Engine rebuild with no former experience........

I spent a long time in the garage today but made limited progress.

First I stripped down the second head.



The tray is now full!



Next was a lot of scrubbing in the hot degreaser bath.



I then checked both heads for flatness, both were good. but both heads don't look great, do you think they will seal ok or do they need skimmed?



Next I went back to the sheared bolt on the first head.



Built up with weld.



Then nut welded on.



I managed to get the bolt turning but had to go through this process a lot of times. I think the thread has galled since I am making such slow progress.



It is now sitting in a puddle of "plus gas" overnight to see if that helps.

I then went on to try to clean up the valves, I will leave them in this oven cleaner overnight, but don't have a good feeling of success. The main ingredient is Potassium Hydroxide. Does anyone have a suggestion of the best way to do this?

Hi Jim,

the camshaft bearing looks not so fine, but it may be worth a try. I wonder how this damage starts, it's the bearing closest to the oil support. The highest stress probably has the bearing on the other end, where the load of the timing chain is on. On this side I would make no compromise.

When you press in the new guides using a threaded rod, you need to lubricate the thread very well. Change the nut from time to time, as well it’s necessary to prepare a couple of thread bar pieces in advance. The stress is very high so you need to change the parts from time to time. I used copper pipes to prevent the cylinder head from damage. The copper as well won’t be very durable.

Later on try to grind as little as possible from the valve seats! The more you grind, the more new shims you need and these little things are very expensive.

Greetings Martin

Hello Jim,

smoke resin remover works very well.
One Liter in a bowl and then let time do the job.

After two days most valves were pretty clean and needed only minor add cleaning.

Kind regards

JP

Hi Martin, it is odd that the worst wear is at the back, however I have heard that this is not uncommon. The 350 engine that was fitted in my car when I bought it had very bad wear on the rear cam towers too.

If yesterday was slow progress, today was a snails pace.

I tried welding on another couple of nuts but made little progress getting the sheared off bolt out, so decided to try to drill it out.

First I cleaned up the end of the bolt to try to get the drill to find the centre.



The head wedged to try to get the bolt vertical, almost impossible without a mill and clamps.



Drilled out, a bit off-centre.



Cleaning up the threads.



Trial fit! I will use a 5mm longer bolt to ensure I get down into good threads as the hole is pretty deep.



Next I split the intake manifold and had a look at the remainder of the bolt in it, I gave the end of the sheared bolt a few hits with a hammer (it's been soaked in releasing fluid for at least a week now), there was zero movement. I will take it to the engine shop to get it drilled out on a mill.





Finally today I cleaned the oven cleaner off of the valves, it had an affect, but there was still bits of what looked like cement left, however it cleaned off well on the lathe using some emery paper.

Only half of the valves had been treated with oven cleaner, these cleaned up relatively easily on the lathe, the others took much longer to clean. This is one of the untreated valves before and after.

Note the valve stems were protected with a rolled up section of coke can.

Good Morning Jim,

you need to be really careful while handling the Exhaust valve stems. The stem is filled with Natrium and has a thin wall thickness.

Regards Martin


Edit: I'm not sure - maybe not at the 450, but at the 500/560 heads...

I finished up cleaning all the valves this morning then this afternoon took the inlet manifold along to the machine shop today to ask them to drill out the snapped bolt. They said they didn't want to do it as they wouldn't be able to secure it to their mill bed due to its odd shape. They suggested buying a second hand one which will likely be cheaper, it needs milling to remove the bolt, tig welding on the parting face to the head where I used the saw to cut through the bolt, then facing, that could easily be over £100, a second hand one is £110.






Any other suggestions (don't say drill it out, there is no way I can do that by hand)?


Anyway, I picked up the block, it's clean but will need a bit or work before being ready for paint.

Hi Jim,

now I found the last pic I was looking for. When fitting the new valve guides in, I covered the threaded rod in the area where it sits in the new guide with a heat shrink tube to prevent the guides inner side from damage.

Martin

I forgot to say that I also ordered some used cam bearings, they look to be in good condition.

I decided to have one last try with the inlet manifold this morning.

I slotted the manifold down the length of the bolt.



Once all the way through I tried to drift the bolt out, it still wouldn't budge, so applied some more heat.



Then hammered again and eventually it started to move.



Cleaned up and ready for TIG welding, I'll get a price tomorrow.



This arrived today, should let me check on my old school torque wrenches.



Back to the block, and rust removal. Poly disc, wire wheel and finger sander with 40 grit.



It's a very rough casting so this was as far as I went.



Etch primer.

For the sides I used the wire wheel.





Then the 40 grit to give a key for the primer.





Prepped for 2k black.



The finished article.

Hi Jim,

nice work. Do not forget to reapply the white "Euro" marks. That is the only way to know that this is a European engine.

Today I dropped the manifold off at the welder, £30 was the quote which was good news.

This afternoon, I started cleaning engine parts, that will take a few days.

First the sump, spot anything in there?



Well it looks like someone changed the chain before me.



The inside cleaned up well....



However there is lots of corrosion on the outside that I can't clean up.



Similarly the front cover is badly pitted.



Any suggestions on how to clean these up better? The sump will likely be too large for vapor blast cabinets. I am not sure how it will look after grit blasting.

Hello Jim,

now would be a good opportunity to retrofit an oil level alarm!?

Frank

That sounds like a good idea, do you have a link to such a thing? One from another Mercedes?

I got the inlet manifold back from the welder today. I am pleased with the results!







Now what can you do with these tools and 4hours?



Still a few small areas to finish off with a Dremel.









Finally I dropped the timing cover and the inlet manifold off at the vapour blaster, that will take a week or so.

Still lots more cleaning to do.

I tried to order a new dip-stick tube (A1160181316) from my local Mercedes dealer (as they are so cheap it will be easier to buy a new one compared to plating the old one) however they said they are no longer available and can't be ordered.

I can see that they are available on line here but the don't ship to the UK.

originalteile.mercedes-benz.de/fuehrungs...4?number=A1160181316

Would someone mind calling MB in Germany to check to see if they are really available or not please?

Thanks

JIm, I will order this item for you today...

Jim, your dip-stick tube is ordered...

Thanks Richard,, let's hope it is really in stock.