Valve stem seals for H2AD ?

Here is the dilemma. I have a H2AD that uses one quart of oil in 5hrs. I have had all cylinders of twice and top overhauled by two different shops now and have the same somewhat high oil usage both times. The first shop measured the bores to be well within serviceable limits, replaced the exhaust guides,checked the inlets but did not replace them and re-cut the valve seats, honed the bores and fitted new rings to the serviceable pistons. Still high oil usage after 100hrs so of they came again and went to a different shop. Cleaned and checked again but still within limits and no new inlet guides fitted. ( Didn't need them they told me) honed and new rings fitted again. Same oil consumption after 55 hrs I realize that 5hrs/qrt is within consumption limits but is very annoying.

The cylinders are standard nitrited and now at 3000 hrs since new(second life). This thing starts easy, idles well and makes heaps of power( my RV6 trues at 163kts at altitude) but uses oil!. The latest leakdowns are all 78 or 79.

The H2AD has the barrel type cam followers and pressed steel type rocker arms similar to the Ford top end set up. It also has heaps more oil circulating in the rocker boxes than a "normal" Lycoming because of that.

This all gets me thinking the oil is being sucked down the inlet guides and burned as well as leaked into the combustion chambers before the rocker boxes can drain when stopped.

My question is this, has anyone fitted "mushroom" type valve stem seals on the inlet valves of these engines (or any other Lycoming for that matter)?. What do you engine Gurus out there think?
Cars use them to stop this from happening why not aircraft?

Cheers
Graham

I think you're headed down the wrong path. Its likely the type of hone finish and/or your breakin procedure. When a cylinder is in service if there is too little in the way of valleys in the hone finish the rings will wipe away the oil, hence high oil consumption. Too much depth in the valleys causes the cylinders to run hot and wear prematurely since the oil film is not effective. The ideal finish is a plateaued finish where there is enough volume in the valleys to allow for good oil retention as the rings pass over. On top of this, is how well your rings are seating, which involves the proper hone finish and breakin procedures.

Find out which # of Sunnen hone stones the shops are using to hone the barrels and report back. Also what is your breakin procedure?

rocketbob said:

I think you're headed down the wrong path. Its likely the type of hone finish and/or your breakin procedure. When a cylinder is in service if there is too little in the way of valleys in the hone finish the rings will wipe away the oil, hence high oil consumption. Too much depth in the valleys causes the cylinders to run hot and wear prematurely since the oil film is not effective. The ideal finish is a plateaued finish where there is enough volume in the valleys to allow for good oil retention as the rings pass over. On top of this, is how well your rings are seating, which involves the proper hone finish and breakin procedures.

Find out which # of Sunnen hone stones the shops are using to hone the barrels and report back. Also what is your breakin procedure?

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The break in procedure I used both times was in line with service instruction 1427B as reprinted here in the Lycoming flyer http://www.lycoming.textron.com/support/tips-advice/key-reprints/pdfs/Key%20Maintenance.pdf

The first shop fitted ECI rings and the second genuine Lycoming. The engine was run for the first 50hrs on Aeroshell 100 oil and now is on Aeroshell W100 Plus. Initial ground runs and flying were completed with OAT around 20C at that time of the year and I was very mindful not to get the oil and cylinder head temps anywhere near the high side of the green range. For the first three hours I did not climb above 2000' and maintained 75% power and higher as suggested in the break in article. The engine oiled the plugs within the first hour or so and required removal and cleaning. On calling the shop about this they told me that this sometimes happens and to keep running it HARD. I then left on a long trip that amounted to 25hrs flying with most legs longer than 2hrs. During this period I ran the engine at 75% power and richer than usual mixture and did not fly above 6000' for the entire trip. I still run it at high power settings( flying fast is more fun!) but I'm sure any break in and slowing of oil consumption I am liable to see has already occurred at this point. It was suggested that I may be running to much oil in the sump and the excess was being pumped overboard so I checked the dipstick calibration ( tailwheel RV6) and do not fill above 5qrts and let it run down to 4qrts before adding more(4qrts being min. for this engine). The oil seems to stay brown not black indicating little blow bye but I'm not sure if that is because I keep tipping more in all the time or not!!

I have not called the shops re the hone stones used but can say that both shops are reputable and have both been in business for many years. I would think the answer to that call would probably be something like " we used the same hone and stones as we always use" or some such reply.

Given that this model Lycoming has what amounts to an automotive type valve train and therefore a LOT more oil in the rocker boxes(than other Lycomings) some automotive buddys of mine suggested that valve stem seals may fix it hence the question.

yes

when i built my engine i have P10 new overhauled cylinders and 9.5-1 comp pistons total seal rings.
And when you use the rings it will puff smoke on idle.
Because of the added vacum, on intake stroke it pulls oil thru the guide.
So i added valve stem seals on exaust and intake valve. I have over 250
hours on valve stem seals and on the new turbo motor im using 1/4 quart oil on 35 hours.
If you need more info give me a call 602 697 4080

airtractor8 said:

The first shop fitted ECI rings and the second genuine Lycoming. The engine was run for the first 50hrs on Aeroshell 100 oil and now is on Aeroshell W100 Plus.

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Aeroshell 100 oil is ashless dispersant oil and you're not supposed to break in on that oil. That could be part of your problem. ECI's procedure works great and I have a couple of engines broken in with their methods of short ground runs which has worked great on both Lycomings and Continentals. Mahlon has a nice writeup somewhere summarizing the ECI procedure. ECI's procedures tell you NOT to run hard. I was watching a show sometime ago about a BMW engine plant that uses electric motors to run-in their engines to avoid heat related problems.

mike in phx said:

when i built my engine i have P10 new overhauled cylinders and 9.5-1 comp pistons total seal rings.
And when you use the rings it will puff smoke on idle.
Because of the added vacum, on intake stroke it pulls oil thru the guide.
So i added valve stem seals on exaust and intake valve. I have over 250
hours on valve stem seals and on the new turbo motor im using 1/4 quart oil on 35 hours.
If you need more info give me a call 602 697 4080

Click to expand...

Mike I'll give you a call...I've been looking for Viton stem seals myself but haven't found any big enough. I have a set of ECI 2nd rings that I had Total Seal modify to be gapless.

Thanks for your comments Bob but I think your mistaken on Aeroshell 100 oil. I have a bottle in front of me right now. It has a blue label and states that it is SAE 50 Mineral oil on the front and on the back states that it is a non dispersant oil suitable for break in. I think you may be confused with W100 perhaps?

It seems you don't approve of the lycoming service instructions for break in by the way I read your post?

Ahh thats right. I forgot there was 100, 100W, and 100W plus.

I can say that ECI's breakin procedures are a bit more detailed compared to the Lycoming instructions and for me have worked well. None of the engines I've overhauled use much oil.

oil consumption

I maintain a small fleet (12) of aircraft. On engines overhauled by our local engine shop, oil consumption (Aeroshell 15W50) averages 1qt/25hrs following a breakin with mineral oil per Lycomings instructions for the first 50 hrs. All engines have run to TBO many times without incident. In a foolish attempt to save a small amount of money, I had 2 engines overhauled at a seperate out of state facility. After the same breakin procudure both engines stabilized at 1qt/3hrs, just below the MAX allowable oil consumption. A complete inspection showed that nothing was "wrong" just that the clearances were all on the loose end of the allowable range. That is just the way that shop sets up their engines. I have returned to doing all overhauls at the local shop-problem fixed. SO your issue could be related to tolerances used at the shop. Now I always request that everything during the overhaul meets optimum new clearances or is replaced with a new part. My local shop says "thats what we have allways done. Good luck, Russ
P.S. Hmm an engine with "AD" in its name......kidding I think the valve seals are a good idea.

H2AD & AD oil break-in?

I don't have it in front of me, but I seem remember my H2AD requiring AD oil for all phases of operation INCLUDING break-in. I'll see if I can dig it up tonight . . .Rick 90432 H2AD

AK4x4 said:

I maintain a small fleet (12) of aircraft. On engines overhauled by our local engine shop, oil consumption (Aeroshell 15W50) averages 1qt/25hrs following a breakin with mineral oil per Lycomings instructions for the first 50 hrs. All engines have run to TBO many times without incident. In a foolish attempt to save a small amount of money, I had 2 engines overhauled at a seperate out of state facility. After the same breakin procudure both engines stabilized at 1qt/3hrs, just below the MAX allowable oil consumption. A complete inspection showed that nothing was "wrong" just that the clearances were all on the loose end of the allowable range. That is just the way that shop sets up their engines. I have returned to doing all overhauls at the local shop-problem fixed. SO your issue could be related to tolerances used at the shop. Now I always request that everything during the overhaul meets optimum new clearances or is replaced with a new part. My local shop says "thats what we have allways done. Good luck, Russ
P.S. Hmm an engine with "AD" in its name......kidding I think the valve seals are a good idea.

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Great post Russ and exactly what I suspect may be happening here.

The fact that neither shop changed the inlet guides makes me think they could be on the outer tolerances as well as the cylinder bores (remembering that they are at 3000hrs since new) with both these things adding up to more than normal oil consumption.

My thinking is that stem seals are cheap and reasonably easy to fit with the cylinders still in place and may just improve consumption a little.

The THIRD time I pull those cylinders of will be to replace them with 4 new cylinder kits!

Regards
Graham

mike in phx said:

when i built my engine i have P10 new overhauled cylinders and 9.5-1 comp pistons total seal rings.
And when you use the rings it will puff smoke on idle.
Because of the added vacum, on intake stroke it pulls oil thru the guide.
So i added valve stem seals on exaust and intake valve. I have over 250
hours on valve stem seals and on the new turbo motor im using 1/4 quart oil on 35 hours.
If you need more info give me a call 602 697 4080

Click to expand...

Thanks for the info Mike, sounds like they worked for you.

Did you in fact find some seals made from Viton as Bob suggests or are they like what I have in the photo ?

seals

yes they are close enough seals are seals and we only run 2700 rpm as long as you have room for the seal at max lift on the valve if not it will smash the seal
good luck

Viton seals







Found some Viton stem seals today at the local cylinder head re-manufacturer for 20 bucks. These ones fit snugly over the guide so I decided to go with them.

To get the valve springs off I made a fitting for the lower plug hole and pumped compressed air into the cylinder with the piston at the bottom of its travel and both valves closed. This held the valve up nicely while I removed the springs and collets with a modified spring compressor tool thats used on cars. It all worked a treat and took less than 15 minutes per cylinder to do.

Now to see if my $20 investment makes any difference to the oil consumption or not

Cheers
Graham

airtractor8 said:

snipped

Now to see if my $20 investment makes any difference to the oil consumption or not

Cheers
Graham

Click to expand...

Graham,
So what was the outcome of the addition of the oil seals on your engine?
Charlie

OIL CONSUMPTION

ALL THE ENGINES I HAVE HAD EXPERIENCE WITH WILL USE THE FIRST 1 TO 3 QUARTS RAPIDLY UNTIL IT FINDS THE LEVEL IT LIKES. AND THEN THE CONSUMTION STABILZES YOU MAY HAVE THE SAME ISSUE. LYCOMING EVEN AGREES WITH THIS YOU DO NOT HAVE TO KEEP THE OIL SUMP FULL

The lycoming flyer you reference says use AD oil for break in on the "H" engine, or am I missing something?

RV Jerry said:

ALL THE ENGINES I HAVE HAD EXPERIENCE WITH WILL USE THE FIRST 1 TO 3 QUARTS RAPIDLY UNTIL IT FINDS THE LEVEL IT LIKES. AND THEN THE CONSUMTION STABILZES YOU MAY HAVE THE SAME ISSUE. LYCOMING EVEN AGREES WITH THIS YOU DO NOT HAVE TO KEEP THE OIL SUMP FULL

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Believe me, I've tried all oil levels from full to the 4 quart minimum with no change in the consumption. I also checked the dip stick calibration to make sure it was accurate (tailwheel instillation).

chaskuss said:

Graham,
So what was the outcome of the addition of the oil seals on your engine?
Charlie

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Hi Charlie

I have flown about 40hrs since fitting them and can only see a small reduction in consumption. They certainly didn't fix the problem totally. I think the cylinders are probably near the outer limits as mentioned in one of the previous posts. I will probably run them a while longer and change them out with new cylinders if consumption increases.

Are the combustion chambers wet with oil? If the cylinders are burning the oil they will be wet. If not then the cylinders aren't the cause of the consumption.
Cylinders can be in limits, but as said, what limits. You need to keep the ring gaps in the new limit range and the skirt clearance at less then .012.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

mahlon_r said:

Are the combustion chambers wet with oil? If the cylinders are burning the oil they will be wet. If not then the cylinders aren't the cause of the consumption.
Cylinders can be in limits, but as said, what limits. You need to keep the ring gaps in the new limit range and the skirt clearance at less then .012.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

Click to expand...

Yes all four of them are wet with oil. After removing the plugs and shining a light in there I could see oil laying in the bottom of the combustion chambers. The lower plugs also show signs of oil but the engine still seems to run fine. The mag drop is probably a little on the high side of normal at 75rpm at this point. The leak downs are all in the mid 70's which is why I was thinking oil past the valve guides but this is clearly not the full story. Consumption is still well within limits but I sure am sick of tipping oil in this thing! New cylinders coming up I think

Cheers
Graham

I don't agree with clearances being the only culprit because one can chrome cylinders to new specs on bore diameter, have the correct end gap and piston to cylinder wall clearances and they'll still use oil. But a chrome cylinder obviously has a different finish with very shallow peaks and valleys.

airtractor8 said:

Hi Charlie

I have flown about 40hrs since fitting them and can only see a small reduction in consumption. They certainly didn't fix the problem totally. I think the cylinders are probably near the outer limits as mentioned in one of the previous posts. I will probably run them a while longer and change them out with new cylinders if consumption increases.

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By chance do you know if your cylinders are tappered or straight bored? Also, a broken oil ring will cause oil blow by havoc...

LifeofReiley said:

By chance do you know if your cylinders are tappered or straight bored? Also, a broken oil ring will cause oil blow by havoc...

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They are Lycoming nitrited tapered bore. I guess it could have one or more broken oil rings but given that the consumption hasn't changed much since the second set of new rings was fitted I would have to be unlucky I think. Murfy says its certainly a possibility though.

airtractor8 said:

They are Lycoming nitrited tapered bore. I guess it could have one or more broken oil rings but given that the consumption hasn't changed much since the second set of new rings was fitted I would have to be unlucky I think. Murfy says its certainly a possibility though.

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My good friend had only one broken oil ring a couple of months ago and it just brings back memories when I read thru this thread. Maybe not...

airtractor8 said:

They are Lycoming nitrited tapered bore. I guess it could have one or more broken oil rings but given that the consumption hasn't changed much since the second set of new rings was fitted I would have to be unlucky I think. Murfy says its certainly a possibility though.

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Do you have the part # of the rings that were installed?

LifeofReiley said:

Do you have the part # of the rings that were installed?

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The first set were ECI the second and current set are genuine Lycoming. I don't have the part numbers near me at the moment.

H2AD/oil

Graham,
I am running an H2AD in my -4. I built the engine up myself, and have reconditioned cylinders on it. I did the first 50hrs with same oil you used,running 75% or higher throttle settings, and now run the 100 plus also. I have about 100hrs on it now, and it is using about 1/2 qt every 8-10 hrs. Like yourself, I never fill above 5 qts. I have heard all the recomendations for the valve stem seals also, but didnt put them on mine. Sounds like you have done all the right things, so I will be curious if you find a solution! Good luck.

How's the intake stems seals working?

mike in phx said:

when i built my engine i have P10 new overhauled cylinders and 9.5-1 comp pistons total seal rings.
And when you use the rings it will puff smoke on idle.
Because of the added vacum, on intake stroke it pulls oil thru the guide.
So i added valve stem seals on exaust and intake valve. I have over 250
hours on valve stem seals and on the new turbo motor im using 1/4 quart oil on 35 hours.
If you need more info give me a call 602 697 4080

Click to expand...

I'm wondering how this is working out? I have a Lyc IO-360-C1E6 that and considering doing the same. Any updates would be appreciated!