Alusil cylinders options
 

Unknown mileage 83 3.0 engine. In the middle of a tear down. If the internals look ok I will just reseal. I'll ask for advice on what the condition of the components look like when I get there. It looks like my cylinders are Alusil. They have 10 fins, no MAHLE marking, and the only part that is magentic as at the top where it meets the head. Anyway, can I just re-ring, clean the cylinders with a red scuff pad and soapy water, and be on my way? OR do I need to get them re-sleeved? Who does this kind of work? This engine rebuild is on a tight budget so if I can get by with just new rings I will. Which rings should I get?

Thanks brain trust.

Alusil cylinder are generally not considered good candidates for re-ringing (search this forum for discussions). Keep the Piston and cylinders matched. Measure all the critical dimensions: bore ovality, Piston to cylinder clearance, ring groove side clearance and ring gap. If all of these are in spec then clean and re-use. If out of spec time for new parts.

john

There's an enormous thread regarding preparation and re-ring of Alusil cylinders. According to that thread, there has been some success simply cleaning with soap and water and re-ring with cast iron rings.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/137346-re-ring-alusils-31.html

Tom thanks, I'll read up on it.

I think the answer is simple , if you need new rings you need new pistons and cylinders , otherwise reuse as is .

Successfully Re-ringed my Alusils 10 years ago with whatever Goetz rings Pelican sent me.
Grey Scotchbrite (red seemed too aggressive) and clean engine oil is what I used. Everything was still in spec at 82,000 miles on the engine.
I read all the doom and gloom threads and all the ones with “it worked for me”.
I figured with everything in spec I had better than a 50/50 chance they would seat.

Good to see a postitive outcome. I've never tried to re-use them due to all the warnings on this site. When I discussed with a friend who runs a 944 turbo, he didn't believe me that 911 people say that Alusil cannot be re-used ; afterall, all the 944 and 928 etc are all Alusil blocks and they often re-ring etc.

I'm not giving an opinion on what is right or wrong, but I look forward to seeing the outcome of this one.

If you find you need new pistons (likely wear being ring grooves, I think, not so much the skirts?), now might be the time to source good used Mahle's (discarded by guys who built motors with wider pistons), if not new aftermarket pistons, and have your cylinders Nikasiled. You could sleeve these, but I think Nikasiling is less expensive. The process involves plating the cylinder bore, then machining it down to spec, so the underlying condition of the Alusil bore doesn't much matter.

Do you, by any chance, have leakdown numbers from before it was torn down? In addition to an overall percentage, the leakdown can point to where the leak or leaks are: intake valve, exhaust, or rings - with the slight possibility of head to cylinder seal. If the leakage was low (say under 10%), and especially if mostly from valves (which can be reground, along with the seats), maybe just reuse rings and everything else in that department?

Sure, the best thing is a full rebuild, leaving you with a basically new motor, but you have a budget. So you do a 50,000 mile fix, rather than a 200,000 mile fix? If you do your own wrenching, that tends to look better than if you figure in shop labor to do everything.

Unfortunately I have no leak down numbers except for a cold cylinder #1 which was reading 10% loss. I went to check 6 and noticed a large leak, but then also noticed the broken head studs. At this point I inspected the rear and found 5 total broke so a rebuild was in order.

Depending on the cost to nikasil the cylinders it might be worth it just to go that route. I'll be possibly buying new rings anyway right? I'll get some measurements of the cylinders, rings pistons.

If you get a chance to check on it, I'd love to know what the cost to nikasil the cylinders might be.

My personal experience........
 

Dennis,

In the early 90’s before the advent of Pelicanparts Forum, I rebuilt my ‘78 SC and re-ringed the alusil cylinders using the Goetz rings from the Victor Renz rebuilt kit. I have 30K plus track miles as of today and still running like new.

And subsequently rebuilt more than a dozen SC motors with re-ringed alusil cylinders with no problem. The car owners have not reported or found any problem after many years of driving and recently delivered another one last August 2021. I have yet to see a motor that failed due to new rings on old alusil cylinders. I am not alone, there are many others that have done it successfully.

Tony

You can find cost for nikasil plating a cylinder on the Millennium technology or US chrome site. These are the primary providers of this service in US. Can also have them bored oversize if sourcing new pistons.

john

Tony - thanks for chiming in. Since I'll be buying a rebuild kit and they come in it then I guess I have my answer on that.

targa72e - Thanks! If for some reason I need to go the plating route I now have their contact info.

Tony,
I admire your guts to post your experience. It helps us all to keep these things going. I didn't have the guts to re-ring my alusil. I need a hobby anyhow, but I think it turned out okay. I would have liked new rings, but I read several owners had noticed that the originals were better than the their replacements in some way or other I forget, so just left them in.
Phil

You can not survive by guts alone........
 

Phil,

You can not survive in this business if you rely on guts alone. Nor rely on luck. You need to have plenty of test results and evaluate them. If you could replicate data or test results, you could arrive to a reliable conclusion. Not because it worked the first time, it would work all the time. There are several critical variables you have to consider in your work or test.

I have rebuilt several motors and ran them in the track. The very first time, I was not even sure if they would survive the brutal test run. As time went by, I feel confident that re-ringing alusil cylinders in good condition is an option people could take. And I’ve done it multiple times and found no adverse effect. And I had rebuilt my first motor 25 years ago and few more projects followed.

Tony

We have never had an issue re-ringing Alusil cylinders. Prep them properly and you will be fine. Of course this assumes that the piston and cylinder measure in spec...

Cheers

For me successful re-ring with alusil was using only Porsche rings called out by them. FWIW

reringing Alusil
 

I have done many motors with new rings in Alusil cylinders.Never had a problem.I have found much less wear with Alusil in higher mileage motors than Nicasil.Last month I took apart an SC with 91,000 miles with broken studs.Measured the ring gaps and they were 0.20mm.New spec is 0.15mm or 0.006 thousandths.Lack of knowledge breeds fear.944 & 928 motors a great example of the Alusil design.Do a RA check on Alusil and that will give you a clue.Less drag from less fricition.Oh no not more power and lower oil temp!Say it is not so!Ciao Fred

Hello,is this thing on?EBS.Send your cylinders to them.Like Walt said,the condition or model of cylinder does not matter,because they will turn them into "Nickies".Their fee for this is nominal,The last time I did it was around $800 for the cylinder repair/plating.EBS will also supply new pistons to match your cylinders .You can choose displacement(within reason), and compression ratio.They have most popular sizes on shelf.I think the pistons were about $100 dollars each,with rings and pins.

I believe replating is around $250 per cylinder now.