Keith Black wrist pin lubricant Options

[jmargush]

I was reading the tech sheet that came with the pistons and they mention to make sure you use a high pressure lubricant on the pin and pin bore.

Is Brad Penn break in oil ok or do I need something else?

[rick 918-S]

Engine assembly lube on pins and bearing. Oil on rings and cylinders. It's about film strength until the oiling system is purged of air. Even a primed system can take a few seconds or longer to purge trapped air. This air can cause the surfaces to collide as it passes across the surfaces and looses film strength.

Also I don't think we had this discussion here but there has been mention of ring break in. I've read posts of like 500 miles to break in the rings.... (IMG:style_emoticons/default/screwy.gif) I've read it described as rings wearing into the cylinders. If this were the case and rings could actually wear in that fast they would be worn out in 10k miles.

Here's my take on rings. If your cylinders are true and the end gaps set properly the engine needs to purge the air from the oiling system. Once oil is collected on the cylinder walls the rings become a scrapper. oil is a pressure device filling the space between the piston gap and ring. That's where the break in ends. All you need a full heat cycle and good clean oil pressure.

Let the flames begin.

[VaccaRabite]

for wrist pins I have just used motor oil. Lots of oil.

[DBCooper]

No flame, but the cylinders are honed at a sharp angle, not smooth, so the rings take the top rough surface off the hone, seating the rings into the cylinders. From that point onward it's like you describe it, with the rings being scrapers, and not much metal wear any more. You're also right about it being all in after the first few heat cycles, so the "break in" that we all used to go through, when rings were usually about an eight of an inch wide, is pretty much a thing of the past.

You want a flame? I always used to lube the cylinder walls with oil, American style, from what I learned as a kid with farm equipment. Then twenty or so years ago on the first internet bulletin boards I heard aircooled VW builders putting them together dry, with no cylinder wall lube at all. I though they were crazy, they didn't agree and said they had better break-in experiences that I was seeing, so I tried it. It didn't explode on ignition, instead seemed to run very well, made less smoke but didn't get any hotter than usual, went out the door without problem, and I saw the car every service through probably 75K miles, without any problems. So I've been more open-minded since, but still lube the cylinder walls.

I used to use assembly lube or regular motor oil interchangeably on the pins, no apparent difference. Assembly lube is probably better, though.

[Mark Henry]

Oil with a little blue STP mixed in it. All I have ever used and the only thing STP is good for.

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[rick 918-S]

Oil with a little blue STP mixed in it. All I have ever used and the only thing STP is good for.

(IMG:style_emoticons/default/smile.gif)

(IMG:style_emoticons/default/agree.gif) film strength.