Distributor, spark plug cables and HV coil

[Marco]

Buona sera Nikola

Yes I confirm that I have both EZL and ECU (with gold label) for ECE management, this was verified with pictures and Johannes’ help who was curious and pushed me to power bank test.

My difficulties are to deal with such poor literature in my hand…see the picture I attach I translated from German look my finger pointing to IACV with 3 pins as you correctly highlight: 2 lines to ECU one to OVP relay and the forth line where is going? Is this where on an original ECE you can play with the idle rev…is this the adjusting wheel you played with it ?

Additionally, difficult to answer but they replaced the manifold with 2 PIN IACV and keeping ECE components, so two alternatives: they put a new wire harness for a 2 PIN IACV or I have a loose pair of cable laying in way of it. I’ll check but is difficult to arrive here to a conclusion, do you agree?

[Marco]

I read your PS yes ECE EZL is probably a good point.
I’m not sure if RUF has this possibility but on my it makes a sensible difference if you play with the EZL resistors I feel it driving and was tested the difference at power bank (regardless we say it is trustable but the difference is something we can take): position 1 I reach quicker 240 tachometer then at position 4 that I found when I bought the car. Now I use always 100 octanes for position 1.

IMG_5938.jpeg

Also the fuel distributor I searched in the past and are part numbers for ECE

Best
Marco

[shaq]

Buona sera Nikola

Yes I confirm that I have both EZL and ECU (with gold label) for ECE management, this was verified with pictures and Johannes’ help who was curious and pushed me to power bank test.

My difficulties are to deal with such poor literature in my hand…see the picture I attach I translated from German look my finger pointing to IACV with 3 pins as you correctly highlight: 2 lines to ECU one to OVP relay and the forth line where is going? Is this where on an original ECE you can play with the idle rev…is this the adjusting wheel you played with it ?

Additionally, difficult to answer but they replaced the manifold with 2 PIN IACV and keeping ECE components, so two alternatives: they put a new wire harness for a 2 PIN IACV or I have a loose pair of cable laying in way of it. I’ll check but is difficult to arrive here to a conclusion, do you agree?

Buona sera,

4th pin is perhaps 12v connector for some daisy chaining of another sensor (giving it voltage feeding) looks like schematic describing of one pin connector, because on next to it 3 pin components it is always 12v, earth and last wire is controlling signal input or sensor output depending what is the part on schematic. Usually it is the middle pin but dont take my word as fact regarding it - is always better to double check pin numbers in schematic 1, 2, 3 same numbers are engraved on the connector or component itself and even better doublecheck WIRE COLOR.

wire color is never misleading when you try to figure out which is which!

For 2 pin components is almost always one pin ground and another voltage (PWM) controlling its function sent by ECU.

Take picture of idle valve. 2 pin is thick short and silver (aluminum) and 3 pin ECE is again golden (zinc coated) and I will help you identify

This is how ECE idle valve looks. See black wheel on top? It is for manual adjusting of idle on warm engine:

ECE.jpg

This is how KAT/RuF idle valve looks like. Not adjustable for general public. For professionals little adjustable with that golden screw, but amateurs better not touch it :

KAT.png

To help you understand wires there is german or english 2/2 letters describing wire color. Like BN/WS means brown wire with white stripe on it and every brown on Mercedes is some ground connection, black or red with stripes are 12v and other colors are 99% component input or output depending on its function.

Nikola.

[shaq]

I read your PS yes ECE EZL is probably a good point.
I’m not sure if RUF has this possibility but on my it makes a sensible difference if you play with the EZL resistors I feel it driving and was tested the difference at power bank (regardless we say it is trustable but the difference is something we can take): position 1 I reach quicker 240 tachometer then at position 4 that I found when I bought the car. Now I use always 100 octanes for position

Also the fuel distributor I searched in the past and are part numbers for ECE

Best
Marco

I always use EZL on 1 because it is best acceleration, best engine power, and because on 2.5 16 there is lower compression 9,7:1 from factory or 12-14 Bar new (I have RUF) same like your 2.3 there is no risk for engine damage even with 95 gasoline. Danger is only 92 gasoline on real ECE engine 10,5:1 compression (16 Bar compression new) in my opinion.

Same principle Mercedes put for RuF or KAT EZLs - every position after 1 retardes ignition by 3 degrees. So position 4 retardes 12 degrees and makes engine half-dead IMO.

Risk is higher with higher compression and lower grade gasoline and vice versa...

But you hear it clearly when engine rings during hard acceleration ONLY, happens only then caused by too early ignition - it is clear like night and day I know when I bought my first 190E 2.0 in Milano 25 years ago - it was manual adjusting ignition pn that engine and I know how it clicks or rings how to describe when adjusted too early.

It was icing on cake but more early ignition better all parameters acceleration, consumption simply engine feels more lively

My engine was 2.0 ECE and had manual adjusting of firing point by rotating distributor housing. On later came EZL and turning distributor left or right helps no more because it is read from flywheel and decided based on ignition map inside EZL.

About that switch - every second, third position of EZL switch retards ignition by 3 degrees lowering also engine power and acceleration. I never used them, never ever.

PS one interesting fact - that switch is behind battery only on ECE wiring harness. For all RuF/KAT it is next to the ABS valve block, and switch behind battery (similar place like EZL ECE) is then for adjusting ECU software (choosing operational subroutine)

Ciao
Nikola.

[Marco]

Buona sera Nikola

Yes I confirm that I have both EZL and ECU (with gold label) for ECE management, this was verified with pictures and Johannes’ help who was curious and pushed me to power bank test.

My difficulties are to deal with such poor literature in my hand…see the picture I attach I translated from German look my finger pointing to IACV with 3 pins as you correctly highlight: 2 lines to ECU one to OVP relay and the forth line where is going? Is this where on an original ECE you can play with the idle rev…is this the adjusting wheel you played with it ?

Additionally, difficult to answer but they replaced the manifold with 2 PIN IACV and keeping ECE components, so two alternatives: they put a new wire harness for a 2 PIN IACV or I have a loose pair of cable laying in way of it. I’ll check but is difficult to arrive here to a conclusion, do you agree?

Buona sera,

4th pin is perhaps 12v connector for some daisy chaining of another sensor (giving it voltage feeding) looks like schematic describing of one pin connector, because on next to it 3 pin components it is always 12v, earth and last wire is controlling signal input or sensor output depending what is the part on schematic. Usually it is the middle pin but dont take my word as fact regarding it - is always better to double check pin numbers in schematic 1, 2, 3 same numbers are engraved on the connector or component itself and even better doublecheck WIRE COLOR.

wire color is never misleading when you try to figure out which is which!

For 2 pin components is almost always one pin ground and another voltage (PWM) controlling its function sent by ECU.

Take picture of idle valve. 2 pin is thick short and silver (aluminum) and 3 pin ECE is again golden (zinc coated) and I will help you identify

This is how ECE idle valve looks. See black wheel on top? It is for manual adjusting of idle on warm engine:

ECE.jpg

This is how KAT/RuF idle valve looks like. Not adjustable for general public. For professionals little adjustable with that golden screw, but amateurs better not touch it :

KAT.png

To help you understand wires there is german or english 2/2 letters describing wire color. Like BN/WS means brown wire with white stripe on it and every brown on Mercedes is some ground connection, black or red with stripes are 12v and other colors are 99% component input or output depending on its function.

Nikola.

It’s amazing your knowledge on such details, congratulations once more
Ok very clear the differences, I’ll have a long session Saturday morning in garage in Italy, I hardly believe I have such black wheel on the IACV so it will be confirmed most probably the RUF valve and manifold.
I’m not sure if it helps but here the best picture I’ve available…may be the red wires are those related to such connector (but it seems are three not two)

Yes yes I know the code for the wiring, I was saying that I have very poor literature available and most from a US service manual …

[Marco]

Referring to this :

Quote
PS one interesting fact - that switch is behind battery only on ECE wiring harness. For all RuF/KAT it is next to the ABS valve block, and switch behind battery (similar place like EZL ECE) is then for adjusting ECU software (choosing operational subroutine)
Unquote


Yes I knew only ECE has there behind battery…I’m wondering what changes you can do for CAT/RUF for the ECU software?

By the way position 1 always since when I discovered hot it changes engine reactivity

[Marco]

As you mentioned differential ratio I commented that I’m quite sure it’s the original 3,07 here I don’t have the car and I don’t know where they write this and I’m not sure what this code means but by chance it end 307…

IMG_5946.jpeg

Then some considerations: assuming the differential is still from ECE I guess that we can keep as reference the attached old test from an ECE where in 5th gear they arrive at 230km/h at 6300rpm, so regardless if the power is enough or not but if my car arrived at 230km/h engine would be at same rpm, am I correct?

IMG_5947.jpeg

Thanks for your time and have a good night

Marco

[shaq]

I’m not sure if it helps but here the best picture I’ve available…may be the red wires are those related to such connector (but it seems are three not two)

IMG_ECE.jpeg

Red recktangle is Idle valve, now red marked connector above is either idle valve or air flow meter on ECE (I forgot to be honest but just check the wire color).

They are both 3 pin. One is above and has separating connector for measuring of live values, another I think goes directly to ECU and you can´t interrupt the signals (for measuring) in the middle of wiring like for first one.

Now, because you have ECE gold label ECU I am not so sure that it can control RuF/KAT idle valve (silver) but only its own (golden) it is not only having 2 or 3 wires or not, I think it is completely different airflow to PWM ratio component and not compatible IMO between each other. Black plastic wheel for adjusting should be reachable from above with fingers

Referring to this :
Yes I knew only ECE has there behind battery…I’m wondering what changes you can do for CAT/RUF for the ECU software?

Yes so for ECE engine ECU you can change nothing but for KAT/RUF there is in total 14 different programs to choose, 7 for CAT and 7 for RuF operation, on both 1 is standard and all other are there to solve some problems. There is my post about it here on forum, for example position 3 solves bad acceleration in middle revs for hot engine. And so forth. They can be used also as "chip tuning" because for example position 7 (I am not sure which is which now in the middle of the night - this is just to better describe it) so let´s say "position 7 adds more fuel to from idle to max revs. And so on, every position is described in WIS I think

As you mentioned differential ratio I commented that I’m quite sure it’s the original 3,07 here I don’t have the car and I don’t know where they write this and I’m not sure what this code means but by chance it end 307…

Then some considerations: assuming the differential is still from ECE I guess that we can keep as reference the attached old test from an ECE where in 5th gear they arrive at 230km/h at 6300rpm, so regardless if the power is enough or not but if my car arrived at 230km/h engine would be at same rpm, am I correct?

Marco

About differential it is usually on right side stamped 3,07 or 3,27 or 3,46 but you have something on the left and nothing on the right, but I assume it is the only differential that comes with ECE, the 3.07 variant.

About max speed revs, correct you should have same reading on rev counter for that speed, because rev counter is much more accurate than Tachometer!

But again I dont believe Magazine used photocell or radar like German magazines do - I think they simply wrote down 230 kmh Tachometer reading on 6300 RPM now in theory max speed should be reached when engine is in peak HP but it depends of how gears and differential are choosen. Some cars reach top speed at redline (on ECE 7100 rpm) so on that I must say I can´t give you accurate information.

Also on those speeds circumference of tires grow, so tires gets bigger in middle from centrifugal force (is proven by experts) and it again affects tachometer reading negatively. Therefore photocell or radar or GPS would be much more accurate than watching Tachometer and I don´t know how they measured it during their tests.

Again PLEASE don´t test max speed on road, do you trust your life all the old 3oo.oookm components that can break when you need it most on 230kmh like ball joints holding front wheels etc.

If you NEED to test it replace everything critical, new all suspension parts on front axle, especially all ball joints only then test with some GPS, almost all portable Navigations have this option...

Like I wrote earlier - for me max speed is only theoretical I never test it myself, I live for good acceleration and using gaps in traffic other drivers can not use

[Marco]

Ciao Nikola

is useful the red rectangle you marked, I'll look there, it's a place quite hidden, in the recent past I replaced the injectors and the 4 idle speed air supply lines that go to the injectors, but there below I did not dig too much...as long idle is good is not needed to remove and clean the valve.
FYI as I think that less sometimes is better, I plugged the connection from the engine block that is feeding the coolant supply line for the crankase vent line, I did not remove the vent line, just used a hose going to the air filter, instead of the integrated coolant line that return to the water pump. I suppose this is something too much if we don't live in particularly cold weather, I read about this before to do.

ECE gold label ECU vs RUF manifold...I'm curious like you say because is strange how the IACV valve is controlled...I hope to discover something. I will never ever touch it but in the remote case I still have the 3 pin IACV: turning the black plastic wheel is it supposed the idle to rise and lower?

Those with additional KAT/RUF ECU control...it's quite interesting how Mercedes let clients the possibility to play with 14 (just 14) different programs...

More important, I thanks for you kind and appreciated recommendation to not put my and other lives in dangers going crazy speed. I don't want to give the impression I take any time the car and floor the 5th gear...I think I'm just normal and want sometimes to have fun, if the condition are "safe". I write "safe" because it is never safe the speed, a 40 years old car can't be intrinsecally safe as a modern project with all the safetty improvements. What I aim is not to go crazy speed but have a car that is, as much as possible, safe as if it were out of the factory today, so if it were up to me I'd replace all the parts with fresh component but we know the story that sometime it's difficult...I replaced and asked both Mercedes and my mechanic to check for wear of any component and in doubt to replace, inspecting also together. A lot of parts have been replaced and sometimes only becuase I pushed to replace: front suspension parts replaced, brakes, brake hoses, ball joints . I exagerate on purpose and tell them that car has to go 240 so my life is in their life if a single component is not working at 100% based on requested inspections.
But again I well know that it's still old car and no reassurance or mechanic can do enough.
I also like and prefer the good acceleration but on this regard I don't feel these cars so exiting in acceleration from stand still, you have to stress quite a lot transmission for some decent outcome, so better to accelerate from second gear, but again they did not impress really, except the engine sound that is very nice (no cat, stainless steel pipes) and make the impression you are very quick but probably you are not it's sometimes more exiting to arrive in third gear at 160 or in forth gear at 210 then anything in first and second and for safety reason not in fifth.

Again I can be super wrong saying this but one car I had was a W202 kompressor, it had 192HP very good engind with decent torque, I think it was the unique car I did not tested full speed, it was elegance versions and the suspension was exactly the way Mercedes was well known in the past for an extremely comfortable but also very vague feeling especially at corners. Probably also the aerodinamic kit but the 16V I feel it's much more stable at high speed that many other cars, but again, yes there are also other components to consider and the rear spoiler is not a parachute that can deploy and take high in the sky to save your life.

target is to discover the IACV and I want to see how mechanically (not 3 or 2 pin) are the IACV different to require a different manifold...one is just longer...in/out connections look identical...go to know...

best
Marco

[shaq]

Hi Marco,

No I mean if you exhanged all ball joints on front axle, has good suspension on rear axle, springs are remounted with aluminum sheet like in WIS described so they can´t break without a reason, has new accumulators on rear end then go 240 don´t worry.

I am not paranoic saying that car will fly away. I just mentioned like chain is old and need replacing, and you didn´t know it - but your mechanics say "dont do it is still silent" same can happen if they test suspension and expect FIAT or AR part jumping up down when there is wear but it can fool them sometimes this old Mercedes...

Problem I know with component lower joint that holds each wheel at front axle lots of w201 had accidents not knowing they are defective - when gently tested they look OK because mechanics do not test them bruttaly like can happen to them in real speed and even more when braking or pithole.

So we test no more with half meter lever tool but with 1,2 meter forged lever long tool to see will it fall out or not. Because one friend had brutal accident with ball joint looked quite OK, just passed technical inspection with it and it fell out after that

New Lemförder or TRW in good shape will never complain to our test nor it will receive damage from our testing. Once changed I believe is 10 years normal driving without worries even more as 16v is weekend car for most.

Idle controller - yes you can make idle revs up down with black wheel.

About KAT/RüF big NO - Mercedes did not let customers play with switch (only authorised service stations) therefore it was plombed (secured with a temper evident wire) in place and can not be moved without damaging the security thing making it even instantly illegal in one way or another in Germany.

PS I bought CLK 230K Cabrio for fun last month, the older 192 variant not 197 but they say it has stronger lower end then 197 - a friend close to Mosselman got me a brand NEW Turbo cast iron manifold so because of him I purchased the car. And I have plans to go at least 300 HP maybe more with Turbo instead of Kompressor. So it is fun how you also had M111 K and are able to compare the two but my car will not be loud as Kompressor as Turbo is much more silent.

But after all 16v is more fun to drive as it is pure 80s charme, I agree completely.

I didn´t know you already exhanged all those things, it crossed my mind you just purchased unknown car and tested max speed on it. Therfore I said please dont untill you are completely sure that mechanics wont let you down.

And I think I understand it well, I don´t assume you a boy racer but grown gentlemen knowing what to do - otherwise you woudn´t be on our Forum and I wouldn´t be answering so many questions...

Bye,
Nikola.

[Marco]

Good afternoon Nikola

thanks for the "gentlemen" very kind of you

yes since when I bought the car some of the spare time is invested to keep it in the better conditions, the problem as we know is the time, would be easier to deliver the car to some very good mechanic, you "just" pay and are happy, but it's not so simple because if you want something done perfectly on these old ladies you have to study and do by your own or at least to study and look with your eyes what is done under your control, this is as I'm doing usually or at least I try.
Luckily hese are still very simple car, not so difficult to work and few electronic (just ECU and EZL), but some job requires gorilla's force or gorilla's tools, unfortunately I don't have both. I much prefer when there are precise job to do, like the rebuilt of the SLS pump, the removal of the thermostat housing to change the leaking o-ring behind, and so on, anything I can do when I have my time.

I've seen many pictures of the front lower joints, it can ends tragic, I remember when I bought the car and asked the first inspection at Mercedes, both inner ball joints had broken rubber protection, this is quite common problem...later I returned to complain because I discovered by my own that steering drag link had a certain play and I discovered it by my own turning the wheel up in the air with the floor jack...

One thing I can't identify properly is the "alluminium sheet" for the springs which component are you referring here?
yes in this way we will never end

have a nice evening
Best
Marco

[shaq]

HI Marco,

On W201 front spring can break because when paint is lost after years it corrodes so heavily that springs almost welds it self to lower arm.

Then by turning wheels when steering it simply chaps and cars fails down to remaining part of the spring.

So Mercedes demanded on Service points to put Aluminum crescents under first 1/4 of first coil to stop this from happening (part is called victim anode) on all the cars (Service ACTION) but most of w201 are not maintained by dealers anymore

PS there is German saying "if you want it perfect - you need to do it by yourself" and it is soooo true.

But doing it makes person very happy thats the thing and always there is something to learn IMO.

Bye,
Nikola.

[Marco]

Hi Nikola,
I think I never heard about this alluminium crescents, also in EPC I can see online I suppose they are not present.
But yes I saw some pictures of w124 and w201 especially in UK with front broken springs.
I removed so many times front spring to play with rubber pads there was no rust but regardless of this in this moment I’ve ended with Eibach springs, with thickest rubber pads. These was a separate discussion I opened for this then I discovered from another forum member that 2.5 16 had shortest spring at front but I’ve now these and to be honest I’m really happy how they work with rear SLS, very comfortable, I was concerned on this.
I just wanted a little lower, and I replaced in the past already the front shock absorber from Sachs and upper rubber mounting as well.
Have a nice day
Marco

[Marco]

Ciao Nikola
Sorry to push also this question, so I have these new set of spark plug sold me by Mercedes, they are Bosch H5DCO so thermal grade 5, they sold me these with my VIN where the new engine number is correctly associated. In theory from factory only ECE run with thermal grade 5.
Can I put these proposed by the dealer or can be too cold spark plug if I have RUF piston now…but still the much aggressive ECE ECU, and yes I use 100RON gasoline and EZL resistor 1.
I suppose they now in Mercedes but …you never know if they really know


Buona notte
Marco

[Marco]

Dear Nikola

Meanwhile I post here some outcome of my finding.

It’s clearly the ECE IACV valve I still have, I post pictures self explaining and I checked the PN also.
I confirm also that the connection from my previous picture belong to IACV.


Then the manifold, not possible to take picture it’s hidden below the first cylinder manifold but it’s not the code you got from your contact, it’s this: R 102 141 4401 not sure what does R means, why some OEM PN start with A and some with R? Do you know this curiosity?


I’ll post additional info I’m collecting and tomorrow the compressor testing probably.
Have a nice weekend
Marco

[shaq]

Buongiorno Marco,

It is as I predicted ECE engine ECU can only correctly control its own idle valve (3 pin) not the other one (2 pin from KAT / RuF). It is not problem one pin to disconnect but the fact that between them airflow and electrical characteristics (PWM versus opening angle) are totally different...

About Information from Mercedes they delivered KAT/RuF new engine for your car as a whole, with intake manifold, with exhaust manifold and with KE Injection in plače. They always do it like this if you buy complete engine and not half engine (without cylinder head) it is normal that during installation mechanics make only thing possible by keeping old ECE Manifold and Injection head of that car - as also airflow meter is different between ECE and non-ECE.

RuF/Kat Manifold of that new engine usually is not given to car owner but becomes property of Garage and spare part.

Mercedes as company has Quality control on everything and is not possible for them to deliver engine that is KAT/RuF, has lower compression pistons - but with ECE Manifold mounted on top, instead of correct for that Part No of engine - it’s KAT/RuF manifold belonging to it from Catalogue of spare parts.

I mean they look similar and pins are at the same place BUT electric characteristic of ECE Airflow meter and EHA valve are completely different to KAT/RuF. Seems that they either knew it or it was pure luck not to mount new KAT/RuF manifold. If they have missed it mount KAT/RuF airflow meter on ECE engine ECU engine would of stall and never accelerate correctly. I think during change of engines they got a HINT on that from Stuttgart because it is not Info everybody knows...

About spark plug H5DCO perfect choice - listen ECE and RuF are nearly the same combustion (therefore same spark plugs fit in those engines) and only KAT version of the same engine is different needing colder spark plugs. Why?

Only Compression of theoretical two Bar more (remember every engine is different coming out of same factory not every engine has new same compression therefore in catalogue they say “compression new 12-14 Bar” it is normal industrial tolerances in serial production of any merchandise) don’t heat spark plugs more BUT what can heat sparkplugs more is different camshaft or catalyst backpressure or hotter burning environment because of turbo/kompressor or different fuel like E85 or LPG or lean mixture of fuel and air. Understand?

Otherwise as every engine gets older and compression deteriorates with milleage you would need different type spark plugs every lets say 50.000km, OK?

And in real-world that is not the case as everybody knows!

Because ECE and RuF send exhaust gasses freely out of combustion chamber but KAT does not they are happy with hotter spar plugs.

For KAT car there is always backpressure from Pre-Cats and much higher thermal load on combustion chamber not just on exhaust valves. So it needs colder spark plugs. From this higher thermal load exhaust valves on KAT cars burn on contact surface and ECE/RuF cars don’t burn them (receive heat damage in form of small holes and imperfections)

I have experience with ECE after 250.000km exhaust valve seats were still like new at contact surface and another, the KAT one were already damaged surfaces after just 100.000km - please keep in mind that ECE exhaust valve seats are not bimetallic and of lower quality than KAT/RuF engines!

Therefore we have Forum advice - if you have Catalytic Converter and it has Main Cat under the car and two pre-Cats near exhaust manifold please remove them (precast) to protect your cylinder head and exhaust valve seats as soon as possible keeping only the main Catalyst converter (like Evo2 from factory)

KAT/RuF have Bimetal valve seats to make them more durable and are of much higher quality than factory ECE

But even that Hi Technology feature is not helping to overcome catalytic stress of close to manifold mounted pre-cats!

If cars consumes oil pre cats get clogged even sooner leading to Desaster!!!

This is the reason everybody love ECE or RuF, but RuF engines are more rare even than ECE!

So you are lucky having best of both worlds (same like my 2.5-16 RuF) - you have bimetallic valve seats on exhaust from factory but free flowing from exhaust that will never burn them like KAT do

PS if some Catalogue says for your car take H6DCO spark plugs not considering if you have Catalyst installed or not - that Catalogue is WRONG! Because even in Mercedes they were thinking back in 90s that owners of all RuF cars will convert them soon because of lower Tax, so to make it easy they say RUF or KAT engine we don’t care install same plugs as for KAT and Basta!

Che grande piacere per Motori nostri funziona senza Miseria di Catalizzatore
Saluti - N.

[Marco]

Ciao Nikola
Confermo, motori senza cat è un’altra vita
I did not know RUF are rarer than ECE in 2.3 range. Other strange fact is on this forum it looks more common 2.5 than 2.3, despite so lower production number, probably because many 2.3 have been used and abused without regrets till dead…

Very useful info on valve seat and spark plug correct choice, I please just want to correct one think, CAT has hotter spark plug not colder, H6DCO or equivalents are hotter than H5DCO or equivalent. Colder spark plug are usually for higher rev engine and higher combustion pressure so less risk of pre detonation, they dissipate better the heat at most critical condition but can have more dirt in combustion chamber at normal use, hotter spark plug help for cleaner combustion chamber but give more risk to pre detonation because of their hot.
But again it make a lot of sense your explanations why RUF and ECE are both very fine for H5DCO and Mercedes gave me exactly these.

About the manifold yes it’s very likely as you said, they called Stuttgart and be advised to remove the RUF manifold so they can use ECE ECU and ECE fuel distributor and all I still have completely from ECE. There is one formal think that still does not match to me:

car left factory with ECE intake manifold:
PN: A102 141 31 01

But I have now intake manifold:
PN: R 102 141 4401

Assuming it’s still an ECE part number (for the 3 pin IACV) it has a different number so either they ordered a third manifold and give back original with the original engine or there is something else we can’t discover
This is just for the pleasure to discuss and investigate not changing much on the outcome we already discovered with your help!

I paste separately some pictures of distributor, contacts and HV coil I carefully checked yesterday

Grazie

[Marco]

Here we go, as you recommend I didn’t change anything and all cables and parts looks very fine, cabling are Beru parts with Mercedes part number also.

I’m not sure if this means something but old HV coil has 8,2kOhm vs new bosh I measured 10,5kOhm, according EZL chapter from my US manual supplement to engine 102.983 the range is 7-13kOhm

Tomorrow I’ll check which Beru spark plug I have and in case replace with H5DCO I have bought. If what I have are Beru not resistive copper spark plug with proper thermal grade 5 I’ll keep because they have only 10000km.

What do you think about the contacts in the distributor cap and the rotor? I don’t have much experience here but I’d say they are not bad, this time it’s me that propose to not change them


Buona notte

[shaq]

Ciao Nikola
Confermo, motori senza cat è un’altra vita
I did not know RUF are rarer than ECE in 2.3 range. Other strange fact is on this forum it looks more common 2.5 than 2.3, despite so lower production number, probably because many 2.3 have been used and abused without regrets till dead…

Very useful info on valve seat and spark plug correct choice, I please just want to correct one think, CAT has hotter spark plug not colder, H6DCO or equivalents are hotter than H5DCO or equivalent. Colder spark plug are usually for higher rev engine and higher combustion pressure so less risk of pre detonation, they dissipate better the heat at most critical condition but can have more dirt in combustion chamber at normal use, hotter spark plug help for cleaner combustion chamber but give more risk to pre detonation because of their hot.
But again it make a lot of sense your explanations why RUF and ECE are both very fine for H5DCO and Mercedes gave me exactly these.

About the manifold yes it’s very likely as you said, they called Stuttgart and be advised to remove the RUF manifold so they can use ECE ECU and ECE fuel distributor and all I still have completely from ECE. There is one formal think that still does not match to me:

car left factory with ECE intake manifold:
PN: A102 141 31 01

But I have now intake manifold:
PN: R 102 141 4401

Grazie

Hi Marco,

Yes you are right - I was wrong about what is called hotter and what colder spark plug in spark plug theory as I was never discussing those characteristics before with anybody. In my had I related cold spark plug with colder burning environment and it is another way around cold spark plug is made for hotter enviroment, it is called cold because it cooles more quickly.

But I know from praxis what spark plug to use based on air gap inside on which engine (gap inside housing not electrodes gap), larger air gap inside body of spark plug and it will heat more and smaller gap is for hotter burning environment because it disipates heat more quickly into cylinder head - because that is the thing I see when I look into the (cleaned) spark plug

When I see lot of residue means spark needs larger gap inside housing, inside hole around central electrode to be able to self-clean, self-burn it. On the other way I never had problem of self-ignition or burning of electrodes when I experimented with spark plugs with big gap around electrode. Theory is one thing, praxis another. Only what I witnessed on LPG 2.0 when it needs a colder plug (too big air gap) it will consume middle electrode more quickly, gap will increase by itself and once gap becomes too big you will clearly hear misfiring or valves rattling especially on cold(er) engine

My conclusion from my praxis, wrong thermal value means spark plug will not last 50,000 but max 20.000km nothing else. no big deal

About 2.3 or 2.5 - in Germany I think everything is much more related to tax reasons, as RüF is very expensive in terms of taxes and Germans are practical people so they rather choose to install catalyst on them or sell them for export. About 2.5 RuF I think they were mostly made when new ONLY for export to like France, Italy BUT in Germany nearly all 2.5 were sold as KAT therefore they are so rare today. I saw few RuF 2.5 for sale in Germany and it always says something like "reimported from France or some Spanish island"

Also about 2.3 or 2.5 - praxis showed that 2.5 had better rust protection from factory than 2.3 so it is quite rare to find used 2.3 that was driven as daily and free from rust in northern Europe because salt killed them. But again, Italy or Spain climatic saved many 2.3s - there are still perfect examples of 2.3 in south Europe even if many were re-imported to Germany in recent years.

Also in 80s some towns in Germany had ACID RAINS because of heavy industry. Some not all, and some regions more than another, more agricultural regions or regions with more wind were less inflicted or not at all. You can google it but there were towns where not just salt in winter was a problem but during sommer months rain was so acidic that it has same pH as lemon!!! It make lots of 2.3 rust even more, can you imagine something rosting 365 days a year... 2.5 16 was more lucky because when it was released ecology was already fighting the acid rains so it is quite rare to find 2.5 killed buy rust and also quite rare to find 2.3 that is not

I did myself restoration of two 2.3 16 and it is real pain with rust. Engine can be restored in one week if you are an expert - but for rust-free Body it takes one year or two to do it correctly. On some is even impossible if structural parts are damaged - is all a big secret and big problem and a lot of work - economically not feasable at all. Always better idea to buy another car in South Erope altouhg paint will mostly be killed and interior too - from the sun heat and UV, but paint is easily restored and rust not.

It is exactly same thing as importing car from Texas or California. Killed by the sun but rust-free. Than standard procedure - repaint it, put new leather seats it is all much easier than fight with rust everywhere for years and never win this fight.

Answer to your question about manifolds - it may sound strange but Mercedes changes Part Nos. quite often. Also on 2.5 16 if you check Cylinder Head in Catalogue it is one part number that you will not find on actual manifold. On manifold there are two part numbers engraved, one on upper part and one, different under manifold collector.

First part catalogs were not electronic but Microfilms. There was everything documented but then transfering information to electronic parts catalogue EPC then to newer version VEDOC in the begining they described with footnote which was which and later just let it go. Today I know how to track it but even if I call Mercedes today they will give me actual Part No nothing more as in new VEDOC software they are unable to track changes since production.

I assume in your case they didn-t change manifold at new engine - but just changed idle valve with its hoses and Injection head. Because castings are the same I think. New part No is related to new type idle valve IMO. Because exchanging manifolds is lot more work and gaskets get damaged, they need to order new gaskets etc. so I think they did it an easy way.

About distributor cap, yes they all look like that. Use sand paper 600 and polish to high gloss end of distributor arm. Try to polish out holes. And cap those graphite inside on contacts is only thing that gets damaged over time from sparks jumping inside. If holes are big and lot of graphite burned out exchange it. If not keep it and exchange later.

Ciao,
Nikola.

[Marco]

Hi Nikola,

ok, if in the future I have to choose between a roasted car from Texas or central Africa and a rusted exemplar the first is easier to restore

about the manifold I know what you mean, at the beginning I was looking for the PM on the 4th cylinder manifld, but I can ensure there is nothing I found ony the one below the 1st cylinder manifold, I remain with this unsolved point I tried to search with this PN R 102 141 4401 (different PN from the supplied new manifold wiht new engine) but found nothing, if the ECE IACV seat on this, I guess this is an ECE part number as well.

I've been told that would be better to find and use the original part number catalogue, but I also understood this would require a dedicated old computer to have it on....

Thanks for input to use sand paper to polish the distributor cap and distributor arm, may be I'll do next time, as you are an electronic guy any comment on the different resistance values between old and new HV coil? 8,2 vs 10,5 kOhm

Now the completion I promised, tested today cylinder compression, warm engine, full throttle, from first to fourth cylinder:
- 11,5 bar
- 11,9 bar
- 11,6 bar
- 12,2 bar
I think this is confirmation I've still a healty RUF engine with benefit of full ECE management (injection, ECU, EZL).

I've now in hands the chain (Febi) and next job is this with valve clearances check, may be compressions will be more equal after the valve job, is this possible by your experience? More important where can I buy these kavasaki shims kit? So I can have it ready instead to measure the clearance and then just find and order in Mercedes the single shim I may need...and for sure they will return me "sorry Sir not available the desired shim"

I found Beru 14K-6DU so thermal grade 6, not bad assuming a generic mechanic installed these knowing nothing about the car…and one of the screwed connector above the spark plug was missing!!!! Can’t understand how it worked, but I've put now fresh Bosch H5DCO thermal grade 5, ok they had only 10000km but from the picture combustion looks fine, what do you think?

grazie
Marco