Cylinders to Engine Case, How tight? Options

[jimbot2000]

When I was tearing the 2.0 down the other day, I noticed that the fit of the cylinders to the engine case was pretty sloppy, like 0,5mm maybe a little more. What's that supposed to be like? I can't imagine such a sloppy fit was intended, maybe I'm wrong.

Still waiting for the book........ things take a long time to come from the US and asking for a manual in english, for a german car in germany is well.... not good form. I can read write and speak German, but this is my free time we're talking about! (Sorry for the rant) just being impatient waiting for my book (IMG:style_emoticons/default/blink.gif)

[jimbot2000]

Does anyone have a case in such a state that they can measure the holes where the cylinders fit for me? I can't remember what I measured with by bore measuring gage, but they were all the same, and all round, so I'm wondering if the last guy fit the wrong cylinders. But the cylinders were all 94mm. Confused.

[pcar916]

Need more information. My assumption is that your heads have been removed. It not please give a more detailed description of your measurement.

There are shims that go between the cylinder and the case and they vary in thickness. They contribute to positioning the cylinder to the proper height to establish the deck height and head/piston clearance. That defines your compression ratio eventually when combined with your head volume and stroke etc..

What is the thickness of your shims because .25mm and .5mm are common.

[jimbot2000]

Oh yes, the shims. I'm aware of those. I'm talking about the fit of the cylinders in to the case. Without the heads pistons or others. Seems that the OD of the cylinders is smaller than the ID of the case hole. I didn't expect an interference fit, but rather a snug one.

I think the shims will adjust the deck height, correct. Have no fear, I'm not going to put this engine together until I've measured everything, corrected or replaced what needs to be corrected after consulting the proper references and procedures. I'm an engineer, it's in my nature! ;-)

[nathansnathan]

The head studs locate the heads and the registers at the heads locate the cylinders. When it's all fitted up, it there's only one place each cylinder will want to sit on the case, iirc.

[jimbot2000]

Thanks Nathansnathan, I was hoping for something like that. I was a little worried I had a bad case problem.

I was thinking of replacing those studs by the way. Good idea? They seem like a bear to get out. I was a little worried about breaking something. Any tips in this area?

[nathansnathan]

Higher performance studs are mad money. They say it's not worth it unless you are building a pretty crazy engine. -Stock head studs and case bolts should be fine.

It's hit or miss whether double nutting will work on any given stud, they can be in there too tight for that alone. If the case needs align boring, the studs have to come out for that, but let the machine shop do it. Otherwise I'd just leave em.

[VaccaRabite]

DO NOT use aftermarket studs unless you need to. Use the stock steel ones.

If you are using cast iron cylinders, the aftermarket, super expensive studs will net you NOTHING. And, since the studs will expand at a different rate then the cylinders, you may even develop leaks.

If you use non-cast cylinders, that is the point where you need to start getting better head studs, and then you need to get the studs that are matched to the cylinders. Expect a mild heart attack when you see the cost of the studs, too. Its just not worth the money if you are staying with cast iron cylinders.

Zach

[Don M]

When I was tearing the 2.0 down the other day, I noticed that the fit of the cylinders to the engine case was pretty sloppy, like 0,5mm maybe a little more. What's that supposed to be like? I can't imagine such a sloppy fit was intended, maybe I'm wrong.

case and heads should have ample clearance to avoid any misalignment during assembly, cylinders should fit cleanly into the case and past the studs with zero interference heads should drop on in the same manor any binding during this procedure will deform the cylinders when torqued. for this reason .015"-.020" over cylinder outside diameters at both ends are safe numbers as it allows them to "self center" and avoids distortion of the bores.