Assessing an unknown engine

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RobFrost
DDK 1st, 2nd and 3rd for me!
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Re: Assessing an unknown engine

Post by RobFrost »

After the disappointment of the last assembly failing, and being busy at work, reskinning the doors, plus some other commitments, I've neither had the time nor the emotional energy to attempt another uniting of the case halves until now, especially considering it could fail again.

But I did get the wind in my sails last weekend with a few hours to spare, and tubes of all the required seals and lubricants.

I was a three aluminium washers short for the case perimeter nuts, so I drilled some aluminium sheet and the makeshift drill lathe came into service again.

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I allowed four hours for the assembly, and spent the first of those looking for one single missing blue o-ring which i knew must be in the garage somewhere.

I elected to coat the o-rings on the through-bolts with silicone, as per Dempsey. These bolt holes double as oil tubes, exposed to full oil pressure, so require a reliable seal.

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No con rod stands for me, just careful balancing, plus a daughter with a bent-over welding rod to hook the upper chain through the case at the crucial moment. In recent years I have noticed the usefulness of my belly as a third limb, and it faithfully served me in this endeavour to hold the central con rod vertical as the crank went into place.

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The required torque did seem quite high, especially on the perimeter flange, but all the studs held perfectly and I was soon looking at an assembled short block and praising Mike Bainbridge's very kind advice regarding which studs to time-sert.

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One slight question-mark remained. Dempsey said 23 flange nuts were required, which i set out carefully in advance as a way of ensuring every one was applied. By the end, one nut and one of my freshly-fashioned washers remained. It tentatively looks like the earlier cases have one fewer stud and nut than the later ones.

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Last edited by RobFrost on Mon Dec 08, 2025 8:22 am, edited 1 time in total.
1970 911T, Signal orange (Restoration thread)
1988 3.2 Carrera backdate, Black
2001 996 Turbo, Lapis blue (am I allowed to put that here?)
I'm looking for a pre-impact bumper 911S or other high-revving 911 to restore - please let me know if you see one.
911hillclimber
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Re: Assessing an unknown engine

Post by 911hillclimber »

One over...awkward.

I've never read early cases had one less (M8 ones).
You must have been round the lot several laps.
There are several around the flywheel end but those are obvious.

You may probably have had one too many in the gasket set.
73T 911 Coupe, road/hillclimber 3.2L
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Lightweight_911
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Re: Assessing an unknown engine

Post by Lightweight_911 »

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I think that figure of 23 includes the one inside the chain housing ...

.
Andy

“Adding power makes you faster on the straights;
- subtracting weight makes you faster everywhere”
RobFrost
DDK 1st, 2nd and 3rd for me!
Posts: 2448
Joined: Thu Jul 08, 2021 8:18 am
Location: Lichfield

Re: Assessing an unknown engine

Post by RobFrost »

Lightweight_911 wrote:.

I think that figure of 23 includes the one inside the chain housing ...

.
Here's the spot where I believe later cases have an extra stud (going by the diagram in Dempsey)

Image

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1970 911T, Signal orange (Restoration thread)
1988 3.2 Carrera backdate, Black
2001 996 Turbo, Lapis blue (am I allowed to put that here?)
I'm looking for a pre-impact bumper 911S or other high-revving 911 to restore - please let me know if you see one.
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