Spark Plug Horror! Look!
 

Looking for our hot misfire on my sons 88 300TE.
Car has done 67,900 miles.
I put these plugs in new about 2500 miles ago.
Oil was changed just before that, and has been changed again last week.
The car is loosing oil, but we thought it is mainly leaking from the pan gasket.
Coolant was changed when we did the leaking radiator... 100 miles ago. We used the correct Zerex clear stuff, and the level has not moved since.
we use 91 ron gas, and we did pull the ignition timing resistor yesterday, to see if it made any difference. It didnt.
I planned to do a compression test this morning...
I pulled these plug about 5 mins ago...
We started the car from cold... drove it into the garage and pulled the plugs.

I was stunned by the condition of the #1 plug... enlarged pic below. Plugs are in order... left #6 to #1 on right.
Duty cycle was set to about 45% last time I did it about 2000 miles ago... it was about 70% before.

http://img.photobucket.com/albums/v2.../dad/Plugs.jpg

http://img.photobucket.com/albums/v2.../dad/plug1.jpg

I will do a compression test now and post when we are done.
I will clean the plugs up and check the duty cycle again.

What the hell are those deposits????
I have never ever seen anything like that before!

Ideas?

Yeah, you need valve stem seals, and badly. Possibly guides to, but you're at pretty low miles to need them. Fairly low for the seals too, but it's old enough that the seals have probably hardened over time.
Gilly

the resistor style plug isn't helping your cause any either.. Get some proper non-resisotr plugs (NGK, Beru, even champion if you must..).

But yes, VGS look to be in order given the overall low mileage.

What weight oil are you running? If you're not running 20/50 (Dino) I would switch.

Jonathan

I can see the misfire on # 1 for sure ( bridged gap ).
That greyish fluffy-looking stuff, is ashes that are left over after the burn.
Conventional oil used?
Of course " Gilly " is right about the valve guide seals.
AGE is the killer of them, so is not running the engine, as for example on vehicles that are store for extended periods of time.

Manny, can you do me a favor and drop the quotation marks around my user name? It's just my nickname. Tanks
Gilly

Thanks Guys!
I guessed it was oil being burned!
The plugs were bought from Phil!
Did we get the wrong ones?

Oil was 5/30, but we put in 20/50 this time.

Ok we just did a compression test with my Craftsman good quality gauge.
1/ 180
2/ 180
3/ 185
4/ 185
5/ 195
6/ 190

Would the oil leakage past the seals account for the hot misfire?

yes no doubt about it classic case of screwed up valve stem seals.replace them and the plugs and the car will run like new.

i wonder if it is DIY job to replace stem valve on engine 103 and how much it would cost at good shop. i have the same problem on my 1986 300E.

Well, now we know!

We did put 20/50 in this time, so that should help until we can get to it.
Is there any risk in leaving it for a month or so?

I saw that the stem seals can be done without pulling the head.
We seem to have a coolant weep from the back of the head, so I guess it would be best to replace the headgasket and all at once.
Anything else that you guys think we should cover if the head comes off?
Where can I find out if the valve guides will need doing ... is it obvious?

you will not need to pull the head at your mileage.you need very special tools to do this job so not diy.should cost about 500 including parts.

Valve Seals
 

1984 300d Turbo 140,000
I Did A Valve Stem Seals With A Kit $75.00 On A 5 Cyl Deisel 8 Hrs
Guide Book, Push On Tool, 5 Extra Lock Nuts, 10 Seals, Plastic Covers For Valve Stems, Oil Seals Overnight No More Smoke, Move Ea Cyl To Top Positon Then Replace The Camshaft,$175.00 Rockers $280.00 , Camshaft ,4Bearing Towers $150.00 Adjust Valves,diy

Best/easiest way to do the 103 valve stems seals is to use compressed air to hold the valves up, but there is a fairly specialized tool normally used to compress the springs. I imagine a little ingenuity would go a long ways to getting this done, any thing you could come up with to compress the springs with the head on. Might need a failry large tank compressor, although once the cylinder is pressurized it shouldn't take too much to keep it under pressure. There are ways to get around this that I'd heard of too, such as feeding rope into the cylinder with the piston down, the bringing the piston up until it won't turn any more, then removing the springs. Amything to keep from letting the valve drop into the chamber.
You are OK to drive it this way.
If your coolant leak is on the left (drivers) side rear, it may be an o-ring, the part that the heater hose attaches to has an o-ring around it and these often get brittle and crack and cause a coolant leak. Sometimes the leak follows the angle to the right and will drip off the right side of the rear of the block. Be sure of where the leak is from. Should take less time than Raymonds diesel.
Gilly

Thanks Gilly,
Do those Engine compression reading look about right to you and balanced enough??
The coolant leak looks to be off the back of the head on the passenger side under #6 exhaust bolts. I have looked on the other side and it looks ok, but I have been wrong before!:D .

I have a 5hp 50g tank compressor that will do 90psi easy.

I could knock the porcelin out of one of those Resister plugs, and get our fabricator at work to TIG a length of pipe and air hose fitting to it. Would that work?

Compression reading look great.
To pressurize, if you want to go the route you mentioned that would work, then just come up with a coupler to attach your compressor too. If you have a compression tester (with a quick release coupling) or cylinder leakdown tester you should be able to make either one of those work, we always just used a leakdown tester, works fine with no modifications.
If you have a pressure tester, test the coolant leak with a stone-cold engine, and watch the drivers side of the block near the oil filter for drips coming from under that heater hose down onto the block, then the drip runs down the back of the head and down the other side of the block, really sounds like the classic "heater hose nipple o-ring" leak, very confusing as it drips on the other side of the engine.
Gilly

Do the seals. All my plugs looked like your worst one, and I've got more than twice your mileage. I went from a quart of oil every 300 +/- miles to nearly 3000 miles. The valve seals are very DIY. A universal valve spring tool is all you need. Don't have compressed air to pressureize the cylinders? Put a length of thin rope in through the spark plug hole and turn the engine by hand to hold the valves in place. I suggest using a replacement lawnmower start cord. It's the right size, costs only a few bucks, and has a handle on one end so you can't accidentially lose the other end of the rope in the cylinder.

If you decide to pull the head, then you might as well do the valve guides at the same time, though I doubt they're already shot.

EDIT: Letting the job go for a while is probably not a good idea. Oil through the engine and out the exhaust will eventually kill the catalytic converter. Leaving it for a few miles should be OK. IIRC, I did about 1000 miles between the time I replaced the converter and when I did the seals. Still passes emissions.

Thanks guys!
I planned to buy a leakdown tester anyway, it on my Christmas list, but why wait? :)

I will pressurise the cooling system when cold and see where its leaking. Last time I looked it was the radiator! Done that now!
Next!

If it ( the leak) is coming from the heater hose, it's pretty DIY too. It helps to remove the air filter assm and the oil filter. You'll see the engine lifting hook back there, you'll see the one allen-head holding that on, and there is also one UNDER the part the hose attaches to, called the heater hose nipple. The nipple is all one piece with that lifting hook. Don;t even bother removing the clamp for the heater hose. Just get the 2 allens off and the nipple part will remove from the block. The part that engages into the block has a grey o-ring on it, which is available separately. I'd consider getting the MB part for this.
Gilly

Thanks Gilly,

I think I've got exactly the same leak on my 86'. Heck, maybe I should do the valve seals also- 95k miles. Lot easier on my time than a valve job.


Michael

IMHO the replacement of the valve stem seals don't really have a bearing on the guides. If anything the oil going past the seals might actually extend the life of the guides, but then you have to live with the crappy plugs and oil consumption, so not a good trade-off. I'd replace the stem seals if you have driveability concerns or oil consumption related to them.
Gilly

Thanks Gilly.
We drove the car a bit after cleaning up the plugs.
I will try to get the non resister plugs this week.
At first it ran really nice, then when the temp gauge got to 85/90, it started to misfire agin.
I felt that changing to 20/50 might help it run better, but it seem as bad as before.
I saw in my MB CD, that the usa/cal cars should have the Duty cycle set to 35% to 45%. I knew that last time I set it to 45/50, and when I checked it today, thats what it was. I tweeked it down to about 40% and its close to that at 2500rpm too.

Do you think the misfire we have is just the bad oil seals, and have you seen this before or am I just thinking wishfully that the seals will cure it.

VERY common on the 103
Gilly

Oh my!! :eek: :) I do not think I have seen spark plugs do that before. Looks like something I would want to scrape off of there posthaste. :D


Good luck to you and yours.

Yeah!
I think you can see from the thread header... I was in shock!
We swapped back the plugs for the champions that were in there when we got it until we can get the correct non resisters.

Link to valve stem seal DIY article for M103 below.
http://www.peachparts.com/Wikka/M103ValveSeals

Hey Gilly, does it have to be a special German rope?:D

I learned something today! I never heard of the rope trick, but that is great if no air is available. I suspect once at the point of the rope holding the valves up, you'd want to lock the crank in place somehow, so it won't rotate.
Thanks Gilly!

Yah special German hanging rope or maybe some Shania Twine.
Gilly

Jeez...
All fed up now!
Cant find the correct plugs anywhere.
Even NGK dont have non resister anymore!

Maybe someone can tell me how I will know if the guides are toast?

Hey, I'm as traditional as they come and would LOVE to see non-resistors available. Bottom line is you NEED valve stem seals, those plugs aren't CAUSING this. Just buy whatever is "currently" correct, whether or not it is technically correct. Replace the stem seals and move on.

Gilly

Oh, on the guides you just "wiggle" the stem to check for looseness. At your mileage I doubt they are worn. To be nuts-on accurate you use a dial indicator and find out how much play there is. In other words you wiggle them just as I am suggesting but measure the results, not just a "general feel".
Gilly

Thanks Gilly,
I plan to do these stem seals in a couple of weeks. Up to my elbows in my Jeep waterpump and now it looks like I have a shot A/C clutch bearing and idler too!:rolleyes:

I was just looking for the correct plugs in the hope that it would help the plug fouling and make the car run smoother in the meantime.

Getting ready to do the seals on my daughter's M103 soon here. I've never seen an acceptable number for "wiggle" for checking guide wear though. Assuming this would measure play at the top of the valve, correct?

Anyone have numbers??

TIA, Joe

How many miles on the car? Anything past 150K and they'll be loose. Past 200 and they'll be shot.

Jonathan

This is just by interpretation of new values and critical limits: new is was about .030mm, critical limit would be out around .050mm (not inches!)
Gilly

Valve Stem Seals
 

Hello,

I'm not sure but I think I remember reading about valve stem seals in that engine being problematic. I think MB replaced some of the early ones under warranty. Does the name Viton sound familar....just guessing.

The Tenor Man

P.S. That mileage sounds awfully low for that year...hmmm.

Right mileage is low, but older car. The seal material hardens with age and then they don't seal very well.
Gilly

Interesting....
I stated that the oil had been changed to 20/50 and sure enough the oil consumption went from a quart every 300 or so to a quart in about 1500 miles.
After my last post I did a 1300 mile trip to the Bay area from OC.
I set off from Orange County and the car was running rough.
Frustrated, I stopped in at a local Kagen Autoparts and grabs some new plug, and put them in ... the only had Bosche platinum 2's.
It didnt make much difference and the car grumbled and misfired all the way to Monterey......... It still did 21 mpg and I did that leg of the trip on one tank... 380 miles!
Here is where in got interesting...
As I said the car was a little unhappy all the way. When I stopped for gas, it refused to restart straight away. I spun the starter 3 times and it would not catch, on the 4th attempt I gave it a little gas, and it started but stalled as soon as I let it drop to idle. 5th attempt I kept it at 2000rpm for about 20 secs, then let it idle... it didnt stall, and I drove off. It continued as before grumbling and misfiring until I stopped for the night soon after.
Next morning it started instantly!
It grumbled until it was warm, then it ran PERFECTLY all day!
So for the next few days, that was how it was.... bad on startup and perfect when warm..
Driving around San Francisco in traffic, on a warm day it didnt miss a beat.
The only thing I did notice was a that the SRS light was flashing now and again.

When I got home it was running great!
I thought it would stay that way.... but now its running really bad again!
We checked the Voltage Regulator bushes, just for fun, and they looked fine.
Any other ideas?

Check the OVP fuse
Gilly

Checked the fuses... look fine. OVP is about 2 months old.

Is it possible that the temp sensor is bad?

Could be but wouldn't explain the SRS light, which I believe the OVP might. Good call on the voltage regulator brushes, might want to have the charging system and battery checked and think about checking or just replacing the OVP relay.
Gilly

I did my search on the SRS light and so that was why I did check the VR brushes.
I am less worried about the SRS light for now... maybe its a bad contact on the steering wheel.
Felt that the VR brushes might be the culprit for other stuff tho!

I will do a search on the Temp sensor.

Here we are again!
Just finally got around to doing the valve stem seals...
Look at the condition of the engine inside!
Now almost 19 years old and has 72,000 miles on!
Awesome!

http://i135.photobucket.com/albums/q...alveSea2lE.jpg

http://i135.photobucket.com/albums/q...ValveSealE.jpg

http://i135.photobucket.com/albums/q...alveSea1lE.jpg

The job took us about 5 hours going slowly. The old seals were soooo hard!
Funny thing was that the old seals were brown on the Exhaust valves and black on the inlets... and the new ones were the opposite... and yes, we did check the sizes and fitted the correct ones on the correct valves!

Sadly the misfire is still there, as bad as ever.:confused:
We put in new Champion plugs, but we finally got some Non-Resistor style and the will be here next week.
I am really frustrated with tracking this silly misfire down.
Any more ideas????

Those images are beautiful. I look forward to the day that I can get my 2.3 liter 190E to stop the oil leaks. Your engine is stunning.

My engine has never been cleaned. I've only owned it a little over a month.

Bruce

Thanks Homer!
We have not cleaned it, or only a little rinse to get rid of the grit and grime before we opened her up. It was the inside that stunned me. We bought this car for $3000 with 64,000 miles about a year ago. No history really, and I have never seen an engine that clean inside!

Ok, here is the real update!
I think we have the misfire figured out....
Today after my son got home he said it was running worse than ever.
I pulled the plugs just to see if they were looking black or something. They all looked light grey as they should. I reinstalled them and it was then I did something from an old past memory. I grabbed a pair of insulated pliers and pulled the plug leads off one at a time, just to see if I could isolate the misfire to one cylinder or another.
It was very noticable that when #1 was pulled there was NO clicking as the plug boot was pulled up!
I stopped the engine and grabbed an old plug, inserted it in the lead and held it against the head. The spark was weak and inconsistant.
I pulled lead #1 out and grabbed my multimeter. Guess what.... it read OL or open... no connection!
I swapped it for an old Jeep one I had in the garage.... BINGO!
No misfire!
I dont believe it!
The leads are BERU and according to the receipt from the PO they are 18 months old!
Maybe that is it, but we need to get some new leads before we are sure!

Car is running better than ever. It seems that the recent problems were a bad #1 plug lead. Most probably caused by pulling the plugs out every 500 miles and cleaning them!
Oh, also for everyones info here is the valve spring compressor we used for the job. It worked fine, even in the area of #5 and #6 cylinders where there is no room. You reverse the lever end and push up on the bar instead of down.
This item is much cheaper than the official tool and I can only say it worked great!
http://i135.photobucket.com/albums/q...prnigCompE.jpg

I didn't make comment before but the seals were so hard you couldn't squash them... like hard plastic!
We looked at the valve side clearances too and it was barely noticable side play.

I will report back on the oil consumpsion.... it was running at about 1 quart per 500 miles!

if those are the good leads, they might be damaged and not worn out.

i would consider just changing the known bad one with the parts kit from mb.

tom w

That's a nice kit. Who makes/sells it?
Congrats on job well done.

The spring compressor was off Ebay... I looked and the same one is marketed under a few names. Kinetic, or Schley or JTC, but all the same.
I think I paid about $50.
The two black towers fit on two of the cam towers, and the long bar goes in to them to act as a leverage point. We used the holes either side of the center. The red handled lever arm goes under this bar and the spring hold down goes in the first of the 5 holes. It works great!
The best moment was when we realised that you cant pull down on the exhaust valve springs on #5 & 6 because of the firewall/battery tray area.
We reversed the spring holder into the hole right on the opposite end and pushed up to compress the spring. You have to be strong tho!

So we did the Stem seals but the misfire was still occuring.

After some testing with my dad (Merkey) we established that there was no electrical connection on the ignition wire #1 and so we used a makeshift spark plug from one laying around and the misfires instantly were reduced to a small shake.

So we thought that this was the problem all along and the last few misfires were most likely coming from the other plugs.

So today I purchased a brand new set of Bosch Ignition leads and hooked them all up and the misfire is still there....GRR!!!

Also, on spark plug #4, I can hear ticking, or the spark...so we were thinking and it could have been possible that we mixed up one of the small little metal things on top of the valve's when we replaced the stem seals, because I know that we mixed them up (they looked identical so we just guessed it would be ok)

http://i135.photobucket.com/albums/q...alveSea1lE.jpg
^I dont know the name of it....its silver and is between the clamp and the valve. You can see a shine from it in the picture....thats the thing.

Grrr...Could the last misfire be coming from that ticking spark plug #4? Could the distributor be a possible problem?

Also on a side note, 2 weeks after doing the stem seals, I checked the spark plugs and there is 0 deposit :) So the job was successful.

the valve retainer? a tapered thing in two halves?

tom w

No, the valve shim directly under the rocker ball that bears on the valve tip.
Am I correct in saying that the valves have hydraulic lifters and therefor need no adjustment?