Bentley Manuals

[Porshaah]

Can I assume the "Porsche 964 Bentley Technical Data Without Guesswork " will have all the technical data required for an engine rebuild as opposed to the "Bentley 911 964 Service Manual"?

[Spenny_b]

It certainly has a lot - probably all you'll need, but in rebuilding my 964T engine, I've used a combination of Waynes rebuild bible (mostly this, in fact), the Bentley manual (good for numbers, not so much for procedural info), the official Porsche rebuild PDF's that are online somewhere, Porsche 911 Enthusiast Handbook (by Anderson, good for very in depth explanations) and Streathers 911 Enthusiasts Companion (also by Bentley)

[Porshaah]

I've been using the Porsche service manual and Wayne's book but it still leaves me with questions, since it only covers up to 1989. I'm looking for numbers mainly and where the measurements should be taken. For example the cylinder diameter, there are references in Waynes book to measure 30mm below the upper edge and the Porsche service manual refers to a point 56mm below the upper edge but no explanation as to the significance of this point. I can only assume that due to the built in cylinder taper and my measurments indicating this is the largest diameter, that this is the point I should be measuring cylinder diameter. I use Streathers book for general information. Is the Bentley Technical Data book a more complete reference, compared to the "Bentley 911 964 Service Manual"?

[Spenny_b]

The Tech Data Without Guesswork also says - for your example - to measure 56mm from the top, no real commentary as to explanations (I guess this is why its referred to as a Technical Data book)...the whole book is mostly a set of bullet points, albeit sometimes very useful.

My 2p - for the sake of hopping onto Amazon and spending £20, it's worth having on the bookshelf, if for no other reason than to arbitrate between disparate sources of information.

[Porshaah]

Thanks Spenny_b for your response.

I'll likely purchase the Bentley Technical Data Without Guesswork as opposed to the Bentley service manual as the title lends itself to being a manual which likely instructs one when to change the oil. I'm looking for numbers/specs as opposed to how to manual.

Is there any reference to the stampings on the pistons and cylinders and how to interpret them?

I'm having difficulty understanding the Porsche service manual description and how to identify my pistons.

The wordage taken directly from the manual reads: "Letter "E" in the middle (towards the inlet side), with identifier change level, internal Mahle code; the tolerance group (0, 1, 2 or 3) is indicated to the left next to the "E", with the weight group indicated next to the tolerance group.

Note:

The -- signs (minus/minus) for weight group indentification may also be indicated in a vertical plane. "

The image in the manual shows the top of a piston with the following markings:
0| E /2

What are they refering to when they say "with identifier change level, internal Mahle code"? I understand the tolerance group is "0" in this example, positioned to the left next to the "E". But the weight group (i.e. which I believe is the 2 in this example) is not next to the tolerance group. If it is the 2, then it would be better described as to the right of the "E".

In my case I have 2 types of piston stampings:
++3 E /23
0+ E /23

Which I interpret as the tolerance group being 3 and 0 respectively, but what is the significance of the "++" signs preceding the "3" and "+" sign following the "0". Also, if my interpretation of the weight group from above is correct, as being to the right of the E, what does it mean when there is 2 digits in this position, as in my case the "23"?

Thanks again Spenny_b
All responses welcome