Urq project

[V6quattro]

Oky so there are more bearings damaged.

Your wear looks like the bearing at the half of this page right?

http://www.agkits.com/bearing-failure-analysis.aspx

[diesel des]

Would you say it was wiped? Most bearings were ok maybe a bit stressed.



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[V6quattro]

No i would say it looks more like the 'fatigue' photo. But I must admit I'm not that good at this kind of stuff.

[Error404]

Did you measure the BE bore & crush height of the bearings on installation? Also are you sure you're map isnt knocking?

[diesel des]

Don't have the numbers to had but everything looked good with tolerances between the middle and larger end which should be perfect for a powerful build. The map is only running 1 bar boost and an afr of 0.7 and retarded timing compared to my other stroker so should be very safe.

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[Error404]

Bearing fit is really important to prevent them spinning - I would check this on the other rods. You want about 0.1mm for our size big ends. Oil clearances can be perfect but if the shells are loose in the bore then they don't conform to shape properly and there isn't enough friction so they are liable to spin

[diesel des]

Bearing fit is really important to prevent them spinning - I would check this on the other rods. You want about 0.1mm for our size big ends. Oil clearances can be perfect but if the shells are loose in the bore then they don't conform to shape properly and there isn't enough friction so they are liable to spin

It was only oil clearances that I have measured building any engine. Live and learn. To measure crush are you torqueing the rod bolts with bearing fitted but not on the crank and then loosening 1 bolt and measuring the deflection between the 2 halves?

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[Error404]

Yup that's right mate

[diesel des]

And even with the location dowls they open up ok?

Also thinking I need to change my new expensive oil cooler too. Just in case the oil thermostat was letting a trickle of hot dirty oil in. Which it must of been. Crap another 300 quid...

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[Error404]

Yup, the radial force is really quite strong when the size is right- this force is what stops the shells spinning in service. You can swap the shells round to match up the halves to even up the crush across all the journals / pins
Yeah definitely replace the cooler after a failure unfortunately

[S2central.net]

It was only oil clearances that I have measured building any engine. Live and learn. To measure crush are you torqueing the rod bolts with bearing fitted but not on the crank and then loosening 1 bolt and measuring the deflection between the 2 halves?

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I have also only ever done plastigauge before for bearing clearance.
Can you explain that better ?

[diesel des]

I have also only ever done plastigauge before for bearing clearance.
Can you explain that better ?

Does this help. Basicly fit the shells to the rod while on the bench. Tighten up the bolts to torque. Then loosen on bolt and measure how much the cap opens at the slack end.

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[diesel des]

Can also repeat on the big ends too I suppose before the cranks fitted.

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[Error404]

Mains and big ends. Very important job, often overlooked

[S2central.net]

OK - thanks Des, but what is the spec for how much is too much when you do that ?
I am not really getting it though - why test clearance with one bolt loosened ?