Engine Rebuild (Part 6) - Cylinder Head and Rockers

Putting the cylinder head on also means refitting the inlet valve rocker assembly as this is held in place by some of the cylinder head bolts.

Succinct assembly and fitting instructions for the rockers can be found at step 33 in Operation D.100-3 of Section 2 of Volume 2 of workshop manual 814.

When a cylinder head is removed, the inlet valve rocker assembly comes off in one long tangled, oily lump. 

DX2 Rockers on the DS - 27 October 2015 

The DX rockers had stayed that way since Adie first removed the head the day Richard and I went to pick the engine up back in November 2015.

Inlet Rocker Assembly

Now preparing for reassembly, and with frequent references to the workshop manual diagrams and part listings, all the parts were dismantled and accounted-for. The cylinder head bolts were difficult to with draw from the rocker mounts as the rubber oil seals on the base of the mounts had hardened. I ended up hacking the seals off with a Stanley knife.

Exhaust Rockers

Everything was present and correct and so was washed in Jizer. The long rocker shaft is hollow so that it can carry and distribute oil. I made sure the oilways were clear. Similarly, I made sure that the oil distribution hole on each rocker was unobstructed.

Inlet Rocker Shaft

After rinsing and drying with compressed air, I then subjected everything to a clean in the ultrasonic cleaner. This removed the last stubborn remnants of oil and dirt. As they were now thoroughly de-greased, parts were given a spray with WD40 to prevent flash-rusting.

I similarly took apart the rocker assembly from the DX2 engine – partly out of curiosity as it had looked so tired and worn, but also in case I needed donor parts.

Removing the DX2 Rockers - 10 September 2017

The exhaust rockers are lined with a (bronze?) bush with a lubricating hole. One difference I did notice between the two assemblies was that the exhaust rockers from the DX2 had an extra ‘tick’ shaped groove etched into the surface of the bush – presumably to aid oil distribution. The DX exhaust rockers didn’t have this.

DX2 Exhaust Rocker: Groovy

As I had expected, the parts from the DX assembly were in a better condition than those from the DX2 engine. Both long rocker shafts showed noticeable signs of wear, and this might also mean that the rockers were also worn. To replace the rocker shaft and four inlet rockers would have cost something in the region of £250 - and it was money I simply didn’t have. So the DX shaft (that was in better condition anyway) got re-used.

I reassembled the parts on the shaft checking the diagram in the repair manual and accounting for all the parts. 

Inlet Rocker Shaft: Ready For The Refit - 14 November 2017

Two important considerations: firstly, the rocker shaft has to be orientated so that the lubrication holes along it’s length are facing down and towards the valves. The shaft is also ended. Details of this are in Operation D.100-3 in the manuals. Secondly, the small support at the end of the shaft has to be fitted so that it’s bevelled edge faces ‘inward’ towards the rockers: this is to make room for the push rod to move past it. New oil seals for the base of the rocker mount towers were included in the engine gasket set I’d bought (I’d wondered what they were for!) and were subsequently fitted. The relevant cylinder head bolts were slipped into place…..

The cylinder bolt holes were blown out with compressed air and the engine block deck was checked for any lumps or grit that would prevent the head gasket sealing properly. The surface was a little pitted, and I had, several days before, dressed these imperfections with a little Hylotite Red. After it had cured a little, I used a Stanley knife blade to remove any excess.

With the tappets already in the block (don’t forget those!) the head gasket was put in position and the head ceremonially lowered. I was careful to make sure it sat correctly on it’s locating pins.

The cylinder head bolt threads were lightly lubricated. The push rods were put in their respective locations before the rocker/ cylinder head bolt assembly was lowered in place. The washers and springs were carefully jiggled into place to make sure that they sat either side of each bar cradle. The cups on the ends of the pushrods were aligned to the rockers, and the rocker ‘fingers’ aligned to the valve stems. Working my way up and down the row of cylinder head bolts, I gradually took up any slack on the bolts (without actually tightening them) to bring the shaft down into position on the many cradles. As I did this, I turned the engine - trying to seek the optimum position that meant that no single push rod was being put under undue pressure. I didn’t want to risk one bending.

Fitting the Inlet Rockers - 14 November 2017

I lubricated and fitted the remaining cylinder head bolts on the exhaust vale side. Studying the re-tightening order in the workshop manual, all bolt tops were numbered-up with a Sharpie – just to avoid confusion. As per the manual, I did a cycle of an initial tightening, followed by a final tightening. In fact I think I did it over four cycles – gradually increasing the torque each time. As I reached the higher/ final torque levels I held my breath – dreading a ‘ping’ as the block cracked or a bolt sheared. There were no problems and I could breath again. The rocker shaft lubrication pipe oil between the head and block was fitted with the new copper banjo washers that came in the engine gasket set.

With the cylinder head and inlet rockers fitted, the DX was starting to look like a working engine.

Getting There: 14 November 2017

Pleased with progress I put a message and photo up to the D Section Group on Facebook.

Then I suffered a setback…. I had refitted the exhaust rockers on their cradles and was torquing them up. The last nut wouldn’t reach the correct torque and I suspected the stud was turning in the head. I didn’t want it working loose when everything was assembled, so I removed it and added a little chemical metal. When I went back to finish the torquing the stud snapped! It must have been going ‘elastic’ – not turning?

Anyway, the only way I could get any mole grips on the broken end of the stud was to remove the whole of the inlet rocker assembly I’d previously fitted – that meant undoing half the cylinder head bolts….with the associated risk of one of those snapping too…..

I managed to get the stud out and replace it. As the threads in the hole were not at fault, the majority of the chemical metal I had added had been squeezed out when I put the stud back in  – so it wasn’t bound too tightly.

As I had to remove the head bolts on the inlet side, and on taking advice, I went the whole hog and removed them all – for fear of warping the head otherwise. Similarly, I decided I didn’t want to risk re-using the head gasket again, so sourced another from Citroen Classics – together with a couple of replacement banjo washers for the rocker oil feed pipe.

The gasket cheered me up as it was a NOS Citroen head gasket – rather than a Glaser brand one. Psychologically, and even though it wasn't that old, I just liked the idea of the connection that it represented to the past. So much so that I took a photo:

In short, I had to go back and refit the head and rockers from scratch! Having started fitting the rocker assembly in mid November, it wasn’t until the end of December that I finally had all the rockers back on. Not a bad way to end the year though.

Exhaust Rockers - Finally Fitted.....