Juggs and Cylinders from China?

[MotoSook]

The plater I use states their "bores are straight and round within ± .00025" ."

I don't disagree that used cylinders can be out of round. Hopefully, it's just the plating and not the cylinder itself. As with all things, if you start with crap...and you don't do anything to the crap but dress it up, you just end up with pretty crap after all the work.

The other thing I wonder about the QSC jugs is the metallurgy. I don't need to tell Henry, but there are some folks out there who think that all "Nikasil cylinders" are the same. Nikasil is just the plating on the bore.

Don't get me wrong, I am always looking for low cost alternatives that don't compromise on the engineering. I have a couple of hi-po engines in the works, and if I can get a better solution (cost, material and quality) than boring and plating stock jugs, I'll be all over it, but I'm too particular. I must satisfy that little voice in my head.

[Eugene at Pelican Parts]

Originally posted by 88-diamondblue
Wayne was looking at these but have not heard if PP has started handling them.

It's true, we will be offering these in the very near future. As discussed earlier, long-term durability is still undetermined, but the overall reviews have been positive so far, and based on our own inspections, we believe them to be of good quality. Once they're available, we'll be sure to post an announcement.

[tech 1]

If you start alusil cylinders for example; K.S. 95mm, they must be bored before they can be plated.One would hope that the boring bar being used can hold tolerances in the .0001" range rather than the .001" range.This also tends me to believe that the Chinese cyls. should be in the .0001 range as well.Don't you think we might be picking fly***** out of the pepper here.As far as just replating insted of boring,I would bet money that if you start with an oval hole you'll end up with one.It is difficult to get a hone not to follow a crooked hole.Even something as sophisticated as a Sunnen CK10 hone.All of the good honing machines I have ever seen or used have a tension dwell meter.This allows the machine operator to view the tight spots in the bore.Tim.

[thomschoon]

Having just come back from touring several factories in China, I would say that many of the assumptions being made about capability are outdated. There has been a rapid increase in Quality and capability especially in tooling in China, driven by the customer base. You can buy junk made anywhere, I wouldnt worry about where it came from as much of how well they will stand behind it.

Just my $.02

[cgarr]

Whats the spec with a torque plate? ever bring one up to temp and check it?

Just wondering what the distortion is?

[mb911]

Originally posted by thomschoon
Having just come back from touring several factories in China, I would say that many of the assumptions being made about capability are outdated. There has been a rapid increase in Quality and capability especially in tooling in China, driven by the customer base. You can buy junk made anywhere, I wouldnt worry about where it came from as much of how well they will stand behind it.

Just my $.02

Very true. I am seeing it first hand my students are lossing there"skilled jobs" to other better processes being performed over seas. the chinese tools that everybody laughed at 5 years ago are getting to be in the league of some the snap-on tools etc. remember they are in there industrial revolution with one advantage that the US did not have in theirs and that is the ability to look at what everyone else has done..

I will keep everyone up to date on how mine work out

[Henry Schmidt]

Here's a long needed update.

One of our customers elected (with my blessing) to buy a set of Mahle 100's for a 3.5 engine we're building. The cylinders arrived new in the box with mismatched pistons and cylinders. Cylinders were 0 and pistons were 2.

Mahle offered to replace the cylinders as soon as they could verify the origin.

In an attempt to make the process move more quickly, we sourced a set of 2s at Andial. They offered to trade. Those guys ( Pete and Dieter) are great for helping, remember there was nothing in it for them.

When the cylinders arrived we checked them for ovality (just a habit now) and found that they were .0005" to .0008" out of round. If they were QSC we would have rejected them. Don't misread this as a criticism of Andial, it is not. I repeat they were great to help.

I called Mahle Motorsport to ask them about the inconsistency and they thought it was a little high but they should work just fine. What?
He told me that Mahle does not use a bore gauge to measure their cylinders. They use differential air pressure. I sure wish we could afford equipment like that.

While talking to the tech, he told me I could just tap on the cylinder to make it round. "one good rap should do".

I wonder if I told my customer that I beat his cylinders into spec if he'd let me finish his engine?
Who know? My guess is that ovality in those small increments is not an issue.

QSC cylinders are going out of Supertec with less than .0002 ovality.

[Jeff Alton]

Good info and a good update! Whack a cylinder? Yikes!

Cheers

[TimT]

Whack a cylinder? Yikes!

You do know how a bent crank is straightened?

[cnavarro]

I have heard of the practice of peening cylinders to correct for ovality, not that I have done it myself. Was mentioned to me by one of my customers who used to run 3.2 cylinders in a type 4 for his racing class and peened his cylinders (before I made him custom cylinders to suit his needs). He must have known what he was doing, he won the runoffs last year.

[Jeff Alton]

Originally posted by TimT
You do know how a bent crank is straightened?

Yes, but the "yikes" was more of a statement as to the visual of someone standing in the garage and whaling away on a cylinder with a hammer and not really knowing what is going to happen....


Cheers

[Porsche_911s]

At first, I did not realize that the Chinese jugs were referring to the QSC brand. I figured this referenced AA Performance Pistons.

http://www.aapistons.com/index.asp

They make sets for the early Porsche and even 90MM sets. If these are cast iron, wouldn't that create too much heat on a bore of 90MM? Isn't that why Porsche went away from the iron?

[cnavarro]

You are exactly right Stephen.

[dfink]

Here is just a thought. I have no clue if this is relevent. In discussing P&Cs with a friend the issue of ovality came up. He indicated that on bikes the cylinders need to have a torque plate installed and then be torqued to spec before testing. He indicated that some cylinders that would test out of spec would come into spec when torqued. I have no direct experience but thought I would throw it out there for discussion purposes.

[shbop]

Senior Member

Registered: Jul 2003
Location: Fremont Nebraska
Posts: 756
Here is just a thought. I have no clue if this is relevent. In discussing P&Cs with a friend the issue of ovality came up. He indicated that on bikes the cylinders need to have a torque plate installed and then be torqued to spec before testing. He indicated that some cylinders that would test out of spec would come into spec when torqued. I have no direct experience but thought I would throw it out there for discussion purposes.


__________________

Interesting comment. I remember my old xr750 Harley cylinders were this way. (long time ago) Brand new they had ovality. Maybe someone else from the 1/2 mile and mile-track world could comment.

[304065]

Mahle's QC issues aside, an air gage is more accurate and repeatable than a handheld bore gage. By not contacting the workpiece the distortion of the surface that occurs even with the lightest contact pressure cannot occur. It doesn't seem like a lot but when you start measuring in millionths a lot of new variables come into play.

It does make you wonder why oval cylinders are making it through, however. You would think that they would be checked for ovality at many stages of the manufacturing process and the rejects would be fixed or junked before they left. Do you think it is as a result of the fact that the quantities produced are too small to justify more rigorous QC?

[Henry Schmidt]

The issue is "acceptable ovality or manufacturing tolerance ".
The engineers at Mahle like all other manufacturing facilities have to call out a tolerance that is close enough to function properly and loose enough to make the product affordable.
Mahle has decided that these cylinders met the criteria for success.
This should remind all of us that "perfect is the enemy of the good".

Put more simply, this is not rocket science. A .001 here and there just doesn't matter.

[Lukesportsman]

What this makes me wonder is: How many OLD cylinders that measure oval are to be contributed to wear? OR were they oval upon initial installation and therefore wore a little faster to be pulled and discovered to be oval. Just something to chew on for a second.

My recent set of Mahles came in a Porsche box already assembled. Would this not be how the Porsche assemblers would have recieved them? On another thread I was instructed to break them down and check everything which I'll likely do, BUT would this be done on a regular production engine? If so, how would've Porsche double checked what Mahle sent them in a mass production setting?

[sp_cs]

Guys

Just wanted to re-ignite this thread having exchanged a couple of emails with Henry at SuperTec.

Does anyone have anymore feedback on the QSC/JE setup? Any problems to report?

On my Euro spec engine, thinking of running 98mm cylinders, JE pistons at Euro standard 10.3:1 - single plug.

Cheers fellas

[sand_man]

Originally posted by sp_cs
Guys

Just wanted to re-ignite this thread having exchanged a couple of emails with Henry at SuperTec.

Does anyone have anymore feedback on the QSC/JE setup? Any problems to report?

On my Euro spec engine, thinking of running 98mm cylinders, JE pistons at Euro standard 10.3:1 - single plug.

Cheers fellas

At this time, no problems to report regarding my 98MM (3.4L) QSC cylinders with JE pistons (purchased from Supertec) on a daily driven 930. Nearing 9,000 miles on the rebuild.

I should also add that I have not done a compression check or leak-down test. The engine has given me no reason to do so.