Torque Plate? [Merged 11-6]

[turborebel]

I had my engine builder put on the head, torque down the ARP head studs and measure the roundness of each cylinder. I did not use a torque plate. The car is running very well. If a torque plate is available use it, if not don't. 500hp+ being the exception.

 

[insanewayne]

Just wanted to add that when torqing down my head with a MLS and ARP's to 100 ft-lbs, there was .002 of distortion in the upper quarter of the cylinders.

I'm very glad I waited for a shop that was willing to order a torque plate.

 

[gsx951]

This is an educational article about hot honing: http://www.circletrack.com/techarticles/82438/index.html

I was mostly looking at the last table, that shows how the out of roundness changes with heat. Seems like it's over a thou in some cases. I don't particularly like their data though because all of their configurations are warped. It would've been much more legible if they had heated an already straight block or cooled a block that was hot honed straight.

Those of us who are machinists are all over this. The ISO standard for inspection is 68*F. and our CMM room is climate controlled for the same reason.
Thermal expansion is huge but a variable we as low budget DSM people can't at this time control.

 

[Defiant]

When ever possible use a tq plate. Especially on iron blocks, even if you just hone it.

You'd be suprised how much the head bolts pull on cylinders.

You can see shadows in cylinders that have been run and didn't use a tq plate.

Which is about the extent of the effect. They still run just fine. There is a point where attention to detail crosses over a line of unhealthy obsession. If you have the opportunity to use a torque plate, there's no reason not to. But I know of no real-world, street-use reason to go out of your way to find one for the job if it's not already handy.