405 XUD9- Head / belt questions & storytime

[Goc3k]

Evening all,

I've been off and on the forum since late last year, hungrily eating up the excellent info for all things french related - mostly info for a head gasket change on my 405. The story follows later if you like an accompanying story - I certainly do!

I have a habit of not getting to the point so i've bolded the actual questions! And for reference, i've called the car Wilson

Following evilally's troubles with his 405 back in 2009 as a guide to my now sickly pug (massive pressure in the cooling system, head gasket gone at 125k), I popped the head off, in order to see if he could be saved. I'd managed to stop before the temperature gauge got much over 90c, steam pouring from the engine made a good indicator, so I was hopeful. The bores and pistons looked great, some surface corrosion here and there on the block face. nothing too shocking, the head itself looked crack free to my untrained eye. Now sated costs were justified I took the head to an experienced local engineer for appraisal.

Luckily all was well, no cracks and the swirl chambers were crack free throughout, pressure test turned out a good result. He said it had a slight twist in it, and he "over-skimmed" to compensate (he took about 0.11mm off). Curiosity: He said the XUD 9's swirl pots were made of a slightly different alloy to the head material, and should be skimmed while separate and then re-inserted ever so slightly proud for the best outcome, I presume this is standard on most pre chamber engines?

The old head gasket was a 2 notch (listed as 1.4mm) - It did not seem to have been changed before, but was under the impression original thickness should be 1.36mm. Going on that assumption i needed a 1.47mm ish HG replacement. Could only find fibreglass ones in the right size, and I wanted a steel one. Only MLS one I could find was the 5 notch, as I'm not keen on putting old school fibreglass HG's in cars given a choice. I'm guessing the over thick gasket will not really make any noticeable difference? (as it's only 0.05mm oversize).

While removing the head, I stupidly spun the union nut on the turbo oil feed, even after reading to watch for that , and proceeded to put strain on the pipe while hefting the head off, so to save aggro I'm after a new pipe, union, the male to male oil fitting on the oil inlet to the turbo, and the little plastic strainer which sits in the block. I can't find any diagrams or part numbers for the life of me on the internet for these parts, and the parts man in my local dealer also cannot find them (he said they don't have proper parts diagrams, I'm guessing he was just trying to fob me off). Any direction to a catalogue / numbers would be cracking!

Also - have a cambelt kit, there is no new spring in it however for the tensioner, is it fine to re-use the old one? (the bit that sits in the engine mount)

Wilson came with A/c - my opinion is usually to just ditch it when i have time. Does anyone happen to know the correct belt or size for a pulley setup that has lost its ac compressor? the PAS pump looks like it sits where my A/c compressor is on non A/c cars so im guessing I cant just use the non A/c belt. Did similar on an old car and found a belt off a lawnmower that did just the job, aha!

Cheers in advance if anyone can help.




And now the story!

I have always previously had old bimmers, thoroughly enjoyable cars the lot of them, went through older and newer ones alike and always loved them - never had any trouble, and I really like fiddling with cars (which invites trouble into bed with you), cheeky adjustments here and there to squeeze out another couple of miles from a gallon or put another horse in the stable. I currently have a 50~ mile a day round trip commute, and usually rack up another 90-100 miles over the weekend - I decided to make the jump to home brew fuel as I discovered I could pick old oil up for free, was easily spending 3 to 4k a year on dino derv while averaging 50-55mpg so it seemed logical.

Of course, the common rail car I had at the time was certainly not going to enjoy that, as I didn't have enough space for the level of refining it would have needed to remain reliable, so I did my research and decided on an old m51 engine'd e34 - ideally manual. waited 6 months for one worth buying (narrow minded choice looking back of course!), lovely old maroon tank from up north on a healthy 250k miles full dealer inspections up until 2014 - oh how very chuffed I was with this crafty purchase. Wasted all summer last year doing it up and converting it 'proper, heat exchanger, upgrade lift pump, the likes. Also a big intercooler, and some choice adjustments to fuel and boost as I am a child. If anyone wants a hand with the principle of the "evry" mod do ask - took me ages to find any real explanation of how it actually worked / what to do, principle applies to any car with an old school IDI system with an ECU controlled pump, so as to increase fueling.

Within 3 months i'd slid the car into a ditch - smashed every N/S panel up and hit a tree stump which shifted the rear crossmember back about 50mm (the killing blow). Was only doing about 20, must have hit a greasy patch coming off the roundabout I was on . Repair forecast was sniffing the low end of 2 grand (even doing a fair bit of welding and hammering myself), so I flogged it.

Suddenly I had a shed with 150 litres of grubby fuel and no car to burn it, after some searching the XUD9 engine became the apparent golden choice for homebrew fuels. This little engine kept cropping up while I was searching for alternatives, and on the advice from the forum I trundled off intending to buy one. After looking at some suspect 306's and a Xantia (all rusty, clattery and one of very questionable paperwork), I found a MkII 405 nearby. Sadly on turning up it was apparent the plugs needed changing and the HG was weeping oil at the crank end - not good. I decided to take the risk, as it is staggeringly rust free for a 23 year old frenchie, and was fairly low miles at 125k - the engine sounded sweet as a nut vs the other 3 i'd been in.

One month in on derv, and new oil and filters, all is well I think to myself - handling is quite crispy, doing 600 miles on a tank, no smoke and no problems. She seem very slouchy for a diesel at low revs however so I stuck a boost gauge in - was only really coming on at about 1900 - 2000 RPM, and holding at about 1bar once shifting. This was to be expected I discovered so I set out to "improve the drive-ability ". Following some excellent guides in a well known auto magazine it was obvious there were many easy mods. I binned the recirculating silencer off for a glasspack, instantly gained a few pounds of boost earlier on, rerouted the airbox (no ABS on Wilson), stuck half a tank of homebrew in after a few tests, all was lovely jubbly.

A short while later my spanners seemed to look a little itchy for adventure, so I decided to fix a few more niggles and invite trouble - eased the govenor off a smidge (solved the power tail off after 3,800rpm), started playing with the boost actuator diaphragm and spring, and did a wee turn on the max fueling, also found some extra joints in my arm to wind the waste-gate in, and a bendy spanner to advance the timing a touch. At this point I was smug as a Cheshire cat, who would have thought such a fabulous engine was hidden away in so many cars? Early boost, climbing power all the way to the redline, and just a brilliant drive-ability I've never really had in any other 4 pot diesel. Most of their cousins are slouchy low down, and flat at the top - even the modern recent generation common railers!. At this point I was now a convert (and still very smug).

Sadly, the little voice in the back of my mind was now entirely stamped on and i was thrashing about the southern countryside with glee. Trouble loomed, and -obviously- the extra boost and heat finished the head gasket off within the next 6k miles and brought me here .

Hopefully that little tale amused somebody - Wilson's now awaiting re-assembly, hopefully with a variety of new bits to promote longevity.

Any thoughts for further improvements or things to watch for on re-assembly would be handy

Cheers,
Goc

[Pug_XUD_KeenAmateur]

Head Gasket sourcing and thickness, not a clue, be curious to hear how you get on with sourcing one should there ever come a day when I need one.

Turbo union: I probably know a man who's got one, fabulous chap with and old school workshop and piles of parts: that's the good bit; the bad news is he's not always very good at actually finding what you need.

He's also got two 405 estates, a TD that I've got my eye on for the future (tidy but needs HG) and a normally asp'd Exec estate that's cosmetically poor (lots of bumps). Also an engineless Mi16 saloon and a written off and tattty but mechanically good 205TD (that's the smaller XUD7 lump). NSF corner damage.

I'd love to buy the Exec and strip it, returning him the engine which I know he wants; but I've got nowhere off-road to put it. Have you got off-road space to strip it, take what we each need and dispose of it?

I also know of a very good old school breakers in South Oxon; supply of 405's dried up surprisingly recently (last year), but 306's are still common there and there's often a 309D or two, too.

Cam-belt spring, no idea. Would luv to help you with the cam belt fitting though as am bricking it about doing mine soon, its due in 5k miles. Over-seeing and helping you do yours would be of some value to me and with that in mind would be prepared to drive to Winchester which isn't far from me (I'm near Swindon)

A/C: there's only two aux belts for the XUD9, the 'AC' belt also known as the 'Serpentine', coz its long, and the non-AC belt. The Serpentine's a bit of a puzzle to refit, and you'll do well to consult the book of lies before trying else much swearing and lost time will undoubtedly result.

If you lose the AC, you need a different cast iron mounting on the front of the block, I've got one I can show you, as I've considered this and got the parts to do it (including the shorter belt) but not actually bothered yet.

Also the sump is different on the AC cars, its alloy with mountings for the AC compressor, whereas its steel on the non-AC's. I believe but can't be 100% sure that you don't need to change the sump, the AC mounting holes simply remain empty.

Hope that's helpful. Do have a look at my old posts here as you'll doubtless find something informative and I also know there's lots of posts here about Head Gaskets.

Also: be VERY thorough bleeding the system. You'll find info about that in the old posts too. The 405 differs from other XUD applications in not having a header tank and the rad filler being lower than the lowest point in the system, which makes it easy to not bleed properly. For that reason I've never put a Thermostat in mine, knowing its absent / stuck open [instead the rad's blanked off as best possible this time of year]. I'm a bit paro about it actually.
I'd recommend buying a new bypass hose with a bleed in it, which I've done from a popular auction site in the last few months and am keeping in case of future trouble. You'll almost certainly find that your existing bleed screw won't open and will sheer off if you apply any force in attempting to do so.

My car: 'N' plate 405est: daily driver, 'Camper' all over the UK & North Europe and general workhorse. I've owned two 405's since 2008, clocking nearly 100,000miles in them over that time. Just changed all the front suspension bushes and boot floor's beginning to 'go' as they usually do so keen to be getting on with that when the weather changes.

[Goc3k]

Just grabbed one from the local motor-factors in the end - max size ones in all materials are easy to find. Seems to be the ones in between that are harder to get as steel.

Yeah pass me on the details if you know a breaker / feller with some good bits, that would be brilliant. Most places i've tried are not particularly interested when they find i'm only after a small part that's not a 2 minute job to get out.

Can't say i need any bits for the car other than that really - don't have time to part things out at the moment, and I have a number of naff cars taking up the available space , certainly the best way to learn the ins and outs of an engine though.

There's actually not much to see when it comes to the cambelt. I was a little concerned initially, but as everyone suggests the best bet is to undo the lower mount and head engine mount, and then lever the engine up and down as you need access. Pump and camshaft are easily set with M8(?) bolts (good design that), and the crank can be set using the alignment hole behind the starter - I just stuck an old bolt through it (8mm). Take your time and remain methodical - certainly not a job you want to rush, workshop manual outlines the steps you need take and the order to do it in. Swindon is quite a treck otherwise

i'm going to leave the old sump on. not bothered about the extra bracket down there, I wont lose any important pulley contact by binning it (as im not going to re-locate the pas pump to where it sits on non-ace engines, too much work). Was hopeful someone may have already done it and knew the size is all! Know a place that will make custom belts just down the road.

Another perspective is always handy! I shall have a rummage.

I changed the coolant when I got the car, did the old trick for other cars lacking a good cooling system design - use a huge funnel / bottle or adapted reservoir that can accommodate a good 3-5 litres that will site nicely in the filler neck and drill a small 1-2mm hole in the thermostat (this also solves the wandering temperature issue). Now with all the weight of the coolant in the jury rigged filler bottle and the open waterway it will bleed fairly well, follow the usual steps after that. Does waste a fair bit of coolant admittedly, but saves hassle. Good shout on the extra filler reservoir higher up the system, might investigate popping one in to save future work.

Good luck with the floor, welding thin sheet material is certainly my least favorite activity!

[spider]

I'll confess the few XUD/XUDT head gaskets I've done I've just fitted the thickest one. Yes, yes I know but I've never had any issue or complaint with this. Using one not thick enough could cause knocking as you're raising compression in effect.

There is no cambelt tensioner spring as such, well there is but its part of the mounting and plunger itself. It can be a right "£$"£$ to put back in if it falls out, there is a tool to hold it together actually (I made one its very easy) but it does not tend to fit much with the engine in place ( ! )

There are numerous bleed points on the 405 before they decided to be sensible about it in later cars. One minor thing watch the outlet pipe from the top of the thermostat housing, depending on the age of the car (this really only effects the 1.8 to be honest) if its a straight screwed in outlet here then it can get blocked, I drilled mine out a bit larger. If its the pressed in piece (with a right angle in it) it will not generally suffer from this.

I've never used the header tank method on *any* PSA car even when I was at the dealership and never had a problem. I do tend to slowly (slow is important here) fill them without them running with all the bleeds open then close them when coolant appears (if it does) then start them and let them idle opening the bleeds again. Once I'm happy the air is out I run the engine at about 2K for a few minutes again I may open the bleeds and also feel the hoses.

There are a few ways of doing the 'no ac' method, the layout is different for non AC cars. Most will just obtain a belt that is the correct length minus the compressor. I'm not sure if the 405 has the annoying auto tensioner and spring arrangement with A/C, imo this was a silly idea that persisted for the 406, having an auto tensioner (with a fiddly pin to put in) with a spring that wore out its rubber bushes *and* a manual tensioner as well. I do wonder what they were really thinking with this.

[Pug_XUD_KeenAmateur]

Thanks for that Spider, only just noticed the response. Must remember to check the 'email reply notifications' box.
I delayed response to the original question Goc, coz I knew I'd be stopping by the Breakers in question; which I've now done. No sign of anything suitable on this partic visit tho. Unusually for a breaker, you can't just phone and say "have you got xyz in at the mo", if you do, the answer's always the same "Dunno, come see".

[Peter.N.]

The last head gasket I replaced which was on a 2.1 XUD was a laminated steel one, supposed to last forever but they were only available in one thickness - so I used that, worked fine.

Peter

[spider]

The last head gasket I replaced which was on a 2.1 XUD was a laminated steel one, supposed to last forever but they were only available in one thickness - so I used that, worked fine.

Peter

I think that's normal for the 2.1. But as I say I've always used the thickest one on the 1.9 (and 1.8) and no one has ever complained.

The 2.1 (in a 406 at least) seems a bit of a "£$"£$ to do actually, I never had the pleasure of this.

[Peter.N.]

Its certainly not as easy as the 1.9 but its doable, lovely engine though in XM form with a Bosch pump. Previous to the steel gasket you could get various thicknesses.

Peter

[Goc3k]

Cheers for looking Pug_XUD - I went to the trouble of looking up a part number for the new feed pipe (needed to get the blower back on to progress over the weekend!), 38 quid later I had the right shape pipe with the wrong size threaded u-nuts. D'oh! Risked the old pipe in the end after some time with the blowtorch and very wishful bending back into shape. fingers crossed it doesn't leak like a sieve on the unions i spun.

Bought a new tensioner spring that sits in the mount as well for those curious, it was 2 pounds - the old spring was about 3-4mm smaller than the new one, quite a difference (no idea if it matters however).

Head and everything back on, nothing out of the ordinary to report. My solution for the AC removal was to simply use the belt for non-ac cars that have power steering as suggested. I dremelled out the manual tensioner so it was about 3-4mm further away from the belt when undone fully, fixed it in place and proceeded to use the automatic tensioner to tension the belt. I used a ratchet strap to wind it back, slipped the new belt over the strap, then simply slid the strap out from underneath. Got the idea when you mentioned the foolishness of having both methods of tensioning the belt, spider - bizarre design!

Edit: Just spotted a post by xaccers from a few years back in the aircon forum (wish i'd found this sooner). Disregard my nonsense method - http://www.frenchcarforum.co.uk/forum/v ... 12&t=44573

[spider]

As far as I'm aware (I don't know what Renault do) its only really PSA that insist on the (imo silly) dual tensioner arrangement. A look at any BOL for most PSA vehicles will show a lot of accessory belt choices ( ! )

There's absolutely no need for it really. In 99% of cases with a large belt run one or at most two fixed idler pulleys and one (ideally spring loaded so its automatic) tensioner will do. For smaller runs a single manual tensioner or a single auto will be enough.

It works well for nearly all other manufacturers and on other cars I've looked after I've never had any issues, some of which I've looked after for close on 10 years...

[Goc3k]

I'd never seen it before, I suppose it's a case of sticking something on out of the parts bin to make an accessory work, instead of designing a new pulley or mount. Little bit of a throwback to our own car history right there perhaps!

Update for the sake of - my little pug is back together, still no drama to report other than my own self inflicted stupidity with the turbo feed pipe, and the buying of a £35 radiator which needed every joint drilling dremelling and resealing before it fit (serves me right for the stinginess).

Sadly the MOT has slipped by during the 6 weeks off he's had.

[Goc3k]

Almost forgot this last wee update, but if anyone's curious a fresh MOT is on and he's is up to 400 miles without any scary problems!

Also had the injectors rebuilt - smoke is way down even on my shed brew on extra fuel and boost, certainly something worthwhile if any of you guys are thinking about having some old ones serviced

[spider]

There is a performance difference with the newer ones despite what people say. I've driven hundreds of them.

The early 1.9TD's (K/L plate) were the fastest. The N plate ones were a fraction less (more so in a 306, you can 'feel' it if you compare a 306TD L plate to an N plate one) , then later (306) new shape were a lot lot less eager. This was not really due to the Lucas pump though. If you look in the BOL at the dynamic timing figures you'll see it gets slightly less as the car gets 'newer'

No matter its not a problem to put it where it was originally and it still meets all requirements.

[Goc3k]

Handy bit of info that - always amusing what manufacturers get up to over the years. Also explains the verbal bashing the lucas pump gets !

Timing was the only thing I elected not to alter, extra advance seems to make for bent rods over time from other ventures i've read. The big concern was running 90% ~ 95% waste oil then suddenly needing a tank of diesel owing to some factor or another. Then that presents the too much advance scenario. Probably worry over nothing but I don't want to throw my good man hours well spent away

[spider]

Handy bit of info that - always amusing what manufacturers get up to over the years. Also explains the verbal bashing the lucas pump gets !

Timing was the only thing I elected not to alter, extra advance seems to make for bent rods over time from other ventures i've read. The big concern was running 90% ~ 95% waste oil then suddenly needing a tank of diesel owing to some factor or another. Then that presents the too much advance scenario. Probably worry over nothing but I don't want to throw my good man hours well spent away

Tis probably best to ensure its spot on (for its 'year') if you are not running um, 'standard' fuel. I'm not really familiar with running it on veg or other oils, other than the heating issue but there's lots of ways of doing that.

Regarding bent rods, I'd personally only expect to see that if it was advanced too much or possibly the boost had been played with. I think the standard boost is quite high enough. The other thing that might cause over advance is a sticky 'cold advance' on the Lucas this is the tiny penny / round switch on the end of the fast idle cable. On the Bosch its that 'advance capsule' thing. I threw mine out (Lucas Pump) on the 205TD and threw the solenoid away too, fitting the blanking plate from the normally aspirated pump there. As well as not having to worry about sticky advance (mine did stick on occasionally as the solenoid was a bit iffy) it also gave more room to reach the oil filter. , I (personally) see 'cold running advance' a bit like 'post heating glowplugs' , its not 100% essential. Early models did not have any post heating and did not really suffer much for it. I suspect its more a emission thing than 'better idling' but I'm no really sure.

^ ^ Errors and omissions accepted, this is all just my personal thoughts on things. I do know without the c/s advance and post heating there is little actually lost however and it makes for simpler wiring too.