Automotive WI – ATL Leyland Motor’s engine rationalisation

Unlike the previous thread that explored the two possible engine path an ATL BMC could have successfully pursued, this thread explores a different subject.

The goal being to rationalize of the engine families of an ATL Leyland Motors (composed of Leyland – former Rootes Group, Triumph and Jaguar as well as possibly Reliant) from around 9-10 down to around 2-3 by the mid/late-1980s to early-1990s via a new generation of complementary engines developed by Triumph and Jaguar respectively.

One of the engine families would be developed by Triumph, in essence an ATL Leyland version of the OTL (already Triumph-influenced) 1.1-1.4 Rover K-Series* 4-cylinder (plus a 750-973cc 3-cylinder and turbocharged along with diesel variants), along with a possible half-related 1.6-2.0 4-cylinder (that also spawns 2.0-3.0 90-degree V6 / 3.0-4.0 V8 variants along with turbocharged and diesel versions) as opposed to a stretched version of the former (as done with disastrous results in OTL which were exacerbated by BMW cost-cutting).

The half-related 1.6-2.0 engine refers to an OTL stillborn project between Rover and Kia that ultimately went nowhere, yet if needed (mainly for Leyland with V6s/V8s for Triumph) would have been more suitable in place of stretching the existing K-Series (though in ATL would be developed in-house instead of being a collaboration with another carmaker).

*- The OTL K-Series engine design was heavily influenced by Triumph from the stillborn 2-litre Sabrina Twin-Cam to aspects of the Triumph Slant-4.

The other engine family would be best described as a production version of Jaguar’s initial modular plans for what became the AJ-V8 engine (called AJ12 / AJ26), which was to feature a 2.0 4-cylinder (with displacements as low as a 1.6 via 3.2 V8), 3.0 6-cylinder (think AJ-V6 without Ford content followed by an AJ-V8 derived 90-degree V6), 5.0 V10 (possibly derived from AJ-V8 though doubt it reaches production) and 6.0 V12 (think Aston-Martin V12 minus Ford content).

The following marques had planned developing the following engine families:

-Leyland (formerly Rootes)-

Imp engine (originally displacing 800-948cc with unbuilt tall-block 5-bearing crankshaft version displacing 998-1150cc. Capable of Twin-Cam 16v variants.)

Swallow engine (originally envisioned as 1250-1750cc with potential tall-block version pushing displacement to around 2000cc. Capable of Twin-Cam 16v variants.)

Avenger engine (features potential displacement range of 1100-2000cc with engineers drawing inspiration from Fiat Twin-Cam for OHC/Twin-Cam versions without cost-cutters forcing engine to be OHV, also potentially spawns diesel and turbocharged versions.)

Rootes 60-degree V6 (allegedly a reverse-engineered Ford Essex V6 to displace 2000-2500cc though potentially capable of being enlarged to 3000-3400cc+, unknown whether engine was designed as OHV or OHC,)

-Triumph-

PE166 4/6-cylinder OHC (displaces 1300-2000 / 2000-3000cc replacing earlier loosely related 803-1493cc Triumph 4-cylinder / 1596-2498cc 6-cylinder OHV units, potentially capable of spawning diesel and 4-valve / Twin-Cam variants)

Triumph Slant-4 / V8 (features displacement range of 1250-2000cc+ / 2500-4000cc+ plus hypothetical 1900-3000cc+ 90-degree V6, not underdeveloped or cost-cutted down like in OTL)

-Jaguar-

V6/V12 (displaces 2500-3500cc or 4000cc and 5000-7000cc or 8000cc respectively. Also spawned a 60-degree V8 though it should have been possible to develop a more viable related 90-degree V8)

AJ6 (was also loosely derived from V12 though capable of spawning diesel, along with turbocharged and supercharged variants. ATL version would likely displace 3200-4000cc.)

XK6 (becomes an all-alloy 134-197 hp "net" 2.6-3.2 short-stroke 6-cylinder prior to being replaced)

Coventry Climax CFF/CFA V8 (a V8 displacing 1812-2496cc for a Jaguar Junior XJ project, the engine may or may not be distantly related to a V8 for an inchoate form of the earlier Swallow project that was initially envision with both a 4-cylinder and V8, which would suggest it was capable of further enlargement to 3500cc+. Tuned versions of the 2.5 V8 were putting out over 200 hp.)

-Reliant-

Reliant OHV (displacing 598-848cc it is basically a reverse-engineered all-alloy version of the 803-1493cc Triumph 4-cylinder, which was later planned with an OHC version capable of producing up to 60 hp.)


Rationalizing down the above from 1970s-1990s, my conclusions:

-Leyland (formerly Rootes)-

Swallow engine discontinued in favor of Avenger engine as latter is cheaper to build, with Imp engine staying a bit longer prior to being replaced by either Reliant/Triumph-derived small 4-cylinder engine or managing to hold out until the ATL Leyland K-Series. Rootes V6 either enters production or is overlooked in favor for Jaguar V12-derived V6.

-Triumph-

1300-2000cc 4-cylinder PE166 ends up replaces 1250-2000cc Slant-4 on grounds of cost, scope for dieselization and ability to be mounted in FWD cars (given its relation to the 1296-1493cc OHV used in FWD Triumph 1300/1500), with Triumph V8 remaining in production and possibly spawning enlarged version for Jaguar.

-Jaguar-

Continues to use V12, along with V12-based V8 (if 90-degree). Otherwise Triumph-based upscaled 4200-5000cc V8 is used in place of both the V12-based V8 and Coventry Climax V8, with Jaguar possibly deciding to develop AJ6 as a 3.2-4.0 rather than using V12-based V6 (albeit still vacating sub-3000cc 6-cylinder segment to Triumph and Leyland).

-Reliant-

All-Alloy OHV / OHC is possibly superseded by an updated tall-block OHC version similar to a downscaled 4-cylinder PE166 displacing around 748-998cc with scope for around 1050-1150cc.


Would that have been the best approach to take in rationalizing down the different engines each marque had prior to being replaced by a new generation of 2-3 engines developed by Triumph and Jaguar from the mid-1980s to early-1990s?
 
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