W124 Idiotic mistake. Missed timing chain cover bolt when lifting head and... 'CRACK'

Bellow

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Thoroughly check the guide rail for signs of distress.
 
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RogK

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Removing upper timing chain guide rail pin - 1993 190E M102 engine | Engine
the problem was you didn't remove the timing -chain guide rail pin/s which effectively attach the front of the head to the block before lifting the head causing the head casting to fracture- best now with a replacement head the 2 litre won't fit the 2.3
Alas, it's worse than that. I had no problem at all removing the guide pins - I missed a timing chain cover bolt when lifting the head.
 
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RogK

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Thoroughly check the guide rail for signs of distress.
For sure - new guide rail going back in, new sensors etc. Would have been a by-the-numbers job if I hadn't had taken that chunk out of the timing chain cover :(
 

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For sure - new guide rail going back in, new sensors etc. Would have been a by-the-numbers job if I hadn't had taken that chunk out of the timing chain cover :(
Less of a concern given it wasn't it but the bolt that caused the fracture.
 
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RogK

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Quick update - left the head with an engineers outfit today. At least I caught it in good time - there is absolute minimum warping.

So whatever the guy takes off the head he'll also take off the broken piece.

His opinion is that he wouldn't weld it as it's such a thin wall at the front cover; but, given that it is a cover, not under pressure and not subject to shear stress, he's fairly confident a high temp bonding agent will see me right, so long as I fettle it all in.

Sourcing a used head was looking like a very expensive option - not impossible but not much choice in Ireland (and shipping has become a real nuisance and very expensive)
 
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RogK

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I would say absolutely, were the casting not so thin on the timing chain cover - but maybe it would be possible to plate it though? 🤔 Bit agricultural, maybe! but for now, I'm not so concerned about neatness.

When I get it back from the shop I'll get a few pics from different angles.
 

Will

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Quick update - left the head with an engineers outfit today. At least I caught it in good time - there is absolute minimum warping.

So whatever the guy takes off the head he'll also take off the broken piece.

His opinion is that he wouldn't weld it as it's such a thin wall at the front cover; but, given that it is a cover, not under pressure and not subject to shear stress, he's fairly confident a high temp bonding agent will see me right, so long as I fettle it all in.

Sourcing a used head was looking like a very expensive option - not impossible but not much choice in Ireland (and shipping has become a real nuisance and very expensive)
I reckon that whatever bonding agent is used, the moment that chain guide pin is refitted it will split that crack right open again :-(

You can pick up a used head for a little over £100, and that’s where my money would be :thumb:

These heads never seem to warp, the stretch bolts towards the rear of the head tend to work loose and/or they suffer corrosion when left in poor condition (ie leaking) for extended periods of time.

I think if you pay to get it skimmed and new gaskets/bolts etc you’ll be kicking yourself if it doesn’t work out? :)
 
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RogK

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I reckon that whatever bonding agent is used, the moment that chain guide pin is refitted it will split that crack right open again :-(

You can pick up a used head for a little over £100, and that’s where my money would be :thumb:

These heads never seem to warp, the stretch bolts towards the rear of the head tend to work loose and/or they suffer corrosion when left in poor condition (ie leaking) for extended periods of time.

I think if you pay to get it skimmed and new gaskets/bolts etc you’ll be kicking yourself if it doesn’t work out? :)
I hear ya, I really do! I've made a few calls and I'm watching ebay and the small ads. But no luck - as yet - with an alternative head; and shipping prices and logistics across the Irish Sea are nuts at the moment. I might check with a pal in Belfast, could maybe get one shipped there. When the 124s were still being run as taxis, the breakers around Dublin were full of them. But they tell me they crushed a lot of older cars when metal prices were high. It's almost as cheap to pick up the whole engine now as just the head.
 
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RogK

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Will

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Yes, it’s missing everything - only 8 on this engine though. To be honest I’d probably be fitting new guides and stem seals if the valves were out as a matter of course unless it was a low mileage head.
 

optimusprime

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Markjay i never looked at the picture ,,just had guide raill in my mind . The way out is to get it welded . Or for a once only 100% finished job a second hand head ..i know the one i would be heading for ...
 

optimusprime

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Rog K i would never buy anything from over the pond . The hold ups are so very time consuming. Mater of fact i would do my shopping in Ireland there are sellers on Ebay shipping out to UK . Shipping cost will be expensive from Germany . Or try the 190E Forum in uk
 

optimusprime

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Found this one just bare cylinder head looks like work to get it nice .But seller will ship to Ireland after you message the Ebay seller .Item number is
202655363198 . Seller is MSJ Parts B/Ham Screenshot 2022-01-13 at 17-24-53 (OM) MERCEDES W201 190E CYLINDER HEAD R1020163201 eBay.png
 
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RogK

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Really appreciate the help. I've bought from MSL before with no issues, I'll ask them for a quote on shipping, but I'm not too hopeful it will be economical. I'm also still looking out for a head locally. I tried a few guys who helped me out with stuff before, but they're not keen on breaking a good engine for just the head, which is understandable. Of course, at approx €450, picking up a whole engine is not out of the question.

I'll attach some pics of the now skimmed head - I got VIP service from the engineer, as by pure fluke, I teach his sister! (I work in Adult Education). He really went above and beyond in getting the broken bit to seat neatly for either bonding, welding or possibly plating. However, you can see in the first pick just how thin that wall is... I'm dropping by a tig guy this weekend who'll give me a yea or a neigh.

I can see myself putting it back together with a bonded repair, while I wait for a suitable head so as I can do a more satisfactory job over Easter.

Thanks again
 

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grober

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That,s pretty damn thin! As Will said the major stress to any bonded repair will be replacing the chain guide retaining pin which is an interference fit afaik
 

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