FYREANT

NOTE: This How-To guide is neither endorsed by or property of Corvette Forum or myself in any way/shape/form. All liability stemming from any actions taken in relation to this guide is solely placed upon the end user. (This means you!)

Many of you know I'm doing a rebuild on my motor for more power. I've got a lot of material for "how to" guides, so here's one of them.

Once you have fully disassembled your engine and have it down to the bare block (pistons, rods, crank, etc. all must be out of the motor!!), you’ll need to scuff the cylinders to provide the needed “cross hatch” for the new piston rings to seat and give a proper seal. This process is called “honing the block”. In order to do this, you need a cylinder hone as pictured below:




A proper hone is achieved typically with a 45° cross hatch. What is a crosshatch? Well, first we need to understand how to perform a hone to understand the crosshatch that it provides. A hone like the one pictured above is put into a drill and then the person honing start spinning the drill and then puts the hone into the cylinder and as the drill is turning they are moving the hone from the top of the cylinder to the bottom of the cylinder repeatedly.

By doing this the rocks on the end of the hone will scratch the surface of the cylinder wall in multiple direction. Where these scratches meet, it will create “angles” which we call the crosshatch. You want the angle of these scratches to meet and be around 45° as this will allow the right amount of grab for the rings to wear them into the cylinder shape properly. Here is an image to help give you a visual of the crosshatch concept.




There are two main types of cylinder hones you can use, the glaze breaker hone, and the brush/ball hone, also known as a flex hone… or as I like to call it, the “dingleberry hone!”.. Lol. I have never used the glaze breaker type before as the ball hone has always been perfect for what I needed and since the ball hone has multiple points of contact, it will make sure to get any minuscule high or low spots of a cylinder wall if they exist.

For our guide here, we use a brush/ball hone to scuff the surface of the cylinders. There are many different size brush/ball/flex hones made, so in order to get the correct one for your application you will want to choose the next size up from your cylinder bore size. For the LT1 with a bore size of 4.065” (103.25mm) we use a flex hone with the size of 105MM. there are also other options such as the sanding grit and the type of material used. I chose to go with Silicone Carbide at 320 grit. The part number for the hone I used is GB41832 from Brush Research, the makers of the flex hone, which can be found here, as well as other online retailers.

http://www.brushresearch.com/out-of-....68&item=93745

Below is an image of what a glazed cylinder looks like after many thousands of miles of use:



Here is an image of a cylinder after it has been honed properly. Notice the crosshatch:




Now in order to do this as I described above, you need to make sure you properly lubricate the cylinders before, during, and after the hone. For this, I use WD40. WD40 is thick enough to provide the necessary lubricity while also being thin enough to stay out of the way during the process. First, you’ll want to spray down the cylinder walls and use a paper towel to spread the WD40 to all areas of the cylinder walls. Do this for all cylinders.

Next, you perform the hone process as I briefly outlined earlier. Start spinning the drill, before inserting it into the cylinder and move it up and down while the drill spins ensuring your hone touches all areas on the cylinder walls. Do not go too slow, and do not go too fast for the drilling action as well as the up and down action. You’ll have to find the sweet spots for this as it takes practice to get the right speed down.

Make sure that you only hone the cylinder for 20-30 seconds or so per cylinder! Remember you are removing the shininess from the surface, not boring out the cylinder! Also, make sure when you pull the hone out of the cylinder you continue spinning the drill until you are clear. Failure to do so will result in you dragging the hone ***** vertically which will scratch the cylinders and cause blow-by in your final product.

Now you’ll want to clean the cylinder out with some brake parts cleaner and examine your crosshatch to see how you did. As long as it looks good, it’s time to clean up the excess crap left behind on the cylinder walls. Use plenty of brake clean to get all the gunk out. After this, you should also use an abrasive nylon brush (also looks like a hone that mounts to a drill) with some warm water to clean the scratch ridges, or “plateau’s” as they are called, thoroughly. Once all cylinders have been done, you’ll likely have to use about a dozen cans of break cleaner to get all the excess material out of the block.

Once this has been completed, you will want to use WD40 again to lubricate the cylinders while the block sits. This will prevent any rust from steel sleeves from setting in while the block awaits pistons.
Hope this helps!

Ant

rrsperry

First, not saying you can't do that, but if you are building an engine, why wouldn't you have an actual machine shop do the line boring, and honing when they're doing everything else that building an engine requires?

And yes, I'm assuming you don't have a bunch of Sunnen engine building machines in your garage...

FYREANT

I am not having anything done to the block by a machine shop. No line or cylinder boring, milling, etc. I am simply cleaning up the block, crosshatching the cylinders, replacing bearings and doing drop in pistons. If you are having other work done at a machine shop, by all means have them hone the block. This is not intended for those folks. I have all the tools I need to check clearances and tolerances on the block itself for my build. Building an engine does not necessarily -require- a machine shop do all that work unless the block is believed to be way out of wack or high mileage. Rebuilding an already "new" motor is much simpler.

I will be doing several other How To's this week including how to file fit piston rings, trunion upgrades, cam phaser limiter install, how to degree your cam, etc. this is just a piece of a larger build. thumbs:

Ant

robert miller

Ant well on your way here on the motor. Looks like you have done all of your research on each & every step of your job's on the car.

This one I wouldn't try to do with all the little things that if you don't get correct will mess up the motor. Like oil pump to get the best pressure on it. Plus the cam

Putting blower on the car & meth no big deal. headers & all that stuff is a little job. Tuning is a no no also for me

Kevin Parent

Take it to a machine shop and let them touch hone it. Would suck to get it together and not have ring seal only to tear it back down.

FYREANT

Thanks Robert

I sure have done my homework on all this!

Having the machine shop do it is always an option. I chose to do this at home simply because I have all the tool for this, can measure tolerances such as bore diameters, bearing jounal diameters, runout, etc. getting a good seal will also depend on proper ring end gap which will be one of the upcoming how to's. In any case, this can serve as information for those that had no idea how this works or how its done.

davepl

If I were slapping together a Mark IV big block, I'd get the drill out and hone it myself just like you are doing.

If I were building an LT4, though, I'd have questions about surface finish, thin metric rings, low tension rings, and so on. I don't know enough to know if things have changed in 40 years, but I have a suspicion they might have.

In other words, how confident are you that the old "ball hone on a drill" is going to meet whatever requirements of your ring package are? Since you're likely the guy buying the rings, they might have specs...

FYREANT

The rings are part of the drop in piston kit. They are file fit rings. Vengeance did all the homework with the rings and piston kit working with Wiseco, all thats needed is to file fit them to your cylinders after honing. In my case, I also measured for cylinder bore size, taper, out of round, oil ring tension, etc. I am confident the ball hone did a fine job.

Ghostnotes

Exactly,

When i went forged on my L76, i kept the same bore size since it was still in spec. I did not want to add any further weight to the rotating assembly since i would be turning 8500rpm. So i simply did a manual hone on it. If done right, there is no difference between cleanup hone by hand or CNC.

robert miller

All machine shops are not the same, At least if you do it your self you know for sure how & what was done..

lakemg

L76??? I remember seeing "Ghostnotes" on GRRRR8 and/or G8board, I assume that was you?

FYREANT

Word!

JHEBERT

Its going to be fine, as long as you don't remove any more material than you need to, and use the proper grit ball hone per the ring manufacturers specs. Personally, all the ring filers I have seen take too much time to get a square gap. I use a dremel extension mounted in a vise to get them near perfect, and I can have them gapped and matched to the bores in under an hour with minimal gap taper (.001). Get the finish wrong and the rings will fail to seat, and you will have blowby and a host of other issues.

Personally, I think you got this, all the way

John

Rookieracer

How about using a torque plate to simulate the distortion the cylinders experience when the head is bolted to the block?

FYREANT

Good question. Is it required, no. Will it yield an overall better ring seal, probably. I don't have a torque plate for the LT1 so I chose to forego this step. A fair question nonetheless.

Ghostnotes

Yep that's me.

StarFox

There are a lot of people saying you should leave this to a shop. But there are guys who won't do an oil or air filter change themselves, and there are guys who won't don't think a shop will put as much care into their build as they will. Both are fine. If you're not comfortable going this deep into the engine, leave it to the pros.

But for people like me who want to learn, I'd like to say thanks for doing all these detailed writeups. Even if I've done this on another engine before, it's reassuring seeing a full explanation of it being done on my current engine.