I was still at school when Henri won't the Lombard RAC rally in the Sunbeam Lotus
The unmistakable sound of the Lotus slant 4 lovely. I've not heard that sound in years. The Sunbeam 911 unit was a lovely thing to work on. Except for the exhaust manifold, which required the engine to be removed, to change a gasket.
I've not played with one since the mid 90s. Fond memories though. A friend of mine finished restoring his 81 Sunbeam Lotus last summer. His is only mildly tweaked though. I forget the exact figures now but it's 220ish Bhp. QED built the engine for him 1990, at huge cost iirc. He's got a works LSD fitted which means it actually accelerates, rather then spin the wheels.
Nice engine, except for it being half a V8, making it hard to do some simple jobs.
Hi Nodge. My chevette and SBL shared a certain heritage in the engine compartment
. I love the 'written hsitory' of the 911 lotus engine.
If you believe the pundits - which I don't for one minute - then the story goes that Chapman was browsing at a motor show and say Vauxhall's new slant engine in cutaway form and due to - so they say - the bore centres being the same as 'his new design' - he sources several complete units from VX to develop a new engine.
Well, I think the truth of the matter is that Chapman saw something he liked and THEN came up with an idea. The lower profile of the VX slant engine was excellent for fitting into lower spaces. Also, all the development work had been exhaustively done. Chapman was by all accounts a bit of a 'wide boy' as well as being a genius.
Anyway, so the 9XX series was eventually born from the VX slant. - Chapman knew a good deal when he saw one. He didnt scratch design any bottom ends afaik -his field was really cylinder heads. The lotus cortina etc were based (iirc) on the 681F Ford short engine with added chain driven twin cam. Don;t know if you ever saw one of the 4 pot lotus / ford units but they were rough as hell. (in the casting and finishing department) they looked like an amateur concoction, but went pretty well.
Chapman, of course, kept the whole design philosophy including the amazingly strong bottom end design and forged rods (standard on the VX slant - which was quite funny as companies used to sell 'forged rods' as an update -- ha ha - more fool them) - anyway, I digress...
As you are probably aware the VX slant was designed as a family. Petrol, Diesel and a V8 petrol and V8 diesel. The bottom end thus was amazingly strong.
Chapman tweaked and re-cast the block in aluminium and also produced the 9XX series twin cam cylinder heads in aluminium. The similarities are vast though and basically he ripped off the VX slant design completely. I am sure it was with VX's blessing and appropriate financial matters were sorted. He never come up with the basic idea though.
The HS Chevette was designed as a ford beater in the WRC. A twin cam head (cast ferrous) was designed with vertical cam covers.
It is a fact that when the Chevette HS first competed the twin cam cast head was not completed and they used Lotus 907 heads with tiny mods
. which received a volley of objections from some very disgruntled teams (as it was so bl00dy quick) .
Bill Blydenstein - the brains behind DTV eventually tuned the cast twin cam VX head to perform far better than the maxxed 911 head.. Probably with a 'ya boo sucks'
I think I mentioned this before, but road rally cars were getting too quick in the late 70's and designs like my 'shove it' and especially BDA units were outlawed. We were restricted to a single camshaft and only two carburetor chokes / inlets
.. - note - NOT on wrc and stage events - just the RAC governed Road Rallies of the time
It shows how good Blydenstein was he went on to develop the single cam head to produce over 220 BHP - on SU's !!!. My single cam with HS bottom end and Blydenstein head, cam and twin SU's gave a solid 180 - at the wheels with his truly wonderful single cam head and GT4(X) cam - which IIRC was something like 310 degrees !. (it could easily rev to 9K but a sensible limit was 7.5K !!!!!!!!!!!!!!!) . When it was turned off it often used to run backwards for 4 or 5 seconds (seriously!) lol - without any harm at all - made a hell of a din though. Went like sh!t off a shovel.
When we watched the WRC and forest events with SBL and CHS it was quite a topic at the time on which engine produced the most. I think some of the best looking rally cars ever were the GP4 Chevette HS, SBL and Escort Mk2. They still look awesome today.
Here's some nice piccys of the development. - a v8 would have been awesome.. Eee them were the days.....