Nov 29, 2012


After spending almost 15 hours with the grinder I decided to bring the Volvo to a soda blaster.  Because the interior was still good the blaster only blasted the outside of the 122S.

Volvo 122S before soda blasting
Before soda blasting

Volvo 122S after soda blasting
After soda blasting

Soda blasting is better for your car than sand blasting because the soda doesn't damage the underlying metal. The only problem is that the soda doesn't remove all rust. So after the blasting it was time for some more grinding and a chemical treatment. The normal surface rust is easy to remove with the grinder but  the hood, roof and boot where "pitted".
I used phosphoric acid and Rustico to get rid of the rust pits. Not all the rust in the pits was removed by the chemicals but it went soft after the treatment and was easy to remove with the grinder without taking of too much off the healty metal.

Pitted surface of the roof Volvo 122S
Pitted surface of the roof

Boot Volvo 122S removing rust
Boot - Left side done

Boot Volvo 122S rusty pitted surface cleaned
Almost done

Soda  residue will give problems if you don't clean the metal before painting. However if you want to wait a couple of months before painting it's also a perfect rust inhibitor.
After removing the surface rust I started to get rid of all the soda dust in the car, especially inside the chassis. 
And it took alot of time...hours became days....So don't expect to get rid of the hard labour with soda blasting. There's no easy way out :-s
I used compressed air and a vacuum cleaner with a high tec (masking tape ;) attached flexible hose. With the amount of baking soda that came out of the Volvo you could easily bake cakes for the whole neighbourhood..

Cleaning Volvo 122S removing soda from soda blasting
Cleaning the 122S

CLeaning Volvo 122S removing soda from soda blasting
Baking soda everywere

Cleaning Volvo 122S removing soda with flexible hose and vacuum cleaner
Vacuum cleaner with hose extension to clean the chassis 
When all the baking soda was removed I started to clean the bare metal surface of the doors. The blaster told me to wash the car with warm water, add 5% vinegar, to neutralise the soda, then hit it with a pressure washer, then wash again with 5% vinegar water, then pressure wash again and dry immidiately with a blower or rag before flash rust starts. That's the main reason I cleaned one panel at a time instead of the whole car at once.

After cleaning it's best to hit the bare metal with an epoxy primer within 1/2  an hour, otherwise you'll get flash rust again. I didn't because I was still looking for the best epoxy primer. So there will be a little, almost invisible, flash rust on the doors. Luckely it's been very hot (35-40 C) and dry the last couple of days.
Sanding with 120 grit before priming will be neccessary, but it won't take too long.

Nov 8, 2012

Fitting cylinder head

After 13 years and a last inspection of the pistons and bores it was time to fit the cylinder head of the B20B engine. First I fitted the new water pump. The pump came with two sets of rubber rings: 1 set with a height of 8.5 mm and the other one with a height of 9.5 mm. The 8.5 mm rings are for the B20B engine which has a thinner head gasket than the B18 engine.
I lubricated the new tappets inside and out with assembly oil and put them into the bores. Be careful not to drop them in the sump...

New tappets and original pushrods Volvo B20B engine
New tappets and original pushrods

Tappets fitted in their bores Volvo 122S
Tappets fitted in their bores

After the bores and pistons were also lubricated with an overdose of oil the gasket was alined with the bolt holes and the cylinder head was placed on top of it.

Cylinder head gasket alined with bolt holes Volvo 122S
Cylinder head gasket alined with bolt holes

"TOP" is on top of cylinder head gasket Volvo 122S B20
Make sure the word "TOP" is on top :-)

Before that I cleaned and checked all the cylinder bolt holes just by putting in the bolts and made sure they went in all the way.
The cylinder head bolts have to be tightened in a special sequence to the first torque of 39.5 Nm. There will be two more stages of thightening...

Old -  and new cylinder head bolt Volvo 122S
Old -  and new cylinder head bolt

Tightening sequence of cylinder head bolts Volvo 122S B20B
Tightening sequence of cylinder head bolts

Next thing to do is fitting the pushrods on top of the tappets. The rocker shaft and arms were already assembled so after good lubrication of the shaft I fitted it to the head with a torque of 33.5 Nm.

Lubricating the inside of the rocker shaft Volvo Amazon
Lubricating the inside of the rocker shaft
Turn the arms until you see the holes in the shaft underneath

Rocker shaft bolted to the cylinder head Volvo 122S
Rocker shaft bolted to the cylinder head
According to the manual you have to tighten the cylinder head bolts to a torque of 78.5 Nm after the rocker arm assembly has been refitted. But...... as you can see 5 of the 10 bolts are underneath the rocker arm.... There are special spanners/sockets for this but they are very rare and expensive so I did it the cheap way: taking off the rocker assembly in order to tighten all the cylinder head bolts.

Example of the special Cylinder head bolt spanner Volvo 122S
Example of the special spanner (thanks  for the pic Mr Popta)

After refitting the rocker arm assembly for the second time the valve clearances have to be adjusted. The valve clearance is the gap  between the cam/pushrod and the top of the valve. For a Volvo B20B engine the clearance is 0.50 - 0.55 mm (both inlet - and outlet valves).  

Cylinder 1 in TDC --> adjust cylinder 4 valves
Cylinder 2 in TDC --> adjust cylinder 3 valves
Cylinder 3 in TDC --> adjust cylinder 2 valves
Cylinder 4 in TDC --> adjust cylinder 1 valves

* TDC = Top Dead Centre - the point that both valves are completely closed

Valve clearance adjustment Volvo Amazon 1969
Valve clearance adjustment
Rocker cover fitted Volvo B20B
Rocker cover fitted