Distributor Tower - Strip Down and Overhaul

One of the steps in an engine rebuild is replacement of the camshaft seal. As the camshaft drives the distributor, it passes through an eye at the base of the distributor drive tower, and that is where the camshaft oil seal is. All this hidden away behind the bell housing. 

Distributor on the drive tower - August 2015

I planned to vapour blast the drive tower. To do that, I would need to dismantle it - so this was also a good time to change the distributor spindle oil seal. 

When I ordered a load of new seals from Citroen Classics, I'd very rashly also ordered a replacement seal for the distributor drive tower spindle, as well as the cam shaft seal and oil pump seals. Money changed hands and I started to put the phone down. "Good luck with the distributor drive tower seal" were Matt's parting words. Whatever did he mean?

I soon found out. You won't find it in manual 814, but instructions for dismantling the drive tower are covered in Operation DX.211-6 of Manual 518. The oil seal is located near the top of the drive spindle, just underneath the slotted head. 

And that is where the difficulty lies..... The technique for removal involves pressing the spindle and its cam down and through the slotted distributor drive socket, in the course of which it also pushes out the sealing cup (a hefty core plug) at the bottom.....That's a lot of pushing, and the ledge on which the drive socket sits would take all the pressure.

I was worried about the force on the cast alloy underneath the drive socket - and so was my local engineer. He welded a threaded bolt to the cup at the base and used a nut to pull the cup out. He left me to remove the spindle.  

The manuals make no mention of the need to align the distributor drive socket with the teeth of the cam on the spindle - to preserve ignition timing settings, but I would strongly advise you do mark the relative alignment, as there is no way to check or adjust this once the distributor tower is rebuilt. 

With the cup removed by my local engineer, there was less resistance to the spindle and, with the alignment marked, I carefully drifted it out from the drive socket. The oil seal was then easily removed - as was the camshaft seal. The spindle seal was lubricated and fitted back into place.

Something You Don't See Every Day: The Oil Seal in the Distributor Tower 

While the body was vapour blasted I zinc-plated the distributor clamp and cleaned up the drive socket and spindle. Reassembly was pretty straightforward. My engineer gave me a replacement core plug for the bottom but it was not as hefty as the proper Citroen one - which I decided to re-use.

Drive Tower Stripped - 16 December 2017

With the spindle and oil seal lubricated with engine oil, The spindle was orientated on the drive socket using the marks made earlier, and the spindle was then pressed back on from the bottom of the tower.

With the spindle pressed back through the drive socket, as per Operation DX.211-6, I checked the freeplay at the base (0.15mm to 0.30mm) to make sure the spindle was free to rotate. Once happy, and leaving the feeler gauge in place, I used a long socket of the appropriate diameter to press the cup back into place until it just touched the end of the spindle. (The feeler gauge prevented me from pinching the spindle too tightly in the tower body). The gauge was removed and, with a bit of judicious wiggling, so was the welded bolt on the cup. 

The camshaft seal was lubricated and pressed into place using a socket. On my first go I pushed it all the way to it's base - only to find that it snagged on the pinion of the distributor drive spindle.  Luckily it could be pushed out a little from the other side.

All back together and ready to go back on the car

I'm still deciding on whether or not to buy 123 electronic ignition, or to rebuild my distributor. However, since my distributor is not the right one for the car, I'll probably go for the 123. If so, I'm hoping to be able to fit a new Ducellier distributor cap.

A Quick Word About.......Oil Filter Replacement

Before I try to fill the engine up with oil, I thought I'd better put the oil filter in. While I remembered......

I'm not going to go over the procedure for changing the filter as that's a routine maintenance thing. However if it's a job you've not tackled yourself (or you've never changed your oil!) then the  'DS Technical Team' people have produced a very handy video showing you how to go about it. You don't need a car hoist but if you plan to crawl under your car remember to support it properly on axle stands  - not the car jack:

DS Technical Team - Oil Filter Change

Well I don't know about you, but whenever I've changed my oil I've simply wiped the oil filler assembly down with a rag, popped a new cartridge on, then bolted the assembly back in. My focus has always been on three things: the new filter, the new gasket on the closing plate and the new washer on the sump plug.

It wasn't until I began the engine rebuild that I had cause to actually stop and consider (by which I mean 'clean') just how many pieces there are in that oil assembly. Lots! Here they all are:

Oil Filter Components......

In the picture:

Top row:

• Bolt
• New flat copper washer
• Pre-filter Plate
• Pre-filter
• Pre-filter 'O' ring
• Large Cup
• Spring
• Flat washer
• Ring Seal (small 'O' ring)
• Small Cup

Bottom Row:

• Sump Plug (with new copper washer)
• Cover plate
• Fixing Bolts and washers
• New 'Purflux' Filter
• New Filter Gasket

Phew!

You should really replace the copper washer on the bolt each time - which means pulling the assembly apart. And it wouldn't hurt to check the large and small rubber 'O' rings on the pre-filter and by the small cup. These go very hard and brittle over time so, before you go snapping them out in pieces (yes - that brittle), make sure you buy your replacements first! The other thing that goes missing is the small cup right on the end of the assembly.

All those parts can be bought from the usual suppliers and Citroen Classics have produced a video showing you how it all fits back together:

Citroen Classics - Oil Filter assembly

Anyway, having got the sump back on my car, I was finally able to fit the oil filter and it's cover - and that all important sump plug. Mustn't forget that.

Engine Rebuild (Part 7) - Studs and Inlet Manifold

With the head in place I went round and put in new studs for the inlet and exhaust manifolds, plus two replacements for the water pump housing. When the time comes, I've got new copper nuts for the exhaust manifold and locking nuts for the water heater pipe.

The cylinder head is odd in that some stud holes are 'blind' i.e have an end to them, whereas others are drilled right through into the water way. Ideally I would have used some kind of thread lock to prevent the studs from working loose, but with some stud holes open to the water way, it was more important that they were sealed again leaks. In the end I used Hylomar Blue on all the studs. 

Exhaust Manifold Studs Fitted.....

My thoughts turned to the inlet manifold.The inlet manifold had looked a mess.....

Mount Point for Clutch Re-engagenment Control 

When I'd first got the car going back in November 2014, I'd found a water leak under the manifold. It was impossible to get down there and find out why and where - especially in the gloom of the barn. I assumed it was a burst hose - maybe frost damaged. When the cylinder head was pulled in October 2015 I was able to look more closely and found the problem was actually a rusted-out core plug.

Silted Up Coolant Nozzle and Rusted Core Plug - 27 October 2015

I initially tinkered with the manifold earlier in 2017 and found that the little metal breather inlet (that takes a pipe off the sump breather tube) was completely blocked. I took advice and was assured that it was meant to be hollow. I eventually cleared out all the impacted silt with a small twist drill.Whatever it was meant to do - it hadn't been doing it for some time.

Cleaning the Breather Tube - 15 July 2017

I turned my attention to the core plug. Using a socket that fitted neatly within it, I tapped the rusted core plug into the manifold. I couldn't find a reference for it in the parts books, but It seemed to be coming up as 30mm diameter. I ordered a replacement from Ebay - for just a few pence. It wasn't quite as heavy duty as the original, but it was the best I could find.

Dead Core Plug

Having discovered the joys of vapour blasting in summer 2017, I put the inlet manifold through the process. It came out looking fantastic. 

Nice and Clean Inside - Excess Petrol Drain Hole

I fitted the new core plug. I smeared a little Hylomar Blue around the circumference and gently tapped it into place using a socket inside the cup of the plug. It seemed to fit quite nicely so I was happy with my choice of 30mm. Just to be sure, and using a screwdriver as a chisel, I bent over the three tangs that stop the plug popping out too readily.

The three gaskets for the inlet manifold are part of the engine gasket set and I soon had the manifold fitted and torqued-up. I'd ordered a new hose that runs between the water pump housing and the manifold and did a test fit.

Inlet Manifold Fitted

New Core Plug Fitted

Core Plug, Water Hose and Petrol Drain Nozzle

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.....