2.9 Rebore to 3.0 or 3.1

[Samson 0]

Hi,

I have a 2.8 highline but recently purchased the 2.9 raddo engine, can it be a simple transplant and remap of the ecu or do I need a raddo ecu?

I know this has probably been asked before but I couldnt find it after doing a search on the forums, but can you rebore the 2.9 Corrado engine to a 3.1, i know people have rebored to 3.0.

I was wondering if it made the walls too thin or if it lowered the working life of the engine after it has been done.

Also if anyone has done a rebore to a larger size, where did you get your pistons from? Not really bothered about forged pistons, although to be honest I'm not sure what the benefits are of getting forged over non forged.

All help is appreciated

Thanks

[adam_christie 0]

http://www.motorcycleproject.com/motorcycle/text/cows-pistons.html

[Samson 0]

very interesting, thanks

[adam_christie 0]

There's also some interesting info here

I'm in the process of getting bits together to SC my VR, and knowing that the stock engine can take up to 15 PSI with a copper head gasket is brilliant! :-)

[mike 6]

theres a guy on edition 38 has rebored a 2.9 transplanted engine to 3.0 and it blew up of something and he doesnt recomend it! makes the walls too thin. think his forum name is mark...

[Samson 0]

Ok, update people.

I have my eyes on a rebore to an 83mm piston for the 2.9 block, does anyone know if this will cause me issues, it'll take the block to a 2975cc or something along those lines apparently. I am looking at getting some wosser pistons, or JE just not 100% which ones yet as not entirely sure of the difference. Also, do I HAVE to replace the rods at the same time as the pistons, do the new pistons come with rods or on their own, sorry for the silly questions but dont want to get this wrong as 1) It is a lot of money and 2) more importantly it will take my VR off the road if it all goes wrong.

[VRmonster 1]

a few pointers to note before you go further.

what engine mods do you have, or have planned. if the answer is none, or exhaust/filter. then dont bother with overbores, not cost effective. if you say s/c, turbo. then will be worth it on a forged piston level (low compression), but still not cost effective as you can just up the boost for the same gains. but if you say your building a big NA motor, and you have cams/schrick vgi and various other stuff, or individual throttle bodies, then it works more effectively if you raise the compressions. but realistically not worth the pain and heartach on an everyday engine when it breaks (which it will lol)

the rods can stay, just make sure your bushes/bearing shells are all in good order, pistons should come with piston, rings, gudgeon pins and clips.

JE are a noisy piston in my opinion, theyre bad for piston slap when cold, but every engine takes it differently. im going for wiseco for my 2nd rebuild (1st 3.0l blew up) so now im going for a 2.9, 82mm as i think the walls are to thin to shed heat effectively from an 83mm.

all that said though, there have been many engines used 83mm and lasted forever, so can be done. but id spend the money elsewhere like a good filter/exhaust, cams and remap. you would see the same gains as a basic rebore. or budget a little higher and throw a s/c on it lol.

[Samson 0]

Excellent advice, thanks.

I am going for a NA engine, prefer them to FI, I find them a bit more reliable on a daily basis if you know what I mean.

I have heard that the 3.0l makes the walls too thin but then like you have said others have gone on forever.

Oh the problems of life eh?

My goal is to get a couple of cams, MAYBE a shrick, not sure yet, definately an exhaust and go from there really. Thanks for the advice again though, really helpful.

[Lizard Racing 0]

I run 83mm JE pistons (2931cc) and they are very noisy when cold because of the clearance required being forged, If you run Wossner forgies they will run with half the clearance and they will run much quieter when cold. I run mine every day and very hard when I can, I have seen 25PSI of boost and the block has been fine. I wouldn't recommend going bigger than 83.5mm (2967cc).

As said already NA its not worth doing unless the bores are badly worn and require a rebore to save it.