Liners and pistons - Hone? Bore? Replace?

1971 5.3L V12 from my E-Type.

As I’ve progressed through the tear down I’ve found good and bad. The rod and main journals on the crank are in spec and in excellent condition. The bearings show no rubbing or scoring but the coating is mottled and not something that I’d trust so they’ll get replaced.

On to pistons and liners. Long story short. At some point I had run the engine after it had some surface rust in the cylinders. No amount of lamentation will undue the damage so I am moving onward. There is some light scoring in the cylinders from top to bottom and light scratches on the skirts of the pistons. Nothing that can’t be homed out.

I marked and pulled the liners today and checked them all with my bore gauge. I do not know what grade of cylinders were installed to begin with. Grade A gives a bore of 3.543 and Grade B is 3.544.
Bore chart shown below. The bores went from 3.545 to 3.546 with most having a max oval of .001. Ring ridge was negligible if nonexistent. My assumption on honing is that it would open the bore up another .002 or so.

The cold weather gives me a chance to develop a game plan as the garage is not too usable for the next week.

Options available.

  • Hone the liners. Use a slightly larger ring and adjust end gap appropriately. Possibly have the skirts built up to meet the required tolerance.
  • Bore the liners. Pick up oversized pistons and rings. Where to get 9:1 compression pistons though?
  • Pick up new liners and pistons. again, where to get 9:1 pistons?

I’ve got plenty of time to mull this around, so I’m just looking for some input. What are some good resources for pistons, rings, etc…

Thanks. Keep warm.

I havea set of pre-HE pistons, rods, liners and crank all 18,000 miles old and I think the higher Euro CR not sold in the USA.

PM me for info.

Pete

I fired up the heater in my shop and took some skirt measurements today. They all came out at 3.541 to 3.542. The base of the liners don’t see any ring wear and I was able to barely fit a .002" feeler gauge in there.

If I were to home these liners, it would open up another .002" I believe.

I did find some liners for $600.00 delivered, so I an probably going to reuse these pistons and pick up new liners and rings. All should fall within spec with that.
Thoughts?

You must be using a SERIOUSLY aggressive hone! When I ball honed my Rover bores, I measured less than a 0.00015” increase in measurement.

I’ve seen some freshly bored cylinders in worst condition, all fine in my book.

I have a set of liners delivering tomorrow, so it’s all kind of a moot point now.

But, had that deal fell through I found the Lisle LI15000 Engine Cylinder Hone. There are ball hones, spring arm hones and then these kinds of hones which are adjustable. These styles can remove ovalness and take out a fair amount of material pretty quickly. If I had another very worn engine with which to work, I’d pick one up, machine out a torque plate and take these liners out another .005" to .010" and get some custom pistons made for it. Oh the things that I could do if I had more time on my hands.

I have custom pistons for my long stroke XK engine. There’s no point spending on anything custom if you’re only going for a tiny oversize IMO. Going the custom route should mean you use the options of optimizing rod length and CR, plus squish etc

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The only reason that I’d get custom pistons made would be because finding .010 over 9:1 pistons has proven to be difficult. Putting my original pistons into liners that are running .005" over the original 3.543" bore would give excessive skirt clearance.
Luckily new liners are showing up today, unless FedEx pulls their usual stunts, and I can reuse the original pistons.

If the purpose of the hone is to finish the cylinder to seat new cast iron rings, a “dingle berry” hone is fine. The Lisle hone with fine stones will also do the job but use plenty of coolant. But if you intend to resize the cylinder for oversize pistons, it’s impossible to do it outside of the engine and end up with a straight, round bore. I spent a lot of time and money trying to do it without success. I’ve had a couple sets done by a local race shop using a Sunnen machine but he had to go extremely slow(and expensive) to get them done right. I’m currently working on a jig to constrain the cylinders during honing which I hope will speed up the process.

I missed your post regarding the new liners showing up. Never mind. :slight_smile:

Were I to have gone the route of opening the bore up .005", I’d have made a torque plate to put the liners under load and used one of the Sunnen style hones. Luckily though, I have new liners in hand and they look great. I’ve not mic’d them yet as I’ve been checking everything going back into the engine.

Are they new liners or good used? The only way I could find new liners is with pistons and rings.

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I was also only finding liners with pistons. But… They were almost always lower compression. These are brand new from a vendor that isn’t one of the usual suspects. They are actually owned by the same company that owns one of the usuals but not listed on that website.

I have yet to run the bore gauge through them although the shoulder height is correct.

I’m not sure the concept of a “torque plate” is valid when dealing with loose-fit wet liners, as we are. It would hold the liners securely in the block so you’re effectively using the block/plate as a fixture to hold the liners still while boring. It’s not easy to properly hold them otherwise; chucking them up in a 4-jaw lathe head certainly won’t do it. Really, for this job I’d think it’d be OK to build a plate to hold ONE liner still, and move that plate from bore to bore – or even just swap out the liners and bore them all in the same cylinder position!

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You are correct: it’s essentially useless on a wet liner engine.

You are correct. They are very prone to chatter or so I have read from others experience. Were I to bore out some liners with anything other than a precision hone, I’d probably build up a dedicated fixture for my Hendey lathe to hold the liners tight enough to reduce chatter. It is truly a 1 ton monster and capable of turning something like that.

This engine design is kind of an odd one as the liners are loose fit through the block with the exception of the pressure fit of the liner shoulder between the head and the block. My assumption, and it is only an assumption, is that as things heat up, the block and liners expand to a tight fit. One would have to bring the entire engine up to normal operating temperatures to see if the clearance between the two closed up or not.

I almost wish that I had a spare engine around with which to tinker. I might have to keep an eye out on the market to see if I can scrounge up another Pre HE V12 to tinker with as time permits.

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I think the liners are designed to remain loose in the block regardless of temp. The liner skirts are really thick iron, presumably stout enough to not require reinforcement by the aluminum block. I have heard that the guys who go to larger bores often fab up new liners that are, in fact, a press fit so that the aluminum block does reinforce the thinner liner skirt.

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