Documented forum build · G-Series · air-cooled

1983 911 SC 3.2 rebuild

Don "Gordo" Gordon documented a long-planned 3.2-litre upgrade for their 1983 911 SC Targa from cleaned and machined parts through bottom-end assembly, cam timing, PMO carburettor setup, a 570-mile road trip and a later durability update.

Evidence: Opening thread page — project background, preparation and bottom-end assembly · Page 3 — cam timing, engine change and installation preparation · Page 5 post 84 — completion and links to startup, tuning and driving · PMO tuning thread — finished specification and calibration record · PMO tuning post 71 — 570-mile road-trip report · Rebuild post 89 — December 2025 durability update

Vehicle: 1983 Porsche 911 SC Targa
Engine: Original 3.0-litre 911 SC flat six retained in running condition while a second engine was rebuilt → 3.2-litre air-cooled flat six with JE pistons, Dougherty GT2-102 cams, 46 mm PMO carburettors and Electromotive XDi ignition
Forum: Pelican Parts Forums
Thread author: Gordo2 (Don Gordon) · 7 December 2013

Vehicle and engine evidence: Opening thread page — project background, preparation and bottom-end assembly · Page 3 — cam timing, engine change and installation preparation · PMO tuning thread — finished specification and calibration record

Why it came apart

This was a planned performance rebuild rather than a documented mechanical failure. The author had researched the project for years and bought a second engine to rebuild at their own pace.

Source: Opening thread page — project background, preparation and bottom-end assembly

What the project aimed to do

Create a stronger 3.2-litre road engine for the SC while retaining the dependable original 3.0-litre engine during the build and avoiding a long period with the car disabled.

Source: Opening thread page — project background, preparation and bottom-end assembly · Page 3 — cam timing, engine change and installation preparation

Who did what

The owner documented and carried out the assembly and tuning work; external machine work included connecting-rod reconditioning, pin fitting and balancing before the parts returned for home assembly.

Source: Opening thread page — project background, preparation and bottom-end assembly

The author's forum signature identifies the 1983 SC Targa; the project used a second engine so the car did not have to remain off the road throughout the rebuild.

Vehicle context: Opening thread page — project background, preparation and bottom-end assembly

Documented sequence

Parts preparation and measurement
The author records case and oil-gallery cleaning, crankshaft preparation, reconditioned and balanced connecting rods, ARP bolt measurements and bearing-clearance checks before assembly.
Source: Opening thread page — project background, preparation and bottom-end assembly
Bottom-end assembly
The connecting rods were installed using bolt-stretch measurements, the number-eight bearing seal was revisited and the case halves were sealed with the documented ThreeBond and Loctite products.
Source: Opening thread page — project background, preparation and bottom-end assembly
Cams, timing and installation
The thread follows chain-housing installation, GT2-102 cam timing, the engine change from the original 3.0 and preparation of the engine bay and oil circuit.
Source: Page 3 — cam timing, engine change and installation preparation
Startup and carburettor setup
After completion, the author continued the record through first running, PMO carburettor tuning and wideband-guided roadside adjustment during break-in driving.
Source: Page 5 post 84 — completion and links to startup, tuning and driving · PMO tuning thread — finished specification and calibration record · PMO tuning post 71 — 570-mile road-trip report
Long-term follow-up
A December 2025 post returns to the build and reports that the engine was still running.
Source: Rebuild post 89 — December 2025 durability update

Named components and work

Crankshaft, rods and fasteners

Prepared crankshaft, reconditioned and balanced connecting rods, JE wrist-pin fitting, ARP connecting-rod bolts and ARP head studs are recorded in the build specification and assembly notes.

Source: Opening thread page — project background, preparation and bottom-end assembly · PMO tuning thread — finished specification and calibration record

Pistons, heads and cams

JE pistons described as nominally 9.5:1, reconditioned 3.2 cylinder heads and Dougherty GT2-102 cams formed the documented top-end specification.

Source: Page 3 — cam timing, engine change and installation preparation · PMO tuning thread — finished specification and calibration record

Induction, ignition and exhaust

The finished configuration is described with 46 mm PMO carburettors, Electromotive XDi ignition and B&B headers.

Source: PMO tuning thread — finished specification and calibration record

Reported outcomes

Forum-author-reported road trip

About 570 miles over roughly 13 hours

The author reported a Virginia-to-Ohio break-in trip, approximately 20 mpg, just under one quart of oil used and carburettors that performed well after a roadside mixture adjustment.

Source: PMO tuning post 71 — 570-mile road-trip report

Forum-author-reported durability follow-up

Still running in December 2025

The author returned to the thread and described the engine as still roaring; no contemporaneous inspection or test data accompanied the update.

Source: Rebuild post 89 — December 2025 durability update

Evidence limits

Road-trip consumption, fuel economy, tuning quality and long-term condition are forum-author reports and were not independently verified.
No completed dyno result was identified in the reviewed build and tuning posts.
The exact provenance and original specification of the second engine are not fully stated in the cited posts.
Fresh automated requests to the main thread returned HTTP 403 from the forum's bot protection; the cited material was reviewed through public browser-indexed pages and exact post views without authentication.

Access note: The thread content, cited page extracts and exact follow-up posts were publicly readable without account authentication. Raw automated requests to the main thread met the forum's HTTP 403 bot protection when rechecked.

Reviewed source trail

Opening thread page — project background, preparation and bottom-end assembly · reviewed 2026-08-25
Page 3 — cam timing, engine change and installation preparation · reviewed 2026-08-25
Page 5 post 84 — completion and links to startup, tuning and driving · reviewed 2026-08-25
PMO tuning thread — finished specification and calibration record · reviewed 2026-08-25
PMO tuning post 71 — 570-mile road-trip report · reviewed 2026-08-25
Rebuild post 89 — December 2025 durability update · reviewed 2026-08-25