930 rebuild -- the process in pictures.

[Craig 930 RS]

Started with loss of power - down 57 hp
Then 40% leakdown:


So let's take a look inside. Heads had been shifting on the cylinders:


#3 exhaust valve had 40% leakage:


Broken rings.....fairly common:


Shop recommends new ARP rod bolts......just in case.
Also getting ARP head studs in lieu of the Dilivars from the previous rebuild.


What ho? A wobbly rod? OK, let's take it down further:


Cylinders got very hot:


Rod bearing just about gave up......LUCKY, eh?

[Craig 930 RS]

Just about the worst news one can get.......soooooo close to disaster:

[Craig 930 RS]

So, that's the bad news.
Time to move on.

The parts:

98m Mahles:


Long skirt Mahle pi$tons:


Ni-resist ringed the cylinders and heads to prevent leakage and shifting (not a good pic):


Imagine Auto fuel head, checked/balanced injectors:

[Craig 930 RS]

Going with 7.5:1 pistons instead of 8.0:1.
After engine break - in, we will working our way slowly upwards on the dyno with:

Increasing boost (probably not exceeding .8 bar)
AFRs watched closely. Aiming for very low 12s.

[Craig 930 RS]

Crank did not receive any damage at all other than the scratch in pic above. Needs only a polish.
Heads might be done this week.
I pick up injectors tomorrow.
Imagine Auto $500 'flowed' fuel head will be here today.
K27 Hiflow turbo needs no work and is in great shape.

[Craig 930 RS]

Soon she'll be back doing this:

[ianc]

Looks pretty icky.

What were the rest of the leakdowns? How about the compression? Could you hear the air escaping out the tailpipe on #3?

ianc

[Craig 930 RS]

All other bearing surfaces and leakdown numbers were great.
#3 had the air a-comin' out the pipe, yep.

I will try to make this thread as fun and involving as this 24,000 view thread I started in 2004:

Brother.....I have seen the light! A 3.6 Varioram...

[Craig 930 RS]

Injector test rigs and actual test. Injectors look good!

[Zeke]

Would you consider reworking the oil passages in the crank? Seems like nos. 2 and 5 (especially 5) get shorted on oil.

[patkeefe]

Craig:
Who's testing the injectors? I need to get mine cleaned and tested, and I can't find anyone here in the East. And, what kind of rings are you putting in?
Thanks!
Pat

[Craig 930 RS]

Rings are the ones which came on the Mahle pistions -

http://www.witchhunter.com/
Local guy working out of a nifty little home shop

Oil passages.........damn.....good idea. I'll check -

[Craig 930 RS]

I intend to use either .8 or .9 bar MAX with the 7.5 pistons (were 8.0, ready for EFI), taking baby steps and working towards low 12 AFRs in conjunction with gradual timing increases on the dyno --- all the while while under the watchful eye of a local wrench and ex-935 Bayside mechanic:

[Mr Beau]

Be careful with creeping up the ignition timing while on the dyno. I did this once and ended up with too much advance when taken to the track. We were doing relatively short pulls which didn't build the same heat as on the dyno.

[Craig 930 RS]

Heh, exactly why I am bringing a seasoned vet along -

[Asjac]

Any progress/ideas about the oil passage enlarging?

[Emission]

Craig,

Did you ever test your oil after changes? Would you have seen the rod bearing failure in the oil analysis?

- Mike

[Craig 930 RS]

Additional oil passages are added to the crank with that process -
We cut the oil filter open - and found just traces of bearing 'dust' - so a majority of the metal loss ocurred quite some time ago.

[PorscheGuy79]

Criag, its great to see you making steps to get your car back together. I hope your luck continues as you shoot for .8 and 12s.

[Asjac]

I didn't want to say anything, being the newbie I am, But did you notice this (circled in red)?



What, if anything can be done about it?