Pull your Balls to properly clean your Crank

[BogusSVO]

Pull your balls to properly clean your crank


I know this topic has been talked about some.
Some say it not needed, but I disagree.
The crank for a 4g63 is of the cross drilled design.

This means that there is an oil galley through both the main and the rod journal with an intersecting oil galley that joins the main to the rod. Due to the way the oil galleys are drilled, from the side of the rod throw to the main journal oil galley, the factory installs a press fit ball.



Now a segment of the intersecting galley is “dead space” this segment is from the cross drilled oil galley in the rod journal to the outside of the rod throw.
The common way to remove the ball is to heat it with a tig welder to loosen it, then weld a pull point on the ball and fight it out.

Once the ball is out, you will see the hard packed crud that builds up in the dead space.


Once you have the crud exposed, use a drill bit slightly smaller than the oil galley and drill the crud out, then a small copper brush and compressed air to get the rest out.
You will have 4 piles of crud.


A closer look of the crud from one galley.


So you can have an idea just how much crud is built up in the crank.


I believe that the solvent tanks and spray cabinets that a machine shop uses, also the cans of brake clean the DIY use, breaks down the bond that holds this crud in place and softens it so in a rebuild it gets washed when the engine is primed with oil on the stand, then the new break in oil picks up a small amount of the loosened crud and washes it into the new rod bearings.

 

[prove_it]

You are so machining my next block assembly and prepping my parts.

Holy cow batman. I've always wondered if the "recesses" had crap in them. Now I know.

 

[BogusSVO]

Prove_it, Thanks for the complement!

Years ago, when I first joined another DSM fourm board, I would read thread after thread how a "new" rebuild would spin a rod bearing in under 50 miles. I knew there was not that many badly assembled builds, so I started looking at a few spun cranks, and the light went off, once it dawned on me to inspect behind the balls.

I have prepped somewhere between 125-150 cranks, like this, some I assembled, others I have just machined and the owners assembled. Not only 4g cranks, but Nissan, Honda and other import cranks, all have had some level of crud build up.

Out of all those cranks, I have only seen or heard of 1 crank failure, and that was was not due to crud in the crank or assembly, but the oil cooler hose blew off and dumped the oil out of the engine.

 

[prove_it]

Yea, might not cause an immediate failures, but that crap will score the bearings.

 

[dustyduff]

Or even more importantly, MAKE SURE THEY ARE EVEN THERE!!!

The shop that put together my built together didn't notice that one was missing. Spun #4 bearing about 400 miles into new setup then had a new set of bearing installed only to have #4 bearing go again.

After getting a different motor installed in the car, the tear down of the older block revealed that the "ball" was missing.

 

[James]

Just seems like poor design. Motor is has a 100% chance of failing over time becuse of that. Was there no better way to build it?

 

[fuel]

how else do you propose to drill into the crank for oil galleries and close off the drill holes? The balls are press fit inside the bore and the edges are pressed over so there's no way a ball is going to come loose at any stage - as said by Bogus it takes a bit of work to pull them out.

 

[James]

I mean no better way to build it to prevent that build up that's going to contaminate the oil system.

Step1- what allows the crud to build up
Step2- can it be stopped

 

[fuel]

oh right - the crud build up could be put down to infrequent oil changes, poor quality oil and/or oil filters and perhaps too high an oil temperature.

 

[James]

I see. So in a well cared for motor you wouldn't see very much build up.

 

[fuel]

probably not but it could be like the rocker cover baffle plate which behind it seems to accumulate crud no matter how well the engine is looked after. I guess Bogus will step in and comment!

 

[BogusSVO]

It is just going to happen over time. First the manufacture will not care, it is out of warranty. They do not make money if a car lasts 20 odd years. Get the car to last a year past the end of the warranty then have a it fail.

Think of the crank as a centrifuge, so as it spins, the heavy particles that are floating get slung into the dead areas with out oil flow and the crud packs up.

About the only way I can think of keeping it from happening is machine a long plug that would fill the dead area all the way down to the cross drilled rod galley.

 

[vr4play]

Do you put balls back in or do you drill and tap and install a threaded plug?

 

[BogusSVO]

T tap and plug, Ill do a write up on on that and post it in the next few days, I have a few cranks to finish up.

 

[G]

This is standard practice by any competent crank machinists. Mine were done when I had the crank knife edged.