Alusil 885/3A +

[TibetanT]

Hello everyone:

Does anyone know what these cylinders should measure?

I believe they are from a 3.0L engine, 1982-1983, so they are the 95mm.

I am trying to see if they are within specifications, but am having trouble finding the correct D1 and D2 measurements, per Porsche 911 Workshop Manuals.

Thanks in advance for your help.

[TibetanT]

Whoops! I forgot to mention that there is a number "5" within a triangle stamped on them. Also, a small marking that looks like a number "2" and another small mark that looks like M11.

Thanks.

[911Freak]

Pictures?

[tom1394racing]

This should help.

[911Freak]

So if I'm looking at my cyclinders, the only way to identify them while the engine is still in the car is to determine the color? Yellowish vs grey? I'm assuming the code will not be visible while the engine is in the car, correct? I'm trying to determine if I have Nickies or not...wasn't there a magnet test that could tell?

SOOO many questions...sorrry guys. I'm planning a bump from 3.0 to 3.2 w/98mm pistons and want to make sure I have cylinders that are worth re-using...

Excellent! Thank You!

[tom1394racing]

You can't see a difference in the exterior color.

The KS have a rib running perpendicular to the fins.The definitive tests are:

1. KS are almost always Alusil and Mahle are always Nicasil in 95mm cylinders

2. The inner cylinder bore will be magnetic in Nicasil and non-magnetic in Alusil cylinders.

KS/Alusil on the left
Mahle Nicasil on the right

[911Freak]

Thanks Tom! those are great pictures....

The KS/Alusil are less valued than Nicasil/Mahle right? Something about not being able to do much with an out of spec Alusil, correct?

Thanks again and sorry for highjacking the thread TibeteanT

[TibetanT]

No hijack done here! I am pleased to see these pictures, since I don't have this information.

However, my question is still not answered. I can see from the printout that the information given is for the 3.0 Carrera and the Turbo, but does not address the 1981, 1982, 1983 Alusil cylinder D1 and D2 measurements.

Unless, I am totally slow here and those measurements never changed after 1978??

The Official Porsche Workshop manuals that I have only explain the measurements for the 2.4, 2.7 and the 3.0 Carrera engines, but not the newer 3.0L engines built after 1981 different CIS components etc.

But am I to understand from Tom's information that I should go by these measurements to check my application?

Thanks for all your help Tom...not trying to be difficult about this, just don't want to reuse cylinders that are not spec'd correctly.

[fumanchu]

Yep, Tiby_T you nailed it. I am in the same boat as you. The 3.2 liter motors are obviously 95mm, but have different piston pin heights. Do the cylinder specs Tom has shown work for SC motors as well? The documents I have dont show wear limits for late SC's.

muffler came as described Tom,,.. thanks

[TibetanT]

Okay, Fumanchu: This is what I am going to take away from this information.

If I remember correctly, the Carrera 3.0 was the precusor to the 911SC's 3.0L engine. If what Tom has posted presents itself in that light, then I can take that to the bank as a measurement for the newer 3.0L engines.

But, I don't know what to say about the Carreras (911s) built from MY 1984.

Now, I do know that the Porsche factory printed newer Workshop Manuals to cover that model year and later, so that may be where you need to look.

The 95mm measurements here do pose the tolerances to be aware of.

I'll see where this leads me in the future.

[tom1394racing]

The cylinder diameter specs for all of the Nikasil 95mm cylinders (3.0 Carrera, SC and 3.2 Carrera) are the same as those shown in the above diagram.

Note that these are the manufacturing spec limits for new parts and not the wear limits for rebuilding.

The wear limits are:
Diameter - 95.1 mm
Ovality - 0.04 mm
Piston to cylinder clearance - 0.01 mm

I have checked over a dozen used sets of these 95mm cylinders recently and have found them to range between 95.015 mm and 95.050 mm in diameter.

[TibetanT]

Tom, very good explanation and it makes more sense to me now (Porsche manuals specifications).

[turboteener]

Wonder if you could bore and Alusil cylinder oversize slightly and then coat it with Nikasil? Anyone got a set we can test?

[tom1394racing]

Originally Posted by turboteener

Wonder if you could bore and Alusil cylinder oversize slightly and then coat it with Nikasil? Anyone got a set we can test?

This is common practice on 95 mm 3.2 Carrera cylinders. They are bored and replated to 98 mm.

On the 95 mm SC cylinders, the sealing ring groove on the top of the cylinder limits the overbore size.

[turboteener]

I thought the 95 cylinders were all Nikasil? What I meant was take an Alusil cylinder and replate it to operate as a Nikasil cylinder

[dtw]

Originally Posted by turboteener

I thought the 95 cylinders were all Nikasil? What I meant was take an Alusil cylinder and replate it to operate as a Nikasil cylinder

Definitely not. In fact the last several 3.0s I've looked at have been Alusil. Can't remember the last set of Nikasil 95s I saw.

[MarKoBrow]

Originally Posted by tom1394racing

This is common practice on 95 mm 3.2 Carrera cylinders. They are bored and re-plated to 98 mm.

On the 95 mm SC cylinders, the sealing ring groove on the top of the cylinder limits the overbore size.

I have done just that successfully using US Chromes Ni-com plating my 3.0 has 12k on since the rebuild and is working great, if I do again I am going to increase the bore to 98mm and get some JE's to fit.... LM engineering also can chime in and I believe they can perform this service using a different vendor for the plating. It's a great way to re-use Alusils without the added worry