Starting after a head rebuild

[Simpler=Better]

My motor has been on the stand for ~2 months, I'm hoping to get the head back on tonight and start it up. Any tips/ tricks/ warning for starting it after sitting for so long?

I'm planning on pouring MMO on the pistons, and turning it over by hand a dozen times or so with the glow plugs removed before actually starting.

[vstech]

has the block been covered the entire time? get in each pot with compressed air, and get the pistons and the sleeves, PRISTINE! I'd also finger a thin layer of oil around the sleeves just before setting the head on.

I'd not mess with MMO unless you need it to clean up some glazed pots... stuck rings?

[Simpler=Better]

I soaked about an inch of MMO down past the cylinders when I pulled the head a few weeks ago. I'm just a little nervous about the potential for damage from a dry start.

[bamba]

Turning it over a lot by the crankshaft bolt is a good idea. Then, before fully starting it, I would hold down the "STOP" valve while cranking it with the starter. Do this until you see the oil pressure build up to "3", then release the STOP valve and let her fully fire up. If you're starting on the stand without an oil pressure gauge, maybe do this crank-stop procedure for about a minute or so. It'll be tough on your starter, but will allow oil to circulate and pressurize.

[Jeremy5848]

Also remember that your IP hard lines will need to be bled and even then it will take a little cranking to "clear the air" and get fuel into the cylinders.

[97 SL320]

Originally Posted by Simpler=Better

I soaked about an inch of MMO down past the cylinders when I pulled the head a few weeks ago. I'm just a little nervous about the potential for damage from a dry start.

What would you do if the car was sitting not run for 2 months? ( I'd turn the key, let the motor run for 60 sec then drive. )

The real worry here is that the oil you poured in the cylinders has gotten between the top and 2nd piston ring. If the motor is run hard before the oil has a chance to escape, the expanding oil will break ring lands. Not to mention if you don't get nearly all of the exposed oil out, compression ratios go sky high.

A similar problem happens on gas race motors that have been flooded with fuel.

If you want to do something to limit dry starts, pull the glow plugs crank the engine until you get oil pressure.

[Simpler=Better]

I'll definitely be babying it, I will install an oil pressure gauge to make sure that everything looks good. I've already tapped the oil filter back plate for 1/4" NPT.

Side note-My girlfriend helped me install the head last night. Yup she's a keeper

[Diesel911]

After a rebuild or work on the Cylinder head it is always a good idea to turn the Engine over by Hand several times. That way you are sure nothing is hangeing up and going to cause any damage.

The same thing should be done when torquing down the Main Main Bearings.

Where I worked a Mechanic toqued down main Bearing Caps not knowing he had been given a Bearing Set for and Undersized Journal Crankshaft. He did not rotate the Crank when He did the Torquing.
As a result the Crank of couse would not move at all when it came time to rotate the Crank and install the Pistons and Liners.

[Simpler=Better]

It's short, loud, and there is cursing:

OM617A First start after head work - YouTube

It's alive!