The V8 Owners Forum -

Can anyone recommend a machine shop/engine specialist that can bore out the old liners and replace with 3.9 liners? - I have the liners and pistons.

Preferably in the South of England if possible. Thanks

Might be worth trying Turner Engineering.

Chris.

You do not bore out the liners - you heat up the block with a big propane torch (or a dedicated oven) and tip the block upside down and the liners fall out. With the block hot you put in the 3.9 liners in and let the lot cool locking the liners in place. There are plenty of videos on Youtube showing this.

If you are going to change the liners then go for top hat liners and get the block machined for this with the liners out.

However given the cost of doing this why not just get a 3.9 engine complete - they are cheap enough.

Garry

Our machine shop always machines liners out. We just had three oversize liners fitted due to a major overheat. I can't see the liners falling out from just heating the block and I seem to recall the blocks were heat treated during manufacture. If this is the case then the heat treat will be lost at the temperature you will need. You can also remove liners cold by manufacturing a suitable puller,

Alan

bigaldart wrote:I can't see the liners falling out from just heating the block and I seem to recall the blocks were heat treated during manufacture. If this is the case then the heat treat will be lost at the temperature you will need. You can also remove liners cold by manufacturing a suitable puller,

Alan

Well have a look at the vids on Youtube and you will see they just fall out when the block is heated. That is also how they were made in the factory - liners cooled and block heated and liners pressed in.

If the 3.5 and 3.9 liners are the same fitting to the block, can't you just bore out a 3.5 to 3.9?

Out of interest I have removed a liner by heating a block over a gas ring.
The liner tapped out easily. I don't know what distortion damage this caused , but it was a scrap block.

I have read that Rover reduced the interference fit at one point as they were concerned about vehicles located north of the Artic circle. Their concern was that when cold , the stresses in the aluminium may induce hair line cracks due to the differential contraction rates and strengths of the two metals. This change in interference fit may well account for the increase number if slipped liner incidences in later engines.

Getting slightly off topic but this is interesting viewing-
https://www.youtube.com/watch?v=qmVI1gza9kQ

[quote="ChrisJC"]Might be worth trying Turner Engineering.

Chris.[/quote]

Yes, they were my first thought as I've had a couple of top-hatted 4.6 short engines from them in the past, but no. As far as I could understand, Richard Turner didn't want to cause extra wear to his machining equipment by boring out the old liners.

Fitting the 3,9 liners into a 3,5 block requires removal of the old liners as well as fair amount of machining of the block. Roughly 5 mm bigger bore in the block. I would say that machining costs to remove the original liner, then 5 mm of the material, then final machining to press fit and then possible boring/honing to the final size adds up quite fast. Is it really worth it given the number of 3,9 blocks ?

I removed a liner from a 4,6 block with a die grinder I just cut a vertical groove through the liner. You just have to be careful not to grind into the block.

[quote="minorv8"]...Is it really worth it given the number of 3,9 blocks ?[/quote]

Now I've found out exactly what is involved, and the probable expense, I'm beginning to think that going for a replacement block is a more realistic option. Thanks for all the responses. In the meantime, anyone interested in a set of new 3.9 liners and pistons, give me a call.