Not from the hone. Either the shop got the bore centerline off location on that bank or it wasn't bored enough to fully clean it up. That defect is below the honed surface finish.

It's a defect that didn't clean out from the .030" overbore....block should have been bored .040" to remove that (barring that off-centerline possibility).

If it's low in the bore it's not a big problem, but it its up near the top of ring travel it will be a blow-by issue.

 

I agree with Eric. It was there before they started.

That being said . . . . I dont know if it is the magnification in your picture or not but that hone finish seems incredibly "rough" to me. Looks like it was done with a cinder block. It looks terrible to me. Also, the crosshatch angle looks way too shallow which can cause ring seal issues. Post a couple of pictures from a little further away.

Is there another shop who can give you a second opinion ? Modern rings do not need a rough finish for breaking in like the ones from 50 years ago.

 

I was gonna say it looks a little rough. As far as the mark, it’s hard to tell from the picture.

 

Good morning,

This was a very clean, low mileage block and they tested it for cracks.

Also, same type of scratch in all for cylinders but at different locations? Two at 10 O'Clock, one at 4 O'Clock and one at 3 O'Clock. It definitely looks like it's been added since I dropped it off.

Some photos below, it's not easy to photograph:

Here's a photo of the bore from a bit further away:

Can I email the shop and ask what type or grit the hone was? What kind of terminology do I need? What should the correct roughness feel like?

Also, how do they set the hatch angle, when I watch videos of this being done, the machine just cycles up and down on its own, they shouldn't really be getting that wrong.

Anyway, as said, I can only barely feel the deepest scratch, and it is length-ways, so maybe not such a big problem. A re-hone with a finer stone could potentially fix it, I'm guessing?

Machine shops doing V8s are far apart here, it was a two hour drive getting to this place.

Regards,
Henrik Morsing

 

I can almost guarantee you that the scratches were there before you sent it to the shop. They were probably a lot deeper and longer before they bored the block. I have seen them plenty of times in used engines. They are from dirt etc getting in the rings. I simply cannot think of anything in the machining process that would make them. They should have seen them either after boring the block or during the honing process and called you and asked you what you wanted to do. Going to .040 would be the easiest fix.

The crosshatch angle is set with the stroke speed. It looks a lot better in these pictures.

As far as the actual finish goes they should be using a 280 to 320 grit final stone and then I always use a plateau finish brush for a few strokes. You should just barely be able to feel the hone marks. It really is hard to tell from pictures. There are tons of different articles on cylinder honing. This is just one I found that is pretty good. Scroll down a ways to get to the honing suggestions.

High Performance Piston Rings and Cylinder Finishes - Engine Builder Magazine

Today’s performance ring sets are thinner, lighter and more conformable than ever before. Thinner, low-tension rings reduce friction for more usable horsepower. Less weight reduces ring groove pound out. Narrower rings also allow tighter tolerances and less blowby. All very good things when...

www.enginebuildermag.com

Most of the ring manufacturers have something on their web sites.

 

Ok now I see it. Yes, the black in the groove shows it was there previous. The one with the black in the groove is really the only one I would be concerned with. I've seen worse than the other 3. But yeah, now the question is do you go with it or try .040 over and see if it cleans up.

 

I have to agree that those scratches are left over from not over boring far enough. It's hard to believe a " reputable" machine shop didn't see them.

 

Just curious, have you measured the actual bore size ? Is it exactly .030" oversize ?

 

I measured #8 and yes, it is.

 

Reputable shop owner retires or passes away and someone else takes over not so Reputable, BTDT

 

Nope, original owner still there and he seemed very knowledgeable when I dropped it off and spoke to him. He has been doing motorsport for decades and setup the shop to do his own engines for it.

Maybe they did see the scratches. I am giving them the benefit of the doubt at the moment. It may be that they deemed them so microscopic they wouldn't cause a problem.

I will email them and ask about the crack and grit of the honing.

Would the crack do anything worse than a tiny bit of blow-by?

Regards,
Henrik Morsing

 

If this is a street engine I would not worry about that too much, if it's a race engine for a class in drag racing then "no" I'd get that fixed.

 

Also, given your location, maybe the availability of +.040" pistons was a consideration in not going another 10 thou.

 

I would take another .0005 - .001 out of it with the correct grit finishing stones. Most piston manufacturers recommend a little more clearance for performance applications anyway. What pistons and rings are you using ?

 

I agree at least finish the surface. 150 is too rough. Maybe for old cast iron rings in a diesel but not for this.

 

Seems like they left out doing the final step to finish the honing, I'd do what BillK is recommending, even if you have to get different pistons or change rings you'll sleep better knowing your engine is done right

 

They didn't leave out anything, they have sent me another mail saying this is what they have been doing in their race engines with moly rings for many years and they've never had an issue.

Regards,
Henrik Morsing

 

I'll let Bill be the expert here, but I will say this, you are the customer and if you're not happy with the final work, I would hope they would make it right. If the manufacturer of the rings recommend a finer grit for a final hone, I would take my proof to them and/or have them call the ring manufacturer themselves. If they won't do it at no cost to you, pay to have them or someone else finish hone that block!

I worked in sales/customer service for 33 years and even if we had a customer with unreasonable expectation, we did what was necessary to make it right. If you can show them that the ring manufacturer recommends a finer grit final hone, that is not an unreasonable request to have them finish it.

 

I'll let Bill be the expert here, but I will say this, you are the customer and if you're not happy with the final work, I would hope they would make it right. If the manufacturer of the rings recommend a finer grit for a final hone, I would take my proof to them and/or have them call the ring manufacturer themselves. If they won't do it at no cost to you, pay to have them or someone else finish hone that block!

I worked in sales/customer service for 33 years and even if we had a customer with unreasonable expectation, we did what was necessary to make it right. If you can show them that the ring manufacturer recommends a finer grit final hone, that is not an unreasonable request to have them finish it.

Hi Gary,

I totally agree, and I won't sleep at night building this if it is not corrected. The problem is always the hassle of wrapping it up and shipping it or the time spent on dropping it off.

I will tell the shop it needs finishing and see what they suggest.

Regards,
Henrik Morsing

 

Everyone above is on target.
I would never buy pistons for anything until the bore was done. Buy the pistons and ring set and follow the directions for the rings.
The scratch might accelerate the wear on the rings, reduce compression, contaminate the oil, etc.
Take it to a better shop with your pistons and rings. They might have a solution or might take your pistons and rings as payment to fix the block.
Rick

 

I would never buy pistons for anything until the bore was done. Buy the pistons and ring set and follow the directions for the rings.

As far as I knew, you can't bore and hone without measuring the pistons, and the shop said the same when I booked it in for the work. They measure and number the pistons for each bore.

I just checked the website for another shop here and they have the same clause on there. No boring or honing without pistons.

Regards,
Henrik Morsing

 

I have always had my blocks finish honed to the actual piston diameters. But when rough boring you never know how far oversize you need to go if there are scratches in the bore.

 

Maybe, but the problem would be the two month wait for pistons.

Regards,
Henrik Morsing

 

I agree that is a mess. Even if the marks weren't there the hone finish is terrible. You will lose ring material trying to chew through that rough honing finish. Tell them to make it right.

 

Well, just to throw everything up in the air, JE Pistons (the rings are JE S100S8-4030-5) has come back with the following:

"
Hi,
150 grit insures the rings break in quickly and there should be no issue.

Best Regards,

Frank Cedillo

JE Pistons – Technical Sales"

So don't know what to think anymore but I certainly can't demand free shipping from the machine shop as they haven't done anything wrong according to the manufacturer.

Regards,
Henrik Morsing

 

Well, just to throw everything up in the air, JE Pistons (the rings are JE S100S8-4030-5) has come back with the following:

"
Hi,
150 grit insures the rings break in quickly and there should be no issue.

Best Regards,

Frank Cedillo

JE Pistons – Technical Sales"

So don't know what to think anymore but I certainly can't demand free shipping from the machine shop as they haven't done anything wrong according to the manufacturer.

Regards,
Henrik Morsing

This makes no sense at all considering their own recommendations:

Boring & Honing Instructions - Race Winning Brands Europe

Boring & Honing a cylinder needs to be done accurately and properly to be sure the piston runs smoothly.

www.performancemotorsports.eu

And for those that dont know, RWB owns JE, Diamond, wiseco and others.

 

Again Im not a builder but I would not accept that bore finish, I think the engine will be using oil and smoking in no time, down on compression and power too, JMHO

 

His part # is for a 1/16 - 1/16 - 3/16" Ductile Iron, Plasma Moly File-to-Fit 4.030" bore ring set.

I honestly can't believe a rep at the company would even say that "rough so it will break-in faster".
because it sounds like 1950's thinking.

Call again, talk to a different person if you can.

 

Thats why I mentioned old diesels, we used to just try to get the big scratches out in the field and put them back together. Thats what 150 was good for.

 

Bill, is SRP in that piston group ?
Rick

 

SRP is part of JE.

 

Technology has advanced ICE for decades. Performance had driven some of this but mandates by governments for emissions and fuel economy have been a huge part in technology. What we did 40 years ago for cast rings is not what needs to be done today. The finish of the cylinder and the cross hatch angle need to be done to fit the ring package of today.

An excellent example is what Lake Speed did with a NASCAR engine of his Dads. This engine ran at Daytona and came in 2nd. So you have a power plant was at the top of its game 40 years ago in 1985. Fast forward to 2023. The same engine was taken apart and honed using today's technology in both rings and cylinder wall finish. Steel rings not plasma moly, different cross hatch angle and different RVK and RPK numbers. Put back together and it yielded a 30HP increase!!!!!! Now keep in mind, this engine finished 2nd at Daytona. This wasn't your buddy's pump gas SB in his car.

A profilometer reading of the cylinder walls puts all opinions to rest and internet BS. Cross hatch angle. Get a good pic of the cross hatch and then use a protractor to get the angle of the finish.

In today's world we want a much deeper RVK number. Why?. Simple, cast rings were porous, they held oil. Oil does 2 things, it lubricates and it cools. Steel is not porous. So to lubricate and cool the oil has to be held somewhere. Deeper RVK, V for "Valley", is where the oil is stored in cylinder walls with modern day parts. RPK, P for Peaks, is the surface that does the sealing. Technology has give us honing for NA pump, NA high compression, With NOS, with boost, blower or turbo. All of these applications have finishes and there is no "opinion" as the profilometer will give us the readings to verify this finish. This has all come about by OEM R&D. Look up a company called TraceBoss. It is technology used by shops on hones to verify what the finish is for the customer.

Terminology has changed. The JE guy may be saying rough because he is referring to the RVK numbers. Rough as far as RPK numbers is a different.

Rottler and Total seal have done a ton of R&D on honing and finishes today. This can be seen on the Engine Performance Expo YouTube and the Hidden Horsepower YouTube channels.

 

Best I can tell from reading you are in a location (Buckinghamshire) that tool, parts and knowledge is not as readily available as it is here in the states. Growing up poor (1960's) in the hollers of eastern Ky we had to do the best we could with what we had. If I had looked at your block without reading I would have thought your block was a low mileage .030 engine that had been freshly honed, not a new bored and honed cylinder. The first picture shows a very rough finish but the others not photographed as close look a little better, still 150 grit but better. I think the first picture shows a low spot in the block that did not clean up.

One solution, though it may incense the perfectionist on this board, might be this. Summit sells a ball flex hone, 320 grit, for cylinders 4-4.25 bore, part number GBD41432. Cost is $199.99 American dollars. I would use this hone to try and knock the sharp peaks off the honing you have. The flex hone will not remove much material. I would first coat the cylinder in either diesel or kerosene. Fill a bottle of some type, a 2 liter soda plastic is good, and put a small hole in the lid. Get a drill that isn't really fast and start honing while a friend lets the liquid in the bottle flow into the cylinder. How fast or slow you go will determine your crosshatch. Somewhere in the 32-38 degree range will be good. You can measure it with a protractor. I would do about 15 strokes and see what I had. Do more or less depending on what the cylinder looks like. I guess you could call this a poor man's plateau honing. It will smooth the cylinders up so the rings will not be eaten up on start up.

I would put my piston in upside down and with a feeler gauge see how much clearance I had on the skirt to start with. I have run cast pistons at .004 with no problems even though that is loose. Do not hone too much, keep checking as you hone.

 

Based on what he has been saying about difficulty to get it back to the shop I don't think this is a bad alternative.

 

Only problem I see is the OP Paid a shop to do a job and in my opinion they did a very sub par job, and as Ive said Im not a builder just bolt stuff together, I did pay a shop to do a valve job on a set of 063 heads and they screwed up then said to bring them back, I found a better shop

 

I will address this to you and the mod that asked you to comment.

1. I was the one that asked Chris to comment.

I was referring to all the internet engine builders that have someone else build their engines and the only way one will ever have a quality engine is to have it built with the latest and greatest computer controlled equipment. We all don't have access to that.

2. I would be willing to bet that less than 5% of automotive machine shops in our country have "the latest and greatest computer controlled equipment" I certainly do not. My hone is over 40 years old and uses the old Sunnen AN system. Guess what, I can do just as good a job. Maybe not as fast and maybe not as profitably but I can still do it. There might be some certain blocks that I will not be able to do but I know that and know when not to take them in.

About a month ago just for grins I did a block, borrowed a profilometer from a friend who has a precision type machine shop and sent the scans to Lake Speed at Total Seal. He basically replied to me that whatever I was doing it looked fine. I purposely did not tell him what type of equipment I was using.

My point is that you dont need a million dollars worth of equipment to do a very very good job. So that is not an excuse in my opinion. But you absolutely do have to want to do the job right. If you dont then you shouldnt be in this business or any other type of business honestly.

Back to the original post here . . . . . the guys that did his block appear to have modern equipment and do good work. I wont name them unless he ok's it. They just do not seem to have kept up with the advances in piston ring design and the bore finishes that are needed. They should be able to do the job just fine. They just need another set of finishing stones

I believe he has found another shop close to his work to give him a second opinion.

By the way I do want to add that every bit of this conversation has been going on due to pictures. It is very possible that the bore finish is fine but you cant tell that from 3000 miles away. But a good hint is the fact that they admitted to using a 150 grit stone for the final finish.

Hopefully we will hear the results soon.

 

1. I was the one that asked Chris to comment.



2. I would be willing to bet that less than 5% of automotive machine shops in our country have "the latest and greatest computer controlled equipment" I certainly do not. My hone is over 40 years old and uses the old Sunnen AN system. Guess what, I can do just as good a job. Maybe not as fast and maybe not as profitably but I can still do it. There might be some certain blocks that I will not be able to do but I know that and know when not to take them in.

About a month ago just for grins I did a block, borrowed a profilometer from a friend who has a precision type machine shop and sent the scans to Lake Speed at Total Seal. He basically replied to me that whatever I was doing it looked fine. I purposely did not tell him what type of equipment I was using.

My point is that you dont need a million dollars worth of equipment to do a very very good job. So that is not an excuse in my opinion. But you absolutely do have to want to do the job right. If you dont then you shouldnt be in this business or any other type of business honestly.

Back to the original post here . . . . . the guys that did his block appear to have modern equipment and do good work. I wont name them unless he ok's it. They just do not seem to have kept up with the advances in piston ring design and the bore finishes that are needed. They should be able to do the job just fine. They just need another set of finishing stones

I believe he has found another shop close to his work to give him a second opinion.

By the way I do want to add that every bit of this conversation has been going on due to pictures. It is very possible that the bore finish is fine but you cant tell that from 3000 miles away. But a good hint is the fact that they admitted to using a 150 grit stone for the final finish.

Hopefully we will hear the results soon.

You give good advice. You live it every day. I guess my mistake was to use the word "perfectionist" in the singular. If I had said "perfectionists" it would not appear I was talking about one person. We have still had a good discussion.