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IO-360-A1B6

High_Flyer

High_Flyer

Well Known Member
Good morning,
Another engine question:
I have found a lycoming IO-360-A1B6 that was on a Cessna Cardinal (F 177 RG).
Question: are there any issues to mount this engine on a RV-7?
I know the RV-7 cowlings are tight around the engine but I believe the A1B6 has the same cylinders as the A1A?
Has anyone mounted this engine, the A1B6, on a RV-7?
What issues can I expect?
Thank you very much.
Alain.
 
Lots of RV have used the IO-360-A1B6. In fact I do believe this is the "standard" angle valve version that Vans sells.
 
As far as I have been able to find the -A1B6 is the best angle valve engine there is for the RV-7. Especially with the counter weighted crankshaft. It's the engine I'm planning on using in my -7.
 
Yep!

This is the engine that Van's used to fit the cowling, Motor mounts, intake snorkel, Baffles, and so on for the 200hp. RV-8 and 200hp. RV-7. Most all of the stuff in Van's catalog for the big "IO" is for this engine.
Most builders would love to have a good deal on a good clean engine of this type. Your airframe had this engine in mind as it's max weight and Hp. up front. So did my 8. Hope you found a good one.. Yours, R.E.A. #80888
 
Also, the c1e6 is a good choice. Put on a different sump and your good to go. The nice part is that the prop governor is at the front of the engine, freeing up some valuable space.
 
A1B6-D

Thanks a lot for all your replies.
Since yesterday I've learnt that the engine is an A1B6 D.

This is from wikipedia:
IO-360-A1B6D
200 hp (149 kW) at 2700 rpm, Minimum fuel grade 100 or 100LL avgas, compression ratio 8.70:1. Same as the A1B6 but with Bendix Series impulse coupling dual magnetos instead of two S-1200 Series magnetos.[4]

I think this means that there is only one output shaft for the magnetos. I want to adapt dual P-mags on my rv-7. How complicated would it be to modify the back of the engine for that?

And finally with this compression ratio 8.70:1 can this engine burn mogas?

My first choice would be the Aerosport IO-375, but recently the Euro took a big hit compared to the Dollar, so everything from the US is about 25% more expensive now than it was a year ago, so if I can secure a good deal with this A1B6D...

Thanks
Alain
 
To convert an A1b6d to an A1b6 is a really big deal. It involves crankcase modification or replacement, changing all the gearing in the rear of the engine and replacing the accessory housing. Normally not economically feasible.
Good Luck,
Mahlon
 
A1B6D to A1B6

mahlon_r said:
To convert an A1b6d to an A1b6 is a really big deal. It involves crankcase modification or replacement, changing all the gearing in the rear of the engine and replacing the accessory housing. Normally not economically feasible.
Good Luck,
Mahlon
Click to expand...

Thanks a lot for the info, that was very helpful and saved me a lot of trouble.
Well, I guess I won't be buying this engine then...
it looks more and more likely that I'll have to save some $$ and get the Low compression IO-375 !
I think it's a better engine for the RV-7 anyways (lighter and mogas compatible).
In the meantime I still have a lot to do on the airframe.
Alain.
 
High_Flyer said:
Thanks a lot for the info, that was very helpful and saved me a lot of trouble.
Well, I guess I won't be buying this engine then...
it looks more and more likely that I'll have to save some $$ and get the Low compression IO-375 !
I think it's a better engine for the RV-7 anyways (lighter and mogas compatible).
In the meantime I still have a lot to do on the airframe.
Alain.
Click to expand...

Be careful with a "lighter" engine and rear CG. I believe the 7 has the tendency to be tail heavy due to it being designed around the larger heavier 200 hp engine.
 
Electronic Ignition

An option for the A1B6D is to install a dual electronic ignition system with two crank triggers (two forward or one forward plus one aft on the magneto drive). A second option is an electronic ignition with one forward crank trigger plus one magneto or P-Mag aft.
 
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I don't believe that the P-Mag will work with the A1B6D mag drive. I have one of these engines in my RV-6, the mag drive is like a six cylinder Lycoming and does not use a gear on the mag. The mag has a flat bar or key on it that interfaces with a rubber cushioned drive cup in the accessory case.

On my engine I have hybrid mag assembly that consists of a single four cylinder Bendix mag with the six cylinder mag drive installed. Then I have an Electro-Air ignition with a crank sensor driving the other set of plugs. Works great!

You may be able to get the P-Mag folks to build you up a similar hybrid assembly now that they are "close to done" with their six cylinder P-Mag
 
A P-Mag Too Far!

Thanks for the correction, Bill!

As I recall, there was an RV-7 advertised for sale with an A1B6D converted to run an Electroair ignition and a single Bendix 1200 magneto. I just assumed that a P-mag could be installed in place of the Bendix 1200, but maybe not. Searching, I?ve found inquiries about the installation of a P-Mag on the A1B6D?s magneto drive, but, as you correctly point out, there does not seem to be any evidence that it has been accomplished. It looks like the P-Mag is not an option for the A1B6D; at least for now.

Thanks Again for keeping me on course!
 
Great info

Thank you very much for all this.
Apart from basic understanding of these engines, I know nothing about these techincalities.
As usual this VAF forum is like a goldmine for informations from very knowledgeable people.
Alain.
 
Rear CG.

pazmanyflyer said:
Be careful with a "lighter" engine and rear CG. I believe the 7 has the tendency to be tail heavy due to it being designed around the larger heavier 200 hp engine.
Click to expand...

Hi.
There are a few RV-7 flying here in France with the IO-375 and the lightweight RV-200 Whirlind propeller, and they have no issues with rear CG. No avionics installed in the back, everything is behind the instrument panel, and a standard PC-680 battery in the engine compartment.

Could you be a bit more specific and tell me if anyone you know had issues with rear CG with the above setup that you know about?
I have seen a few posts about this, but the people I spoke in person with have had no such issues.

Thank you,
Alain.
 
High_Flyer said:
Hi.
There are a few RV-7 flying here in France with the IO-375 and the lightweight RV-200 Whirlind propeller, and they have no issues with rear CG. No avionics installed in the back, everything is behind the instrument panel, and a standard PC-680 battery in the engine compartment.

Could you be a bit more specific and tell me if anyone you know had issues with rear CG with the above setup that you know about?
I have seen a few posts about this, but the people I spoke in person with have had no such issues.

Thank you,
Alain.
Click to expand...

Do they limit their luggage and fuel burned to stay within CG? Do they use a heavy prop ballast to stay within CG? I have no personal experience with this combination but have read almost all the comments and discussions for the engine selection for the 7. I to am building a 7 and need to keep concerns like these fresh in my head so I don't do anything silly that I could have avoided. Here's an example of my readings as well. http://www.vansairforce.com/community/showthread.php?t=79191 Now I didn't say it couldn't be done and I know there are many with IO375's. I'm just saying be aware of the cg concerns with lighter engine choices.
 
I have an IO-360-A3B6D in my RV-6, which is the same as your potential A1B6D except with prop bushings clocked differently. 550 hours ago, I installed dual Lightspeed Plasma II, both crank-triggered. I used the Lightspeed-supplied mag block-off cover to mount the coils for the bottom plugs. So far, this has been a flawless setup.

One thing about the dual-mag engines as they're called, is a better accessory layout on the back of the engine. Better access to the oil filter, oil cooler line fittings (and they're O ring instead of pipe thread), and a 1/2" bolt holding on the crank accessory gear. Go dual electronic ignition and eliminate the dual-mag and that ought to make a fine engine. If you absolutely MUST have one mag, do the Bendix 1200 conversion and one crank-triggered EI (search the archives for part numbers).

HG
 
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