Exhaust manifold removal tips and tricks - assembly problem!

[jameshoward]

Thanks to everyone who very kindly got in touch about the exhaust manifold. Mine finally arrived last week from the US.

I hope to be able to replace my broken rear one in a few weeks, work dependent, and wondered if there are any funnies I should be aware of.

Grateful for any pointers if anyone has completed this job previously.

Thanks.

JH

[Cees Klumper]

Good to hear James. The only thing to watch out for is separating the manifold from the pipe, and hopefully the nuts will come off easy from the studs going into the head. The bolts/nuts on the manifold/pipe connection are difficult to get to, I used several extensions. You may want to get one or two new gaskets for that connection as well, and new nuts and bolts would't hurt either. Good luck, should be an hour's job.

[ja17]

Hello James,

Yes, I also use a long extension, with a 14mm flex socket at the end for the manifold/head  nuts. With this arrangement you can unfasten a lot of the nuts from the top once the heat shield is removed. You may have some difficulty separating the front pipe from your broken manifold, as they do get badly stuck together at times. In your case you can use a large hammer vigorously to loosen things up since your manifold is already  broken. Get a new intake manifold gasket, the two crush rings at the front pipe/manifold connection and six new bolts and lock nuts for the connection. Some like to use new manifold/head lock nuts but I find they can be re-used in most circumstances. Lastly I coat the ends of the front pipes with silicone sealer (its slippery and helps everything slide together and mate-up nicely). The new crush rings make the seal but the silicone probably helps a bit also. No sealer is needed with the new gasket at the head. Tighten up the six manifold/ front pipe bolts and nuts evenly  moving back and fourth so as not to over-stress the brittle cast iron (it can break). Don't be surprised if you have to come back and snug these up in the future as things seat and loosen during the first few heat cycles of the connection.

[ctaylor738]

In my experience, this goes a lot better if you take an extra few minutes and remove the intake manifold.

And, have three 12mm box-end wrenches and position them on the nuts that hold the manifold to the down-pipe.  Then go under the car with your ratchet and extension.  That way you can undo all three bolts without crawling back out from under.

[jameshoward]

Joe, Chuck, Cees,

Thanks for your replies, that's really helpful. I knew about getting new nuts and washers thanks to the usual top advice from Naj, but had no clue there are gaskets and crush rings in there. I will try to get on the EPC to take a look.

Many thanks,

James

[jameshoward]

Today was the day. I have sprayed the manifold nuts and studs every day with Plus Gas (which is absolutely brilliant stuff - no idea where I'd be without it). Everything came apart so easily.

However, I don't really understand the employment of the various washers, especially an odd 'wavy' washer. The EPC is little use, as it has the wrong quantities in it, but it says I need 3 of these washers (picture attached). Problem is, I have no idea where they go. When I took everything off my car, the 3 wavy washers were all together on the front-most stud (the one closest to the can). Whilst this could be correct, it doesn't seem right. Can anyone please advice?

Also, the EPC doesn't show any washers on the bolts that join the manifold to the downpipes. Should I use a washer here? Grateful for the advice. I'm a bit stuck anyway, because I have the wrong gasket, it seems. So there'll be a delay whilst the right one comes. (Anyone know what car the gasket is from?)

Thanks.

James

[Benz Dr.]

Are those wavy washers 13mm? If they are, they're probably for the down pipe screws.  However, the nuts used are self locking so washers are of less importance.

That intake manifold gasket looks to be from an earlier non fuel injected engine. Possibly a 220S.

[jameshoward]

Thanks, Dan. So you think downpipes to manifold? I don't have the parts at home, but I'll measure them tomorrow and check. Not being Sherlock Holmes, I can't help but wonder why I have 7 washers, and 8 nuts, and three wavy washers on the front-most stud. The EPC says I need 3 wavy washers, but for the exhaust downpipe I'd need 6 (3 for each manifold).

I had a look through one of my BBBs and that's pretty hopeless. Nothing there.

At least I've not found the correct gasket PN. Oddly, the 113 230SL on the EPC shows a part number for the wrong gasket (the wrong PN being 1801420780). If I go to the 250 or 280 pages on the EPC, it gives what appears to be the correct gasket, which is A1231420180.

Good old not so infallible German automotive designers!

[jameshoward]

OK. Some clarity.

Been phoning around and got pointed to a Mercedes classic car specialist from a renowned Germany company I'd used for parts in the past. The answer is as follows:

Two wavy washers are required, (not 3). The two washers go on the stud closest to the fan, so the front one; it doesn't matter which way the washers go on, it seems. I didn't speak to the engineer (he only spoke German) but he said that the washers are there because of the timing chain mechanism, hence the difference to the remaining studs. I don't know the detail due to the language barrier (I'm ashamed...) but it does clear up the issue of the washers. It also shows that my engine was correctly put together, thankfully.

He also said that there is no need to use washers where the manifold joins the downpipes, but that you must use the correct copper-plated nuts. Tighten carefully.

Here's a photograph that is the best I have at present. It shows the front of the engine. Aim for the forward most stud and put the washers there. I'll take a proper picture when I do the work later this week for the forum.

JH

[Paul & Dolly]

James,

I looked at my manifolds but I cannot see any of these washers fitted, however I do not
really know where I should be looking, & access is not easy !

They are actually called "Bellevelle" washers, and can be stacked to provide the correct  preload.
.We used to use them on a 2000 psi Hydrogen Compressor, to hold the valves in !
 - they are often used where a large temperature change occurs during operation.

They also had a military use as a trigger system.

Look forward to the photo of the finished installation.

Good luck
Paul

[garymand]

Was wondering what they are called.  Mercedes uses them in place of lock washers, much nicer on the surfaces. 

[tel76]

The front stud has a thick washer fitted as do the other studs, except the rear most stud does not have a thick washer under the nut because this is the only stud that does not secure two items, ie, the front stud has the exhaust manifold and hydraulic tensioner to secure, the rest have the inlet manifold and exhaust manifold to secure.
The wavy washers are for the throttle linkage cross shaft securing bracket ( the ally: bracket that bolts to the inlet manifold, it has the 10mm hole for the locking tool ) only two are required, these flat washers are used when you are bolting down aluminium, if you used a spring washer the ally: would get badly marked.

[jameshoward]

Eric,

The information I have, which is from a very reputable source, plus the way my manifolds came apart, suggests that the 2 bellevelle (thanks, Paul) washers go on the front stud (the one the links with the hydraulic tensioner). All remaining studs have the thick 2mm washer you mention, including the rear one. The bellevelle washers may also be used on the throttle linkage; I haven't stripped that (although I have greased the ball joints).

Can I ask where your different info comes from? I've search the two BBBs I have to no avail. Whilst I can accept that it's possible that the advice I was given is incorrect, it would be very surprising given where it came from.

I will take some pics soon that should help explain things a little more clearly.

James

[tel76]

James,
Can I suggest that the info: that you have been given was because of the language barrier and the person did not really understand what you required.
If you look at it from a practical point of view if a thick washer is required between the inlet and exhaust manifold why would two thin washers be satisfactory between the exhaust manifold and the hydraulic tensioner ?
Can you really see MB using two thin washers in such a position when it is more practical to use a thick washer.
I base the information on what I have found when I have stripped down engines in the past.
As matter if interest when I replace the manifolds I also put a s/s spring washer between the nut and the thick washer and on the rear stud I put a small plain washer and s/s spring washer.

[jameshoward]

Hi Eric,

You could be right. The reason I didn't speak to the guy is because my Germany is truly terrible. However, the guy who did speak to him is a fluent German speaker and a mechanic, thankfully.  I'm pretty happy that the view I was given is 100% accurate. These guys are world class restorers, sadly charging eye-watering prices. The difference between the thick washers and the thinner ones isn't just width, of course. One is the wavy one. I confess to not having got the justification. I could call back and get a more detailed explanation, and may do that. Or rather my friend might!

I don't know nearly enough about engines to add washers and other bits, but I know you do. I wish I did. I'll stick to the spec for the other studs. Having stupidly put myself in this position in the first place by clumsily putting my down pipes back on to the manifold, I'm nervous about doing anything out of the ordinary. I definitely don't want to do this again!!

Good discussion.

James

[garymand]

He is right.  I suggest you go back with a camera and take bunches of pictures from different angles.  Io even take notes on a hand drawn picture.  We don't always use the same terminalogy for same thing and we can easily assume the listener understands when they really don't. 

[stickandrudderman]

I confess I don't know the absolute answer to this little conundrum but I don't see any need to add spring washers where Mercedes didn't. I have never come across the wavy washers installed on the front stud in all my years working on these cars but that's not to say that they shouldn't be there. I suppose it's possible that they are necessary to accommodate the different rates of expansion between the cast iron manifold and the steel tensioner.

[tel76]

There would be a bigger rate of expansion between the aluminium inlet manifold and the cast iron manifold.
Colin, you have never seen them because they were never there in the first place.

[stickandrudderman]

The forward stud doesn't have anything to do with the inlet manifold.

[jameshoward]

Perhaps this is turning into one of those threads that is now starting to generate more heat than light (no pun intended).

I'm happy that the answer I have, (and would recommend to others given its provenence), which is that the wavy washer x 2 go on the front stud, and that this is related to the timing chain. More than that I cannot say.

I am also happy with the pictures I have that show that this was also the case as I disassembled my car. As for the language issue, living in Germany and finding engineers who speaks fluent German in my line of work is not difficult. Afterall, we're communicating in a modern European language, not trying to talk to Martians. I'm entirely certain that the both the question and the ensuing answer, both of which have been restated today for clarity and the benefit of all of us, were understood perfectly.  

It's not for me to comment as to whether members want to add additional washers where MB didn't put them. I have no idea of the potential benefits or pitfalls, I'm afraid. I also don't know diddly squat about heat transfer, but I can't really see that a 0.5mm washer here or there will make a blind bit of difference. The manifold serves that purpose to a degree, not the washers so far as I can determine. The exhaust gasses are what heats the outlet manifolds, and the radiation from those manifolds and the engine, presumably, imparts a little heat to the inlet manifolds. The washers will serve a different purpose in my view.

Anyway, the great thing is that we can each make our own choices on how to put the things back together. Hopefully, without breaking the manifolds!! (This time).