Laust Pedersen

hosrom_951, here is a Vacuum Line Diagram (circulated many times) that should answer your question and that's how I have mine hooked up too.

hosrom_951

damn....i have that same diagram and never noticed the bent arm on the thermo valve i MUST keep my eyes open from now on....sorry!

Laust Pedersen

Here is a picture of the pistons just after the head was removed. Note the absence of “carbon cakes” in the presence of water injection and some of the oil/carbon deposits shown may be from the overheating, after the coolant was lost. Cylinder #2 has some semi-serious scratches (that I decided to leave alone), hence the extra oil/carbon deposits.

Laust Pedersen

And here are the pistons again after thermal coating on the top and anti-friction coating on the skirts. HPC claimed a more durable anti-friction coating so I had it applied for an extra $30.

hosrom_951

So you are biting the bullet and going for a full rebuid right? are you changing anything? (as in crankshaft, cross-drilling, head job etc).

sl951

<quote>a step diameter change on the intake of the compressor to minimize boundary effects</quote>

Please explain more. Picture or describe what a step diameter is? What boundart affecter are you trying to minimize..

Danno

"<quote>a step diameter change on the intake of the compressor to minimize boundary effects</quote>

Please explain more. Picture or describe what a step diameter is? What boundart affecter are you trying to minimize.."

Think of a venturi...

Laust Pedersen

On the road again (and it already runs better than ever).

What a relief to have the car back in one piece again. There certainly were a lot of tricky bolts to screw on and I appreciate Danno’s help in planning the sequence and actual participation in the repair/improvement.

The natural sequence of events is deciding how deep to go (I went for HG, con-rod bearings, pistons and oil-water cooler seals), take needed parts off, analyze/decide what parts need replacement, analyze/decide if engineering changes are needed (modified, coated parts, etc.), order parts and have changes made, wait for parts arrival, clean old parts, install parts, test if repair functions as intended and if necessary make necessary tweaks (tightening bolts, etc.).

Here are a few events from the repair activity:

1) The inside Allen bolts for the cam tower were dangerously tight (Loctite?) and “pretzelized” an Allen wrench (see photo). Fortunately a hardened socket Allen wrench did the job (with a loud crack).
2) We found a 10 mm wrench in the abyss of the engine, which I lost ½ a year ago.
3) I was trying to get a gapless top ring from Total Seal, but in their attempt to make on they chipped one I sent them (essentially destroying it), since it was too hard to machine, so I settled for their gapless 2nd ring, new standard top rings and 3-piece oil rings.
4) As mentioned I found an asymmetric wear pattern on the #2 con-rod bearing and piston and as a result found the con-rod to be bent. That cylinder also had some semi-serious scratched, that I decided to leave alone. Another of these little PO surprises. I got a straight rod replacement from Parts Heaven.
5) It is worth noting that there was no trace of oil starvation on the #2 bearing or journal (standard unmodified crankshaft).
6) The MLS headgasket was covered (both sides, but not in between layers) with copper spray and installed with great care that the middle layers did not overlap.
7) It was a PITA to install the heater valve hose with lots of wires in the way.
8) We also re-sealed the oil water housing with new O-rings and outer seal and judged by the condition of one of the old o-rings it appears to be a very good idea.
9) I had bought a 2nd X-over pipe on eBay, had it thermal coated, but only to realize that it did not fit the stub to the wastegate. Since I was impatient we re-installed the old X-over pipe. Does anyone have a wastegate stub pipe they don’t need?
10) The cam tower was installed 3 times without damaging the gasket, dropped a socket in it and one bolt was (and still is) missing.
11) On the (late model) cam belt tensioner, I was foolish enough to loosen all 3 nuts/bolt. Unfortunately one of them was for the attachment of a pulley with an inaccessible bolt on the opposite side. I got creative/lucky and managed to tighten the nut from just one side.
12) I found the venturi separated due to the high boost pressure, which may have been part of my brake problems. It got a new O-ring some silicone adhesive and a hose clamp to keep it together in the future.
13) I had to re-install a “plasticized” (hard and brittle) idle valve hose, since a new one had to come from Germany.
14) The idle vacuum with the new rings is already a very healthy 17 in-Hg vs. the 18 in-Hg before the repair.
15) Only for the sake of the discussions on the Rennlist I left the old K26-6 in place (have 3 modified version waiting), since it is very likely that my car produces ++300 WHP.
16) In the near future I’ll put the car on a treadmill to get the actual numbers.
17) After the assembly and final nut and bolt tightening I have after 30 miles not found a trace of oil drip or seep. Power steering hose and pump has a very slight drip, but that should be an easy fix.
18) One of many lessons learned: clean the engine before starting the disassembly. Slowly transferring oily dirt from the engine to the hands to the kitchen sink is an annoying process.

The picture also shows the much too small water filter that got clogged and the new larger transparent (fuel- used as water-) filter.

Since I also found and installed a well functioning check valve the water injection system got upgraded (as initially intended) to a re-circulating system (similar to fuel injection), which should keep the water cleaner and dirt away from the nozzles.

Hosrom_951, no need for a full rebuilt, head is perfect (see leakage numbers previously mentioned), no oil starvation on #2 bearing, but it was a close call with the scratches in cylinder #2.

SL951, when I actually install one of the modified turbos I’ll explain more.