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Is This Okay..

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nissan200sx.dk Community Regular

nissan200sx.dk

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Hi.

Have a question about me RB25DET s1 engine that im building.

My tourque wrench is one from work, our test department uses it. Its calibrated 2 times a year, and uses a dial gauge built in it. Goes from 0 - 80Nm.

Just tourqed down the main cradle, but now my crank sort of "binds".

When the crank just has been turned around, it will spin free, and only require ~2 N to be turned. (You cant really measure it as it really doesnt move on the dial.) Easy to turn by hand.

When the crank hasnt been turned for a minutte or so it "binds". Will need around ~5 N to get it to spin free again. (On the dial gauge you can only see it move, and then drops back to nothing as the crank begins to turn / frees it self from the "bind")

Is this just oil friction I have to overcome just when turned? or?? Could this be a problem?

Best Regards

Ronni

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nissan200sx.dk Community Regular

nissan200sx.dk

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The applied force just need to be a little higher to get it to turn over when it has been standing still for a little minutte or so.

After it has begun to turn the applied force to turn it is close to nothing. It turn freely the hole way round. There are no spots were it feels more or less freely to turn.

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nissan200sx.dk Community Regular

nissan200sx.dk

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Have measured both crank and cradle, ordered correct bearings, got the ordered bearings. Mounted with clean surfaces (back side of bearing) and used plenty of motor oil to lubricate.

When it is turning it feels free and top nice. My only concern is what it is that is "holding" it when it hasnt rotated for a minutte or so. What i need to overcome for it to turn.. Could it just be oil friction? Because when using the tourque dial gauge the applied force to get it turning (when i have to overcome what is holding it) is only just the needle moving, only just moving, not even up on the dial...

But when it has just been turned, and then turned again there is nothing holding it. The needle doesnt move to turn it.

Tomorrow i will try with a different tourqe dial gauge. goes from 0 - 8N. Should be apple to see more accuratly.

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SilverECR33 Veteran

SilverECR33

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On older engines, it was perfectly fine to use oil, i cannot comment on whether grease would have been better or worse. But I thought your not ment to use grease on ur main cap bearings.

What I can say, (which sounds like your describing), is that when the crank is stopped, its harder to get moving, then once its free its fine. then when u stop, it sort of sticks.

On the last rebuild on my v8. The crank did the same thing. and it was perfectly fine. If your really worried about it, borrow another torque wrench, and retorque it. and see if its the same.

since their is no oil pressure, the bearing oil hole and groove, can only pickup oil from spinning. when you sit still, the oil is pushed back off the bearing into the groove, you have to then spin it to pick up the oil into the hole and groove again.

Thing is, you must still be able to move it buy hand, at the correct torque. if its harder than that. its possibly too tight.

but i would rather a professional post here. as Im a novice. good luck.

Edited by silverbulletR33
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