Page 2 of 2

Re: 2.7 CIS Engine rebuild - suggestions please

Posted: Mon Nov 09, 2015 5:07 pm
by 911hillclimber
Shuffle-pinning has been discussed several times for different engines, all mag alloy based.

Some say (as ever, many opinions, inc mine) that a standard engine does not need them.
Tuned engines do/maybe
Highly tuned engines do.

If the block is in need of line honing then I presume it is distorted. Honing removes metal so the bearing shells need to be appropriately thicker, not sure if such shells are readily available?

Some argue that the old mag cases are unstable etc.

It is difficult to get a clear answer, so if your man Alan says it needs doing and you respect his opinion then best go ahead in that direction?

Re: 2.7 CIS Engine rebuild - suggestions please

Posted: Mon Nov 09, 2015 8:41 pm
by AndrewSlater
Thanks for the response.

I have asked some questions about the recommendations but not heard back yet so thought I would ask here so that I understand any implications.

I was originally told not to bother with the shuffle pinning but now it seems to have been recommended but don't understand why.

Also I need to understand whether the line bore will definitely affect the bearing size, I was led to believe a minor bore may not alter the sizes.
I'd prefer not to have to source non-standard bearings - especially as I was told they were £700 a set.
I would be interested to know what the measurement threshold is that triggers a line rebore and what the consequences of not doing it would be.

As I find out more I'll post the explanations.

Thanks again
Andrew

Re: 2.7 CIS Engine rebuild - suggestions please

Posted: Mon Nov 09, 2015 9:13 pm
by 911hillclimber
IMHO, leave the engine standard. It was a good design for all those Porsche engineers, why not now.

Get it all rebuilt with new parts so no worn out areas, and it will last you years.