21 replies to this topic

[yaaan]

So at some point in the not too distant future I'll be fitting new(ish) pistons to my replacement engine and with this new rings. Presumably I therefore need to get the cylinders honed. To that end, does anyone have any recommendations for good machine shops in and around Bristol?

[Nelly Vx]

If your replacement engine has good bores with no "lip" at the top , simply buy a honing tool that fits in an electric drill and do it yourself , easy enough process , wet the bores with WD40 , insert hone tool into bore and gently glide it up and down each bore, you can't go wrong . The idea of this is to deglaze the bores ready for new rings :-)

[Boombang]

Honing should be done to a specific diameter leaving specific angle cross-hatch finish.  This gives good combination of seal, oil retention and wear.

 

Using a home type tool will de-glaze but not hone, and the tools themselves are prone to wear off square regardless.

 

Whether you need the bores honed depends on specified diameter for the new pistons, the current bore wear / surface finish, and how they measure up.

[yaaan]

Thanks for the replies. I've not removed the old pistons yet so I'm not sure what state the bores are currently in. I'm not sure that it's something I'd want to do myself (I've only got the one block to get it right on ) plus I'll need new valve seats cut/fitted so figured I'd find someone to do it all in one go. I'm fitting Z22YH pistons so hopefully the diameters should be the same.

[fezzasus]

Ian, I picked up a very cheap bore scope on ebay, think it was £25. You can pull out a spark plug and pop it in to inspect the honing, given the z22se has separate liners I wouldn't be concerned with the state of the bores. I would be very hesitant to do any work on it unless there is an obvious need to.

[yaaan]

Thanks Tom, that might be a good plan then. I'll check out the bay and see what I can find. Presumably if the bores are in good condition there's no problem with the new piston rings seating? Out of interest, why does having separate liners reduce the impact of the bore condition?

[Nev]

Thanks Tom, that might be a good plan then. I'll check out the bay and see what I can find. Presumably if the bores are in good condition there's no problem with the new piston rings seating? Out of interest, why does having separate liners reduce the impact of the bore condition?

 

I would imagine (at a guess) it's cos they are made of steel rather than iron like the Z20LET.

 

BTW, I have a bore scope at home if you need to borrow one Ian.

[fezzasus]

Separate liners are made out of the block so the quality is much higher, most importantly they are round and stay round, so have much less likelihood of wearing through normal operation.

[Nev]

When liners are installed into the block, are they an interference fit? If so, wouldn't that have a tendency to bend them out of shape a bit?

[Boombang]

From XU series PSA engine experience they are interference but don't require pressing in, just precisely machined so slide into the block.

 

Certainly on an XU PA engine they have a rubber o-ring seal that sits around the bottom of the liner and the block and when head is fitted they naturally seal by compression.

 

Good practise when removing an XU head, unless swapping out liners, is to then clamp the liners to the block before touching crank/rods/pistons to ensure you do not break the seal.

 

I would imagine the same practises exist on any wet linered engine.

[Arno]

When liners are installed into the block, are they an interference fit? If so, wouldn't that have a tendency to bend them out of shape a bit?

 

'Factory' liners in the Z22SE and maby other ali engines these days are cast-in and not pressed in. The liners are in the block mold when the aluminium is poured into it, fixating them in the block permanently.

 

Pure ali blocks with nikasil coating or MMC alloyed blocks without any liners as such are much more rare.

 

Aftermarket liners/sleeves usually need to have the originals milled out, a sealing surface created at the bottom of the block and then the new liners pressed in with O-rings at the bottom.

 

These then need to be bored/machined as normal.. Darton is a big liner/sleeve manufacturer and has a lot of info on their site on the procedures:

 

http://www.darton-international.com/

 

Bye, Arno.

[yaaan]

So, in a nutshell, if the bores look ok I don't need to hone them before fitting the new rings? Presumably ok would mean not too shiny/glazed?  

I would imagine (at a guess) it's cos they are made of steel rather than iron like the Z20LET.   BTW, I have a bore scope at home if you need to borrow one Ian.

Thanks for the offer Nev. I was thinking I may well take you up on this but then it occurred to me that as the head will be coming off anyway I should just be able to look at them and see    

Good practise when removing an XU head, unless swapping out liners, is to then clamp the liners to the block before touching crank/rods/pistons to ensure you do not break the seal.   I would imagine the same practises exist on any wet linered engine.

I guess if the bore liners are cast in I don't need to worry about this then?

Edited by yaaan, 23 June 2013 - 12:01 PM.

[Boombang]

Nope, sounds like things have moved on since 198X!

[Exmantaa]

 

When liners are installed into the block, are they an interference fit? If so, wouldn't that have a tendency to bend them out of shape a bit?

 

'Factory' liners in the Z22SE and maby other ali engines these days are cast-in and not pressed in. The liners are in the block mold when the aluminium is poured into it, fixating them in the block permanently.

 

Pure ali blocks with nikasil coating or MMC alloyed blocks without any liners as such are much more rare.

 

Aftermarket liners/sleeves usually need to have the originals milled out, a sealing surface created at the bottom of the block and then the new liners pressed in with O-rings at the bottom.

 

These then need to be bored/machined as normal.. Darton is a big liner/sleeve manufacturer and has a lot of info on their site on the procedures:

 

http://www.darton-international.com/

 

Bye, Arno.

 

 

Nop, Z22SE liners/sleeves are simply pressed in. You can buy pre-honed replacement liners from GM (around $120/st) and there is an official toolset for in-situ replacement.  ;-)

 

[oakmere]

When I rebuilt my engine I had the block honed for the new rings (still on original pistons). There were no hone markings left on the cylinders they were smooth. I can't see how the rings will bed-in correctly if yours are the same as mine. It didn't cost very much to get done.

[yaaan]

When I rebuilt my engine I had the block honed for the new rings (still on original pistons). There were no hone markings left on the cylinders they were smooth. I can't see how the rings will bed-in correctly if yours are the same as mine. It didn't cost very much to get done.

Well I have to get valve seats machined and fitted so I might as well spend the bit extra and get the bores done too. Just need to find a good machine shop now

[2-20]

Flexhone if the bores are fine.

Recommended by Guy Croft

http://www.guy-croft...php?f=13&t=1128

 

[Arno]

Nop, Z22SE liners/sleeves are simply pressed in. You can buy pre-honed replacement liners from GM (around $120/st) and there is an official toolset for in-situ replacement.  ;-)  

 

 

Oops.. My bad, sorry.. 

 

Very curious design decision though.. Cast-in liners are so common on many ali blocks these days.. But then again the Z22 (and it's siblings) do seem to have some more 'weirdness' here and there compared to many other engines. (the bizarrely high oil pressures it runs for one)

 

Bye, Arno.

[techieboy]

then again the Z22 (and it's siblings) do seem to have some more 'weirdness' here and there compared to many other engines.

 

 

Lotus designed = weirdness engineered in.

[Exmantaa]

 

Nop, Z22SE liners/sleeves are simply pressed in. You can buy pre-honed replacement liners from GM (around $120/st) and there is an official toolset for in-situ replacement.  ;-)  

 

 

Oops.. My bad, sorry.. 

 

Very curious design decision though.. Cast-in liners are so common on many ali blocks these days.. But then again the Z22 (and it's siblings) do seem to have some more 'weirdness' here and there compared to many other engines. (the bizarrely high oil pressures it runs for one)

 

Bye, Arno.

 

 

Well, GM turned to cast-in liners in the latest DI Turbo Ecotec engines... :-)