difference between semi and finished liners

Submitted: Monday, Oct 12, 2009 at 20:38

Alec L

whats the difference between semi finished liners and finished liners in an engine rebuild kit?

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AnswerID: 386768 Submitted: Monday, Oct 12, 2009 at 21:45

Richard Kovac replied:

Alec

An semi finished liner is fitted to the block then honed to size, a finished Iiner is as it says finished to size, you can put the piston straight in.

To use semi finished liners you would need a machine shop or engine recon shop as you just don't hand hone them they have to be set up in a machine..

Regards

Richard

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AnswerID: 386772 Submitted: Monday, Oct 12, 2009 at 21:53

Geoff (Newcastle, NSW) replied:

Hi Alec,
My understanding is finished liners are ready to go, just drop the pistons in. Re-assemble the engine and fire it up.

Semi finished liners once installed in the block require a honing to the correct bore size before the pistons can be inserted.

Generally finished liners are a hand push in fit with an O-Ring or similar seal to the water jacket. Semi finished liners are generally a press fit hence the need for further finishing once in the block.

Note: These answers are courtesy of a couple of marine engineer mates shared over a bucket full of beer one night many years ago. No responsibility taken for any brain cells missing in action.

Hope this helps,

Geoff

Geoff,
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Grey hair is hereditary, you get it from children. Baldness is caused by watching the Wallabies.

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FollowupID: 654335 Submitted: Monday, Oct 12, 2009 at 22:09

Richard Kovac posted:

Hi Geoff

"Generally finished liners are a hand push in fit with an O-Ring or similar seal to the water jacket. Semi finished liners are generally a press fit hence the need for further finishing once in the block."

My understanding is only dry liners can be machine honed after placement. other wise they will / can turn while honing and damage the o-rings.

I have fitted plenty of finished dry liners in my day, 4.236 Perkin's in JCB's all good as long as you prep. the parent bore first, we would curio freeze them just drop them in and make sure they don't bounce.

please don't take this the wrong way, I'm no expert... :-)

Cheers

Richard

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FollowupID: 654339 Submitted: Monday, Oct 12, 2009 at 22:17

Geoff (Newcastle, NSW) posted:

Hi Richard,
No offence taken.

I'm no expert on this either, I'm struggling to remember a conversation that wasn't in my area of expertise that occured at best 20 years ago.

I can only ask one of the marine engineer mates for clarification now days, the other bugger died of cancer three years ago.

Honing wet liners in the block and damaging O-Rings if they spin most certainly makes sense to me. On that one I believe you are 100% correct.

Geoff

Geoff,
Landcruiser HDJ78,
Grey hair is hereditary, you get it from children. Baldness is caused by watching the Wallabies.

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FollowupID: 654343 Submitted: Monday, Oct 12, 2009 at 22:26

Richard Kovac posted:

Geoff

Trying not to push the chit chat button, but it's been 20 years since I've done that type of work.... you know .. boss man nowadays only use my tool box to lean on... LOL

I'm sure small diesel engines would all run dry or no liners, as for the size of the engine they need to fit under the bonnet.

Richard

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FollowupID: 654346 Submitted: Monday, Oct 12, 2009 at 22:36

Geoff (Newcastle, NSW) posted:

Hi Richard,
I agree totally, I doubt these days if there's a main stream small engine that runs liners.

They are all built to a price and size. That price and size doesn't take into account the ease with which they can be rebuilt.

As to chit chat rules, we are still talking the original topic, engines and liners.

I've got a tool box too, I saw it some time last month!

Geoff

Geoff,
Landcruiser HDJ78,
Grey hair is hereditary, you get it from children. Baldness is caused by watching the Wallabies.

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FollowupID: 654353 Submitted: Monday, Oct 12, 2009 at 22:49

Richard Kovac posted:

Geoff

Engine blocks made of metal other than Steel / cast iron would have to have a liner of some sorts, properly not removable.

I see our engine does not have liners so it wont be a problem to us, as I was thinking of keeping my Troopy for 10 to 20 years it still wont be a problem I will need to worry about.. :-))

Cheers

Richard

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FollowupID: 654360 Submitted: Monday, Oct 12, 2009 at 23:09

Geoff (Newcastle, NSW) posted:

Hi Richard,
Very true, anything other than cast iron or cast steel most certainly requires a liner.

One of the most obvious engines now my memory has been jogged is the Land Rover Freelander diesel. It has an alloy block, for that to work successfully over a long period of time it really must have a cast steel or cast iron liner. As you say, this sort of mass produced engine is unlikely to be rebuildable.

Most certainly my Troopy is here for a very long haul, just like yours. I suspect just like mine, your choice of vehicle is no accident.

This is a really great discussion, one day we may be able to continue it around a campfire.

Geoff

Geoff,
Landcruiser HDJ78,
Grey hair is hereditary, you get it from children. Baldness is caused by watching the Wallabies.

Lifetime Member: My Profile My Blog Send Message

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FollowupID: 654362 Submitted: Monday, Oct 12, 2009 at 23:17

Richard Kovac posted:

"This is a really great discussion, one day we may be able to continue it around a campfire."

yes it is and something I could go on & on & on all day, I love Machinery, Hydraulics are my thing now..

When in WA look us up, we can't be that bad we both drive Troopy's. LOL

Richard

I think this maybe pushing it ......

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AnswerID: 386928 Submitted: Tuesday, Oct 13, 2009 at 20:43

Alec L replied:

well, if the difference one you have to machine and the other you don't, why would you buy semi finished liners?

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FollowupID: 654524 Submitted: Tuesday, Oct 13, 2009 at 21:23

Richard Kovac posted:

Alec

You may have a problem with the block and by fitting semi finished liners and having them machined honed you will / may solve the problem.

Also the clearance and tolerance will / can be better with machined semi finished liners than finished liners.

Regards

Richard

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