Can A Diesel Be Turned Over To Preoil Bearings Before Starting?

[ezrider]

My 603 oil pump is being replaced. I am curious to know if it is possible/easy to turn a diesel over without it starting so the bearings can be preoiled before starting the motor? Or, is this something to not be concerned about?

Thank you.

Not sure how difficult removing the glow plugs
is on this engine, but it would accomplish a no
start condition and save wear on the starter by
allowing the engine to turn over easily. I am
inclined to say this is not necessary since
the engine was not just rebuilt..therefore
it still has oil in the critical spots. Preoiling
is necessary after a rebuild when the old oil
has been cleaned off. However, It might take
a while for the pump itself to prime itself and
start pumping oil. To be safe take the glow plugs
out and run the starter in 10 second intervals until
adequate pressure is attained. Perhaps before
you get around to this someone else will offer
convincing reassurance that it is not necessary.

[whunter]

Refer to this post:
Prestart oil prime of a long storage engine can save your bearings and bank account.

http://www.peachparts.com/shopforum/showthread.php?threadid=86683

Have a great day.

[leathermang]

"Preoiling is necessary after a rebuild when the old oil
has been cleaned off. "

An engine being rebuilt should be put together with Moly Assembly Grease on all friction surfaces... this stuff will stay there until washed off by oil......
Most actual oil pumps should be filled or primed before installation on the engine.
The combination of these two procedures should eliminate concerns about initial start up excess friction.
However, I love preoilers.... use it if you got it ....

[P.E.Haiges]

EZ,

You can preoil the ENGINE by removing the GP cable from the GP relay and cranking the ENGINE with the starter until the oil pressure comes up. This will put less strain on the engine to oil it than running the engine until the oil pressure comes up.

P E H

[ezrider]

P.E.,

I think it will try to start on compression alone when cranking without the glow plugs, it did when I was having glow plug problems some time ago. I'm not sure about doing this as it fires off very unevenly when I did it? Anyone else?

Thank you.

[Rick Miley]

Have someone hold the stop lever down while you crank it.

Turn the key to the Start position immediately without glowing. It shouldn't start to fire until you've cranked for at least 30 seconds. Stop cranking when you see some oil pressure indicated on the gauge.

[Rick Miley]

My 240D starts in about 5-6 seconds of cranking even without a preglow.

[ezrider]

Is there any risk to damaging the Stop mechanism or anything else by holding it down while starting the motor?

Thank you.

[Rick Miley]

No, it just cuts off the fuel supply.

[P.E.Haiges]

EZ,

I agree with Rick.

P E H

[ezrider]

Sounds like a good idea to me to pull the glow plug relay plug out in case there is some fuel in the system and hold down the Stop lever to get some pre-oil through the motor after the oil pump replacement.

I also read that the new oil pump needs to be primed before it goes in.

BTW, the oil pump is being replaced due to a sudden drop of oil pressure to near nil at idle and just over "2" on the gauge at higher RPM's. Have any of you guys experienced this problem? (I have posted this problem elsewhere on this forum in case you haven't seen it).

Thank you.

[P.E.Haiges]

EZ,

I thought of one other thing that could be causing the low oil pressure. If the new oil pump doesn't fix the problem, test the oil over pressure release valve. If the spring broke, it could cause the oil pressure to drop suddenly. If you haven't installed the new pump yet, you might look at the release valve first.

P E H

[ezrider]

P.E.,

Where is the "over pressure release valve?

Thank you.