sitting engines, rust on valvetrain?!? - PeachParts Mercedes-Benz Forum

2.5-10 · #1 12-31-2009, 10:08 PM

I have a 1989 5.5L M117 and a 1976 OM616 sitting in my shop and I decided to look in the valve covers tonight and what did I see?

Rust!

on the M117 I saw it on the top of a cam lobe and the OM616 I saw it on the part of the cam between the lobes

is this normal?

what should I be doing to deal with this?

GregoryV022 · #2 12-31-2009, 10:25 PM

lots and lots of WD40. and keep them cleaned.

2.5-10 · #3 12-31-2009, 10:32 PM

how did this happen?

this engine was perfect when I pulled it from my 560 last year

Kestas · #4 12-31-2009, 10:34 PM

How long have they been sitting? The oil will dry off any engine is it sits long enough.

Did the cars come in out of the cold into a nice warm (and perhaps humid) shop? This could be a condensation problem.

2.5-10 · #5 12-31-2009, 10:35 PM

they have been sitting for about 6 months,

they came from hot to a non climate controlled shop, now its super cold and winter time.

GregoryV022 · #6 12-31-2009, 10:37 PM

Quote:

Originally Posted by Kestas

How long have they been sitting? The oil will dry off any engine is it sits long enough.

Did the cars come in out of the cold into a nice warm (and perhaps humid) shop? This could be a condensation problem.

seconded. you always have to keep the parts lubricated. what you might try is fogging the engines. its a marine term. an additive in the fuel produces a "fog" of oil that coats every part of the engine. its used for putting boats away for the winter.

2.5-10 · #7 12-31-2009, 10:38 PM

neither engine is connected to anything to make it run, how might I do that?

strelnik · #8 12-31-2009, 11:17 PM

Quote:

Originally Posted by 2.5-10

neither engine is connected to anything to make it run, how might I do that?

Given your circumstances, I would take a small brush and paint grease on the cam, it's not for real lube but for protection. Open the plug holes and glow plug holes and squirt a fair amount of oil in the cylinders.

I have a friend who has some very expernsive engines and he just fills the crankcase to the top with 30W oil after he has put oil in the cylinders, painted the cam and replaced the valve cover. He's toyiong with hooking a small pressure pump to one of the oil lines to pump grease everywhere. But he takes them 100% apart when he works on them, so he's not typical. Plus he has space and MONEY.

2.5-10 · #9 12-31-2009, 11:22 PM

alrighty, I havent pulled the valvecovers to know if all the lobes have this on them, but I would like to hope they arent

I'll make sure to put oil in the cylinders, they both currently have full sumps

Kestas · #10 12-31-2009, 11:51 PM

I'm not sure if this is what strelnik suggested, but I've heard of some people prepping the engines for storage by filling the engine with oil until it can take no more. This would immerse the valvetrain in oil.

pawoSD · #11 01-01-2010, 12:57 AM

Seems odd.....we've had one of our diesels sit for 4-5 months before and there was still oil on the cams when we took off the valve cover.....we run it with synthetic. No rust at all.

strelnik · #12 01-01-2010, 08:38 AM

Quote:

Originally Posted by Kestas

I'm not sure if this is what strelnik suggested, but I've heard of some people prepping the engines for storage by filling the engine with oil until it can take no more. This would immerse the valvetrain in oil.

yep, as long as the valve cover doesn't leak

Kestas · #13 01-01-2010, 09:55 AM

Also realize that cast iron is more prone to rust than steel.

Strife · #14 01-01-2010, 01:00 PM

I might try using assembly grease on the parts - what you would use on a freshly assembled engine (or new cam, etc). There are varying opinions on whether or not you should change the oil within 500 miles of doing this...

long-gone · #15 01-01-2010, 01:26 PM

But what should he do about it?

Should he remove the cam and carefully clean the affected lobes with x-fine steel wool and oil? Maybe try something like stainless steel polish or naval jelly to dissolve the rust, or just oil it and turn the motor and let it sort itself out?
Would he risk compromising the hardened/polished surface if he tried to clean it?

When I did my head gasket I sprayed the cam w/ WD-40, wrapped it in paper and the put it a couple socks and it still got some areas of fine rust which I lightly went over with x-fine wool and oil. But it was very light and easily wiped right off. If the rust is bad enough that it shows any visible pitting at all I'd be leery about using the cam (or the rockers if they're the same).