liner puller

[tommylad]

Recently discovered that one of the tell-tale drains is wet on my JP2, so I also have the un-enviable task of changing these o-rings! I wonder if someone could advise what the exact outer diameter of the liners is? I'm going to make the extraction tool before I start stripping the engine.

I also wonder if anyone knows how likely it would be that my liners would be re-usable after extraction (assuming they're not too worn) or do they suffer much damage from the forces of removal? Pretty confident my engine has never seen salt water, and has had anti-freeze in it for the last 10 years, so I'm really hoping that they're not too bad to get out, but then....

 

Ta!

[Boater Sam]

You will be the first to reuse a liner that I have ever heard of.

Not done any JP listers but on old truck engines if they were tough to shift I used to run a die grinder down to put a thin line down the inside of the liner. Boring one out is a last resort, it takes ages and is not good on the boring bar when it starts to break through, I wouldn't let you do it with mine!

[tommylad]

28 minutes ago, Boater Sam said:

You will be the first to reuse a liner that I have ever heard of.

Not done any JP listers but on old truck engines if they were tough to shift I used to run a die grinder down to put a thin line down the inside of the liner. Boring one out is a last resort, it takes ages and is not good on the boring bar when it starts to break through, I wouldn't let you do it with mine!

Cheers Sam, with the availability of liners being quite tricky now I was wondering if it might be possible to re-use them, but I can see this is a long shot. If I was to replace the liners, would it be possible to re-use my existing pistons (but with new rings) or would this be bad practise?

I happily have access to a 60 tonne hollow Enerpac jack, so I hope that should shift it!

Another question I had was if it's possible to use a plumber's blow torch to heat the pistons for gudgeon pin extraction? The Lister manual says to use toweling soaked in hot water but this sounds quite laborious!

[Boater Sam]

Gudgeon pins will slide out easily if you just put the piston crown in 3" of hot water, never done them any other way. Liner will possibly distort when being pressed but if not and they come out easily there may be a point in replacing then 90 degrees round to even the wear.

Its daft economy to refit used rings. Pistons need careful checking for groove wear as well as ovality/scuffing if they are to be reused. Little end wear is usually not a problem. But new pistons avoid all these pitfalls.

I found latterly that it was almost as cheap to buy new pistons complete with rings  as it was to buy just rings.

[tommylad]

5 minutes ago, Boater Sam said:

Gudgeon pins will slide out easily if you just put the piston crown in 3" of hot water, never done them any other way. Liner will possibly distort when being pressed but if not and they come out easily there may be a point in replacing then 90 degrees round to even the wear.

Its daft economy to refit used rings. Pistons need careful checking for groove wear as well as ovality/scuffing if they are to be reused. Little end wear is usually not a problem. But new pistons avoid all these pitfalls.

I found latterly that it was almost as cheap to buy new pistons complete with rings  as it was to buy just rings.

The issue is, to get JP pistons out you remove the big end cap, push the piston half out the top, and then drive out the gudgeon pin allowing you to pull the piston out the top and drop the con rod out the crankcase. Therefore it isn't possible to dip the piston in hot water. Maybe I'll try just pouring hot water over the piston crown to achieve the same effect!

It's not possible to re-fit the liners 90 deg out as there's cut-outs on the lower edge to clear the big ends ?

I see your point about the economics of buying new pistons c/w rings. Stationary Engine Parts have aftermarket liners and pistons c/w rings - does anyone know if these are good quality replacements? If anyone has NOS pistons and liners for sale I would be very interested to speak to you!

[Boater Sam]

Sorry, forgot that lots have conrod cutouts, turning them 180 degrees will be OK.

 

The hot water is to get the pins out of new pistons.

If you have an electric iron, sit it on top of the piston in the bore, that will do it, Or a hot flat iron?

I hate "driving" gudgeon pins out especially in situ, its easy to bend a rod surprisingly.

The JP is a lump of an old engine, its not critical about the quality of new pistons, its a safe bet that the cheapest you can find will be as good or better than the originals As long as the size/fit is good you will be fine.

[steamraiser2]

The Lister JP / JS / JK range of engines were built to tight tolerances for their day and remain a reliable and robust engine. We restore a lot of them and have dealt with many that have never been overhauled before. To last up to 80 years without major surgery is a fine record indeed. If you find that you need new parts fit quality stuff and avoid the dross that is out there in such large quantities these days.  As to reusing your liners, the chances of that will depend on the level of corrosion as much as bore wear. JP blocks rot immediately above the point where the O rings sit which can be a challenge when reassembling them. If your engine has never seen sea water it should be fine, if it has good luck to you. We often have to reblock sea damaged engines. Our liner puller can exert 60 tons of force and we have topped it out many times. Again this is dependant on the level of corrosion at the bottom of the block.If they come out very easily I would be very suspicious that they are low quality aftermarket parts. Some of the pattern parts available are slightly undersize at the bottom where the O rings sit. Lister did both chromed and plain liners the chrome ones being commonest.  On inspecting yours if the chrome is worn or rusted through the liner is scrap. A wear lip means scrap. As I said built to tight tolerances.  Don't use sealant on the O rings ,a little swarfega or washing up liquid will help a lot. Pop the liner into the block and tap it home with a dense block of hardwood. I use a piece of greenheart as broad as a railway sleeper about a foot long. One firm thump with the block,no hammer, and it's always home. Make sure you set the bumping clearance correctly and avoid the over thick knock off head gaskets out there. Check out the various JPs on the Marine Power Services video pages and if your engine isn't running as cleanly as those something isn't right.

[RLWP]

Just to be sure, I'd be very wary of jacking the liner out from the crank end (if that's what you are considering).

 

I'm paranoid about breaking a chunk out of the deck of the block, so I have made a stripping plate to sit on the deck with a bore just bigger than the liner OD. That way, the forces from the puller go through the plate, into the deck.

 

I have seen welded up block decks, not pretty

 

Oh, and I bet there's half a ton of silt in the block

 

Richard

[steamraiser2]

Only half a ton ? ?

[RLWP]

Just now, steamraiser2 said:

Only half a ton ? ?

Can't be a ton and a half - he's got a weep from the tell tale so there must be some water in there

[steamraiser2]

And then there was the guy who had leaky o rings and listened to " man on the canal" who advised cracking an egg into the header tank, which he did every day. Death by omelette ?

[tommylad]

Thank you for the wise words - I really appreciate your time taken to help

With regard to the replacement parts, I was looking to buy them from Stationary Engine Parts - can you suggest if this is a good source for liners and pistons? I'm struggling to find any alternative with a quick web search! I was also hoping to buy the head gaskets from Marine Power Services to avoid the over thick gaskets.

One question about the bump check - Is the best practise as per the workshop manual, using some lead to measure the height? If so, I'm not clear on whether the head nuts should be fully torqued to correctly compress the head gasket during the test?

I know for a fact that the liners in mine haven't been changed in the last 30 years, and it wouldn't surprise me if the engine is largely undisturbed from original build. My Dad believes that the engine was not cooled with sea water directly - I just hope he's right!

Oh, and no worries RLWP, I wasn't intending to jack beneath the liners, I have access to a hollow jack, so can use the method described by Martyn earlier in this thread

Part of me is dreading this job due to worries of what I'll find and damage that could be caused from dismantling, but another part of me is really looking forward to learning more about the engine which I've thoroughly enjoyed listening to since I was about 3! (35 now)

[RLWP]

I don't think there are any 'overthick' gaskets still in existence. We (Marine Engine Services) don't have any

 

[bizzard]

These keep popping up in VNC by Canal World. Three there at the mo.

Edited August 27, 2018 by bizzard

[RLWP]

16 minutes ago, bizzard said:

These keep popping up in VNC by Canal World. Three there at the mo.

It's RichM performing witchcraft in another dimension: 

 

[cuthound]

15 minutes ago, RLWP said:

It's RichM performing witchcraft in another dimension: 

 

 

Bizzard started it by talking about pins and effergies ?

Edited August 27, 2018 by cuthound
Missing worm

[tommylad]

Just thought I'd share my experiences on pulling my JP liners which I successfully did yesterday!

Many thanks to all on this forum who's advice was a great help!

I had the following plates laser profiled from 20 mm steel plate, and machined a register on the one which would locate on the underneath of the liners (I didn't want it slipping)

I was then extremely fortunate to be able to borrow a 60 tonne hollow jack which sat on top, using some M30 studding to tie it all together.

I was quite nervous about putting this much force across an old casting, however it ended up being quite anti-climatic - both liners came out with only 6 tons of force, with no bangs or alarming noises - just drifted out smoothly.

I'm going to create a new post offering the three plates for anyone to borrow if they wish to use them themselves.

 

Edited September 19, 2019 by tommylad