Volvo B18 engine rebuild, part deux

We continue the rebuild of an early Volvo B18 engine.

As mentioned in the first installment of this resto, my machinist is retiring in three weeks so no time to waste. I plan reassemble the engine as a “short block” for now without carburation as that can wait.

Once this is done, I will get back to the body that is now in the metal shop.

Flywheel is looking a bit ugly. Turns out, just like me, it was only ugly on the surface.

This is what it looks like after a yummy vinegar bath and a little wire-brush action. Now the machinist can just take a “skiff” off the surface.
The good news: I can later use the vinegar for my salad. I call it greens and rust…JUST KIDDING! Don’t DO that!
Here is the flywheel with the clutch surface machined. Nice!

 

Oil pan after degreasing and after a de-rusting bath in vinegar.  The fitting on the side is for the oil temp sender. For some reason, I feel this oil pan is extremely heavy. It’s been a while since I had a B18 apart but it just feel “thick” to me. Not a bad thing!

 

Lots of tubing cleaned and ready for paint. The tubing with the flanges is for the oil cooler. The bottom tubing is the “draft tube” for crank case ventilation. In later years, it was replaced with closed system using Positive Crankcase Ventilation (PCV) which recycles the smelly crankcase fumes back in to the combustion system.

If you wonder about the strange backdrop, it is the bed on the old Chevrolet truck.

New bores…sexy cross hatching.  The cross hatching help speeding up the break in of the rings, like a “file”
A good machinist will ask for the new pistons before boring as the bore to piston clearance is the most important measurement.  Too much will result in noisy pistons and oil consumption,  too tight could possibly seize the piston in the bore when hot.
Volvo recommends 0.02-0.04 mm or 0.008-0.0016 thousands of an inch. piston clearance. How do I know that?
Zee Bible! Volvos green book of wisdom.
Gospel…
Silver block? I thought this was a red block!! It is, just take a moment to enjoy hours cleaning with a wire brush. Soon to be a snazzy red block again.
The top deck was pretty straight but not perfect. It also had some darker areas close to the water jackets.  I want perfect! My machinist removed 0.0015 inches or 0.038 mm as in less than a half a mm.  This is called decking.
The pistons come wrapped on the kind of foam sleeve you find for the expensive fruit in the super market.
The pistons come with new wrist pins and clips.
0.020 over. That is the first available oversize for B18. For B20 engines they start at 0.010. Also, note the piston is directional.
Nicely wrapped presents. New valves.
No, this is not Bigfoot’s wedding ring, these are the hardened seats for the exhaust valves. These will be machined in to the head. This allowed the engine to perform well with unleaded fuel.
Head back from machining. About a half a millimeter was shaved off the surface to make sure the head surface is flat. Also, the valve seats were machined to match the new valves.
Between the decking and the head surfacing, we ended up with about 0.75mm worth of “lowering the lid”. This will increase the compression somewhat but will still perform well on pump gas.
The head was also media blasted. This make for a great surface for paint and also offer great grip on the gasket surface.
I made the guide studs from 5.5 inch long  7/16 bolts. As the top of the water pump is flush with the head and o-rings are just compressed by the head, I don’t want the head to move around at all as it goes on to the block. The studs will locate the head exactly where it is supposed to go.
Parts used so far:
275194-X B18 Piston kit 0.020
275283 B18 Piston Ring Kit 0.020
419292 B18 Exhaust valve 35mm
419368 B18 Intake valve 40mm
VP1460 Exhaust hardened seat for B18-B20-B30
More later…
By Rolf Åström