Anyone have experience with offset boring?

[Heimedw]

Just called the machine shop today to let them know I'm still looking for a block. I have found a few more complete engines. Then the builder suggested that if I don't have any luck finding a suitable candidate block that he could offset bore my block. They have the proper equipment to do it and it leaves me another option. Just wondering if anyone has experience with doing this?

 

[493 Mike]

Just called the machine shop today to let them know I'm still looking for a block. I have found a few more complete engines. Then the builder suggested that if I don't have any luck finding a suitable candidate block that he could offset bore my block. They have the proper equipment to do it and it leaves me another option. Just wondering if anyone has experience with doing this?

I do. My machinist offset bored one cylinder in my 493 eight years ago. Motor runs well. I have a set of RPM heads, 10.6:1, Hughes solid lifter cam and kit, and a six pack factory manifold. Thru the exhaust cutouts it made 453 HP at the wheels.
Mike

 

[67 GTX]

How would that work? Is the offset bore not enough to cause any interference with larger valves that I'm assuming you'll run?

 

[Jcharger]

I think it has to do with the boring method (head) not with the center point of the bore in the block.

 

[moobster]

Just called the machine shop today to let them know I'm still looking for a block. I have found a few more complete engines. Then the builder suggested that if I don't have any luck finding a suitable candidate block that he could offset bore my block. They have the proper equipment to do it and it leaves me another option. Just wondering if anyone has experience with doing this?

Offset boring. I love this topic!!!
We did it all on my Big Chief engine. PM me and I'll go over it with you.
Nobody wants to here about 1350HP, naturally aspirated, Pontiac motors, here.
If your looking for all out performance, your doing the right thing.
But things like, offset boring, or offset doweling the heads, or offsetting the valve guides, are typically tricks used in class racing.

 

[fratzog lover]

Nobody wants to here about 1350HP, naturally aspirated, Pontiac motors, here.

I would!

 

[dvw]

I asuming in this case the desire to offset the bore is due to core shift causing one side of the cylinder wall to be to thin?
Doug

 

[Heimedw]

That is correct Doug on three cylinders. The machine shop would offset the bore to compensate for the shift about ten thou or so. I wanted to know if this would affect reliability or cause vibration. It sounds like it won't affect reliability or cause vibration at all and even my builder said that in most cases it will actually produce more power. It also saves blocks from being boat anchors.

 

[wyrmrider]

I would not screw with .010 but if not a big deal to the machinist why not
I thought you were offsetting the bore centers for bigger sleeves
(and they said we were cheating)