Line boring one piece vtwin kohler block

[FTlatheworks]

That easily could be done on our L&S or our old 1917 south bend.

The older machines had t slots on the carriage just for this TYPE of work.

Can yours, maybe.

Line boring required a bed long enough to move the work PAST the cube that is mounted in a mandrel between head and tailstock.

The alignment needs to be perfect.

Work held on carriage perfect.

This is a quick and cheap job for a engine shop, they do These in their sleep.

You will not save any money, your setup time will be long and one chance to destroy your block.

Also of note, how thick is the special lining?

We changed rings in a Command 20 that had so many hours the rings were almost gone, but no Ridge or bvious wear in the cylinders, look at getting correct size pistons Orr correct shop.

Sent from my SM-G781V using Tapatalk

From my experiences with kohler v-twin engines I would have to say I don’t think your lathe would have the swing to bore a cylinder. Have you checked?? Also you would need to bore about three to four inches length. Which I would suspect would be pretty flimsy. Idk the standard way would be setting up in a mill or dedicated boring machine. I think your best bet would be a mill and a stout boring head.

Thats why I was saying lay it on its side and make a boring bar similar to line boring tool, but it wouldn’t be between centers. It’s looking like my lathe is too small for that even.

 

[FTlatheworks]

The answer is NO you can't bore cylinders satisfactorily on a lathe that small. Maybe on a much bigger lathe. A lathe carriage is
not ideal for holding workpieces. It's made for holding cutting tools. The carriage is only stable with downforce applied.
The block will move around too much and ruin the bore, I'm sure of it.
Plus you'll spend hours trying to align it correctly- impossible meat
Need a milling machine with power downfeed

That’s what I thought, but wasn’t sure if it was Possible with the right kinds of jig to hold it.

 

[FTlatheworks]

I have a large mill with power down feed so I would bore a cylinder on that, but you can accomplish what you are attempting to do, just check the clearance over your carriage with your part. I think you can use the 2 bolts intended to hold your follow rest for a carrige fixture hold down and I would personally hold the boring bar between centers..... In the attached video Quin does a simlar operation on a much smaller machine.

Can’t hold between center because it’s a solid block.

 

[FTlatheworks]

That easily could be done on our L&S or our old 1917 south bend.

The older machines had t slots on the carriage just for this TYPE of work.

Can yours, maybe.

Line boring required a bed long enough to move the work PAST the cube that is mounted in a mandrel between head and tailstock.

The alignment needs to be perfect.

Work held on carriage perfect.

This is a quick and cheap job for a engine shop, they do These in their sleep.

You will not save any money, your setup time will be long and one chance to destroy your block.

Also of note, how thick is the special lining?

We changed rings in a Command 20 that had so many hours the rings were almost gone, but no Ridge or bvious wear in the cylinders, look at getting correct size pistons Orr correct shop.

Sent from my SM-G781V using Tapatalk

This block is an extra and it has thrown a rod. There wasn’t much damage, except for a few gouges when the piston finally stopped sideways. I don’t know the thickness of the sleeve, but the max you can bore this specific block is .078 over, unless you resleeve it and stud the block. Again, I was just trying to do this as cheaply as possible to show myself that I don’t always have to buy every custom part and that engines will run without doing everything perfect the first time.

I have a very bad habit of being overly cautious and a perfectionist on everything I work on. I spend too much time and money this way. For once I was going to use all used parts and was thinking of not even overboring to clean up the cylinder walls to see how long the engine lasted at high rpm and hp.

 

[matthewsx]

This block is an extra and it has thrown a rod. There wasn’t much damage, except for a few gouges when the piston finally stopped sideways. I don’t know the thickness of the sleeve, but the max you can bore this specific block is .078 over, unless you resleeve it and stud the block. Again, I was just trying to do this as cheaply as possible to show myself that I don’t always have to buy every custom part and that engines will run without doing everything perfect the first time.

I have a very bad habit of being overly cautious and a perfectionist on everything I work on. I spend too much time and money this way. For once I was going to use all used parts and was thinking of not even overboring to clean up the cylinder walls to see how long the engine lasted at high rpm and hp.

Yep, if it was me I'd probably use a ball hone and throw new rings at it. A few gouges, unless they're near the top of the cylinder, shouldn't keep it from running.

Put it back together with as little $$ as possible and it just might run for another decade or two.

John

 

[FTlatheworks]

Yep, if it was me I'd probably use a ball hone and throw new rings at it. A few gouges, unless they're near the top of the cylinder, shouldn't keep it from running.

Put it back together with as little $$ as possible and it just might run for another decade or two.

John

Well the gouges are right at the middle of the cylinder and they are about 1/16- 1/8 inch in diameter. They are pretty deep too, but I think you’re right. I will just ball hone it and see how she runs. It’s for a high hp racing lawn mower anyway, not a fancy regulated racing league.

 

[verbotenwhisky]

Cylinder boring is a specialized operation because you need to stay perpendicular to the crankshaft. I've built many, many small engines (racing karts), believe me this is a job to outsource with a shop that has the right equipment.

You could make the equipment yourself, but probably not practical for one-off use.

Here's the type of tool used for this job.

KWIK WAY BORING BARS AND STANDS

allstates.com

Most automotive machine shops should be able to handle this job, I'd recommend calling around to shops in your area to find one with experience here.

John

I have owned a portable boring bar. I would not shy away from tackling a small engine bore with the equipment I currently own.

 

[verbotenwhisky]

Can’t hold between center because it’s a solid block.

You are assuming you will be spinning the work piece, I am talking spinning the tool, watch quin's video and she has another where she bores a steam engine cylinder.

 

[FTlatheworks]

You are assuming you will be spinning the work piece, I am talking spinning the tool, watch quin's video and she has another where she bores a steam engine cylinder.

I am not assuming that. Line boring doesn’t mean you hold the work. I thought I made that clear in the post. I wrote, could I attach the work to the carriage and hold the tool in the chuck?

I have seen that video, and many others on line boring. I have also done some small line boring. Not between centers, so I’m not sure it’s considered line boring. More like milling on a lathe with no milling slide.

I’m saying that I would have to hold a very long boring bar, or boring tool in the chuck. the steady rest would have to go before the engine block for support. The engine block oil sump/case is in on the same axis as the cylinder. It would only work if I’m going to bore through the side of the block. Then the boring bar could be held between centers. I can only hold onto a boring bar from the chuck.

 

[FTlatheworks]

I have owned a portable boring bar. I would not shy away from tackling a small engine bore with the equipment I currently own.

Is it the Chinese portable boring machine that’s like 1-2k. I have always wanted one. How does it perform?