Plate honing

[Galon]

When you are plate honing a block, how critical is the time between plate torquing and honing. I like to leave the block set with the plate torqued (couple of hours) to allow for complete distortion. Or is this a waste of time? I've always felt it was necessary to allow the block to stop moving. Just curious of other opinions. Also, many shops in my area don't allow the block to set after honing and check for distortion. A common practice is to hone a .0005 big and let it cool to size. I know this to save time but I have have seen that it doesn't produce the truest bores especially since you have gone thru the trouble of installing a plate. Just looking for the best methods.

[cardo0]

Well if you're that concerned about ring seal then look for a shop that can flow/circulate hot water near 200*F through the block while they plate hone it. Sky is the limit when chasing ring seal. But do you really need the expensive machine work? What is the motor used for? Just a street rod? Ya know very few production car motors are plate honed from the factory and the car will run fine w/o plate honing while saving you 200 bucks.

I read most the gains in plate honing are 1% or less and you need a very accurate calibrated dyno to see them. Not the $100/hr dyno most of us can afford. But the gains do add up. Plate hone, drilled pistons, zero gap rings, vacuum pump. Maybe gain 5% to 10% hp.

Good luck with your build and please share what you find.

[statsystems]

I leave the bores .0005-.0007 small, loosen the plate and let it sit overnight. Retorque the plate and check the bores. They won't be round. Then I would finish the bores to size.

I never found a block that would change after the plate was torqued twice.

[PackardV8]

Interesting

I leave the bores .0005-.0007 small, loosen the plate and let it sit overnight. Retorque the plate and check the bores. They won't be round. Then I would finish the bores to size. I never found a block that would change after the plate was torqued twice.

We'll try that sometime soon.

It will all depend on the block. We've found some engine families, mainly the older pre-thinwall, that aren't affected by the torque plate. Others, SBC, SBF, BBM, Clevelands, large bore BBCs, which move all over.

[ProPower engines]

When you are plate honing a block, how critical is the time between plate torquing and honing. I like to leave the block set with the plate torqued (couple of hours) to allow for complete distortion. Or is this a waste of time? I've always felt it was necessary to allow the block to stop moving. Just curious of other opinions. Also, many shops in my area don't allow the block to set after honing and check for distortion. A common practice is to hone a .0005 big and let it cool to size. I know this to save time but I have have seen that it doesn't produce the truest bores especially since you have gone thru the trouble of installing a plate. Just looking for the best methods.

It always depends on the block and what finish you want to use.
I always hone blocks in 4 steps starting with .006" from finished size that way the last .0005" is done with very light pressure and also done in stages to allow the block to normalize back to shape while getting closer to final size.
And always use the same type of gasket between the plate and block that will be used when the engine is assembled to keep the distortion the same. I have seen different bore shapes after a block is finished using an MLS gasket when honing and when a customer finds they are not in his budget and assembles it with a conventional composition gasket

The middle of the bores always seem to grow back thus you are using too much honing pressure but going from .006"to .001" and allowing the block to cool for about 3-4 hrs before going the next little bit will allow you to see the high spots.

What machine are you using and what stone numbers are you using to finish the bores for your most common ring type??
There may be a technique change thats all that is needed to get you to where you want to be when finished.

[Zmechanic]

I read most the gains in plate honing are 1% or less and you need a very accurate calibrated dyno to see them.

That's such a massive over-simplification of the issue I'm not sure I'd be able to trust the advice of whoever wrote it...

[SupStk]

I'm on the side of torquing and letting it sit for a while. During the hone process they get untorqued and repulled. Also let the block cool before the finish hone.
Agree with using the same gaskets and fasteners the engine will use, including figuring the grip length.
Probably won't work well in a production shop but that isn't what I'm after.

[modok]

I don't do the ".0005 over and let it cool", although that used to be common.

Rather I take out the last .001" 7-12 strokes at a time, and I don't measure the cylinder right after I pull the hone out.
Rather I will FIRST I measure the cylinders, guess how many strokes each needs, then just hone each that much, then switch to the other side of the block or go do something else for a few minutes. Repeat as necessary until base finish is at desired size.

As you reduce honing pressure, need to switch to softer stones so they don't load up.

I don't know if letting it sit BEFORE honing would be better than just taking your time in general. It does seem to be true that there is no such thing as going too slow. The more you drag your ass the better the results in general.

I don't know if re-torquing the plate is a good idea but maybe it is. Seems reasonable.

[cardo0]

I read most the gains in plate honing are 1% or less and you need a very accurate calibrated dyno to see them.

That's such a massive over-simplification of the issue I'm not sure I'd be able to trust the advice of whoever wrote it...

Then can you enlighten me with how much of a difference that should make and the source of your information? As I don't dyno engine builds for a living I have to read from those that do and I'm interested in good references. What are yours?

[FloydODB]

I read most the gains in plate honing are 1% or less and you need a very accurate calibrated dyno to see them.

That's such a massive over-simplification of the issue I'm not sure I'd be able to trust the advice of whoever wrote it...

Then can you enlighten me with how much of a difference that should make and the source of your information? As I don't dyno engine builds for a living I have to read from those that do and I'm interested in good references. What are yours?

because of the same reason a .030" warn nonplated honed engine still runs. I have a homemade torque plate for SBC. 416 SBC with AFR 227 Comp VII makes 720hp. @ 1% I'd like to make 727hp but can't afford all goodies. some machinist spend too much "time" searching for 2hp when the owner should spend a little "time" on the car for a far better improvement in "time".

[Zmechanic]

I read most the gains in plate honing are 1% or less and you need a very accurate calibrated dyno to see them.

That's such a massive over-simplification of the issue I'm not sure I'd be able to trust the advice of whoever wrote it...

Then can you enlighten me with how much of a difference that should make and the source of your information? As I don't dyno engine builds for a living I have to read from those that do and I'm interested in good references. What are yours?

Mine are reality. Could it be 1%? Sure could. But can someone so brazenly say that and have it be accurate all the time? Not a snowballs chance. I don't take issue with the number, I take issue with something being asserted that can't possibly be applicable in every case as it is suggested.

And on a philosophical note, someone whose response to a very complex topic would be "ahh, it only matters about 1%..." would likely not be someone I'd take advice from for very long. Even a simple "there's no way to know without trying" or "it depends on the block" would earn my respect.

Why do I say that? Because I've asked similar highly complex open ended topics to very knowledgeable people. And they responded "no way to know until you try". At first I was disappointed. That's not satisfying. But then I realized their integrity wouldn't let them just assign some blanket sweeping generalization because they knew better.

[KnightEngines]

I just fit the plate & start honing, gonna take a while to finish it so no point in letting it sit.
Knock it to .002" to go with coarse stones, then to .0005" or so to go with whatever I reckon will suit, then let it sit for an hour or so & go back & go to finished size (working across the bank honing each cyl a bit at a time). Then let it cool again for another hour, then recheck, touch up as required (usually minimal) & 6 or so strokes with the finishing stones.
Then on to the other bank.

Big shops can't afford to keep a machine tied up for a day to hone 1 block, so they almost never let it cool, they just guestimate where it'll end up, you can tell those ones, they are always a bit tight about 1" down from the deck.

[machinedave]

I have found that you can spend all day carefully honing a block to final size, come back 8 hours later and check it again. I use my IR temperature guage to confirm 69 degrees. Now come back the next day and it can shrink a few tenths even at the same temperatures.

[Roundybout]

I think taking the time to get a perfectly round bore exactly placed with the finish you need for the application and taking the time to measure each component (piston, crank, rod, bearing, ring, ect.) and setting clearences as appropriate at as close to the same temp is worth more than 1%.

[rustbucket79]

I have found that you can spend all day carefully honing a block to final size, come back 8 hours later and check it again. I use my IR temperature guage to confirm 69 degrees. Now come back the next day and it can shrink a few tenths even at the same temperatures.

I've experienced the same thing. The block is going to be in the hone for a few hours of cooling time before the final few sweeps, job (time) management is one of the many tasks of a competent machinists.