[jmkcc]

I ended up stripping the salvage yard motor all the way down since I had to replace the head gasket. The timing chain and guards were well worn and once the head was off I figured I might as well pull the pistons and crank and measure everything. The valve train, head, timing cover were exceptionally clean which made me think someone did some work before, each rod also had a "B" written on it in perm marker. Not sure why they did not do the timing chain - I would've dropped the engine right in if the chain was not worn. Pistons are stamped AB and the cylinders still have crosshatch so I'll probably hone at home and replace rings and replace crank/rodbearings. Maybe drop the head off to check for straightness, clean and replace one stud that broke 1/8" in the head, but don't think it even needs to be planed.

I am really struggling with the the balance shaft (BS) delete decision. Has anyone actually done a BS delete in a Viggen with stock mounts? I found posts where people say it's hardly noticeable and some that say it'll shake your fillings out of your teeth.

If I keep the BS, I might try to swap the timing cover from an NG900 with the higher volume oil pump. I have a spare and the outer ring gear but can't find the inner gear which is somewhere in the parts bin. It looks like you need to use the power stereing housing from the 900 and maybe grind a tab on the lower left of the housing down by the intermediate shaft mount.

 

[jvanabra]

What's your goal in deleting the balance shaft?

 

[Jeremy R.]

You definitely have to use the 900's power steering pump bracket with a 900 timing cover. The 9-3 has an extra threaded hole on the timing cover for its own power steering pump bracket. Without that bracket, you can't use the piece that bolts on top that helps to support the cobra pipe, but having a higher-flowing oil pump is probably better.

I had the same balance shaft dilemma when I was rebuilding a B235R in a 9-5 Aero about a year ago. I figured with regular oil changes with full synthetic, sludge wouldn't be an issue and I shouldn't have any problems with keeping the balance shafts.

 

[jmkcc]

What's your goal in deleting the balance shaft?

I bought the car not running with a bad head gasket. I replaced head gasket and timing and balance chains (full kit). I did find a 3/4" curved strip of metal in the pan but nothing else and not much metal slurry/dust. The metal did not look familiar so I hoped PO dropped something in the pan.

Once running I could never pinpoint a low rumbleish sound/feel at certain rpms. I changed bearings to no avail. Oil pressure was acceptable but not great so I was thinking it was balance shaft related. A few months later the turbo blew. When I disassembled the engine I found the balance chain idler sprocket had fallen apart. The unidentified metal strip was from the idler sprocket and there were additional pieces in the sump and a bit of metal sludge. I'm thinking now the sprocket and metal bits did in the turbo but I can;t be sure.

In any event, I'm leery of having the BS, chain and additional failure points in the engine if it's not really necessary. On the other hand I don't want to slop my coffee around a bouncing car if the no-BS vibration is really bad.

Just thought of another question. What size spring compressor sleeve is appropriate for standard size pistons? I haven;t measured or checked specs, but I seem to recall 90mm.

 

[summerof96]

Yes, 90mm for standard pistons.

 

[jvanabra]

There are mountains of balance-shaft equipped Saabs on the road... I don't think I would get hung up on the chance of another failure. That strikes me as the intersection of a freak occurrence and poor maintenance, maybe a little "Saab can't get it's PCV act together" for good measure. Good rebuild, good maintenance... I wouldn't give it another thought.

 

[jmkcc]

Next question. what is the head bolt thread/pitch? i want to be sure i have the right tap to chase the threads.

 

[jvanabra]

Wanna say M12 1.75