Don Terrill’s Speed-Talk

Hi.
I tipically work on import 4 cylinder engines, 80 to 90mm bore size, and sometimes I have oil consumption problems on fresh rebuilt engines, that in my opinion is due to inconsistent hone finish by the machine shop.
The quality of machine shops in my area in not that high, so I'm trying to give them precise instructions for the honing process.
We have no profilometer.
They use no fancy stones, very basic stuffs, or maybe emery cloth wrapped around the stones.
So, whats your advice on grits, number of strokes, etc. to obtain the best cylinder finish?

Torque plate should always be used, especially high performance builds. In addition to that, the cylinders should have a definite cross-hatch pattern and the final hone should be completed with a "plateau" hone. The plateau process will take off the very sharp peaks of material, therefore helping to seal the cylinder. The cross-hatch pattern is necessary to insure that adequate amount of oil is available to the piston rings.

Thanks, good infos, but I already know them. Can you share some more in depth details? Best cross hatch angle? Grit to use to obtain the correct plateau hone?

eTiLiKo wrote: ↑Tue Mar 13, 2018 1:05 pm Hi.
I tipically work on import 4 cylinder engines, 80 to 90mm bore size, and sometimes I have oil consumption problems on fresh rebuilt engines, that in my opinion is due to inconsistent hone finish by the machine shop.
The quality of machine shops in my area in not that high, so I'm trying to give them precise instructions for the honing process.
We have no profilometer.
They use no fancy stones, very basic stuffs, or maybe emery cloth wrapped around the stones.
So, whats your advice on grits, number of strokes, etc. to obtain the best cylinder finish?

Are you just honing to tidy up a cylinder for new rings OR boring then honing for oversize pistons aswell?

what rings?
is the block iron, aluminum, open deck?

IMPORT??? cmon man that could be anything.

Torque plates aren't required on all engines, only low quality ones.

joe 90 wrote: ↑Tue Mar 13, 2018 11:34 pm Torque plates aren't required on all engines, only low quality ones.

It depends how accurate you want to be and how tight you want to run the piston. All blocks distort to some degree when torqued up.

I m talking of a complete boring and honing job. Honda, mitsubishi, nissan, tipically alu engines with integral iron sleeves, some are open deck some closed, but I don t think that it makes any difference for cylinder finish. I alwaysbuse torque plate on open deck or resleeved blocks. Rings....what come with wiseco, CP, JE, i think low tension japanese made rings.

eTiLiKo wrote: ↑Tue Mar 13, 2018 1:05 pm Hi.
I tipically work on import 4 cylinder engines, 80 to 90mm bore size, and sometimes I have oil consumption problems on fresh

In my part of the world the people who run machine shops are qualified and experienced and it's the wannabe builders who ask the questions who get it wrong.

So maybe you should look at the problem from a slightly different point of view?
There's plenty more possibilities than getting the hone wrong.

eTiLiKo wrote: ↑Tue Mar 13, 2018 1:05 pm
The quality of machine shops in my area in not that high, so I'm trying to give them precise instructions for the honing process.
We have no profilometer.

I think that if you tried that one here, you'd get sent away to the opposition down the road.

joe 90 wrote: ↑Wed Mar 14, 2018 4:42 am

eTiLiKo wrote: ↑Tue Mar 13, 2018 1:05 pm Hi.
I tipically work on import 4 cylinder engines, 80 to 90mm bore size, and sometimes I have oil consumption problems on fresh

In my part of the world the people who run machine shops are qualified and experienced and it's the wannabe builders who ask the questions who get it wrong.

So maybe you should look at the problem from a slightly different point of view?
There's plenty more possibilities than getting the hone wrong.

Mate, I build engines from more tha 10 years, and I have one on the most reputable shop in the south of Italy. I haven't any problem when I buy a cylinder block from the factory, so I have seen the problem from the correct point of view.
My only problem is that in this part of Italy there is no machine shop used to work on performance engines. In my area only one machine shop out of four is able to give me a perfect concetrcicity valve seat on cylinder heads, just to give you an example.

eTiLiKo wrote: ↑Wed Mar 14, 2018 4:05 am I m talking of a complete boring and honing job. Honda, mitsubishi, nissan, tipically alu engines with integral iron sleeves, some are open deck some closed, but I don t think that it makes any difference for cylinder finish. I always use torque plate on open deck or resleeved blocks. Rings....what come with wiseco, CP, JE, i think low tension japanese made rings.

Quoting myself, rings with these pistons are : Gas nitrided top, cast iron with a taper underhook groove face 2nd, two gas nitride rails with a low-tension expander OIL.
And I'm talking of an honing machine, not a drill work. Italian made honing machine, old BERCO if I remember correctly. Every machine shop in the south of Italy where I am have italian made honing machines, no sunnen here.

am i the only one thinking low tension oil rings and oil consumption might be related?

For the NPR rings, 1.5mm wide chrome top, I would hone to .04mm short of size with 220 grit medium bond, then change to 220 grit aluminum oxide soft bond, continuing to size or .008mm short of size ,
then finish with 7 strokes 280 grit silicon carbide soft at light pressure.

If the rings were thinner or very good quality pre-lapped, I'd change that to a 400 grit on the finish.

Moly faced rings often like a finer finish and less crosshatch angle.

I very much like Italian made machines. Very good basic design IMO, but not very good wiring.

Sorry to give you a hard time, but the number of cylinders and if they are imported or not are not, are not important.
The design and material of the block, and the design and material of the rings can be important factors.

Abrasives you have different bond strengths, and different density (or, sometimes called spacing?)
Also the stone length can be altered. There is a lot that can be done JUST with the stones to make it hone better, and you can never have too many to choose from!!
HARDER blocks, and smoother bores need softer stones. Many of the modern iron blocks are a lot harder than 30 years ago. Aluminum open deck blocks generally the cylinders are not very hard, but they can be very flexible, some I am fighting taper because the tops of the cylinders flex so much. Perhaps lower density stones might allow honing with less pressure. I don't feel that open deck blocks require a torque plate as a general rule. but it is true that at least having it on there will make the top of top more rigid, and that may be a positive.

how are the engines being run in, and with what oil?

joe 90 wrote: ↑Tue Mar 13, 2018 11:34 pm Torque plates aren't required on all engines, only low quality ones.

Torque plates are necessary for optimum sealing for ALL engines. The plate mimicks the cylinder wall distortion as the fasteners are torqued, has NOTHING to do with the quality of the casting. Dart Big M blocks will exhibit just as much bore distortion as a 1932 Ford V-8 will . . . . .