I will be putting together an engine in the next month or so. Obviously when you assemble a motor, it must be turned over by hand several times--while installing the pistons, verifying piston depths, & setting valve lash, if you degree the cam, etc. All the while, cam, crank, and rod bearings are in contact with their respective journals.

Things are lubed upon assembly, but how long does this lube last? If you verify piston depth on each cylinder, for example, you have to turn the motor over a few times. While I'm asking, is it easier on a fresh motor where the surfaces are the freshest or one that has ran for a while? I understand hydrodynamic bearings don't (*aren't supposed to*) contact in operation, but I don't know if the surfaces ever contact enough dynamically to actually 'wear in' (i.e. during the fraction of a second it takes the pump to pressurize the system upon startup).

I know the bearing surfaces are highly finished, and turning the assembly over by hand a few times doesn't generate crazy amounts of friction, but how long does the film from lubing upon assembly last (or in the case of a motor that ran, the film of oil from the last time it ran)? How **** should I be about this?

 

If properly lubed upon assembly, you won't have problems turning it over by hand for a very long, long time.

I think "****" pretty well describes it...

 

Thank you.

This is what I figured, but better to be safe and ask--too many times have I been confident in doing something, only to overlook something else.

 

Relax! Like 57 said, it will last a long time. What you need to worry about is when you assemble each part (such as when you torqued each main bearing) you roll the crank over before and after the final torque. That way if it tightens up, you know there's a problem. Same thing with rod/piston assembly. install one set, torque it, and turn the motor over.(if you reverse the rotation it will bind unless you have both rods on that particular crank journal) it should get incrementally tighter with each installation, if it binds, then stop, you screwed up the last one you did. The biggest disasters on new engines are usually from the cam not breaking in and wiping off a lobe. Mellings makes a great cam lube for this, and it's oil pump friendly unlike some of the moly stuff that's out there. Without fail, prime the oil pump before starting.

 

I agree, the lube film in a properly built engine is strong enough to last quite a few turns; even if the engine is running.

 

When assembling a motor, I like to coat the cylinder walls with Marvel Mystery oil. It flashes off quickly at start up and offers good lubrication during assembly.

Also, as stated, use a good assembly lube on bearing surfaces.

And most importantly, prime the oil system prior to start up.

www.geocities.com/dzperf

 

Thank you all for your replies; gives me peace of mind.

 

I've found STP to be a great assembly lube too!!

 

redundant post here, but isn't it like 15 ft lbs. turning force is fine, so you should be able to turn it by hand.

wouldnt it be the accessories that make an engine harder to turn over by hand via wrench?

 

Not sure what the proper torque is but you should be able to turn it by hand even if it is very hard to do. The accesorys along with the trans make it impossible after its been installed.