rebore 928 engine
 

Is there way to use re-sleeve 4,5 liter 1979 model to 4,7?What adjustment needs to be done to the intake system in order to feed it more fuel?How far can you push the 4,5 clylinder wall with cast iron liners?

There are no clear answers since what you plan has only been attempted a few times, and never to my knowledge starting with a 4.5L since good 4.5L blocks often sell for a few hundred dollars.

The existing fuel system is fine, as is airflow, unless you make other performance oriented changes to the heads etc.

More likely
 

A better idea would be to start with a 4.7 block. It would work with the components you have. Or, just buy a 4.7 engine. The block is essentially the same size as a 4.7, so you could feasibly re sleeve it at least that far. The difficulty is that the cost in re sleeving a block is considerably more than just buying a 4.7 short block.

The only reason I can think of to actually do this would be to get a little more umph to an original euro. That way your numbers would all match. Or, If you have already decided that the numbers are worth that much to you, and you are going to spend the dough, you might as well put in the bigger sleeves as the pistons are cheaper for the 4.7.

Tell me again...WHY do you want to do this?

will the piston run on iron as they are iron plated?
 

Is there power gain if i rebore to 4,7 liters?I will use 4,5 block and can get original factory rings and use the old pistons but will they lock up since they are iron plated?Is there Nikasil plating shop in Australia?

fras--

see my responses to your original thread (928 block).


your current block is unrepairable. don't waste your time with it. it costs you more to attempt a sleeve repair (for 8 cylinders) than you will have in purchasing another 4.5L or 4.7L short block.

if you are still un-sure, you can send me $250 USD and the cost of shipping a 4.5L to you.;)







--Russ

fras, fill in your location in your profile so we know what vicinity you are.

he's in Australia---

it'll cost him near $1K USD to have one shipped to him from here, plus the cost of a short block.



his engine is junk (by what I saw on his original post). at least 4 cylinder towers corroded (on the outsides--not sleeve-able), pistons are probably seized (read: un-useable), no telling what the other side of the engine looks like much less the heads.........not even a good candidate for a coffee table.

he should contact Greg Gray there in Australia for help with a replacement (as I suggested).







--Russ

dupe post.
 

He has posted the same thread on RL asking the same question, Hoping for a different answer. Another block is needed. Does he have a matching numbers concern? What is the Deali O?

Oz gets 928 stuff from Japan sometimes. Kinda funny about a year ago I was trying to buy a Euro S motor I found in Adelaide, but the shipping details never gelled. If fras hooks up with 928 groups in Australia I bet something turns up.

http://www.landsharkoz.com

Porsche parts from Japan?
 

Umm. Porsche parts from Japan? That is a new one on me. In The land of the rising sun cars are taxed extra for being old. I don't think there are a whole lot of 20 something year old 928's hanging around waiting to be dismantled. Ya know, he could, theoretically, bore the block to accept any sleeve up to a 4.7....

I don't know what the boring costs would be, but they are probably not much cheaper in OZ. Yea, that IS a tough spot to be in. I am hoping he finds a nice, reasonably priced lower end somewhere on that great big Island. :rolleyes:

if you look closely at the top of the cylinder towers in his pictures you will see that the tops are highly corroded.

this does not bode well for sleeving, as I stated several times.

he needs another block, period. preferably one located in Australia due to the cost of shipping from any where else, be it the USA, Japan---anywhere.





--Russ

I see, I see
 

Ok, I see it now.

http://forums.pelicanparts.com/uploads14/porchcorosion1231748682.jpg

Yea, that IS a mess. are the "sleeves" thinner than the "cylinder towers" ? i.e. no matter what sleeves you put in there, It is still toast as there is nothing for the gasket to seal against. Hmmmm... and it is cast aluminum so welding a bead up will cause more harm than good and probably fail.
Yeppers, It is toast.