Zel's Fleet Blog - BX, Jag XJ-S, Sinclair C5, Mercedes 208D & 230TE, AC Model 70.

[white exec]

I think that the ribs are designed to increase the gripping surface area while reducing heat generated by flexing.

That was my understanding, too. Lots of V-shaped drivebelts/fanbelts have moved from solid vee to the more flexible pattern. Particularly advantageous on small diameter pulleys. All the workshop bench tools here now have the 'new' type.

[Zelandeth]

Makes a lot of sense really. The only real difference we could find comparing the NOS belts and the HP2020 was the profile of the teeth. The original belts had a flat profile to the teeth whereas they're curved on the HP2020.

For such a big belt it does have to go around quite a small diameter pulley on whichever side is running at the lower part of the CVT cone at any given time, so that definitely would be a factor.

I don't know what the actual ratio is, but the secondary pulley does more than one revolution to one revolution of the road wheels (which are only 10" to start with!), so you can imagine when you're cruising at 60 the belt is moving at a fair old rate. There's a good reason that the AC designers put a cage around it to contain the shrapnel in the case of a belt failure...

[Zelandeth]

Today has been frustrating.

Started out well enough, with these picked up from the Mercedes dealership.



That's a gasket to go between the thermostat housing and the cylinder head and the seal that goes between the outer cap of the timing chain tensioner and the block.

Replacing the gasket for the thermostat housing was precisely as awkward as I remembered (because I didn't want to remove the stubby hose between the block and the stat housing as it's a pig to refit), but uneventful. If I do keep this car something I will probably do is go through the engine bay and replace ALL the hose clips as most of them are either half seized or have stripped heads. It's overkill I know, but I far prefer Mikalor (other brands are available, but that style), I'm used to them from having messed about with a lot of ancient commercial vehicles when I was younger, and they're just so much less hassle in the long run.

Things then rapidly went downhill from there. Firstly it turns out that Hermes have apparently lost a parcel which contains the replacement alternator for the Jaguar. Wonderful. Their system shows it as having been delivered...whereas it definitely hasn't been. Not to us, any house on our (short) street, or the same number on any of the surrounding roads. Great. So that's about £300 worth of alternator that's just vanished into the aether as far as we can tell.

Step two for the S123 was pulling things apart again so I could replace the outer oil seal on the timing chain tensioner.

It's the thing which looks like a huge bolt head in the photo below, slightly above and left of the centre of the frame.



This is where the real headache started.



Those two washers should be the same size...they clearly aren't. New one is a couple of millimetres smaller - sufficiently so that it won't fit over the body of the tensioner.

Heading back and talking to the dealer revealed that that washer doesn't actually exist at all on their parts system...so we're not totally sure where the one they gave me came from!

I spent a good couple of hours driving around to everywhere I could think of and couldn't find anything even close to the right size anywhere.

Typing "Mercedes M102 timing chain tensioner oil seal" into Google revealed that it was paying attention to the words "Mercedes" and "timing chain" and completely ignoring everything else. I'll do battle with that when I'm sitting at an actual computer...I just don't have the patience for that nonsense when I'm using my phone.

I'd really hoped this would be ticked off today but it looks like I'll be having to order a stupid washer and wait for that to arrive before I can make any progress.

I have a feeling someone mangled this washer somewhere in the distant past as it was absolutely slathered in instant gasket when I removed it...and I find myself almost wondering if that may be responsible for the historic oil flow issues we've clearly had to the head. Coincidence or causality? Either way, I'm fixing the problem rather than bodging it.

Having been a few hours since I fitted the thermostat housing I went to fill the cooling system...and went and made myself more work. Apparently when I threw everything back into the garage a few days back I threw the wrong cap on a couple of bottles...and the one with the cap which said A/F Blue was in fact not blue antifreeze...it was 20W 50 oil. So a good slosh of oil went in the radiator before I spotted it. This is the curse of Motorserv having NAPA everything now...all the bottles are identical! System was going to need flushing anyway as there was some oil contamination from when the head came off...but there's more in there now! I did manage to skim *most* of it off as it hadn't mixed, but I'm sure there will be more slime to come out.

Moral of the story: When you're shutting up shop, no matter how knackered you are, don't cut corners. You'll end up making yourself more work in the long run. Probably in a way which will make you feel like an absolute IDIOT as well.

[white exec]

Rotten luck! Mark the contents on the top edge of the bottle/container.
To get oil out of the coolant system, can recommend LiquiMoly radiator cleaner #2506. 1 x 300ml can sufficient.

Do Just Bearings (Simply Bearings?) run to sealing washers?

It is annoying that a web search will latch on to any of the words in your search item, so will drag up all sorts of just-about-related stuff. Ebay notorious for this. It's not the answers that are difficult, it's the questions...

[RichardW]

What size is the washer, Zel? I got a box of assorted copper washers from Halfords, might have one big enough - although they are quite wide and that looks narrow, when I needed one for the Velo project I had to file one out to make it fit.

[Zelandeth]

Rotten luck! Mark the contents on the top edge of the bottle/container.
To get oil out of the coolant system, can recommend LiquiMoly radiator cleaner #2506. 1 x 300ml can sufficient.

Do Just Bearings (Simply Bearings?) run to sealing washers?

It is annoying that a web search will latch on to any of the words in your search item, so will drag up all sorts of just-about-related stuff. Ebay notorious for this. It's not the answers that are difficult, it's the questions...

Many of the containers are marked on the bottle too, just not that one! Well...not strictly true, the one which actually had the antifreeze in *was* marked... I'd just got as far as actually putting that one away rather than wedging it behind the garage door, so I came across the other one first.

Think I've got a bottle of cooling system cleaner somewhere in the garage, will just have to unearth it. Not worrying too much at this stage, unless the engine shows promise at staying with us it's all a bit academic.

The washer has an internal diameter of 28mm, so well bigger than anything I've got in stock or that you commonly find for sump plugs etc.

There are a couple of hydraulic specialists locally I'll try this afternoon if time permits - though given the usual complete apathy I've come to expect from specialists around here I'm not holding my breath for them being interested. I do need some hose from that sort of place anyway to replace the one between the header tank and hydraulic pump as it's currently sweating through the line there as it's gone porous...so at least I should have something that's simple for them to find.

[Zelandeth]

Found two local independent hydraulics specialists today...first one barked "we don't do car ***!" at me, second didn't even look up from their phone for more than half a second before muttering that they didn't do stuff like single washers any more.

Step forward Pirtek. Who immediately said "That's an odd one..." and went rummaging.

Couple of minutes later:



It's copper rather than aluminium, but I don't think that will be an issue, it's just sealing between two pretty smooth metal surfaces.

The outer diameter isn't that important as there's plenty of room around it, the inner diameter was the important one and that's spot on. They wouldn't even take anything for it.

Did it fit?



Like a glove...

Problem solved it looks like.



After a good half hour of running...no leak present.



Not by any means the first time that Pirtek have saved my tail either.

I did completely fail to remember to pick up the hydraulic hose for the suction line to the SLS pump though...will need to go back tomorrow for that.

I'm sure the hex head is actually a metric size, though I don't have a clue what size it is...none of my metric sockets are big enough...this worked fine though!



Evidence of my "mishap" with mislabelled bottles yesterday.



The good side of this is that it never really mixed, so I've managed to skim I reckon 95% of it back off the surface. There's a slightly oily film in there now but I don't think much worse than from the head coming off.

The vast majority of the bottles are labelled both on the lid and bottles, like so...



The one that caught me out was very much an outlier! Definitely won't make that mistake again though.

Before I set about running tests I sorted out the other coolant leak I'd noticed, one of the washers was missing from this coolant balance pipe.



I'm not proud of the bodged throttle return spring... I'll be getting a proper replacement for this if the engine is staying with us, but it does work.



Aside from a few plastic covers for the HT leads everything is now back in the engine bay.



Finally meant I could let the car warm up properly until the fan was cycling (which it was also nice to see was working as the switch came with the new head so was untested until now).

So how's our oil pressure looking?

In gear right at the point when the fan is cycling, about like this.



Though the idle is definitely a bit low which won't be helping - at 1000rpm it seems reasonable.



Deliberately checking for it at a set engine speed as that will make it far easier to tell if it's getting worse over time.

Here's a quick look at how it tracks with engine speed.



Definitely sounds a lot better than she used to.



By the time I got to this stage we were well into rush hour so no proper test runs were going to take place...an unproven car and rush hour Milton Keynes traffic just sounds like a recipe for disaster. We did however go for a gentle bumble around our local estate...and it seems to be working okay. Not able to give her enough revs to really tell much though - but we'll do a proper test tomorrow.

It's definitely very noticeable that the engine is running cooler while bumbling around town...would previously have been sitting around the 100C mark, whereas it now seems to sit about halfway between the 80 and 100 marks.



Not reading too much into it, but it seems to suggest the engine may be running more efficiently.

Only a *little* bit of a mess left where I was working...I did try to catch as much as I could in a catch tank, but there's only so much you can do.



I think the vast majority of the oil came from the initial leak we had from the timing chain tensioner. Slightly puzzled as to where the exhaust manifold gasket came from as I'm reasonably confident that two went back on each of the runners...

Let's see how the actual test run tomorrow goes...

At least today was less annoying than yesterday!

[white exec]

When it came to fishing oil out of coolant (after an oil cooler perforation) I found that you could repeatedly dip some rolled-up kitchen roll into the tank, and when pulled out lots of oil would cling to the tissue, leaving coolant pretty much behind. You've likely done this anyway.

[Dormouse]

Given the age of the oil pump and the ravages of poor maintainence, I would suggest that 2bar (30psi) at 1000rpm is reasonable. Better still, the oil pressure rises quickly with revs and fills the gauge at 3 bar (44psi). If the car maintains Full Gauge conditions while driving then it is looking promising. Keen to see the oil at your next flush. Stick in there.

[RichardW]

Moving forwards! Nothing in my kit near that size.... 3/4" BSW is 1.2" AF, which equates to 30.48mm, so it's probably 30mm.

[Dormouse]

The biggest 1/2" drive I have is 32mm but I do have a couple of bigger 3/4" sockets which I use with a 1/2" stepup adapter for large crankshaft bolts.
The biggest bolt I sheared by hand without a tube on was a 42mm - it was probably cracking to start with and I had to slip in the side entrance of Faslane to "borrow" the stud extractor to remove the sheared stub. The alternative was a 2/3 day low loader trip back to the Edinburgh workshop to repair my machine. Wouldn't like to try that again during COP 26.

[Gibbo2286]

That looks like my Elora socket Zel, I bought the set when I came home from national service back in 1955, unbreakable stuff.

[Zelandeth]

That looks like my Elora socket Zel, I bought the set when I came home from national service back in 1955, unbreakable stuff.

This is a Herma combination set which was very kindly sent my way by Jim when he was having the garage clear out a year or so back. Given the tendency for work on the Invacar to involve working with Metric and several flavours of Imperial fasteners from one moment to the next it's been exceptionally useful.



Really feels like this is a set of tools which will still be working as well as the day it was made, long after I've turned to dust.

-- -- --

We've been out and done a bit of driving around today.

Nothing has blown up yet at least!

About 30 miles done, all keeping close enough to base to hopefully be able to limp home if something went awry.



Horrible photo. I'd left the flash turned on on the camera. Derp.

I definitely need to bump the idle speed up a bit, I'm pretty sure that the IAC valve isn't doing anything...I have a spare so I'll probably thoroughly clean that then just swap it over. The one currently on there is the one that was on the spare head, so has probably been sitting disused for many years.

I had the car stall on me twice going into gear, and it didn't really want to restart on those occasions, sounding like the engine was kicking back against the starter.

Figured the ignition timing was most likely out there, especially as performance had felt a bit "flat" even keeping in mind I've been being pretty gentle so far.

You can tell the timing light isn't a tool that gets used hugely frequently from how dusty it is!



Correct setting is 13 degrees BTDC +/-3 at idle (850rpm). Yeah...it was at roughly 38 degrees advanced, so that won't have been helping. How I wasn't getting pinking with it that far advanced I've no idea. I will recheck it once I've sorted out the idle speed/IAC issue as it's difficult to get it spot on right now as the idle speed changes with the setting and is wandering enough to make it tricky to judge. It's at least close-ish now though.

Haven't been for a proper drive since, but on a quick run round the block the engine felt smoother.

Something which definitely is not smooth however is the gearchange. It feels like gears are being changed with a sledgehammer. The box has always been a bit clunky, especially 2nd-3rd and when cold, but every change at the moment is totally devoid of any slip. To the extent it's honestly painful. Definitely can't be doing anything any favours. It's either going to snap something in the drivetrain or my neck...one of the two.

There's no adjustment I'm aware of on the kickdown cable I removed, but I'll definitely double check that tomorrow and make sure I've not routed it wrong so it's binding or anything. I thought it was just a case of unclip the cable and hook it back up, I may have missed something though.

I did note the fluid level was quite low, so topped it up. Well...aside from the half pint or so I felt it necessary to dump over the exhaust manifold...you know, it just seemed like a good idea...or I'm just that clumsy an oaf. Yes...that was it.



Cleaned as much of it up as I could, but it still stank for ages...guess at least it wasn't EP90!

Pirtek unsurprisingly had no problem picking out a suitable hose to replace the leaky suction line for the SLS pump. This has been sweating for ages and I think was responsible for a lot of the oil over the front of the engine.



Definitely looks a bit tidier...plus will be nice to not get covered in hydraulic oil every time I accidentally brush against it. Was a bit of a faff to change it without draining the reservoir but I managed it. I didn't have any of the correct oil in stock so didn't want to drain it if I could avoid it.

Yes...the hose bracket is upside down. I'll sort that next time I'm working on the car...was just out of time today.

Doesn't look like we've had any more leaks present themselves during the day, so that's a plus. Just need to try to get to the bottom of the horrendously harsh gearchange (which is massively worse than before I worked on the car, so *something* has changed) and we can keep testing. Open to suggestions there.

I do have oil and filters in stock again now, so will do another oil change at the weekend. Still looks spotless on the dipstick but after doing work this major it just makes sense I think. Especially given we're still on the lookout for glitter too.

[Dormouse]

I would check the kickdown cable ASAP. Plus any wires or vacuum pipes.
You will get odd bits of "glitter" washed down from the top to the bottom of the block and sump for a while as you have not had the block fully stripped and cleaned. The (fresh) oil will still scour odd bits out of webs and ledges. With regular oil changes now, you should find a positive change in the oil condition and, fingers crossed, good oil pressure maintained.

[Dormouse]

found this site. has lots of info for older mercedes. worth a trawl through?