Cracking OE Liners? Don't wont to go to Steels? How about these?...

[Woznaldo]

I come upon these while doing a bit of research and wanted to know peoples opinions. If it comes up in Italian just click the Union Jack in the top right of the window.

http://www.mespiecesauto.com/72-4-ch...miseacier.html

I've never run Steel Liners so I'm no expert, but people use them because of there increase strength and specifically, their ability to resist cracking under high boost pressures. The down side is that they don't have the same natural lubrication of the OE Liner and thus can be quite hard on Piston Rings.

It looks like these maybe somewhere in between. Not quite as strong as Steel, but do have some good natural lubrication properties.

They don't mention what sort of boost pressures they can withstand, but I think that's hard to define as if your boost comes in pretty quickly it can have more strain than a relatively gradual increase.

Thoughts?

[GTphil]

Cracking liners is down to poor tune more than anything else.

I think that the high cylinder pressures that break liners aren't caused by boost but more by a overly lean air fuel mixture explosion.

I'm only really guessing this tho and anyone more in the know please feel free to correct me.


Before the relative ease of and cheapness of wideband sensors people were busting them all the time. Now it at least seems to happen a lot less.

IMO unless your pushing for over 240hp then steel liners are not needed.

These ones however have caught my eye on a few occasions and I to wonder what to make of them. Worth while upgrade or just another pointless modification.

[Jimmy_GTT]

Yes, I'm also questioning what boost are you running at that have caused the crack.
I'm running at 1,3 - 1,4bar (18-20psi) without a problem so far.

[Woznaldo]

I have never cracked a liner myself, I was merely highlighting the availability of these Liners as I had not seen them before and there are those within the club that may find them useful.

Like GTphil has mentioned above, most are probably down to poor tune and the now common availability of Wideband AFR monitors has reduced this. That said, maybe those who are pushing their engines in Drag, Circuit and Hillclimb events might be approaching or exceeding the Liners limits.

If this is useful to one person in the club, then it's worth the post.

[GTphil]

Indeed, and for €500 if they do what they say then for someone building a lump that's going to be pushed then they are definitely worth investigation.

[R5MJH]

ive cracked a liner on my tungy in the past running 25psi but what happened was i was racing a tvr griffith and i blew the hose that goes into wp near no4 plug clean off lost all water and cracked the liner pmsl

not funny at the time thou

[Woznaldo]

In my original post the company that sell the 700N/mm2 Liners provide documentation to attest to this property. They also state that other companies falsely say that their Liners are rated at 800N/mm2.

That said, here's another French company who sell the 'so called' 800N/mm2 Liners. I'll leave it to some of our French members to fill in the facts.

http://www.gtturbo-online.fr/bas-mot...te-gs-800.html

Food for thought...

[Andrew Cooke]

I've got SG liners somewhere, I just can't remember which ones they are

[martynp]

ive cracked a liner on my tungy in the past running 25psi but what happened was i was racing a tvr griffith and i blew the hose that goes into wp near no4 plug clean off lost all water and cracked the liner pmsl

not funny at the time thou

I bet the tvr driver thought it was funny

[Woznaldo]

Has anyone tried these Liners from CGB Motorsport?

http://www.cgbmotorsport.net/liner-w...our-1348-p.asp

It says they have three times the strength of OE Liners?

I've just had my Liners honed so they will help the new Piston Rings bed in, but the machine shop said they had some wear. I don't know how much yet, but looking at some replacements in the meantime.

[Ian S]

I had a few thou taken out of my liner so the pistons had extra clearance when expanded so they didn't rub and score the liners.

Had a small amount of oil from the breather so made a catch tank to accept the breather pipe that normally goes to the 'telephone hose'. Caught a few spoonful's of oil over several months, ie, very little.