F355 on FerrariAD and Compression numbers found...

Correct. I have no reason to feel that the valves contributed to the compression loss.

I have and I used them in several of the old 80-82 308s that were so well known for oil consumption and worked well but several race engine builders were very shocked by that and warned me to stop. It turns out that the racing community that uses so many of them also attribute very rapid cylinderwall wear to them. For those types of jobs I switched to Sealed Power and have been very happy with them. When everything is fit correctly you get 0-1% leak down anyway. If you get increases with them something was wrong with the prior setup.

 

The increases were small but aparent enough to mention especially on leakdown. Sealed power is a single ring with a high and low notch on the ends that fit into each other. That seems safe enough.

On another note, has anyone fitted the 77mm 360 crank on a 355 engine/piston? Is the wrist pin location higher on the 360 pistons? Is it worth doing?

 

It is not the construction of the ring that is the problem it is the material.

360 pistons have the pins 2mm higher. The 360 crank has no provision for the splined shaft for power output.

 

Well I believe they are mostly grey cast iron as the basic material. Ductile iron is used for the top ring in some high performance applications. Total-Seal is used as a replacement for the compression ring (2nd one). So the material should be just grey cast iron.

As for use in racing, that is a whole other story. Most racers don't have the time to seat/breakin the rings for 500 miles on their engines. So there are problems that can be atributed to that alone.

 

For those that are interested here are the pictures I said I would post when I had time to get the motor apart that was shown in the earlier pictures.

#1 Is the compression ring from Cyl #2, the one that had the burned out header pipe and 41 or 42% leak down. It has about 4.5 mm end gap.

#2 Is the same shot of Cyl#3. It has .4mm end gap.

#3 Is the #2 piston. Look at the width of the upper and lower ridges of the oil ring.

#4 Piston. Compare the oil ring.

The last motor I took apart for this, the oil ring was worn completly smooth.

The pistons are in very good shape but the #2 cylinder is worn to almost the wear limit while the #3 cylinder has less wear than my cylinder gauge is designed to measure. Less than .001mm.
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Wow, that second ring looks like it was the wrong end gap to begin with! It appears the gap was trimmed too much. Since it is very apparent the amount of ring material left is as much as the one with .4mm in the second picture. So that large gap is not because of friction/wear on the cylinder wall. Or maybe the ring end was broken off during installation??

Was that a factory built motor or was it overhauled by a dealer/independant???

 

That ring is worn that far down. If I put the oil rings in the bore they would look the same. #2 ring measures 2.65mm in depth. #3 measures 3.45mm. It is so worn you do not need to measure it, you can see it bare eyeball.
Remember this is not the only one of these I have seen. I've been experiencing it since 99 or so.


This motor except for 2 majors is untouched.

 

So what does the cylinder wall look like? Is it within spec or will it need a new sleeve? Will you be replacing all the sleeves in this example?

BTW My eyeballs have to deal with semi-blurry pictures. But thanks for the illustrations.

 

Sorry new camera and bad operator. But with real eye balls the difference can be seen.

The one sleeve is bad, or at least it is close enough to the wear limit to consider it so. The wear can be easily felt with a finger and can be seen. The other 7 look and feel like new and the one other we picked to pull a piston for comparison shows almost zero wear (less than .01 mm measured at any point). In the end it is the owners decision and he is very technically astute. I expect him to go with my suggestion of 1 new sleeve, rings, valve guides, and manifolds.

 

When you reuse sleeves, do you hone them or refinish the nikasil?

 

On the nikasil (steel, 355, 360, 456, 550) a flex hone works quite well.

I have only done one alumasil ( QV, TR, 328, 348, 288, 575) motor in a 288 where sleeves were not needed and we did not touch them. The are so smooth new we didnt feel being roughed up was required and we were right. It worked great. I have since discussed it with Sunnen and for the purpose of sizing or truing a special type of stone for a rigid hone is used.