20V CQ Tidy Up

[4WheelDrifter]

The pulley just exaggerates any wobble on the crank, making it easier to spot.

[Error404]

Thanks for the tip mate, I'll bolt it up tomorrow and have a look

[mcandmar]

Sgt Balancer refused to balance it, so I had use another crank.

Was that Philip in BDB? He insisted i measured mine before shipping for that very reason

[andy10v]

Andy yes I have found not all shells are equal, so you have a bit of variation to play with.

Trial and error with plastiguage? And then swap tight-loose?

[G60Rallye]

Good to see you going into such detail on the build!

[Error404]

Cheers Hamish

Trial and error with plastiguage? And then swap tight-loose?

Fit the caps and torque them, then measure the bearing tunnel with an inside micrometer or a telescoping gauge. Then measure the journal. The difference is going to be the bearing thickness plus the oil clearance. Then measure the thickness of all the shells and match them up as closely as you can to the cap/journal requirements. Then you can test fit the bearings in the tunnel and measure again the inside diameters to check. You can then use plastigage as a final stage during test fitting to check your work but it is really not designed as a measuring tool.

[andy10v]

Fit the caps and torque them, then measure the bearing tunnel with an inside micrometer or a telescoping gauge. Then measure the journal. The difference is going to be the bearing thickness plus the oil clearance. Then measure the thickness of all the shells and match them up as closely as you can to the cap/journal requirements. Then you can test fit the bearings in the tunnel and measure again the inside diameters to check. You can then use plastigage as a final stage during test fitting to check your work but it is really not designed as a measuring tool.

Great explanation, thanks!

[JariP]

I measured the pistons and weighed them, matching them up with their respective rods. The pistons are within 0.012mm of each other so I will get the block bored to suit the largest piston - better to have a tad too much clearance than not enough. Worth noting that they averaged around 81.94 so just building it going by the box spec would have meant some of them were only running 0.055mm bore clearance - bad news! Always check!

Are you sure the 0.012mm difference is in the pistons themself or is it just the difference in skirt coatings? I think there's a note in some Wossner prochure that says the pistons are measured without the skirt coating. And measuring with coating gives you false readings.

Have you measured the actual cr those pistons give? Those look like the 8.0 cr pistons?

[AndyP]

Have you measured the actual cr those pistons give? Those look like the 8.0 cr pistons?

I was about to ask the same, the dish look very deep for a stock piston?

[Error404]

Are you sure the 0.012mm difference is in the pistons themself or is it just the difference in skirt coatings? I think there's a note in some Wossner prochure that says the pistons are measured without the skirt coating. And measuring with coating gives you false readings.

Have you measured the actual cr those pistons give? Those look like the 8.0 cr pistons?

That is a good point, there was no information in with the pistons, so I will check with Wossner. The only info I have was what was on the box sticker. They are the 8.0:1 pistons

[AndyP]

Big turbo?

[Error404]

not in the foreseeable future

[Pat D]

not in the foreseeable future

[Error404]

Jesus, that'll give me nightmares

[Pat D]

What type of coils will you be going with Alex?