Thread: Liner corrosion

And another Q....

Just looking at prices for piston/ring assemblies and they vary dramatically for standard units (not getting into hepolite or anything serious). Are there any recommended brands or brand to avoid?

G`day Taz ,

i can`t tell from your pic what it really looks like .

If it were me i`d put a hone in it then decide , being up the top of the liner it`s not good as i guess you know because that`s where it needs to seal to work with any efficiency .

Factory 3.9 liners are thinner than Factory 3.5 , after market can be obtained in different thicknesses .

Generally because of the thinness of the Factory 3.9 liners it is not usual to rebore or fit oversize pistons though anything i guess is possible but as to how well it would work i don`t know .

Depending on cost and condition of the pistons you have it may be feasable if the liner won`t clean with a hone to fit one liner to the block , it doesn`t have to have a new piston to mate to a new liner , the liner is honed to suit the old piston .

It would need to be done by people with experence with these engines , well that would be my preference or at least a know capable engineer .

For the pistons/rings ect try an engine builder rather than a Rover parts place or Speacialist the engine builder will generally use non factory but will be able to price either and because they work with all makes you will find , i think that there prices will be more realistic .

Cheers , Peter .

That’s great advice - thanks Peter,

Yes I'm worried about the 3.9 liners moving if they are thinned down. And I'm also worried about having the liners replaced - since the one engine rebuilder in Perth that has been recommended on this forum by LoveMyV8County in Removing pistons with block still in the vehicle? , being Watmor engines in Woodbridge, appears to have closed down. Apparently they understood the nuisances of the whole hot block / cold liner thing.
I figure if a engine rebuilder fits a new liner cold - it's gunna move. And if they don’t know what they are doing with a hot insertion - it may cause the other good liners to move or even warp the block
Hmmm, maybe I'll just drop all the top end goodies I have into my current 3.5 !

Can stepped liners go into 3.9s as they do in 4.6s?? If the answer is yes - maybe this is an option.

Garry

G`day Taz

If you can`t find good people to do the work don`t , would be my suggestion .

If yours is a B or C suffix 3.9 which will make it a 10 head bolt per bank block ? ( i don`t know about the A suffix 3.9 but they may be like a 3.5 )
The bottom of the liner if it was fitted so`s it sat where it should sits on it own surface and is held around its entire circumference which makes the liner depth easy and the height is flush so also easy .
Where the expertise and experence comes into it is the fit in the aluminium the liner which is a different metal but this also should be easy because the expansions etc will be charted .

For the reasons you give i would only be interested in cold fitting of a single liner and a press fit with the correct known tolerance .

As Garry suggests a single top hat liner could be used but they require more expertise/experence to fit than a straight sided liner because there are two depths to be known and in their case the top depth is as important as the bottom . The bottom one can be seen/felt but the top one will only be noticed if it`s not right , this is a reason for seeing any block that has been worked on with the heads off .

Top hat liner will cost more to fit and maybe buy , to my knowledge single factory liners can`t be got only sets , aftermarket of the correct thickness would be required or machined to it but i`d be asking what they intend .

Fitting one liner can upset the liner beside it but this is not guaranteed only possible .

Your use of a 3.9 in your RR is not the same as a 4.0/4.6 in a P38a although they can fail in a similar manner , the likely hood of survival is higher in your RR , this would also apply if it were a 4.0/4.6 . This only applies to an engine that hasn`t been overheated as generally this will be the cause of most failures in these engines that are not in a P38a .

Cheers