Honing?

[squirrel]

Re: Honing?

The problem with motor oil is the oil. Oil is used to float metal over metal.

AFT is best.

I may be really ignorant, but I thought that ATF is mostly oil....????

(I use it to wipe down the cylinder bores before assembling the engine, but I put oil on the pistons and rings)

[Robert1320]

Re: Honing?

Finish you machine work and clean the block.
Take clean white paper towels and wipe the bores.
Try

Carb Cleaner.
Brake clean.
Motor oil.
& AFT.

Now take a clean towel w/ AFT and wipe the other three bores.
You will see how much dirt it pull out of a "clean bore"

Yes the AFT is an oil but it is different from motor oil. It will allow the rings to touch the cylinder walls and seat. With motor oil the ring could float over the walls and not seat.

Richard (owner of Dart Machinery) will tell you to use AFT as well.
{Stealing my ideas > }

[Barry_R]

Re: Honing?

Ra by itself wont show you squat on brush hone finish changes - - maybe if you were a real brute on pressure...you just are not changing that value with the brush. The brush cleans and conditions the surface - very, very little material is removed, thus Ra is unaffected.

Ra is a roughness average and by itself is only somewhat useful in bore analysis. You need the number to be within a given range - but as an average it does not provide info by itself you need to decide whether you're doing it right or not.

Rpk and Rvk numbers will provide information regarding the depth and width of the voids and peaks in the plateau finished bore. You need adequate void volume to keep oil in the bore without flooding the surface, at the same time you need enough surface area to seal and minimize wear (caused by unit contact pressures).

The tool used for this stuff is a profilometer, and for further analysis they use fax film - a name for a plastic mold (dissolved in acetone) of the cylinder wall that is viewed under a microsope. The good thing is that most engines are pretty forgiving and close and clean is good enough in 90+% of the cases.

I will use a variety of things to clean a cylinder - just like the prior post. Hot soap and water, Brake cleaner, WD40 - but my installation is usually plain old oil (often on the bores that are still damp from the WD40). I believe that oil is what will be sprayed on those cylinders with 5 seconds of startup - and that is what should be there in the beginning. ATF is not suitable for high temps, dry (like one particular ring marketer recommends) is stupid, powders are gonna be gone before you hear the first pop - - and I think it all the magic tricks are just a risk with no reward.

[BigBlockMopar]

Re: Honing?

Robert1320,
You mention "AFT", but I suppose you mean "ATF" right?

Good topic.

[Robert1320]

Re: Honing?

Right good old fashion AFT, type F.

Seems to work good enough for 500- 2000 hp set-ups?

[KeithTurk]

Re: Honing?

I wish I knew how to draw on this thing... but here's the way I understand it...

The Peaks and valleys cut during honing create debris ... Think of the peak of the piramid getting tipped over into the Valley sitting beside it... so you have this tip hangin on by a shred of metal.... it's almost perfectly upside down in the Valley and happens to mate and match it... Polishing light honing so on and so for still leaves this tip sitting there...

The Intent of Dupont's products ( I'm sure there are others )... is to lightly clean those peaks out of the valley's while leaving the intitial honed finish as it was....

How many of you have taken a brand new motor apart and seen black stuff on the side of the piston? My friend would tell you that was the Peaks cut during the honing process and ultimately that's where the majority of wear comes from in a new motor.

So there ya go... I don't profess to know anything about it other then I spec the product when I have an engine honed and have taught several of my local engine builders about it by introducing them to Dupont's line...

Like Oil... amoung guys that would frequent our tech section... Honing is always going to be a bit ahhh well personal...

Keith ( I beleive Oil should be clean )

[BigBlockMopar]

Re: Honing?

I wish I knew how to draw on this thing...

http://www.imagination3.com

;)

[JeffMcKC]

Re: Honing?

I too use ATF and have found the rag to be dirty, In our dealership we have had the same issue as Keith is talking about after turning rotors, and putting the new pads on, the damn thing would not stop, from a low speed they are ok, but a panic 50 MPH plus they just slow down, the metal gets into the new pad and rides on that against the rotor.( like a piston on the cylinder wall) After turning the brakes we sand them, then clean the heck out of them, with soap and water, then "rag test" them to see it they are clean.

[min301]

Re: Honing?

I too use ATF and have found the rag to be dirty, In our dealership we have had the same issue as Keith is talking about after turning rotors, and putting the new pads on, the damn thing would not stop, from a low speed they are ok, but a panic 50 MPH plus they just slow down, the metal gets into the new pad and rides on that against the rotor.( like a piston on the cylinder wall) After turning the brakes we sand them, then clean the heck out of them, with soap and water, then "rag test" them to see it they are clean.

Back when my brother and I had the Brake Shop, we rectified that by switching the cutting tool, with one designed for positive rake cutting bits. Just like you stated, we would use Scotchbrite roloc pads, and left a nice non-directional finish on the rotors, smoothing the surface much like the sandpaper would.
Not only does this increase stopping power when the pads are new, but because the surface is smooth, it actually increases the amount of initial pad contact, and allows the pads to seat correctly, without hot spotting the pads, or rotors.