K800 Cylinder Sleeving: Fitment, Heat, and Finish

Today’s deep dive is all about sleeving the K800’s cylinders—arguably one of the biggest jobs on this engine. The goal: restore correct geometry, ensure secure liner seating, and set us up for final honing and valve-seat work in the next episode. It’s a lot of careful measuring, fitting, and a few “hold your breath” press operations. I love this stage—pure mechanics, pure satisfaction.

Sourcing sleeves that can be made to fit

I started with raw cast-iron sleeves from a manufacturer in Iowa—close to final size, but with enough meat left to machine precisely to my bores and interference spec.

The mystery ring-shaped crater

Before any fitting, I bored the original cylinders and found a deep, perfectly circular pit—like a ring etched into the wall. The cause is uncertain, but it demanded a clean, true cut.

Cutting until we’re back to sound metal

I continued boring until the surface was uniform and concentric, chasing out the last of that damage without over-opening the bore. Patience beats aggression here.

A thin casting we can’t trust

Inside the casting, a section of the original sleeve wall was uneven—and one spot was worn through. Leaving that shell in place would be asking for vibration-induced failure.

Out with the brittle inner shell

I removed those risky fragments using a slitting saw on the mill—careful, controlled cuts that protect the parent casting. This was absolutely the right call.

Prepping the bores for maximum grip

With the old shell gone, I dressed the inner surfaces and honed the fresh bores to maximize contact area for the new liners—clamping force loves a smooth, true interface.

I followed with a light, controlled hone to fine-tune geometry and surface finish—this is all about even pressure once the sleeves are home.

Sleeves machined for a precise interference

Only after measuring the bores did I turn the sleeves to size, leaving an interference of 0.0035 in (about 0.09 mm) for a secure, long-term fit.

Heat the jugs, chill the liners

I brought the cylinders up to about 200°C (400°F) in a hardening furnace—thermal expansion is your friend when time matters.

With the sleeves cooled, the press fit goes in smoothly and square—there’s a satisfying moment when everything seats exactly where it should.

Two birds with one heat cycle

While the cylinders were hot, I also pressed in the valve guides I’d prepared earlier—no point heating everything twice.

From below you can see how nicely the sleeves seat—full contact, no gaps, exactly what we want for stability and heat transfer.

And the guides? They snapped into position perfectly—one of those tiny victories that makes your day.

Head-side setup and that quirky 5° plane

Next, I mocked up for machining from the head side to shape the combustion chamber transitions—this is where geometry meets artistry.

Interestingly, the head mating plane is tilted 5° relative to the cylinder register, so I shimmed the setup and used feeler-gauge strips to hit a true reference before surfacing.

Rough, then refine—machining and hand work

I removed the bulk of the excess on the mill, sneaking up on the profile without gouging into fresh liner material.

Then I switched to hand tools to bring the protruding areas perfectly flush and consistent—slow work, but this is where the finish lives.

A pneumatic die grinder is my trusty companion here—plenty of control, good feedback, and enough bite to shape without chattering.

By this stage, I’m freehand blending—eyes, hands, and light tell me when the curves are right. It’s oddly relaxing.

Another check from a different angle—consistency matters as much as absolute dimension when it comes to sealing and flow.

And one more perspective—if it looks right, it usually is right; the hands don’t lie.

Ready for the next chapter

With the sleeves shaped and seated, the cylinders are prepped for final honing to match the new pistons. The fit is excellent—the sleeves only give themselves away by a subtle shade difference in the iron.

I’ll say it: there’s real beauty in well-executed metalwork. On to honing and valve-seat machining next time—can’t wait.

Frequently Asked Questions

• Why remove the original inner sleeve shell instead of pressing over it? Because it was thin and inconsistent, with a wear-through; leaving it risked detachment from vibration. A fresh, solid register ensures safety and heat transfer.

• Why choose 0.0035" (0.09 mm) interference? It’s a sweet spot for cast iron-on-cast iron here: strong mechanical lock and good thermal coupling without over-stressing the casting during installation.

• Why heat to 200°C (400°F)? Thermal expansion eases the press, keeps sleeves square, and reduces the force required—less risk to the casting and a cleaner seat.

TL;DR – Quick Recap

• Bored cylinders until the walls were clean and true; found and eliminated a risky thin inner shell.
• Prepped bores and lightly honed to maximize contact for the new sleeves.
• Machined sleeves for 0.0035" interference; heated cylinders to 200°C and pressed in cooled liners.
• Installed valve guides during the same heat cycle.
• Surfaced the head plane with a 5° correction using shims and feeler gauges.
• Rough-machined from the head side, then hand-finished with a pneumatic die grinder.
• Ready for final cylinder honing and valve-seat machining in the next post.