O320-H2AD on RV-9

[aitor11]

I?ve been offered the engine of a 172N that I fly often to use it on my 9A. The engine is at TBO, but it is in good health. If I decide to go that route I?ll overhaul it before installing it. This bring two questions that I would like your help with.

1) Does Van?s offer everything needed to install it?, I know about the engine mount, but what about exhaust and all the FWF stuff?

2) I read that the mechanical fuel pump will require a bump on the cowling, does anyone have a picture to get an idea of it?


Thank you in advance for the answers!

Aitor

[N941WR]

Try putting "H2AD" in the Advanced Search box.

I think you will be surprised at how many posts there are about this engine.

I have seen one -6A with this engine and the guy added a matching streamlined blister on the other side to make it look balanced. The blisters we're not that big and didn't look bad.

With this engine you are stuck with a single drive dual mag setup. That is unless you make an all electric dual EI setup. In that case, you might as well dump the mechanical fuel pump and talk to Ross F. about electronic fuel injection as well.

[Steve Barnes]

If the engine is in good health, I would go through Phase One with a proven engine. It eliminates one unknown during testing. To R and R an already installed engine is not that big a deal when it is time to rebuild.

My two cents worth, Steve

[aitor11]

Thank you for the replies. I?m going to do another search to see what else I can find. Any idea on how parts cost compare to the more common versions?

Aitor

[Block]

my 6 has this engine w no problems,have 2 matching bumps on cowl looks good,did use tbo engine for phase one then switched to rebuid later as previous mentioned,i believe there is a h2ad exhaust for rv on the bay for sale,can send pics of cowling if needed

[rocketbob]

I overhauled one of these engines recently and I think it has a lot of nice attributes internally. My experience with them has been good.

You will have to get an engine mount from Van's that clears the back side.

You will get into some expense if you decide to switch the cam/tappets with the T mod.

If it were my engine, I would use what you have for the valvetrain (cam, tappets, etc.), have the tappets DLC coated like new Lycoming tappets now come from the factory.

[smokyray]

Originally Posted by aitor11

I’ve been offered the engine of a 172N that I fly often to use it on my 9A. The engine is at TBO, but it is in good health. If I decide to go that route I’ll overhaul it before installing it. This bring two questions that I would like your help with.

1) Does Van’s offer everything needed to install it?, I know about the engine mount, but what about exhaust and all the FWF stuff?

2) I read that the mechanical fuel pump will require a bump on the cowling, does anyone have a picture to get an idea of it?


Thank you in advance for the answers!

Aitor

Altor,
As RB and others mentioned, the H2AD has alot of misnomers attached, mainly from the number of AD's (oddly enough) the engine had back in the 70's. I have flown several RV's with H2AD's that ran great and is a viable option, especially given they can usually be bought for less than a standard engine.

Differences/Concerns: Single port Dual Mag ignition. Bendix D2000
Forward engine driven fuel pump (a standard RV6 cowl will just clear without mod)
Cam AD issues. (T-Mod is one fix)

If the engine could be bought right, and I mean under $5K, I would go with a reputable shop rebuild to include: T-Mod, 9.0 compression, new cylinders (flowed and ported) balancing and use a crank trigger electronic ignition but keep one mag. A Catto prop would complement nicely.
Low budget option: rebuild as RB mentioned with new parts and aforementioned roller mod. Bolt in, go fly with mucho denaro in your wallet comparatively speaking.

Electronic Ignition?
Several years ago Airtractor8, a long time H2AD flyer posted this concerning Electronic Ignition on the AD:

You cannot use a p-mag on a H2AD engine. The drive dimensions and arrangement do not match up with the drive gear in the engine. As Rocket-bob suggested your only option is full dual electronic ignition via the crank trigger method or one crank triggered Electronic and one mag.

To do this you can just use the old D2000/3000 and permanently ground one side.(you may already have this setup?) OR use a single Bendix 1200 series mag in its place. The impulse coupling variety has the same drive dimensions as the old dual mag but must be setup to turn in the right hand direction.(most of them are left hand rotation but can be easily changed to Right hand). Try part# S4RN-1227 10-349365-6
You will not however be able to use an impulse coupling with this setup ( there is none available with the required amount of Lag in the right hand direction that will suit the 1200 series). You will need to use a drive coupling commonly used on 6 cylinder 1200 series setups with retard breakers. Part # AEL 73000. This coupling uses the same drive cushions and arrangement as the D2000/3000 and will work with the drive gear in the engine.
You have to use the Electronic ignition for starting and will have to setup your ignition switch(s) to ground the mag for starting or you will get kickback if the mag fires at low speed.

For the electronic I use a CPI from Ross at SDS.
If you decide to go full electronic,he also has a nice block off plate and drive gear pin setup for dual mag engines so you don't lose all your oil pressure when you remove the drive gear from the engine. A bullet proof fully user adjustable ignition with excellent after sales service.

Good Luck

Flying a H2AD in an RV 6 for 14 years..and luvn it.
AT8

V/R
Smokey

[aitor11]

Thank you again for the replies. I have been doing more reading and it looks like a viable option for me.


smokyray:

If the engine could be bought right, and I mean under $5K, I would go with a reputable shop rebuild to include: T-Mod, 9.0 compression, new cylinders (flowed and ported) balancing and use a crank trigger electronic ignition but keep one mag. A Catto prop would complement nicely.
Low budget option: rebuild as RB mentioned with new parts and aforementioned roller mod. Bolt in, go fly with mucho denaro in your wallet comparatively speaking.

I'm getting a good deal on the engine, plus I know its history. I'm just finishig my wings on the ntext week or so, and that means that if I get the engine it will sit for a while before it gets to fly again. So I'll probably just do what you recomend.

Block

my 6 has this engine w no problems,have 2 matching bumps on cowl looks good,did use tbo engine for phase one then switched to rebuid later as previous mentioned,i believe there is a h2ad exhaust for rv on the bay for sale,can send pics of cowling if needed

I would really appreciete a couple of pictures to better understand how you did the cowling.


rocketbob

I overhauled one of these engines recently and I think it has a lot of nice attributes internally. My experience with them has been good.

You will have to get an engine mount from Van's that clears the back side.

You will get into some expense if you decide to switch the cam/tappets with the T mod.

If it were my engine, I would use what you have for the valvetrain (cam, tappets, etc.), have the tappets DLC coated like new Lycoming tappets now come from the factory.

This confirm some other comments and experiences I've read about. I really like your two approaches on how to deal with the OH.

I emailed Van's asking about the mount and FWF. Once I hear from them I'll also share it here for future reference.

Aitor

[airtractor8]

I would really appreciete a couple of pictures to better understand how you did the cowling.

I am not Block but here is a couple of pics of how I did the 'bumps"on my early RV6 cowl for the H2AD. My cowl needed bumps on both sides. One side for the fuel pump and the other for the prop governor housing on the front right of the crankcase. The RV9 cowl may be a little different.
The baffles for this engine are also different from the standard 0320. I have some pics of them also if you need them.

Good luck
Cheers Graham