Crankshaft Oiling Passages - NAA

Mdparrott · Aug 18, 2015

Question on oil passages in crankshaft......

Starting reassembly of the NAA's engine. Found some rust in oil holes on crankshaft journals, but can't tell if they go anywhere? Old crank holes bottom out also, can't tell if there is a passage to the inside of the crank or not.

Are these oil passages or just holes to collect and distribute oil around the bearing?

Machine shop acquired a used crank to turn for me since my crank wasn't serviceable. They said it had a bit of rust on it when they got it, I'd say I guess so. 😕

So what do the holes do and do they go anywhere? TIA.

Bob · Aug 18, 2015

I can't hardly believe the machine shop would send it out if there was any doubt that it was clean/safe to use 'caus if the debris leads to a bearing failure you are not going to be a happy camper!

If it's like any other common crankshaft from a pressure-oiled engine, the drilling from each rod journal leads to the nearest main journal, to pipe oil to each rod bearing. The drillings from each journal intersects inside the crank to form an individual passage between the main and the rod bearing(s) it feeds.

Grab a can of carb cleaner with a straw and squirt in the holes one at a time and you can verify what I have written and see where each passage leads and what gets flushed out. (Don't squirt yourself in the eye with the nasty stuff!) At the very least, get a set of brushes sold for this job and see how much more you can clean them.

I will leave it to others to comment on if there is any suitable chemical means for removing any remaing possibly loose rust.
ONE source for brushes

Mdparrott · Aug 18, 2015

Thanks, Bob. I went back out and took a blowgun to each hole. Each one is open and flows air. But I can see rust in each rod journal hole. Definitely don't want any rust breaking loose and damaging a bearing.

Told my machine shop I wasn't happy with the rust on the crank but they assured me it turned ok and would work fine. Just noticed the rust in the holes tonight.

Mdparrott · Aug 19, 2015

Here's a couple of photos I've taken:

Bob · Aug 19, 2015

That looks AWFUL!

ASEguy · Aug 19, 2015

I agree with what Bob said, but I wouldn't use the crank. If yours wasn't serviceable due to a structural issue then so be it. I'd get one somewhere else or have the machine shop guarantee in writing they will cover any failure due to the rust coming loose. It doesn't take much to wipe out a bearing. I would politely ask for your money back and search for a crank in better condition. Gerard

TheOldHokie · Aug 19, 2015

(quoted from post at 01:14:50 08/19/15) Here's a couple of photos I've taken:

Time to find a new machine shop. One that can obtain quality used parts and knows how to properly recondition them. I would not put that crankshaft in anything of mine and I hope you didn't pay much for it.

TOH

Mdparrott · Aug 19, 2015

Yeah am thinking that. Thought I'd be ok until I saw the rust in the oil passages. Don't think I need that problem.

Wasn't bad, paid $168 for the crank and $175 to have it turned. Gonna call my machine shop and tell them I can't use it.

NoNewParts · Aug 19, 2015

scrap
If I was going thru my parts pile looking for a useable crank for a common engine, I would immediately reject that one.
The amount of time/work to clean those passages and the external rust(which would end up in the oilpump pick-up too)
not worth my time.
scrap

souNdguy · Aug 19, 2015

really makes me wonder about the machine shop that thought that crank was good.

If i was in a dire pinch.. I'd use it, but not before some prep work.. like a bath in a soloution of phosphoric acid driveway rust remover ( water mix ). might even rig a drill pump and some tubing to circulate rust remover thru the holes and ports and let it then set, then flush again, then blow out.

looks bad...

TheOldHokie · Aug 19, 2015

(quoted from post at 10:15:01 08/19/15) really makes me wonder about the machine shop that thought that crank was good.

If i was in a dire pinch.. I'd use it, but not before some prep work.. like a bath in a soloution of phosphoric acid driveway rust remover ( water mix ). might even rig a drill pump and some tubing to circulate rust remover thru the holes and ports and let it then set, then flush again, then blow out.

looks bad...

I would suggest starting by hot tanking it, tape something like old bearings around the journals to protect them, and shot blast it to clean the exterior. Then follow up with a good reaming job with some stiff galley brushes and a soapy hot water wash BEFORE it ever went on the crankshaft grinder. It might even take more that one hot tank swim to get it cleaned internally....

TOH

souNdguy · Aug 19, 2015

I can't believe they cut it like that and sent it out.

teddy52food · Aug 19, 2015

Drill bits should have been used before grinding. If you do use it, drill them all & have the shaft polished again.

Mdparrott · Aug 19, 2015

I'm happy with the other work they've done. Just an issue with this crank, was a little surprised when they got it in and decided to use it. Always kind of felt like he just wanted the business on turning it in.

I have another option on getting a used crank turned, but these guys saved me $100. They said there was a "Little staining" on one of the journals after they turned it, when I went to pick it up there "little staining" was some minor pitting. But they convinced me that polished out it wouldn't be a problem.

I'm going to see if I can get my money back out of them and probably go the other route. Hopefully they won't fight me on it, if they do I may have to go the cleaning route.

Mdparrott · Aug 19, 2015

(quoted from post at 07:46:01 08/19/15) I can't believe they cut it like that and sent it out.

Yeah. Me neither.

Talked to my guy a bit ago. He told me he thought they had them well cleaned out before I picked it up. I'm going to drop it off, he'll tape the journals and bead blast it, brush and clean the passages. I'll also have him hot tank it and drill the holes to clean out as much as he can then repolish. See where we can go from there.

souNdguy · Aug 19, 2015

Good deal

If it cleans up, I'd be ok using it

TheOldHokie · Aug 19, 2015

(quoted from post at 12:34:04 08/19/15)

(quoted from post at 07:46:01 08/19/15) I can't believe they cut it like that and sent it out.

Click to expand...

Yeah. Me neither.

Talked to my guy a bit ago. He told me he thought they had them well cleaned out before I picked it up. I'm going to drop it off, he'll tape the journals and bead blast it, brush and clean the passages. I'll also have him hot tank it and drill the holes to clean out as much as he can then repolish. See where we can go from there.

In addition to inspecting all the oil passages I'd be sure to mic the thing carefully after getting it back.

TOH

Mdparrott · Aug 19, 2015

Think I'll plastiguage it also.

Mdparrott · Aug 23, 2015

Update on the Jube crankshaft....

Took it back to the machine shop to have them work on it. He drilled the oil passages, flushed them out and repolished the journals. Said it was good to go.

While working on reassembly, I found that the rod journals he drilled had burrs on them. Big enough to catch my finger nail on.

Bottom line, I'm done. No way in hell I'm going to use this crank. I think those burrs would eat the bearings right back out. Don't know how I'd sand or smooth out the holes without scratching the polished journals.

So......anyone have any good sources for a serviceable NAA crank so I can start again? :x

Mdparrott · Aug 24, 2015

"Update" update.......

Called my machine shop and gave him his bad news. Told him I'm not using this crankshaft.

Found another crank at (fairly) local salvage yard that I didn't know existed for a fair price. Machine shop agreed to grind the "new" crank for free, but won't refund money for the cost of the other crankshaft. Did agree to keep it and try to sell it for me.

Overall, better situation than trying to fight or sue for the money back. Being out $150 (until they can sell the old crank) is better than $450......

Crankshaft Oiling Passages - NAA

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