 
Join Date: Mar 2005
Location: SE Florida
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Quote:
Originally Posted by Saville View Post
I'm asking this question to help understand my options when I buy an already-built RV-4.

Each -4 for sale has it's own engine/mount configuration. I may want to upgrade an O-320 to an O-360 in the future. I want to be able to look at a prospective a/c and know whether or not I can do the upgrade without modifying the mount and/or firewall.

thanks
Yes, the engine mount will not be an issue, assuming that you replace a conical 320 with a conical 360 or a Dynafocal I 320 with a Dynafocal I 360. That being said, the 360 is 1" wider than the 320 [cylinder assemblies are 1/2" longer to deal with the 1/2" longer stroke of the 360] Make sure you have room inside the cowl to install the 360 without rubbing. Van never intended the 360 to be installed on the 4, when he designed it. It's not an uncommon upgrade. I would suggest that you contact someone with an O-360 or IO-360 RV4 to find out if you will need to modify [widen] the cowl. That could prove to be a rather labor intensive mod. The RV3 & RV4 cowls are so tight, that even installing the larger 60 - 90 amp ND alternator requires mods to the cowl. Vans sold both 320 & a wider 360 cowl for the RV6/6A.
Charlie
PS Very carefully inspect the lower, outer corners of the firewall on any RV 4 you consider purchasing. Also look on the back side of the firewall at the lower corners, for adding the reinforcing gussets that Vans issued a update in the RVator [going from memory here] for to prevent buckling of the lower, outer corners of the firewall. You can purchase the lower longeron to firewall gussets for an RV8 from Vans and install them, if you prefer not to fabricate them, per the RVator article.
Vans has discontinued the Dynafocal II engine mount per Service Letter. See

https://www.vansaircraft.com/pdf/Dynafocal_II.pdf

So if you buy a RV with a Dynafocal II engine and the mount cracks or you damage it in a ground loop incident, you can not buy a new one from Vans
Charlie

Last edited by chaskuss : 10-07-2014 at 09:35 AM. Reason: corrected & added to my post script
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  #14  
Old 10-07-2014, 09:23 AM
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osxuser osxuser is offline
 
Join Date: Aug 2005
Location: Pasadena CA
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There are not nearly as many O-360 configurations for Conical mount as O-320. Piper used the Conical mounts, as did American Champion. Those are mostly O-320's. Currently, Robinson Helicopter still uses them for the 4 cylinder R22's. The O-360C is conical.

If you are looking for a power upgrade with minimal work at overhaul, you might consider an IO-340 stroker conversion to your current O-320. With 9.5:1 pistons and an electronic ignition setup, you could be looking at the 185HP range with minimal baffling work and the same mount.

This is essentially a crankshaft and connecting rod change marketed by ECi.
__________________
Stephen Samuelian, CFII, A&P IA, CTO
RV4 wing in Jig @ KPOC
RV7 emp built
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  #15  
Old 10-07-2014, 10:32 AM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
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Default Engines

Quote:
Originally Posted by chaskuss View Post
Yes, you can install an O-360 Dynafocal II engine on a Dynafocal II mount which originally had a Dynafocal II O-320. Question, do you already own this mount and engine? Or are you asking to help understand your options when choosing an engine?
Regarding the engine mounts, a Conical mount will work with any 235, 290, 320, 340 or 360 cubic inch engine with provisions for Conical mounts. The same holds true for the Dynafocal I mounts and the engines designed for them.
Regarding the Dynafocal II mounts, they were designed for aircraft with wing mounted twin engines. They have a 30 degree focal point, as opposed to the 18 degree focal point used on the Dynafocal I mounts, which are designed for single engine aircraft. If you do find a great deal on a used Dynafocal II engine, be aware that it can be converted to Dynafocal I, by Divco. The engine needs to be disassembled and the crankcases sent to Divco for this to be done. It's only cost effective if you were planning on having your crankcases overhauled. Divco's web site is linked below.

http://www.divcoinc.com/


Charlie
The type II dynafocal was not designed for twin engine or wing mounted engines. It was designed for the Piper PA30 Twin Commanche which has a long prop extension built in to the hub of the special Hartzell prop. The type II was designed to counter the extra moment arm of the prop.
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  #16  
Old 10-07-2014, 12:37 PM
chaskuss chaskuss is offline
 
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Location: SE Florida
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Quote:
Originally Posted by jrs14855 View Post
The type II dynafocal was not designed for twin engine or wing mounted engines. It was designed for the Piper PA30 Twin Commanche which has a long prop extension built in to the hub of the special Hartzell prop. The type II was designed to counter the extra moment arm of the prop.
Jim,
I could not remember the exact make & model aircraft that the Dynafocal II was created for. I knew that it was a twin, with wing mounted engines [not a Sky Master or similar] As you stated, the 30 degree focal point was to compensate for extended prop. Thanks for giving us the exact use of that mount.
Charlie
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  #17  
Old 10-07-2014, 02:57 PM
jrs14855 jrs14855 is offline
 
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Location: Lake Havasu City AZ
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Quote:
Originally Posted by chaskuss View Post
Jim,
I could not remember the exact make & model aircraft that the Dynafocal II was created for. I knew that it was a twin, with wing mounted engines [not a Sky Master or similar] As you stated, the 30 degree focal point was to compensate for extended prop. Thanks for giving us the exact use of that mount.
Charlie
The angles previously posted are reversed. The very common Type I is 30 degrees. The relatively rare Type II, 18 degrees, was used mostly on the Twin Commanche, also the Wing Derringer, only 10 built???, and an Aerostar. I have never seen a four cylinder Aerostar but the list shows it. They also list some aircraft I never heard of, probably foreign.
Piper singles from about 63-64 on used the type I dynafocal, except for maybe a few Super Cubs.
Cessna used the 0 320D (dynafocal I) on some 172's prior to suspension of production in early 80's.
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  #18  
Old 10-07-2014, 03:24 PM
chaskuss chaskuss is offline
 
Join Date: Mar 2005
Location: SE Florida
Posts: 1,499
Default Doh! My bad.

Quote:
Originally Posted by jrs14855 View Post
The angles previously posted are reversed. The very common Type I is 30 degrees. The relatively rare Type II, 18 degrees, was used mostly on the Twin Commanche, also the Wing Derringer, only 10 built???, and an Aerostar. I have never seen a four cylinder Aerostar but the list shows it. They also list some aircraft I never heard of, probably foreign.
Piper singles from about 63-64 on used the type I dynafocal, except for maybe a few Super Cubs.
Cessna used the 0 320D (dynafocal I) on some 172's prior to suspension of production in early 80's.
Thank you for correcting me. As the old joke goes, of all the things I've lost, I miss my mind the most! :-) I should know better than to trust my memory. While looking on line to verify your statement, I managed to stumble across two pages on Lycoming's web site which list both the height, width & length of the various engines, and their mounting type as well. See below for 320s

http://www.lycoming.com/Lycoming/PRO...ngineData.aspx

Look here for 360 engines

http://www.lycoming.com/Lycoming/PRO...ngineData.aspx

Charlie
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  #19  
Old 10-07-2014, 03:34 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,393
Default Engine

Quote:
Originally Posted by chaskuss View Post
Thank you for correcting me. As the old joke goes, of all the things I've lost, I miss my mind the most! :-) I should know better than to trust my memory. While looking on line to verify your statement, I managed to stumble across two pages on Lycoming's web site which list both the height, width & length of the various engines, and their mounting type as well. See below for 320s

http://www.lycoming.com/Lycoming/PRO...ngineData.aspx

Look here for 360 engines

http://www.lycoming.com/Lycoming/PRO...ngineData.aspx

Charlie
I can't keep all that stuff straight either, I usually have to look it up each time. I do remember the mount angles because I have built a few type I engine mounts. I even built the entire ring assembly for one Pitts.
Have you ever heard of an Aerostar with four cylinder engines?
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