Cylinder bore honing.
 

Anyone have a preference as to the process of honing a cylinder and how straight and round it should be when done??
Steel plate, aluminum plate, studs, bolts, lubes, torques, etc.
Then what about measuring process, how do you know it measurements are real?

Seems there are a lot of opinions on it. I am referring to a Dart Big M block.

Thanks
Dick

has to do with the rings you are going to be running...different ones want a very specific finish...and it is important...Rob

I have been talking to Dick extensively on this. He doesnt mean what grit stone or type of finish. He is questioning some of measurements he is getting when checking the bores for piston to wall clearance and being round and straight.

You need a dial bore gauge that moves up and down in the cylinder and you can watch the reading on the dial indicater as you do so. This will show you low and high spots. You can then use a inside mic to measure the cylinder and then measure the inside mic with the outside mic which you are using to measure your pistons with. This is unless your positive your inside mic and out side mic are perfectly calibrate the same.

I ask my builder to use a steel plate when honing my motors. Good builders will have plates for applications using head studs and non-studded applications. I always have them use non-studded head bolts, as I want to be able to get the heads off without having to pull the motor.

I would say that more than .0005 out of round should be unacceptable. I have a 4-5" mic that I use on my pistons (at room temp) and I measure the bores of my motor at room temp in multiple locations. The only really good way to check the run-out (or straightness) of a bore is to use a CMM. You can kind of use a dial indicator, but you'd need an angle plate mounting system and a precision rotating device. You may be able to do it on their setup, if they let you.

These work very well. Pricey, but accurate.

http://www.sunnen.com/ProductDetails...D=23&NavID=666

Sunnen's are great.

I should have added... Don't buy or use one of those junk gauges from Summit. They're terrible. If you're getting bad readings with one of those things, it is just as likely to be the gauge as it is a machining problem (maybe even more likely to be the gauge).

Thought maybe some of the Big Engine Builders would share a few secrets, or a least tell you what you should be looking for.

I don't build marine engines, but I have built hundreds of race engines that are in the $20k-60k range. No junk, I have been in a premeir engine shop for almost 2 decades... To measure the bore after the plate is taken off is a waste of time. the bore needs to be measured with the plates on by your machinist. This is why you need to drop off your pistons when you drop the block off to get honed.
The type of plate matters, but it isn't as critical as some might say. On a Sprint Cup or a Pro Stock engine we try to simulate the head as close as possible, but we are looking for 1-2 hp. The most important aspect of a plate is how it simulates how the fasteners pull on the cylinder walls. The actual fasteners, lube, torque and gasket need to be used when honing. I try to use Cometic MLS gaskets on everything I build. I use the actual gaskets to hone with, then clean them and use them in the build.

I hope I answered your questions.

Fresh hone with torque plate, the cylinders are barrel shaped. I think the question is how straight and round do they need to be, or should they be.