Hello,

I have two blocks which just got bored & honed with a torque plate & arp head studs.

One of them is an LS3 and the other a Gen V LT1, so both aluminium blocks.

However both blocks got bored & honed without the main caps installed.

How likely is it that the cylinders will be out of round once the main caps are installed with stock fasteners?

Should I ask the machine shop to slightly hone both engines again but with the main caps (and torque plate) in place?

Or should they check first if the bores distort once the main caps (and torque plate) are in place and then hone if required?

 

Is this a joke? No machinist worth his or her weight in salt would ever consider plate honing a block without the main caps torqued to spec. I can prove the cylinders will distort when the caps are torqued with a dial bore gauge.

 

All the machines I am Familiar with require the main caps to be installed when you hone the block.

So it would be foolish not to torque them to spec at that point.

 

Is this a rage bait post? Lol.

 

I agree with the others. In fact, IIRC, aren't the boring, decking, and honing operations done with the block registering off the mains? I could be wrong, but I don't think so....

 

This is not a joke, thanks for the replies.

 

Absolute hard no.

You should take what you have somewhere else. I would not trust any other work they did to the block.

 

Agree with bthomas. They had their chance. In fact, I'd contact them and educate them by bitching up a storm! Have a good shop, if any are in the area, torque everything in place and measure the cylinders with a bore gauge for out of roundness and taper......

 

Thanks for all the replies so far.

I spoke to my machine shop about the issue and they told me that they would need to make a special adapter for their bore/hone machine if I want the main caps mounted in place during boring and honing.

That is why they bored and honed without the main caps in place but assured me that this is not going to cause a problem.

According to them I need to hot bore and hot hone the block anyway if I want to have perfectly true bores.

I am based in Europe, hence they can not specialise in LS engines as those are rare here and it is simply not worth for them to make such an adapter.

The adapter would weight over 200 lbs and would be very large according to them, hence it is not so easy to make one.

However I am disappointed that they did not gave me this information beforehand so I could at least decide if boring and honing without the main caps in place is OK with me.



What would be a good and what would be a max. acceptable out of roundness and taper on a freshly bored and honed block with dual torque plates mounted and main caps installed and torqued to spec?

I read that machine shops aim for 0.002" (good) and .0005" is acceptable, can you confirm?

According to the LT Gen V workshop manual the maximum out of roundness seems to be .0009" on a used engine.

What is an acceptable deviation between cylinders?


The piston to wall clearance was already honed to 0.001" with both engines, so I assume honing them both a second time by another machine shop (with the main caps and torque plates in place) is not possible anymore or the bore size will end up being too large?

 

Being in Europe is a complication on finding a good LS shop. Before going nuclear, I'd torque the mains in place and MEASURE the bore distortion. IMHO, the shop that did the work should be honorable enough to make the bore gauge measurements for no charge. Using stock bolts vs studs on the mains will result in less bore distortion, so you have that going for you. The shop was correct in that doing the work HOT would result in better geometry while running. If you're stuck with some bore distortion, use the thinnest rings you can; they'll be better able to follow the distortion. Is this a "go for the gold" race engine? If so, maybe consider gas ported pistons or top rings.

 

^^^THIS, RIGHT HERE.
Obviously, what happened isn't ideal, but maybe the bores aren't as bad as you think. You won't know until you measure it.

Remember, even a perfectly honed block, the cylinders aren't going to stay "perfectly" round. A little bit of distortion is going to happen, you just try to minimize it.

 

I learned long ago there's no such thing as perfect. Nothing is. But it certainly doesn't hurt anything to pursue it to the fullest, which this shop didn't do. Agree on the "thin ring" (.043"?) post. As stated, measure the bores. They may be OK for what you're planning to do with the car. I hope they are, and best of luck to you....