TOPIC:

Hi all,
I've just got my cylinders back from the machine shop after being honed, but I'm not sure that I will get away with just putting in new rings in. The bores have a very slight lip as you can see in the photos the honing tool didn't manage to smooth them out. What do you think, have they gone too far or have you seen worse?
Thanks Pete.

Not the greatest job I've seen. Looks like they used a fairly course stone. In the second pic I see horizontal rings which would suggest to me that they used a handheld manually manipulated hone and not an automatic precision hone. I really get pissed when I hear of people getting a cylinder honing job done and it wasn't a precision hone. typical manual hones are 3 stones which are spring loaded and they follow the wear pattern in the cylinder. They will clean up the surface and somewhat true the bore in the vertical plane, but they don''t true up the cylinder into a parallel wall round cylinder.
A precision hone has 2 slipper plates and 1 honing stone and it will true up a cylinder properly to within .0002" A new set of rings are perfectly round. If you try to break in a new set of rings in a bore that's not true, the rings may not seat properly and will cause ring blow by of the compressive gases on cylinder fire. That will cause the cylinder to have hot spots and lack of oil in the areas where the rings not seating properly and ultimately cause premature failure of the rings.

If you were installing chromium faced rings in this bore in the pics, the cylinder would eat the chrome right off the rings. Cast iron rings like the ones we use will take the abuse of this honing job but I suspect the course grooves like I see in the pic will take quite a while to settle down and seal up with the rings. One advantage of the course hone surface is that it will retain the oil on the walls of the cylinder better and provide better lubrication.

I would like to know what a cylinder bore gauge reads on the finished cylinder. It could be that your machine shop stopped honing any further because they felt that the cylinder was at its service limit. Going further with the honing may have been detrimental to using the existing pistons.

At the very least if I had to use these cylinders I would get some 800 wet and dry paper, put some oil on it and give the cylinders a light cleanup by hand. Then clean the cylinders with varsol or laquer thinner to clean off the residue left from the light sanding, then oil the cylinder bores with your favorite engine oil. The reason I suggest that is from what I can see, there's some minor ridges left from the course hone stones, and I would like to see them clean up before assembling the engine. You want to get those little burrs off the cylinder before allowing them to get caught in the soft aluminium piston skirt.

Bottom line, there's a lot of machine shops out there doing shitty work. Why? I don't know. almost like they don't care or are taking advantage of the poor slobs who don't know any better. It's hard to find a good shop. the really good ones are doing work for the top racers and they're not looking for little jobs from guys like us. I have a friend who just spent $48,000 dollars on a freshen up on his 5.0 liter Outlaw engine for his 82 Mustang. Like I said the good shop charge high end money, but you get what you pay for.

Well I have seen better but I suppose that in Gibraltar top class machine shops are few and far between. A coarse hone will help the rings settle in on a bore that is not precision. You will be OK but you definately wont get a really good life from the rings. I would say that 20k miles will probably see it needing more attention and don't be too supprised if it happens before that.
With a coarse hone like that make sure there is no grit embedded in the metal. Wash it well scrub the bores with a green nylon pot scrubber It doesnt really have to be green. Then get some red auto trans fluid and smear it on the bores and rub it in a bit then wipe it out with white paper kitchen towel to be sure there is no black comming of the cylinder. It will show up really well if there is any. I have had to do that 3 and 4 times to get the bore clean. A lot of those buggers don't even clean then just wipe them over with a rag thats been used all week.

Pete, what Kawboy says is right on! ESPECIALLY about using some 800 paper to clean off the rougher bits before assembling things. That metal grit will embed into the pistons like he said, then can be the start of a ripping/galling action that will seize up the engine. At best, those little burrs will wear off and get into the oil and go find someplace else to wreak havoc!

Your first and second pics clearly show a major ridge bottom edge still there! Take your fingernail and see if you can feel the bottom edge of that ridge. If you can feel it at all, you're playing Russian Roulette with new rings. The new ring will have a sharper top edge that will bang into the radius of the ridge and can snap the ring when running. The rule is, if the ridge is at all visible, you can't install new rings. It looks like they didn't even try to ream the ridge away before honing. The cross-hatch angles are also not perfectly even, so they definitely hand held a drill to do the job.

BTW, good pics! They show us enough detail to make these critiques of the hone job.

Thanks for the replies,
It's funny how more than one of you thinks that it's a hand held honing tool used.
The guy took me over to the machine that's the size of a small car and showed me how the shaft with the blades/stones drop down into the cylinders. I didn't see him do the job but when I collected the block it was sat on the side of the machine still dripping wet with what smelt like a mix of oil and diesel.
You are all right to think the cylinders look rough because they are. I was thinking the same, that they will rip shit out of the new rings and not good for the pistons either. If I do decide to still go for the rings only option will do as mentioned and give the bores a light going over with oil and 800 paper. As for cleaning after, I'm a bit ocd when it comes to cleaning engine internal parts so no worries there.
I really struggle to feel a lip or ridge and in the pic you can see the stone has just managed in some places to bridge across to the next high point.
With regards to Gibraltar having a machine shop, I think the only one we have on the rock is at the dockyard, so the job was done in nearby Spain.
One of the reasons I'm going down the rings only option is to try and control expenses a bit. Maybe I'm going to have to break into my emergency account and do a rebore and piston kit job in the knowledge I've done the right thing lol. I think this being the case the piston kits from the German site should be good quality.
Cheers Pete.

That small-car-sized machine probably also does align boring of cam and crank journals, plus cylinder boring before honing! Really nice machine if it says "Sunnen" on the side!

A simple hone job would tie up the machine for other bigger projects so I can easily imagine they stood there with a drill and did the job sitting on the edge of the big machine. The machine requires the block to be secured, but one man could do it carefully without going through all of that.

My objection to the hone job is the courseness, but the cross hatch pattern is good enough to break in new rings.

My only other objection to that job is how much ridge was left. It's almost a microscopic issue, but at 8000+rpm it becomes a big deal. The old rings wore a rounded pattern at the bottom of that ridge, and they matched each other as they both slowly wore against each other. But, that old radius still exists under the ridge and a new ring will have a slightly sharper edge on it that will not match the radius of the bottom of the ridge. At lower rpms this might not cause such a hard collision to damage anything, but at higher rpms that ring will have enough inertia at the top of the stroke to slam into the ridge and it will twist enough to shatter the ring! Especially if it is a cast ring.