2.0s-to-2.3lpt

[peteroliver]

I have plans for the C70, I would prefer a manual then chip it, Jetex Exhaust, KN filter and maybe a set of Orestes Wheels. Might consider doing spring and shock change.
I had a number of Opel Mantas including one that I had Bill Blydenstein build the engine, went like s--t of a shovel. I also owned a bit of a rare one a Vauxhall Cavalier Centaur, it was based on a cavalier gls coupe then cut off the roof and ended up a bit like a Triumph Stag with a t bar. A friend of mine had a 38dgas on a Ford Cortina, went like stink and so did the petrol, he sold it and bought a Reliant Scimitar then mounted two 38dgas on it but had cooling problems to start with but did sort it.

[Laird Scooby]

Bill Blydenstein was THE Vauxhall tuner of the 70s, did all the work for DTV as well i think.

Always wanted the Centaur, it was based on the 2.0 GLS Coupé which is what i had. With the cam, carb and other things, mine would rev to 7500rpm in any gear, in 4th it was about 20mph/1000rpm so i must have hit about 150mph when i left that Senator for dust, no wonder the poor boys in blue inside it couldn't keep up!

This Centaur is the same colour as my Coupé was :



Mine had a brown vinyl roof on as well so from a distance looked a bit like the Centaur.

On the C70, i' not so well up on them but i do know the K&N standard replacement filters are worth using. Got one on each of my Rover 827s and they've certainly livened them up! Planning on getting one for my 760 in the fullness of time but they're about £80 for it! That said, they're a lifetime filter, just need cleaning once in a while so works out cheaper in the long run.

The Jetex exhaust should help things along as well, as will the chip. Should have quite a lively C70 after!

[aardvarkash10]

Originally Posted by Laird Scooby

With the cam, carb and other things, mine would rev to 7500rpm in any gear, in 4th it was about 20mph/1000rpm so i must have hit about 150mph when i left that Senator for dust, no wonder the poor boys in blue inside it couldn't keep up!

[Laird Scooby]

They freely admitted they couldn't keep up doing 140+ Ash - on their calibrated speedo.

[aardvarkash10]

140 mph is very VERY fast. TBH, 125 mph is terrifyingly fast on public roads.

The 2 litre engine must have been a tremendous unit to go from a docile 100-odd stock hp to the 225-250hp needed for those velocities!

[Laird Scooby]

The cam was a big part of it and power was an estimated 160-180bhp, it was the fact it would still pile on power all the way up to 7500rpm that got me up there i think. It was a long time ago now but they clocked me at 106mph on the overrun with about 5k still on the tacho.

[peteroliver]

Just a little surprised 160-180 bhp, consider a 2.3 chevette hs engine, similar to C.I.H engine, extra 300cc, twin-cam Twin 1.75/ 2.00 Carbs 135-150 bhp.

[Laird Scooby]

The "Slant 4" is very different to the CIH engine!

Also bear in mind, the "standard" Chevette HS was the 2279cc production engine as fitted to the facelifted FE Victors known as the VX2300 and produced 138bhp on twin Strombergs. I had a VX2300 and tuned that as well, by coincidence with bits that came from a Chevette rally car that was stuffed into a tree on its first outing.

That had a big valve, high compression, gas-flowed head, fast road/rally cam and cam carrier machined to suit, brand new Stromberg carbs jetted to suit on a new gas-flowed inlet manifold, blueprinted and balanced bottom end and a 4 branch exhaust manifold.

I bought everything except the bottom end and 4-branch. The dyno sheet showed in the Chevette, the engine had produced about 240bhp. Being generous and allowing 40bhp for the 4-branch manifold and blueprinting, i'd say my VX was pushing about 200bhp.

Now, if you want to talk real power from the Slant 4 then you needed the twin cam, 16v head from the Chevette HS/R - that was about 180-200bhp without any tuning mods and the engine fitted to the cars they sold through dealers as part of the homologation process. Naturally when they used it for rally purposes, they tuned it a lot more, a bit like Ford did with the Sierra Cosworth - remember the Sierra RS500? It didn't produce 500bhp (about 350bhp i think) so why the 500 moniker?

They had to produce a minimum of 500 "production cars" for homologation with the same engine as they intended to use in the rallys.

Vauxhall later did the same with the 1400cc engine they used in the rally Novas but were a bit more sneaky.
Designated the C14SE (even Vauxhall dealers have trouble finding it on their records because it's so rare), it was an 8v 1397cc unit with a hot cam, bigger valves and a few other things that Vauxhall would neither confirm or deny.
Various different sources report this engine anywhere between 100-125bhp in road spec.
Apart from the special edition Nova GSi, very few people have actually realised what they've got under the bonnet if they have one of these engines.
Vauxhall were sneaky and put them into Police spec cars (with a bit more tuning than standard road spec but still within homologation rules as part of the 500) so if you have an ex-Police Mk3 Astra 1.4, chances are it goes like stink!
The surprising one is the Mk3 Astra estate - a few of those had the C14SE fitted in the factory. I rebuilt the top end on one that belonged to a fiend and took it for a test drive after. Definitely upwards of 100bhp, probably nearer to the 125bhp that i'd heard reported for that engine.

As you can see, things aren't always as straight forward as they seem, the Slant 4 had been around since the mid 60s, starting life as a 1600 and 2000cc pair of engines fitted to the FD Victor and also the HB Viva. It had a bit of an overbore to make the later 1800 and 2300 sizes but it wasn't until the revised head of 1976 came along that boosted the power (and economy) and even in VX4/90 spec, pre-1976 it only pushed out 108 bhp. Following the revised head, the single carb 2300 was now up to 108bhp and the second carb bolted on an extra 30bhp for the VX4/90 and the 2300GLS.

In simple terms, the Slant 4 was a slogger, rumour had it that it was half of a Chevrolet V8 diesel, destroked to drop the compression ratio and swept volume. True or not i don't know but all the fastenings were Imperial unlike the CIH engine that came from Opel in 1584CC and 1897cc capacities originally, the latter being stretched to 1979cc and eventually into a 2.2L for the Mk2 Carlton before the Carlton changed exclusively to the family II engines for the 4-pots.
There were three 12v 6-pots of the CIH that i know of, the 2.5, 2.8 and the 3.0. In Vauxhalls, the 2.5 went into the Viceroy, a short lived luxury version of the Mk1 Carlton, the 2.8 went into the Royale saloon and the 3.0 in fuel injected form found its way into the Royale Coupé
Meanwhile Opels Commodore had been renamed Senator and the next generation of Vauxhalls bore this name for the larger engined cars, except the Carlton 3.0GSi but the Royales became Senators.
The first of these usually had the 12v 3.0 injected engine, about 180bhp and considerably heavier than my Mk1 Cavalier Coupé.
The 24v version of this engine came about around 1989/90 give or take a bit and had a lot more power, i can't remember how much though but i think it was about 205bhp.

[peteroliver]

I drove a Nova Sport quite a few times as I had a friend who worked at a Vauxhall dealer and was a real hoot to drive, probable cost a fortune today second hand. Interesting you mention slant four being half a V8, I had a cruiser (Fairline Sprint) that had a Volvo 5ltr V8 and that turned out to be a GM truck engine and could believe the slant four could be half the V8.
You mention the Vauxhall 3ltr 24v, on a visit to Blydenstein they had a 'B' reg Carlton they were working on for Vauxhall it had the 24v Engine and they were doing head work on it, when they had finish it went like stink.

[Laird Scooby]

I'm pretty sure the Nova i'm referring to was the Nova Sport or as i called it, "special edition GSi", i couldn't remember the name until you mentioned it.

As for the 3.0 24v, it was a beaut of an engine. Fairly sure it didn't appear until the late 80s, i know the Senator that stopped me was a 12v on a D plate, the exact registration is now on a Yamaha so can't even find out when it was registered.

In the mid 90s, a friend bought an ex Police Senator 3.0 24v and that went like stink as well - as i said to him after driving it, you don't pull away, you launch it!

The 24v head was completely different to the 12v head though, for a start it was a cross-flow design, unlike the 8v and 12v heads on the CIH engine.

I guess Blydenstein had to go from scratch with the 24v head, much like Cosworth did for the Pinto engine when Ford wanted to gee-up the Sierra.