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Blowby and a Misfire

Started by Abe_Markillie, 18 August 2021, 07:44 PM

Abe_Markillie

Just bought a 300SD and it sat for a while in a airport hangar, not sure how long exactly. I've notice once it warms up it has a bit more blowby than I'm ok with, and smokes a little out the exhaust. It idles a little off and sounds to me like a misfire. All the injectors return lines leak pretty good so maybe that could relate. I've also heard about mixing a bit of oil and diesel with a gallon of vegetable oil and it loosens the rings up, and helps with smoke. I have a 1985 ford truck with a IDI diesel, which had the same issue. I advanced the timing and replaced the return lines,and it idles perfect, so smoke like it did, and very little blowby. Can I do the same with my turbo om617?

SuitGuy

I am not the most experienced with the OM617, but I would advise against any timing adjustment unless you know what you are doing. Definitely replace the return lines. It will take almost exactly 1 meter to replace the return lines. Buy an endcap for the return lines too, don't bother making your own. You can buy all of those at autohausAZ for relatively cheap. As for the blowby, how long have you run this engine? Is there a chance the rings have just not had a chance to come loose? If you're worried about blowby, try Restore brand compression restorer. They are sold at Walmart in grey cans, for 4 and 6 cylinder engines. I've seen it work wonders for lost compression. Hope something here was helpful.
Kindly,
Suitguy
Beige 1980 300SD

Alec300SD

Adjust the valves cold, if you haven't done so already.
Change all the fluids and filters.
Replace any leaking or deteriorated hoses.
Drive it like you stole it for long rides at operating temperature.

Readjust the valves after 500 to 1,000 miles.

This should  improve compression and reduce blowby (due to lack of regular use) if the engine is otherwise healthy.
78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Abe_Markillie

I just adjusted the valves I've probably driven it 50 miles since then. I've probably driven it about 200 or 300 miles since I bought it. The return lines are coming in the mail because all the injectors are leaking everywhere.