Best way to clean the passages in newly ground crank

[GB SISSON]

I have a 4" crank that was ground for me a couple years back. It came with threaded pipe plugs in a little baggie. The tag claims that the mechanic needs to clean out these passages and I understand that's quite normal. I still don't know why they don't do it in the machine shop and install the plugs. Oh well, can someone explain the best methods, best solvent or solution and tools required? Thank you. GB

[ford38v8]

Originally Posted by GB SISSON

I have a 4" crank that was ground for me a couple years back. It came with threaded pipe plugs in a little baggie. The tag claims that the mechanic needs to clean out these passages and I understand that's quite normal. I still don't know why they don't do it in the machine shop and install the plugs. Oh well, can someone explain the best methods, best solvent or solution and tools required? Thank you. GB

If they provided that level of service, they'd have to charge an arm and a leg to ensure against debris left behind. You don't want to pay a professional to do grunge work, and they don't want to risk the complaints anyway.

[GB SISSON]

Thanks Alan, That makes sense. I guess I'll just use a solvent and some wire and compressed air. I expect that what I will be removing is old congealed motor oil sludge like we find in the valve area and in the sump, mixed with abrasive dust from the crank grinding process.

[KiWinUS]

GB I have performed this task many times. It is very difficult to get them perfectly clean as they need to be and I am anal on this. The crud packs in there hard and dry. Poke and pressure was first. Now dry and using very good tape I use silver polyken , tape up journals very tightly and neat. Poke a hole through tape to let media escape. I now bead blast them until they are clean. ( I have a very large very powerful pressure bead blast machine) it can still take some time to get it all out as I said it can be rock hard. Remove tape and pressure wash again. Dry it and inspect. If it looks clean back to the solvent bath and use your brushes to final clean all galleries. If the grinder did not chamfer the oil holes on journals I now do that and repolish crank followed by another solvent bath. They are a lot of work to do correctly. As stated I have tried many other methods with poor success. Next best is a small dingleberry hone. Don’t try to drill it out. Good luck.

[rich b]

If the crankshaft co. said they cleaned the crank; I would still clean it myself; common sense.

[GB SISSON]

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Thanks! I will dig into it after Christmas. It sounds like a formidable task...

[rotorwrench]

I still use the special soft plugs. If they are already out then at least a person can get all the crud out. If they haven't tapped the sludge plug bores for NTP threaded plugs then it will need either tap threading or the OEM plugs can be driven in. A person can stake them if they were previously or if worried about them coming out in service.

Use a drill bit the same size as the sludge plug bores to aid in cleaning them out. If a drill or punch the same size as the oil flow ports is handy then it can be pushed through each port. The crank could have been hot tanked but maybe they didn't have one.

[38 coupe]

Mart has a video with some nice footage of cleaning grunge out of the crank journals: https://www.youtube.com/watch?v=TTzY3xHNHe0

[ford38v8]

Originally Posted by 38 coupe

Mart has a video with some nice footage of cleaning grunge out of the crank journals: https://www.youtube.com/watch?v=TTzY3xHNHe0

Good idea there. Mart had a video camera recording every event all the way back to the womb!

[GB SISSON]

Perfect! That was great seeing the process up close and personal. I did not notice if my crank had been tapped, but with those allen head plugs I will assume so until morning. I poked in there this afternoon with a piece of 1/4" rod stock and all but one passage made a metallic clank when bottomed out. The one that didn't went thud instead. It had gray crud from that one. I bet mine was hot tanked. It's a pretty big machine shop that does mostly agricultural and industrial engines. Either way, I will go after it with all I've got.