Schnell Gelb

Boxster S -engine rebuild tools
2 questions that may help other Boxster engine rebuilders:
I found the Wiseco tapered sleeves for compressing piston rings -sooo much better than the old fashioned ring compressor!
1. Before I buy ,can anyone please confirm that the 93mm sleeve works? The Wiseco part number is :
WIS-RCS09300
I ask because they have a similar part RCS09250 that is just 1/2 mm smaller also and perhaps someone has experience that the slightly smaller size works better(depending on ring gap)? I would be happy to loan to other Forum members after I am done.
video for 911:
2. Use an undersize Wiseco sleeve to measure bore out-of-round? Measuring bore taper accurately is an exacting task even with the correct tools.I am unsure if I could even trust a local machine shop. Suppose I get the correct undersize sleeve and use the o.d. of the sleeve as a go-no-go gauge? Yes ,I know the degree of accuracy is low but is it sufficient ? I suspect that a sleeve small enough to slide in the bore would be too sloppy to make a meaningful assessment because the clearance would be out by an order of magnitude? Is there another trick way to measure taper accurately ? Yes, I know the conventional 3 points and dial indicator method -just looking for something better.Any experiences to share?

extanker

just auto repair 101. snap on tools make a pretty good universal ring compressor. i do not know if it applies here but harley/davidson "jugs" are checked/machined after they are affixed with torque plates.a good machine shop should be able to mike them quite accurately.many and i mean many years ago a half inch by 12 inch feeler gauges were used to measure the piston/bore clearance by the amount of drag required to pull the stock past the piston in the bore.

Macster

Well, based on my background in machining -- I'm a journeyman machinist though I no longer machine -- I would have to say that with the correct tools and there are several styles, measuring the bore for taper, out of roundness, etc. is not that exacting of a task.

In my career I measured hundreds maybe thousands of bores, of various sizes from less than an inch in diameter to many feet in diameter and I could very quickly and with a suitable degree of accuracy determine a bore's topology.

My advice is if you need to know the cylinders bore sizes -- and I think you do -- buy a dial bore gage tool that will work for the bore sizes you are interested in and can deliver suitable precision. My set of dial bore gages read out in 1/10,000th of an inch. (Often I had to work to a fraction of a thousandths of an inch tolerance.)

Or arrange to have the engine cylinder bores measured by a machine shop which should have the proper tools. You also have to measure the pistons to ensure if they are used they are not worn under size or out otherwise out of specification, or if they are new they are not too small, or too big, or otherwise unsuitable in the size or topology department.

Schnell Gelb

Macaster,
Thank you for your thoughts.
I found a series of videos that may help others:
Unlike most such videos ,it really zips along and gives a review of alternative tools. The poster is Jafromobile in case you need to search on You Tube and the series is called Blueprint Cylinder Bore Inspection. Even some Techs have commented that they found the videos helpful.

Macster

Snap gages are ok. I used them often enough with a *good* micrometer and produced many a job that made it though intermediate and final inspection in the inspection room.

But using that caliper is not going to deliver 0.001" accuracy. (In the shop we used to refer to them as the guessing stick.) To know a dimension to within 0.001" one should use a measuring tool that measures to 0.0001".

Everyone likes them though because they are easier to read than a micrometer.

Schnell Gelb

Apparently I am in good company using a "jug" /sleeve tool for compressing the rings.They use the same tool at the Porsche factory now.

aftCG

I just ordered the ARP 93mm tapered sleeve ring compressor from LN Engineering yesterday.

Having seen them used in a few videos now they look like they work great.

Schnell Gelb

A few hints for M96 rebuilders who find this post:
1. A generic 93mm sleeve works well.
2.Fit pistons from the top only- these is a 'dish' to the bottom of the cylinder walls that makes it difficult to work with this tool.Just tap the top of the piston .Hammering will break rings and is not necessary if you align the tool over the bores correctly.
3.Piston ring pliers -only use the type with an adjusting screw-this prevents over-expanding the ring.
4.Remember to find the 'Top' mark on the piston and rings before clocking the rings and install the piston the correct way up!
5.A piston ring groove clearing tool is essential -unless you have some broken piston rings !
6. Do consider coating the piston skirts with an abradable coating. I used Line2Line and they were outstanding.
http://www.line2linecoatings.com/
Mark Gelstein was very helpful
Porsche original coating was iron but this is no longer available(environmental issues)
7.You will need a dial bore gauge and 3-4" micrometer to measure bore concentricity and to specify the finished bore diameter for Line2Line.
8. Consider using Jake Raby's new circlip insertion tool.Available from Pelican soon?
9. If you want to practise using your dial bore gauge to find taper -use it in the 'Jug' you just bought. Mark 6 different locations and try to get the same measurement from each location 3 times -but don't cheat -no sequential measuring .yes, it is difficult:-).