Honing Aluisil Cylinders ????

flmont · 11-19-2003, 07:03 AM

I am starting to get info from shops that state.If the cylinders are in spec ,..and if you hone them correctly..That it works just fine ,all that is needed for the rings to seat is a roughed up surface??? Has anyone had success with this procedure, Being that I hope to do larger P/C's in the future..I dont what to spend 800.00 on nikisil plating ????? Thanks

BGCarrera32 · 11-19-2003, 07:33 AM

You might try posting this over on the engine rebuilding forum...

Rot 911 · 11-19-2003, 08:17 AM

I believe Superman on this board did what you are thinking of doing. Try a search with his screen name and alusil and honing

1fastredsc · 11-19-2003, 08:29 AM

I just did what your thinking of, although haven't installed them yet. It's not honing technically, it's actually called lapping. The process of putting micro horizontal scares to force the rings to rapidly break-in. Gets rid of the never ending break-in problem that some ausil cylinders have when only reringed and nothing else. I'll post in a next couple of months how it goes with my motor. (my parts are finally coming back next week

)

speeder · speeder's Garage

Do a search on this. The short answer is no, you cannot hone cylinders w/ an impregnated coating such as Nikasil or Alusil. I re-rung my Alusils w/ great success, do a search.

Alan Cottrill · Alan Cottrill's Garage

I searched this topic on the 944 and 928 boards. They also have alusil cylinders.

Many people over there successfully re-ring their motors with no cylinder prep.

William Miller · 11-19-2003, 10:30 AM

I found my P&C's within the wear limits after very careful measurements. My full rebuild was completed and has about 1500 miles on it now. It runs great. I have nothing to compaire it to yet but it was significantly better than before.
I had compression tests of 185-190 psi and leakdowns of 5-10% before the rebuild except for #4 which had a broken top ring from excessive wear.
After careful consideration of all the information here and need to save a few bucks I decided to keep the P&C's like you are considering.
I didn't really hone them. Many people on this board are against. I did a procedure that is like honing but not nearly as agressive.
I took a 3 blade hone that I had from Sears. (Everyone sells these!)
I Oiled the inside of the cylinder and wrapped the inside with "scotch brite" pad. (They make a size that is about 4"x6" with no sponge on it.) It took 2-3 pads to do the set of Cylinders. The spring loaded arm and stone pressed the pad against the cylinder wall. I spun it with a cordless drill about 20-30 seconds at the most and about 8-10 passes up and down. This created a very light honing pattern on the cylinder wall and I think just enough roughness for the new rings to seat. I believe they seated fine using Waynes break in procedures from the Rebuild book. So far I would consider it a sucess. I have no smoke. Like I said it's only been 1500 miles. I would think the rings have seated well by now. I will do a compression test next time I change the oil. I have changed it several times already.
I consider this a risky procedure and I was willing to take the risk knowing the consequences. I built the engine for myself.
Many people wouldn't recommend it because they can't take these risks considering warrantee issues and maintaining their reputation. If I was building the engine for someone else I would probably not do it this way.
So far I'm ahead of the game, but, time will tell!
Good luck whatever you decide.

red-beard · red-beard's Garage

I have a re-rung Alusil engine (3.0) SC. It's funny, in the 911 101 projects book, the car is under going basically a re-ringing. In the 911 Engine rebuild book, you're not supposed to do this.

Car does run well. I think I need to adjust the throttle cable to get full opening.

Of course, I can't get the engine lid open right now...

Doug Zielke · 11-19-2003, 12:03 PM

Quote:

Originally posted by red-beard
In the 911 Engine rebuild book, you're not supposed to do this.

Well, Superman did it, and his car flat-out flys!

Porsche_monkey · 11-19-2003, 12:17 PM

Search Alusil and Mercedes or even Vega and you will fund people who lapp them successfully all the time. I had mine done by an aircraft rebuilder who swears they will be fine with new rings, he does them all the time. (I haven't finished my rebuild yet, so I can't confirm this.)

I believe Sunnen sell a lapping felt and compound for Alusil, they only take about 30 seconds per cyclinder of lapping.

Superman · 11-19-2003, 12:25 PM

Thanks, Doug. It is indeed fun to drive.

I posted my method a number of times, but here's the summary: The Alusil cylinders were well within spec, as were the piston ring lands. The cylinders went through JW's BFPW (large parts washer). So, they were cleaned really really well. This changed the color and texture of the cylinder walls. It looked rough, and felt fairly smooth, but not completely smooth. Looked like a smooth, grey, stone surface. I thought this surface might be just rough enough to show the new rings who's boss. They did.

The car uses essentially no oil, and runs like a top. Bruce Anderson's advice to me specifically was to not baby it during break-in. Don't let it idle. So, I was fairly rough on her during the break-in, within reason. Seems to have paid off.

Porsche_monkey · 11-19-2003, 12:27 PM

I believe that break-in advice should be applied to all engines.

fredmeister · fredmeister's Garage

I re ringed my 3.0 SC engine a few years ago. It was within specs on ring lands and cylinder diameters....so for the money it was worth a try.
All I did was rub a fine grit wet and dry sand paper up and down in the cylinders to create a rough surface for the rings! Just enough to break the polished surface finish.
Car now has 40,000 miles on it without a problem. Doesn't smoke or burn oil excessively.....it is a 911 that is driven hard at alot of DE's where it uses about a quart every 400-500 miles, but it is more from leaks than burning during combustion.
Spend more time fixing the oil leaks while it is being rebuilt to eliminate that headache.....another thread altogether.

stormcrow · stormcrow's Garage

When I did my rebuild on the 3.0 78 Targa, the cylinders were within spec, so I used a fine emery to remove the glaze, cleaned them up to remove any residue and put everything back together. That's been about 20,000 miles ago and the engine doesn't use hardly any oil unless I run it really hard.

I did make the mistake of not removing the glaze the first time around and I had to disassemble the engine again because of no compression - rings would not seat.

Steve

"A Porsche does more then just go fast in a straight line"