Honing pattern cylinder bore

[Hendrik]

Bought a gas engine (four cylinder, cast iron block, approx. 123 cubic inches, 3.5 inch bore) which was said to be overhauled. The cylinder bores (sleeveless) were honed. It appears that the honing operation was done with little or no vertical movement of the hone. The honing pattern on the cylinder wall is "parallel" to the piston rings and the typical "cross hatch" is just not there. My machine shop is afraid it will hurt the lubrication of the piston/piston rings/cylinder wall.
What do you experts think?
(I can return the engine to the seller and get my money back if the engine turns out unsatisfactory.)
Thanks, Hendrik

 

[JayinNY]

Why not just rehone it right, and just put in new rings? I dont think it would be that costly, especially if you already have it tore down.

 

[Jon Hagen]

ideal is a 45 degree crosshatch, but is hard to do without a very low speed drill and some serious drill pumping when done in a garage or small shop. lubrication of pistons and rings should actually be better than a 45 degree pattern. Ring friction may be higher than it should be, so a gentle first 15 minutes running may be wise.

I have seen some no cross hatch hone jobs, done with a too coarse hone, turn out just fine.

Many ring manufactures want you to put a full load on the rings as soom as possible to make sure they seat, just go a little easier on it for the first 1/2 hour with the no crosshatch hone job. Use a good quality multiweight oil for break in.

 

[Hendrik]

Good thought. It is better to do it right from the start.
My question: it being a used engine, will rehoning get it out of tolerance on the diameter of the cylinder? Or, phrased differently, how much increase in diameter will one get by rehoning?
Thanks, Hendrik

 

[ohiojim]

boy howdy,..it would take a powerfull lot of honeing to get any overbore

 

[old]

To get it out of spec it would take hours of running a hone in a cylinder and you would wear out to stones on the hone also. If the cylinder are close to spec and not wore out from running then re-hone and put it back together and you should be good to go

 

[JRSutton]

In theory, it matters a lot.

It's to keep the proper amount of oil between the rings and cylinder walls - especially during initial break in.

Don't do it and there won't be enough oil retained on the walls, and you'll get premature wear.

Do it flat like you've got it, it'll retain too much oil and the rings will never seat properly.

Now - having never actually experimented with it either way - I can't honestly tell you how much of a difference it REALLY makes.

I think these old tractors with their low compression and low revs would probably run just as well with sewer pipe sleeves and wooden pistons.

But - there's that old saying - if you're going to do something, do it right. If you've already got the head off.. not all THAT much more to do...

 

[Walt Davies]

If the bore is stock and there was no ridge at the top then rehone if not then have it bored out to 10 or 20 over which ever pistons are available.
You can use a 1/2 in. Variable drill and hone then quite good with nice cross hatch. Be sure to use brand new stones on the hone.
Walt

 

[LJD]

If the person who worked on it was so inept he didn't know how to run a deglazer/hone properly - I wouldn't trust anything else he/she touched either. Rod and main bearings? Rod bolt torgue? Ring side gap clearance and end-gap alignment? Head gasket ,head bolt torque, valve train, etc. , &c. If it were mine, I'd wind up pulling it all part just to check what damage the "repairman" did.

 

[BDT in Minnesota]

I agree with LJD, pull that engine down.

 

[buickanddeere]

How much bore taper and how much piston to cylinder wall clearance. How much ring gap? How much piston ring groove wear? How much invested in the engine thus far? Intended use for engine?

 

[casenut1]

not much. that result would take hours of honing.

 

[ASEguy]

I agree with LJD. Since The engine is out, I would check it thoroughly. Better safe than sorry.

 

[Bryan inIowa]

depends on the hone. I hone small engines with my Sunnen ridged hone up to .030 rather than boring. done v8 car blocks .010 under an hour floor to floor .

 

[Hendrik]

When first posting this thread I was so concentrating on the technical subject that I forgot to mark it OT; I apologize for that. It is not a tractor engine, it is a 1980 car engine (max. RPM 5000, double overhead camshaft, fuel injected, 9.5 compression ratio).
Thanks for all your opinions and thoughts. My machine shop will measure the bores, and, if within tolerances, rehone in the proper fashion. Although the "cross hatch" honing pattern may not last long (compared to the life of the engine) it is important for proper seating of the piston rings and I don't like to end up with a smoking and oil burning engine.
Machine shop will check the bearings too and will rebuild the engine to their standards, which I trust more than those of the seller ;-).
I'll keep you posted.
Thanks again, Hendrik