O320-H2AD Question

Where could I find information on modifications to -H2AD engines that are designed to mitigate the cam and lubrication issues that have given the engine a "bad rep"?

I am looking at a plane with one of these engines in it. I would like to educate myself on the engine and its issues.

If it has been overhauled before it most likely has the T mod installed with different lifter bodies that are much less susceptible to spalling. Many of these engines run to TBO just fine. My biggest gripe with them are the single drive "dual mag" what a POS, but easy to get around with electronic ignition on an experimental.

Check out this link for more info.
http://www.cessnaowner.org/forums/topic.html?id=8409

My H2AD

I am running an H2AD in my -4. I am an A/P I/A, and built this engine up from a run-out core. The H2 did get a bad rap back in the day, eventually creating an AD ( no connection to AD in the designation) requiring an oil additive to create better oil adhesion during times when engine was not being run. The other series of O-320's are not immune to cam spalling, its just that the H2 is a little more prone to it. The lifter body of an H2 is basically a Ford 302 drop in lifter, where as other variants are larger faced lifters installed from inside the case prior to assembly, giving slightly more contact surface. Several mods for the H2 include larger lifter bore/lifters, spray nozzles for the cam,ect. My engine has no significant mods, and the Aeroshell 100 Plus oil has the required additive already in it. The H2's have long performed well in the flight school C-172 environment, and many are still in service today. It is a 160HP engine and performs very well in my -4. I have over 200 hrs. on mine since the build, and I dont baby it by any means. Feel free to PM me if you have any additional questions about the unique features of the H2.

Hi,

I have an RV-6 powered by an O-320-H2AD that came from a Cessna 172 damaged in a hurricane in Lousiana.
It has almost 2000 h SMOH.
First overhaul was performed with 1850 h.
I tis on the RV since november 1999.
It has 400 h on the RV-6, 290 h with the previous owner 110 h with me.
It is equipped with single bendix magneto that I sent to a shop for rebuilt in 2011.
I use Aeroshell W100 Plus, change every year, cut and check the filter, check the screen, and send oil for analysis, like the previous owner did.
I am very happy with the engine.
Best regards,

Ramiro

I read lately that at the first sign of any metal in the filter on these engines, remove the lifters (fairly easy to do), replace any that show spalling and it will prevent destruction of the camshaft. Sounds good to me.