Mercedes-Benz Forum banner

1 - 20 of 29 Posts

·
Registered
Joined
·
1,218 Posts
Discussion Starter #1
So here is the story, the car has covered about 600 miles since its 3 year body restoration. Since there was a misfire on cylinder 1 before I put the car back on the road (oiled plug), I replaced the plug and just cleaned up the others. I did a compression test at the start of the year and the results all looked fairly good. This is what they now look like, what are your thoughts? I've never seen a plug like this before.




Cylinder 1
2604020


Cylinder 2
2604021


Cylinder 3
2604022


Cylinder 4
2604023


Cylinder 5
2604024


Cylinder 6
2604025


Cylinder 7
2604026


Cylinder 8
2604027
 

·
Registered
Joined
·
28 Posts
#1 looks like a combination of oil and lead fouling. Do you use a fuel additive? The others also look like they are affected by lead or an octane additive.
 

·
Registered
Joined
·
7 Posts
So here is the story, the car has covered about 600 miles since its 3 year body restoration. Since there was a misfire on cylinder 1 before I put the car back on the road (oiled plug), I replaced the plug and just cleaned up the others. I did a compression test at the start of the year and the results all looked fairly good. This is what they now look like, what are your thoughts? I've never
So here is the story, the car has covered about 600 miles since its 3 year body restoration. Since there was a misfire on cylinder 1 before I put the car back on the road (oiled plug), I replaced the plug and just cleaned up the others. I did a compression test at the start of the year and the results all looked fairly good. This is what they now look like, what are your thoughts? I've never seen a plug like this before.




Cylinder 1
View attachment 2604020

Cylinder 2
View attachment 2604021

Cylinder 3
View attachment 2604022

Cylinder 4
View attachment 2604023

Cylinder 5
View attachment 2604024

Cylinder 6
View attachment 2604025

Cylinder 7
View attachment 2604026

Cylinder 8
View attachment 2604027
Here's what I would do. I'd buy new plugs plus one plug that's "hotter" than the others. That is to say the electrode is longer and runs hotter. I'd put a tiny amount of anti-seize on the threads and put in the new ones. If number one fouls again, I'd install the hotter plug. Number one is telling you a story. It is way different than the others and not in a good way. I wonder if the valve stem seal on number one intake is kerplooie.
 

·
Registered
Joined
·
2,745 Posts
Before you do all the other have suggested, run the engine as hot as it gets, spray some carby cleaner in the throat and make WOT at the same time until it chokes and dies. Leave it for a minute, rinse and repeat.

My 450 changed the tune significantly after I emptied 2 cans in the throat and it improved burn up.
It will not fix your problem but it may reduce it by a lot as the net gain is that the valve seats will be cleaner and close better.

Long time ago I had a Mazda that made 1 plug the same way. It was combination of big mileage (400t k's) and valve stems. It did consume oil about 0.5L/1000 km's but it went well.
Because it idled perfectly I presumed it must have been valve stems wear difference that made this plug foul. It would foul abit quicker if driven irregularly or short distances, but freeway run would make it last 10t k's.
 

·
Registered
Joined
·
1,218 Posts
Discussion Starter #6
I almost forgot about this, cylinder 1 inlet valve guide is lose in the head, I came across this when changing the valve stem seals. Perhaps I should try peening and gluing with high temp loctite as suggested by rick back at the time.

2604052
 

·
Registered
Joined
·
2,745 Posts
It would be interesting to know if adhesive can be successful where two dissimilar metals heat and cool at different rates.
I successfully used yellow loctite on almost no interference bearing mount and it lasted well but temp change was minimal and it was very similar hardened steel materials.
Perhaps you can increase interference with roughening the surface in a pattern shape (sorry, not familiar with the term for this - in English)
 

·
Registered
Joined
·
1,218 Posts
Discussion Starter #8 (Edited)
I've been searching through the Loctite website looking for a suitable adhesive, not easy. I have primarily been looking for high temp bearing retainers, as I am sure the guides must get very hot, 620 is good for 200 degC.


My plan is to buy an new guide and an oversized guide and see which one fits best, light peening or knuling should help to retain if the glue fails.

I was searching through the new "EPC" to find the p/n for the valve guides but cant find them, anyone know what page they are on?
 

·
Premium Member
Joined
·
9,894 Posts
On my E320, I used a sealant/adhesive on the rocker/breather covers. Mercedes have a product for this, but I used an equivalent. It is good for 250C (300C max). Do you think that area would ever get that hot? The block doesn't get much over 100C.

Most of the sealants/adhesives are not rated for use with synthetic oils. But this one is :


Not saying this is right for your application, but it may be.

JB-WEld have a product called Extreme Heat - apparently good at very high temperatures!

Maybe you need something that is more liquid? Maybe this one?
 

·
Registered
Joined
·
1,218 Posts
Discussion Starter #10
Thanks for the suggestions, I had seen 2620 and considered that one but then discounted it as its a thread sealer rather than a sleeve sealer, but not being a mechanical engineer I'm not sure if it matters.

As for the temp, I have no idea but as its in contact with the valve, I guessed it must get pretty hot.

The new "epc" is a pain, it doesn't correlate part numbers to chassis numbers. Is there an old version available anywhere?

2604093
 

·
Premium Member
Joined
·
9,894 Posts
I have an epc that might work. If you send me the VIN and model number, I will give it a try.

I have used Loctite on things like roll pins. It worked well. More or less acting as an adhesive, but also thin sealant.
 

·
Premium Member
Joined
·
9,894 Posts
EPC shows same parts for all 044 450SLs with 982 engine. Does have some different sizes of guides. This may be the same as you already posted?
I am having trouble moving epc output from virtual machine. Will try and see what is wrong. For now, this is basically what it said for intake valve guides.

----- A 116 050 35 24 . VALVE GUIDE
. Replaced by: A 116 050 36 24
-
----- A 116 050 36 24 . VALVE GUIDE. INTAKE
. [067, 006] NO LONGER AVAILABLE,INSTAED 116 050 36 24
-
11 A 116 050 36 24 . VALVE GUIDE. INTAKE,REPAIR SIZE I
. [007] 14.043-050 MM

11 A 116 050 37 24 . VALVE GUIDE. Replaced by: A 116 050 49 24
. +001 A 110 053 02 58
-
11 A 116 050 49 24 . VALVE GUIDE. INTAKE;REPAIR SIZE II 14.20 MM
11 A 116 050 38 24 . VALVE GUIDE
. Replaced by: A 116 050 50 24
. +001 A 110 053 02 58
-
11 A 116 050 50 24 . VALVE GUIDE. INTAKE,REPAIR SIZE III 14.40 MM
 

·
Registered
Joined
·
1,218 Posts
Discussion Starter #14
Thanks, yes that is basically the same, so the std part id 1160503624 and is nla, Pelican parts lists the correct part as 1160504724 as do the SLSHOP etc, seems odd that it is not shown above though.
 

·
Premium Member
Joined
·
9,894 Posts
Thanks, yes that is basically the same, so the std part id 1160503624 and is nla, Pelican parts lists the correct part as 1160504724 as do the SLSHOP etc, seems odd that it is not shown above though.
I looked up 1160504724 on my epc ( just a few years out of date) and it shows that that part is for the 5.0 and 5.6L engines. Doesn't include 982 in list of engines!
Checked at ECS Tuning, and they don't list 450sL as car that this part fits. However rmeuropean lists 1160504724 as standard and 1160504924 as the first oversize.
It's all a bit confusing!

Anyway - back to putting W123 back together (after rust touch-ups)
 

·
R/C107 Moderator
Joined
·
31,604 Posts
I don't know but to further confuse here is another EPC version list.
117.985 Valve Guides.png
 
1 - 20 of 29 Posts
Top