Cylinder Boring

[solly007]

I have been told the engine block has to have a inch plate bolted to the deck and the head studs tensioned down, as the bore will have distortion from the head studs being tensioned down ( two thou ovality ). Is this common practice?, The machine shops here have only heard of doing this in aeroplane engines.

[Vevapower]

Are you running the factory girdle or an Atomic or similar race version?

If your running a big girdle and using studs top and bottom I'd check the tunnels and if they need a tunnel bore then best do it.

Not uncommon by any means but a lot of people don't care to check the tunnels and just get on with it!

[Ralph Wiggum]

is this common practice?

Yes google torque plate honing and all your questions will be answered. Its common in Aero engines because they must perform well for there entire engine life. Kind of the same experience you would want from a hypo car engine yeah?

[turbotrana]

For a performance build you bore it with the plate in place and bolts torqued up.

My last block even had the mains all torqued up. Its done as the bolts distort the block so gotta bore it with them in to get a truer bore finish.

[ratter]

years ago this was not a common practice but most high end builders will do it this way now to get a more accurate job

[turbotrana]

I've read that some (in the states)even run hot water thru the block (running temp) to take the distortion idea even further. A bit tricky with the clearances I would think.

[Chaos310]

Its always good practice to machine the block with a torque plate. for almost any type of work, boring, honing, line boring... it all counts. If you're after 10/10ths, get it to a machine shop that knows what they are on about. it may not get you much/if any extra HP, but it all counts for reliability in the long run.

[gaz097]

Anyone here fitted standard pistons to a standard bore. Mahle sell standard pistons to suit 92.28mm bore which is exactly what my bore measures at in all cylinders. even the ring end gap at top, middle and bottom is within a thou?

[JVK]

Std bore size is the best one to run if possible. It leaves the the cylinder walls at their best wall thickness which is better for ring sealing, heat dissipation and strength. The only other option is boring and fitting thick wall sleeves for maximum cylinder strength.