Noz1974

Hi Guys, any thoughts on this, I've fully rebuilt my 996 3.4 engine and used redline rebuild lube on all bearing surfaces etc.
If I don't pre lube was going to pull all spark plugs and squirt some oil down the bored then turn over with no compression to build pressure before going for the first start but am wondering , should I pre lube the engine first with a special pre lube kit which I would have to buy or is it an unnecessary expense , I've spent enough already 😁😁

Hurdigurdiman

Hopefully Jake Raby will be able to answer your questions when he see's your posting.

extanker

imho i would not buy the pre-lube kit. just cranking with plugs in for a bit should do it. squirting oil in the plug holes wont get the oil to all the places....just the bottom....plus you may foul a plug. assembly lube is good,i like to lube the piston assembly and bore with motor oil before going into the block. IF you used a new or known very good oil pump and the motor has not been sitting for a year ...i would crank it until i got a little psi and then fire it up. i do not recommend synthetic oil for break in.

DBJoe996

Just for your consideration - whenever I do major engine work, even just head work, I always leave the spark plugs out and turn the engine over with the starter several times to get the oil circulating. In a fully rebuilt engine, the oil passageways are going to be dry and you need to get oil circulating before doing the first full start. Just my way of doing things.

Macster

The problem is removing the plugs and pullling the fuel pump fuse and cranking the engine is a bad way to prelube the engine. The starter only spins the engine at some ungodly low RPM and the oil gear pump is inefficient at this low speed. Additionally the hydrodynamic bearings need speed to form the oil film that acts as the bearing and at slow speed the film may not form and metal to metal contact can occur.

This is one reason why when the engine first starts the DME takes RPMs to over idle speed to get that pump spinning and oil to the nether regions pronto.

For the engines I rebuilt what I did was use an electric drill motor to spin the oil pump and pump oil through the engine before starting.

One can't do this with the Porsche engines.

My advice then would be to rig up some oil line that connects to the engine at the oil pressure connection and picks up oil from an external source -- a clean small bucket of the proper engine oil and feed pressurized oil through this connection to the engine and its oil passages. The pressure doesn't have to be a lot as you can run the external oil pump -- maybe something driven by a drill motor -- a while to ensure all the oil passages are filled with oil.

Thus when you start the engine normally it starts as it will start every time from then on and that is with the oil passages full or nearly full of oil.

It is important, used to be and probably still is, once the rebuilt engine starts to keep it running and to keep it running at an elevated RPM to ensure the cam lobes/lifters receive a generous supply of oil so these do not suffer and you end up with a flat cam lobe or a damged lifter bucket. The cam lobe/lifter bucket interfaces are splash lubed in these engines and new parts need plenty of oil to ensure they develop the appropriate surface to provide a long and trouble free service life.

After some minutes of this fast running then the engine was shut off the oil was drained and filter was replaced and the engine refilled with fresh oil. The engine was then driven on the street to complete break in.

Chiamac

+1


Noz1974 - you already have assembly lube on all the parts that need it, this will be fine once the oil has a chance to do it's thing.

993GT

I'd personally pull the plugs and fuel pump fuse and crank til you see oil pressure, re-install plugs and fuse and light'er up

Van

Can you attache something to the center port of the oil filter housing and pump oil in?

Chiamac

Yes and no. The starter spins that slow because it's trying to turn an engine with compression. Take away that compression and it should turn much faster.

I wouldn't worry about fluid bearings as they should have some kind of assembly lube which should protect them well enough until the oil pressure is up. Maybe I'm wrong but I've always thought of them as needing oil pressure vs spinning at any one speed. In any event, slow speed without much stress (as in the engine running) shouldn't cause any more harm to them than turning the engine over by hand on a stand or something.

Chiamac

It's important to check what kind of break in a cam calls for, as well as what the rings need to seat.

Again, I'm assuming that the cam and other parts have assembly lube and aren't dry when first turned over.

Byprodriver

Fill the oil filter with oil before installing, pack the M96 oil pump & gears with Vasoline petroleum jelly, I also fill the cam shafts with engine oil during assembly, as the shafts are tubular. Turn key to acc & off several times to allow fuel pump to fill fuel rails with NEW gas. Start engine as usual making sure it fires up quickly & monitor oil pressure. Once oil pressure is good raise rpm to 2000. Most likely excessive wear will occur between cam & followers as this is the highest pressure contact area.

Macster

Not really. While with the plugs in there is compression to overcome this is returned on the other side. Almost all the effort needed to compress a cylinder is returned by the push the piston gets as it goes past TDC and begins the down stroke. Thus the engine won't spin much if any faster with the plugs out than in.

All bearing surfaces should be assembled with some assembly lube. Something that protects agains corrosion forming during the assembly process and lubes all bearing surfaces during the first engine start. I was taught to use engine oil but of course the engines I worked on had an oil pump that could be driven by a drill motor working down through where the distributor drive fit.

Cam/lifters were lubed by whatever the cam maker supplied with the cam.

Flat6 Innovations

Pulling plugs and spinning on the starter will never prime one of these engines properly when it has just been built. I have tried, and tried this with no luck. You'll deplete all of the assembly lube from the components, before the oil pressure builds on the starter. I see people treat this engine improperly all the time.

We start the car and shut it off immediately, like in a split second of hearing the first combustion cycle. I do this 5-6 times before I note the oil light on the dash no longer illuminating, then I fire it up and let it run.

I do NOT fill the filter with oil first. Doing this requires that air push the oil through the filter. Remember, the oil filter in the M96 is AFTER the oil pump, so it will not help with priming to fill it with oil. Its tough to have air push the oil through the filter. Instead, let the filter fill as the air is bled through the oil system.

AWDGuy

good info Jake. can't remember if you went over this on the course. I don't have it in my notes....glad you covered this.

Byprodriver

Ditto for me!

I have always gotten 80 psi within 30 seconds of engaging starter.