[928uk] 4.5 or 4.7 Block

[Ben Hodges]

Thanks for the below James - sounds like your 4.7 will be very sorted when done. 

Does Dave replace with bores with Nikasil?

Machine shop is SRS who have experience with 928’s. The bores are so out I think sleeves and replacement pistons are the only option to salvage it. That or source a used set of 4.7 / 97mm pistons and bore the block out to a matching tolerance 97mm. From what I’ve read though this will leave the cylinder towed a little on the slim side.

After paying for a full rebuild on my 997 last year I’m not sure I have the budget that you have James! I want it done right but not looking for factory fresh perfection if that makes sense.
Agree with what you say re used blocks hence the post on here!

Cheers
Ben


Sent from my iPhone 

> On 4 Sep 2019, at 19:35, james west <quixotixs at hotmail.com> wrote:
> 
> Hi who is the machine shop, as there is only one company in the uk that I could find that can hone/bore the 928 block.
>  
> On my 4.7 i have explored this in some depth:-
>  
> Options are (for the 4.7)
>  
> Rebore 0.5 over size – Pistons kit available from Porsche – mega price of £3,200.00
> Gasket kit £550.00
> Regrind and new shells – circa £600.00
>  
> I would suggest that talking to Dave Anderson – he has a better solution, I will let him tell you about it, if he still has an option.
>  
> If you want to move away from standard Porsche then 928 Motorsport (Carl) gave me a price for custom built Weisco dropped forged piston kits to fit the standard rods, at circa $2600.00, these are designed to work in the Alusil block, but you will need re-bore and treatment
>  
> But then you will still need to pay the import duty and vat and to top off then the gaskets and the crank doing.
>  
> So if you have a spare £5k then new parts is the way to go.
>  
> If you want to buy second hand then you are in the lap of the gods – 4.5 block for about £900-1200 and then you need the gasket set and there is no telling if you have bought a POS until you check it out.
>  
> Risky buying from breakers as you do not know the history – thrust plate – end float worn rings etc..
>  
> Could be a money pit tbh
>  
> If you go cast inserts as most machine shops recommend because they cant hone /treat the bore the the piston could possibly be cheaper.
>  
> I am half way through my engine rebuild and the costs keep going up, but at least I will know that my engine will be sweet when completed.
>  
> Good luck
>  
> Jim West
>  
>  
> Sent from Mail for Windows 10
>  
>  
> From: 928uk <928uk-bounces at lists.928.org.uk> on behalf of Paul R Smith via 928uk <928uk at lists.928.org.uk>
> Sent: Wednesday, September 4, 2019 7:10:48 PM
> To: 928uk at lists.928.org.uk <928uk at lists.928.org.uk>
> Subject: Re: [928uk] 4.5 or 4.7 Block
>  
>  
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