Engine Rebuild (Part 3) - Timing Chain and Sump

With the crankshaft fitted, I moved on to the camshaft and timing gear. The important thing here (for timing/ firing) was to align the marks on the two sprockets before final fitting of the chain. The marks are quite subtle. On the camshaft sprocket, the relevant mark was a single painted tooth (repainted in my photo below)......... . 

Repainted timing mark on tooth of cam sprocket

........and on the crankshaft sprocket the relevant mark was a small notch between two teeth:

I was too busy to take photos, but the principle of reassembly is that with number 1 and number 4 pistons at about top dead centre, and with the chain held taught on the chain guide side (not fully taught in photo below) a straight edge should pass through the centres of the sprockets and these two marks. Turning the camshaft and sprocket and/ or crankshaft allows you to move the chain by a tooth or two until you find the 'sweet spot'.

Marks on sprockets face each other and align

I'd had a new timing chain fitted by Doctor Chevron back in 2002 and it had probably done no more than two or three miles after the engine had been refitted all those years ago. The timing chain got re-used - as did the chain guide and tensioner. I followed the assembly and alignment procedure - reading the instructions in manuals 518 and 814 very carefully. The guide was fitted and adjusted with two feeler gauges (and three hands) and the chain tensioner was fitted and 'activated'.

With the camshaft and timing chain in place, the oil pump could be fitted. The pinion on this is driven by the camshaft. 

The Oil Pump is Driven by a Gear on the Camshaft

The oil pump was correctly orientated so that the hole in the stem aligned to the threaded hole in the engine block. The pump was then pinned in place with the screw and lock nut.

Pin and Lock Nut for the Oil Pump

With the other end of the oil pump bolted to the bearing cap, the sump was fitted. Having had to sort out a stripped thread on the sump plug hole, I thoroughly cleaned the sump of any swarf before fitting it. I smeared a very thin bead of RTV silicon on the mating surfaces. Not too much as I didn't want it oozing into the sump. There is also a cork gasket that fits over the curve of the flywheel end bearing cap. That was similarly held in place with some RTV.

It's important to get the location of the two long bolts correct as these will serve the secondary purpose of holding the triangular bracket that supports the down pipe/ flex-pipe join. Where did I put that bracket.....

Long Sump Bolts for Exhaust Bracket

After the sump, the timing chain cover was fitted.

Bottom End Done - 13 August 2017

Sump Repair and Fitting

While I was cleaning my sump up in July - the sump plug fell out! The thread on the sump was almost completely stripped and the plug was a loose fit.

I have a second sump - from the engine pulled from the car. I wasn't keen to use that as it had lots of stress and fatigue marks on it and I didn't want to use it in case it cracked and leaked. Anyway, my 'loose' sump plug was too tight a fit on that sump - which explains why it stripped the threads on the other sump when it was fitted. It wasn't the right plug for a DS sump.

At least, with two sumps, I had a second, proper, DS sump plug. I could use the other plug, but first I would need to repair the threads on the sump. But how best to proceed.....Sharing my woes on the CCC website forum there seemed to be two options - a heli-coil or a Time Sert. No - I didn't know what one of those was either!

The simplest way to describe a Time Sert is that the principle is like a helicoil - essentially a replacement thread -  except that a 'Time Sert' insert (bush) is a tubular threaded sleeve (threaded on both the inner and outer faces). It is threaded into a over-sized re-tapped hole and pressed into place - (re)creating a tapped hole of the original and desired size.Then I got an offer I couldn't refuse: a kind soul (who wishes to remain anonymous) offered to lend me an appropriate 'Time Sert' kit suitable for a DS sump plug.

The kit arrived in the post a few days later. Excellent service! After familiarising myself with the equipment and process I gave it a go.

Clamping the sump to my work bench to stop it moving about, the process was very straightforward - other than that it had to be done by hand.

• The errant hole was drilled out (no going back now!)
• A seat cutter was used to cut a recessed seat

Preparing For The Time Sert - 12 August 2017

• Next the hole was tapped over-sized
• Fitting the 'Time Sert' bush on to the lubricated insertion tool, the bush was screwed into the hole until it was sitting flush on the recessed seat.
• The Time Sert insert (bush) has part-formed threads on it's inner face. Continuing to rotate the insertion tool did two things: it finished creating the thread in the bush and, as it did so, it expanded the Time Sert bush so that it fitted the tapped hole tightly.
• The insertion tool was then withdrawn - leaving the bush in place.

I used a file to dress the sump/ bush surface to make sure the insert was flush to the sump face - so that I could be confident I could obtain an oil-tight seal when fitting the sump plug. 

Done!

Engine Rebuild (Part 2) - Pistons

With the crank in place I moved on to re-fitting the pistons in the liners. If you follow the procedure for reassembling the engine as covered in Operation 100-3, the pistons are inserted in the liners before the liners are put back in the block.

I actually followed the process shown in a DSSMPassion video and fitted the pistons after the liners and crank:

DSSMPassion: Replacing The Pistons

My liners were clamped in place to stop them moving around, and I'd shaped large flat washers to allow me to slide the pistons past them.

Bolts and washers for Retaining the Liners

All the parts had been ultrasonically cleaned and lubricated and were neatly laid-out. Ring and re-reading the workshop manual I made sure that the con rods were attached to the pistons the right way round relative to the crowns of the pistons. 

The ring set was confusing as, although it was obvious which were the scraper rings, the others looked very similar and I wasn't sure which way up to fit them. it took me ages to find the word 'top' clearly marked on them........

Pistons Ready For Re-fitting - 4 August 2017

I'd bought a cheap pair of piston ring spreaders to help me fit the rings to the piston and they worked very well. The trick was to open the ring just enough to slipover the lands - but not to open them so much that the rings snapped..... All went well. On each piston the rings were orientated so that the gaps were 120 degrees apart and not aligned. I believe this helps to optimise compression. 

With a generous squirt of oil, the bearing shells were fitted to then rods. I'd also bought a cheap piston ring compressor - one of those coiled spring things, operated by a key. Again, things went remarkably smoothly. Making sure the piston crowns were correctly orientated, with the aid of the compressor, pistons and rings were eased down into the liners. With a bit of fiddling I aligned them to the crank by refitting the flywheel bolts in the end of the crankshaft and using a breaker bar between them to rotate the crank a little. I added the other half shells and con rod caps - being careful to match them to the appropriate con rod -  and torqued them up. 

Engine Rebuild (Part 1) - Liners and Crankshaft

I mounted the engine back on the stand. This time I had added some extra bracing bars to the arms of the stand - made from very sturdy angle.  These allowed me more flexibility as to the mounting point I could choose on the engine - thus distributing the load better and putting less strain on particular parts of the block. It had been quite fiddly deciding quite how to cut these and where to put the holes. I also had to factor-in the need to be able to put the sump back on. Trial and error proved the way forward.

With the block painted and on the stand, the serious work of rebuilding the engine could begin. Lots of research....

The procedure for reassembling the engine is covered in Operation 100-3, which you can find in Section 2 of Volume 2 of manual 814.

I also used a very handy set of three videos from DSSMPassion. You can find the first part here:

Engine Rebuild Video - First Part

I'd drawn a blank on trying to find the correct spec. head gasket and liner seals for my DX engine (see other post....) and had decided to go with the contents of the 'standard' gasket set I'd bought from Citroen Classics a year earlier.

The first thing fitted was the liners. That meant fitting the delicate paper seals around their waists. I'd been dreading this...... Not only are these seals very thin and delicate, but they are also a notoriously tight fit around the liners. If they tear and the liner is not properly sealed, coolant will leak into the sump. I won't know if I've done this right until I give the engine a proper test with radiator and coolant fitted.

Several different sets of these paper seals are provided in the Glaser brand engine gasket sets that are available. Taking advice, I used the straight edged set for my 21 engine - not the set with wrinkly edges. Knowing how delicate they were, and not being sure if the seals in the set would be thick enough to give the right liner height, I also bought a spare set of seals from the Citroen Classics stand at the D rally earlier in 2017 - just in case.

Well, the seals that came in the gasket set were tight. VERY tight...... I tried the set from Citroen Classics. They were marginally better. Boy these things were tight!

Fitting The Liner Seals - 3 August 2017

With the inner diameter stretching to fit over the liner, the shape distorted and they wouldn't lie flat. Once they were close to being in the correct location, I had to carefully tease them flat again. Even then, they end -up with a curled inner edge.

May Look It, But These Aren't The Wavy Edged Seals

I did a test fit of the liners: according to step 12 in the version of Operation 100-3 in Manual 518, the liner top should between 0.12mm and 0.16mm higher than the deck. Mine came up a little less than the minimum. When it came to committing for the fit, I believe the seals are meant to be fitted dry, but I put a tiny amount of Hylomar Blue on the bottom face of each seal. The liners were carefully lowered into place and the clearance over the deck check again. Still a little shy of 0.12mm, but very close. My main worry was whether, unseen, any of the seals had torn as they were being compressed. 

Once the liners are in place, they should not be moved or rotated - for fear of tearing the paper gaskets. The tactic is to hold them in place with a couple of bolts and washers in appropriate cylinder head bolt holes. Planning ahead, I knew I would need to insert  the pistons - so I shaped the washers to allow the pistons to be slid past when the time came.

Liners Fitted - 3 August 2017

With liners fitted and clamped at several points I turned the engine over and set to work re-fitting the crank. Bearing shells were lubricated and laid in the journals before the crank was lowered in. Lots more oil.

With the two intermediate caps fitted (caps 1 and 3, the end float on the crank was tested using a dial gauge on a magnetic stand. The DSSM Passion video was very handy for showing how to go about this. The end float is adjusted by using thrust washers of different thicknesses - standard or over-sized. As I only had the one set, I was mightily relieved when the end float came up within tolerance!

Crankshaft End Float Checked - 4 August 2017

With the end float checked, the remainder of the bearing caps and thrust washers were added and the caps torqued up.

All Bearing Caps Fitted - 4 August 2017

A Quick Word About...........DX Cylinder Wet Liners and Their Paper Seals

Well -  never did get to the bottom of this one......

I can't remember quite when it was, but soon after I'd decided to get my car back on the road, I was doing some research. Given the crossover from DX to DX2 engines, any mention of 1968 was going to catch my attention and in manual 814 and I stumbled across something:

So with the introduction of the DX2 engine in September 1968, there was a change to the paper rings that sit on the bottom of the liners ('barrels') and a corresponding change to the head gasket? Whatever this change was and meant, it was significant enough to warrant mention in the workshop manual.

As I needed to buy a gasket set, I made a couple of enquiries with the usual sellers, but no one could offer me "joints with packing" or a head gasket with "circular seal". In fact they didn't know what I was on about!

Intrigued I searched through the earlier Manual 518 (published in 1966 and so before the gasket changes) for further information. It offered a tantalising clue in the form of a photo:

The photo showed a gasket on a liner. The gasket was printed with two parallel lines to enable the fitter to orientate it correctly as per the fitting instructions. So, before September 1968, the paper seals on the base of liners were padded (with brown paper?) - but they weren't just thicker, the padded parts were not around the whole circumference.

Questions, questions: Why on earth would Citroen do that?  Why did they need to be aligned with the piston shoulders? Why were they needed? Why weren't they needed after September 1968? Since these are joint parts, what was different about the parts they joined? Did those parts change after September 1968? What was all the business with the 'oval' and 'circular' head gaskets all about?

However 518 had something else to say:

So even before the change in gaskets and paper seals, there were two different sizes (heights) of liners - identified by a colour mark. Presumably you used whichever colour (height) was needed to give the right height above the deck? At this time, BOTH would have been used with the padded liner seals  and corresponding head gasket - as that was all that existed. The liners I puled from the car were so rusted that there was no hope of finding or identifying any paint marks. 

518 still had more to offer:

Top Photo in the Picture Shows Location of Engine 'classe' Stamp

So there are two different 'types' of liners and two different 'classes' (groups) of engines - and you need to use the right barrel with the right block? Now I was confused. How many variables were there! Were there two different heights of liners for 'classe 1' and two dfferent heights for 'classe 2'? There seemed to be lots of instructions telling you what you had to to do, but not necessarily how to do it! (Or why!!).

I searched for clues on my engine. The photo above from the manual is a bit hard to make out, but it shows an engine block marked as 'classes 1'. Here is the corresponding mark, under the oil banjo, on my block. Mine's a '2':

Engine 'classe' Stamp On My Block

I checked my liners.....

"Classe 2" DX Liner: Two Rings On The Upper Flange

After much searching I found two very faint rings ('00') - corresponding to liners that match with a 'classe 2" engine. So that was good then. Unfortunately, I was planning to use the post-1969 liners that Peter ('Badabec') had given me: so I had a look at those too:

D Super 5 liners - Marked '2' on the Upper Flange

They were marked with a '2'. Was that the later equivalent of the two rings on my earlier liners - meaning they were to be used with a 'classes 2' engine block? I couldn't be sure: other than mentioning the different gaskets prior to September 1968, manual 814 offered no special instructions/ requirements regarding liners matching to engine blocks.

I was way out of my depth now - just turning up questions and possible problems - not solutions. I'd found out too much! I knew things it wasn't healthy to know!

• Charles Vyse had also commented on the paint marks on liners in his recently published 'Goddess' book - finding an old address I tried to write to him to find out what he knew. No reply to date.

• Der Franzose sell two different gasket sets - in both cases these cover several engine variants.  Their part number 30008 is suitable for DX2 engines, but their part number 30009 is said to be suitable for DX engines - but that might just be a typo and, anyway, the set also covered post 1969 engines. With only one head gasket in the set, it can't have been that the difference was that the set included a head gasket with 'oval seals'.

• I found a thread on the "Club DS Deutschland" forum where a DS owner had struggled to get a gas and water tight seal on the head of his DX engine after a rebuild. Was this perhaps down to using the wrong gaskets? 

• At rallies I had checked the engines of some post 1968 cars and these continued to have a 'classe' number stamped under the oil pipe, so it MUST have continued to have had some kind of relevance to SOMETHING!!!!

This continuing uncertainty over gaskets and liners was now stopping me getting on with the rebuild......By the time of the DS rally in June 2017  - and with no clear answers on the horizon - I decided I'd had enough.

Since I couldn't satisfactory solve (understand?) the issues of the padded/ not padded gaskets, I decided to simply things by going back to first principles: when fitting the wet liners, the major consideration is for the liner to be proud of the deck by the correct height when fitted without, and then with the paper liner gaskets. The measurements are given in manual 518 and are in one of the photo's above. THAT'S what I would focus on.

As far back as June 2016 I'd bought a complete engine gasket set from Citroen Classics and at the 2017 DS rally I bought a second set of the paper seals for the base of the liners for ''extra padding' if needed. I would suck it and see.

Like I said I never DID get to the bottom of this one.......