Long overdue 2.7L rebuild on 1977 911S
 

So, back in the Day, I bid on the bay and won a 1977 2.7L 911S sportomatic. Not my first 911... :D (that belonged to the rusted out 1968?69 911L I got for a whopping $950, that I had the bad sense to scrap for the most part. it was 20yrs ago... so.... forgive me.)

I got a suburban in Pensacola off the bay at about the same time, and arranged everything so that I flew down to FL, got the suburban, drove over to Mississippi got a trailer dolly (Uhaul) and picked up the 911. Can we say road trip back north? :)

The upside was this was 2002? or so (I'd have to go look at records) gas was still cheap, and it was a fun road trip, with my gf at the time... well sorta... lots of driving.....
Oh and prices on broken aircooled cars was loooow. :D

In the intervening years, my buddy helped me pull the engine out, tear it down, get the case sent out and done (2006?), get the heads done (Anchor Atlantic) (2013) and then I got busy. Finally this year (2017) its time to get the car on the road...

At least it was stored well (never on dirt, always in a dry garage space) Overall, no major rot (i.e. floorpan's are solid) front suspension cross metal does need replacing, and well, the "running, but smoking engine" wasn't really running. Well we did get it to turn over and fire up and drive down the street in D, just barely... was interesting, to us and the mosquitoes!

So back to 2017, I would like to finally drive the car! So cleaning up the case halves, doing all the appropriate measurements, and prepping for assembly.

Of course my buddy ChrisBennet, is making sure its done RIGHT. And I want it done right too. My back ground is as an EE, but I have also done multiple detroit engine rebuilds and mods in my lifetime. So its not the first time picking up a wrench. :rolleyes:

Time permitting, I'll post up some of the car pic's etc. I tend to stay too busy, but hey I guess that makes life interesting!

And reserving this post too. Will fill in all the blanks shortly!

Okay in examining parts, we came across a problem with the #1 cylinder.
There appears to be a small divot of material missing from the cylinder wall. Yes these are Alusil cylinders btw.

The big question(s) are:

Does it make sense to use it as is? Its deep enough that a honing isn't going to take it out. easy to catch with a fingernail. We can measure that spot and get a delta in the next day or two.

Is it repairable or just get another cylinder? (edited to provide proper cylinder info)
Cylinder height group is 6
Cylinder diameter group is 1
Piston is 1

Can I swap for like cylinder for someone who wants to plate cylinders? Have to keep the cost factor contained for SWMBO. :D
(didn't record ovality of cyl #1 due to the found defect, will go back and do so)

Needed to get this post up since I have to keep the build moving forward!

http://forums.pelicanparts.com/uploa...1498049997.JPG
http://forums.pelicanparts.com/uploa...1498049997.JPG
http://forums.pelicanparts.com/uploa...1498049997.JPG

My take... I'd check dimensions of pistons and cylinders to factory specs. Then make a decision. Might be that cylinder is worn beyond acceptability and possibly that will make decision for you.

Honing Alusil "properly" is a specialized process---the trick being to get the silicone to "stand up" to the correct dimension.

Alusil honing info: Honing Options for Hypereutectic Aluminum Cylinder Bores - Sunnen

Ovality of cylinders
 

Discseven, you are correct, helps to know what the other cylinders are doing. Currently we have the ovality specs for the other five. See below.

I think that with these measurements on the cylinders that they are usable as they stand. Still need to add in info for the pistons.

Measurement was done at two points (A and B) 90* out from each other. Both at top and bottom of cylinder to see any differences.
.....| A
B--O

0.04mm is the limit, which is 0.00157". Measurement tool was in inches
Diff limit is negative under limit positive is over limit to the limit

……... TOP…..………… ………..… +/- || ………… BOTTOM ………… +/-
Cyl# A…… B……..Delta… diff limit || A…… B…….. Delta… diff limit
1
2 0.0016 0.0022 0.0006 -0.0010 || 0.0018 0.0020 0.0002 -0.0014
3 0.0019 0.0029 0.0010 -0.0006 || 0.0022 0.0025 0.0003 -0.0013
4 0.0026 0.0016 0.0010 -0.0006 || 0.0028 0.0024 0.0004 -0.0012
5 0.0015 0.0015 0.0000 -0.0016 || 0.0017 0.0012 0.0005 -0.0011
6 0.0014 0.0019 0.0005 -0.0011 || 0.0018 0.0014 0.0004 -0.0012

I read with great interest the Alusil thread here,
http://forums.pelicanparts.com/911-engine-rebuilding-forum/137346-re-ring-alusils.html
and wouldn't be afraid to tackle the work. However the numbers look good so far that the P&C can be used as is (well at least 5 of them can be reused!)