dr bob

Stan--

Before you start buying pistons and rings, make darn sure to actually measure the bores. Someone has obviously been in there already, so no telling what or why things were changed. The bore gauges and mic's remove all doubt.

GlenL

As noted above, those are the early S pistons with bigger reliefs.

Did you notice that the three boxes are marked for 97.5mm? The one piston is stamped for 97.465.

Lizard928

While I would agree a tolerance 1 block cannot shrink and take tolerance 0 group pistons.

I agree that it should be taken apart and measured. But it looked to me like it just needed a set of tolerance 1 group pistons.

GregBBRD

Agreed the group 0 pistons aren't going to grow..and it is probably sub optimal to have those in a group 1 block.

The only saving grace, as I was explaining to Stan, yesterday, is that once these engines have ran for thousands of miles, it's more about how things measure than what the original tolerance group was.

The size difference between a group 0 piston and a group 1 piston, when new is .0002". Those Germans were working at very close tolerances, when they assembled these engines. I can move a piston from the engine room and into the shop and get a bigger change than .0002" on most days.

And what you get new, from Porsche these days, is like fingerprints....they are all different....even in the same size groups. I don't know if the "seconds" ended up in the spare parts system, or what is going on.

I'm at the point where I'm individually measuring pistons and honing cylinders slightly different sizes to get pistons to fit correctly, in new engines.

A bore gauge and micrometer are no longer "optional tools" to double check things, but a necessary tool to build an engine.

Mrmerlin

I got the pistons out and found the pistons on the pass side had the 3 piece oil ring with the coil spring center plan is to measure then hone with the AN 30 Sunnen paste
NOTE last numpty working here used loctite to secure the rod nuts so a Mapp gas torch and slide hammer with vice grips on the center of the cap were used to remove the caps
Always buy new nuts for this assembly

Euro 928

Just curious, Whats the ticket on this level of repairs?

linderpat

yes; at least a range?

GlenL

Isn't that the original style?

"Nice." So the green, then? Easier to glue them on than to get new ones.

Mrmerlin

yo do the heads and swap out the rings on this 85 Euro
12500.00 parts and labor and Powder coating,
thats a ball park,
remember the engine also has to run well

Mrmerlin

well i will link these two threads as one goes with this one.

https://rennlist.com/forums/928-foru...ns-needed.html

soontobered84

Stan,
I would say that the PO(s) for this particular car are making you really work for it. I hope it's smooth sailing from here on.

SMTCapeCod

Yo!

P/C, say it aint so

Mrmerlin

Yes it will have PC on the intake and it will look very much understated compared to what it has been.

Yes the POs depending on what the skill sets that they possessed,
might have been due a good swift kick
for poor maintenance,
poor repair skills
OR poor driving skills.
The only upside is that they all had extra cash to throw at this machine,
so buying some of the expensive parts was some condolence

my second block is now going to first string.

Mrmerlin

well moving right along,
I got the bores polished with the AN 30 paste,
this to remove the polished marks left from the pistons when they hit the intake valves,
and then the heads are on,
the cams are on , and some pulley work then string the belt.
and drop her into the car

Quite amazing after fitting the new Laso from Roger,
the timing belt tensioner roller sits where it should,
the previous waterpump had the roller more towards the rear of the car so the belt was hanging off the front edge by about 4 MM.

Dan87951

Looks nice Mrmerlin! Good job! I would be interested to see what your leak down and compression numbers are after you get her running. Keep up the good work.