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Discussion Starter · #1 ·
I'd be interested to hear some discussion on this.


IMHO this is the way this works;

On a small block Ford you can get away with the drill-prelube thing because the main bearings are generally fully grooved. This means the oil has a path to the rod bearings. There is though, a whole bunch of engines out there that do not have full groove mains, and it has been my experience that the drill procedure doesn't properly pre lube these engines. The reason is that the crank oil hole needs to be lined up with the path to the rod journal in order for the new rod bearing to get oil. With this bearing type, this only lines up once every revolution, (or 1/2 a revolution on main bearing sets with one grooved bearing shell). The window of opportunity is about 10deg, so that means you have a one in 36 chance of hitting it and actually getting oil to the rod bearing if the engine is static when pre-lubing. It's my feeling that this is the most important part of pre-lubing, because the passage from the main to the rod HAS to be filled to get oil pressure to the rod, it's the centrifugal force that feeds the high pressure to the rods that they require under load, from the rotation of the crankshaft, not the oil pump pressure. This is not to mention the lifters/rockers etc. sitting static and blocking (or not) the oiling holes.

OK, so what's the right way to pre-lube an engine at pre start-up? Well, there's 2 ways I know of:

Also let's assume that the engine was assembled properly using the right assembly lube in the right places. Also we will assume that the oil filter was filled with oil prior to installation.

#1 is a pressure lubing system that is commercially available and is connected at a main gallery. These use outside pressure to do the pressurization and is the best way and a sure thing. They are also not something the home mechanic has on his shelf.

#2. If the oil pump was properly primed on installation, and the spark plugs are out, there is only the friction load of the engine when being rotated. If you crank the engine until you get oil pressure on the gauge or the light goes out, and then repeat this a few times, you will get oil into every possible section of the passages, the main-to-rod passages, and the top end of the engine. You can also do the drill thing while cranking the engine over on the starter and get to the same end, perhaps a bit quicker, but to my experience the distributor turns the pump drive at about the same speed as the drill. (Side note; don't crank an engine on the starter for more then about 1 minute at a time, anytime. the starter will overheat).

From this point, install the plugs, pump it twice and hit the key. Unless there is something else wrong, the engine will fire on the first revolution because now it has fuel to the carb also, or should.

I've heard concerns about cranking the engine before start-up possibly damaging the new cam by digging in the lifters. I can't say this is not possible, but I've never had it happen myself. One thing I do on my engines is to chuck each lifter in a lathe and "break" the outside edge ever so slightly with a stone to reduce that possibility. This seems to eliminate the "cutting tool" effect. I have started a bunch of new engines that have not had this done though and still have never "shaved" a cam at start up.


Hal
Love hard, drive fast, wear your seat belt.

PS, that's my 'bird...... My Mustang is too ugly to take pictures of yet........*G*.

http://www.teleport.com/~cosa/bird2.jpg
 
G

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Hal - Whew!!!

(1) As far as pre-lubbing the engine, assy lube is designed to keep bearing surfaces oiled until pressurized, warmer oil displaces it. This goes for rod, main and cam bearings, lifter sides, rocker fulcrum points, etc... Cam assy lube is a higher viscosity grease used to lube the cam/lifter during initial break-in. If both are used properly, then pre-lubing the engine with a drill (or in my case, a 1/4" nut driver) is completely adequate. The purpose of pre-lubing using a drill is to fill the lifters, pushrods, and pressure oil galleries prior to engine start.

I don't recall the rods having a groove in their bearing surfaces; only the main bearings. I guess I wouldn't go so far as you suggest in #2; #1 is out of my league - no shop air at my house!

(2) I've always hand-cranked my engines all throughout the assy process. I spend about 10 - 20 minutes hand cranking the short block once its put together, just to 'initially' set the rings (I also like to see the pistons pop in and out). If anyone is worried about lifters digging into the cam, then the cam profile is incorrect for solid lifters. More aggressive cam profiles dictate roller lifters, partially because the reduced friction involved, but mainly because the severe ramp angle would cause a solid lifter bottom to dig into the cam.

When you break the edges of the lifter bottom in your lathe, you are also losing its associated temper/annealing properties. Lifter bottoms already have broken edges. Luckily, this is localized and the cam doesn't touch these parts of the lifter. If you look at old lifters, wear is slightly concave, towards the middle of the lifter bottom.

(3) I've found the most unnerving thing is to wait until the fuel pump primes and then fills up the fuel pipe to the carb. Sometimes that takes 10 - 20 seconds...an eternity for new engine starts.

Thanks,

Mike
'66 Springtime Yellow Coupe
289, slightly warmed over
driven daily
 

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Nice treatese....

Wow, there are engines that don't have full groove mains....? *G* Yeah, I've seen some with half groove mains so they only get oil half the time ....hehehe

Seriously, I probably spend too much time on this subject....we've thrown engines together in the pits and they've ended up making it through the rest of the season with no problems....
I've never put together and fired an engine at home any other way so I don't have any alternative experience to draw on...

I've pre-lubed engines both ways you mention, either from a pressurized oil reservior or by spinning the oil pump at 500 rpm with a reversible 1.5 HP drill motor....

As long as I've pre-timed the engine before firing, it usually fires nearly immediately....the only engines I've ever had problems with were those I wasn't involved in regarding the pre-firing procedures...this is one area where blueprinting and double checking everything leads to a predominantly good result.

Re: cams and lifters...I worry more about lifters displacing the lubricant film from excessive pre-fire cranking without any additional lubrication being present to offer some protection to what is one of two direct metal to metal contacts in the engine without pressurized lube, the other being the rings. In racing engines, open valve spring pressures are routinely over 250 lbs (which would exert a load of around 400lbs given the advantage of the rocker arm) on a solid lifter cam and that's a lot of pressure being applied to a thin lubricant film.
Having said that, I've never had an instance of a cam going flat in my personal equipment. As cam followers (non-roller) are usually ground on a 60" radius, there is usually no possbility of edge contact IME...

My advice will continue to be : pay attention to the details, take time setting everything up for firing and don't spend any more time cranking the engine than necessary to get it started. The advice about cranking the engine without the plugs in while pre-timing and setting the valves is sound...it takes the load off of the bearings and rings.

Possibly my opinions get skewed by the reality that I've built mostly performance engines with higher than stock quality parts and materials. With that enormous (for me anyway *G*) investment, I'm possibly more paranoid than necessary about getting everything right....

That's why hearing from the guys who build stock engines for a living is a good thing....there are parts of my advice which need not apply to stockers...

Good discussion Hal...thanks...

Now, about that RHD stuff....*G*

Pat
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