Lycoming O-320-H2AD

[jnmeade]

Has the lifter and cam problem on this engine been corrected, or are they still a problem?

 

[Ted]

Provided you use the Lycoming snake oil, you should get good service life.

 

[dalesnip]

Flying frequently helps too.

 

[Tom-D]

Has the lifter and cam problem on this engine been corrected, or are they still a problem?

It was corrected by the "T" mod, If your engine was rebuilt in the last 10-15 years this was done.
But the engine's reputation was never cured.

 

[Silvaire]

If you're going to print out an AD compliance list for an H2AD (aptly named) make sure the paper bin is full.

 

[strangebird]

If I remember right the engines that self destructed did it the first couple of hundred hours, then the Lycoming additive came out, others are correct it has to be flown and not sit, but that is true of all engines fly them is the key
By now I would think those engines have all been OH with the T mod, back in the late 70's they did have a bad reputation.

 

[Tom-D]

If I remember right the engines that self destructed did it the first couple of hundred hours, then the Lycoming additive came out,

State the purpose of the snake oil.

Any one remember?

 

[Sleepingsquirrel]

If you're going to print out an AD compliance list for an H2AD (aptly named) make sure the paper bin is full.

My Uncle once told me that if I bought an airplane had a H2AD engine I'd been HAD!

 

[Tom-D]

My Uncle once told me that if I bought an airplane had a H2AD engine I'd been HAD!

My customer put 2400+ hours on one never had any big problems cylinder rework at 1300 but that's about all.

 

[Pilawt]

FWIW, the original H2AD in my '78 C-172N went 1527 hours before it was swapped out for a different 0-SMOH H2AD in 1981. That one went 1843 hours and 17 years SMOH, and was still doing fine when it was replaced with an O-360-A4M.

I don't have the logbook for the first engine, so I can't tell you what prompted the overhaul at 1527 hours.

The conventional wisdom about H2ADs is that they don't handle cold climates well. This airplane was based at Truckee CA (5900' MSL) from new to 1988, so it had its share of cold.

Not saying this is typical; just a data point.

 

[Sleepingsquirrel]

My customer put 2400+ hours on one never had any big problems cylinder rework at 1300 but that's about all.

He began to deal in Cessna 175s in spite of the OWTs. I guess he just didn't care for the H2AD.

 

[Dan Thomas]

State the purpose of the snake oil.

Any one remember?

Anti-scuffing additive. The cam lobe/lifter interface has terriffic pressures on it in terms of pounds per square inch. Oil gets squeezed out. The additive seems to be an extreme-pressure lubricant to discourage the metal erosion that occurs on the lifters and cams on some engines, and that wear is the reason Lycoming went to roller lifters about eight or nine years ago. They convert returned cores to roller lifters during overhaul as well.

I use the 15W50 in my old A-65. The oil temp runs as much as 40°F cooler with it compared to other non-anti-scuff oils, and when I used it in the flight school airplanes they ran to TBO and still were like new. No metal, compressions all in the high 70s.

http://www.lycoming.com/Portals/0/t...Lycoming Engine PN LW-16702, Oil Additive.pdf

 

[Tom-D]

Anti-scuffing additive. The cam lobe/lifter interface has terriffic pressures on it in terms of pounds per square inch. Oil gets squeezed out. The additive seems to be an extreme-pressure lubricant to discourage the metal erosion that occurs on the lifters and cams on some engines, and that wear is the reason Lycoming went to roller lifters about eight or nine years ago. They convert returned cores to roller lifters during overhaul as well.

I use the 15W50 in my old A-65. The oil temp runs as much as 40°F cooler with it compared to other non-anti-scuff oils, and when I used it in the flight school airplanes they ran to TBO and still were like new. No metal, compressions all in the high 70s.

http://www.lycoming.com/Portals/0/t...Lycoming Engine PN LW-16702, Oil Additive.pdf

Read the AD, it says some thing different.

The first AD that came out told the purpose of the Snake oil was to provide lubrication of the cam/lifter at start. now thru 2 revisions of the AD and three revisions of the SB, they all now say to prevent spalling of the filter.

Read the Service bulletin about using this in engines that have friction type clutches, like all the Continentals.

 

[Dan Thomas]

Read the AD, it says some thing different.

The first AD that came out told the purpose of the Snake oil was to provide lubrication of the cam/lifter at start. now thru 2 revisions of the AD and three revisions of the SB, they all now say to prevent spalling of the filter.

Read the Service bulletin about using this in engines that have friction type clutches, like all the Continentals.

Yeah, I know that the Continentals with starter clutches hate that oil. Can't get a grip. I had some issues with it on O-200s and changed to another oil and the starter clutches were fine after that. That was a long time before that SB came out.

Spalling is just a term to describe the failure of a metal's surface under high pressure. Better lubrication reduces the friction between the two parts, reducing the mechanical drag stress and reducing destructive temperatures at the contact point.