Author Topic: Straight Sixers - 12 valve versus 24 valve  (Read 30323 times)

carlton_mad

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #25 on: October 03, 2008, 05:48:19 PM »
unless you have cats on yours john it wint fit your senny!
what would life be like if we all drove fwd cars? feckin boring that's what rear drive or bust

Whippit

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #26 on: October 03, 2008, 05:50:27 PM »
Doh......of course.
The Omega one is OK but gets a bit wearing on a run

Scatmancraig

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #27 on: October 03, 2008, 05:59:54 PM »
Doh......of course.
The Omega one is OK but gets a bit wearing on a run
The back box will still fit, it's the mids that are different.  I'd have a bet that the mids on yours are probably the original 12v ones.

For reasons i cannot understand, the mids on a 3.0 gold top & 2.6 dual ram are unique to the car.  Look the same as 24v ones, but the angle of the pipes into the back box is slightly different to those on the 24v as the original style of 12v back box was used.  Why didn't GM just alter the back box?  That way they could have had the same mids across the whole 6 cylinder cat-equipped range, and back boxes to suit each car.  Would have made more sense to me!!!

Anyway.  The back box is in excellent condition as is one of the mids.  They were both brand new not long before i had the car.  The other mid is older, but still in good condition. 

Whippit - if your car still has the mids with staggered conections to the downpipes then it still has the original style non-cat 12v mids & my back box will still fit.  It depends on how your exhaust has been modified to accept the Omega back box.  It may not have been modified at all, i had a gold top with an Omega back box so it may be a direct fit!!!

Whippit

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #28 on: October 03, 2008, 06:12:23 PM »
Sounds about right, the only odd thing with the down pipes is there is no bracket to fasten it to the back of the gearbox like I would expect.

Scatmancraig

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #29 on: October 03, 2008, 06:19:28 PM »
Sounds about right, the only odd thing with the down pipes is there is no bracket to fasten it to the back of the gearbox like I would expect.

I dont think there ever was on early 12v's.  I don't remember seeing on on my 12v GSi. 

Whippit

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #30 on: October 03, 2008, 07:03:30 PM »
That would explain that then ;)

Pedro

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #31 on: October 04, 2008, 12:53:45 PM »
In a feeble attempt to bring the thread back to topic, it's been pointed out that (in general) the 12V is smoother, not having the dual ram "kick".

But there seems to be quite a few 24V's that son't have the kick - either anymore or ever.

Mine being one, BUT that's down to choice (and a certain chip).

I have noticed ads on ebay and in Autotrader that go on about "indestructable" timing chains  -as opposed to what, destructable ones?
Or are they implying that toothed belts snap with great frequency?

I think some people think that something made from steel is stronger then other materials.

Hmmmm - let's make a timing chain from titanium, shall we? That'll be even stronger, but could still snap! ;D

Johnny A

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #32 on: November 17, 2008, 09:19:35 PM »
i've had both the 12v and the 24v engines, the 12v is smoother but for me the 12v and 24v respond the same low down then the dual ram on the 24v kicks in for mucho power increase.

technically yes the 12v is stronger because:
24v has a cast block and alloy head - which react to heat in different ways and with the addition of the engine's length will increase the risk of HG failure (12v will always be better in this respect as they are fully cast iron)
24v is lighter than 12v (24v will always be better in this respect)
24v has weaker chains (Peter Harrison chains offer a fix to this problem)

12v offers the indestructibility but has less power and more weight

If your willing to fork out the cash then rebuild a 24v and enjoy the extra power, otherwise 12v is the way.

You could always just get a 3.0 24v Twin turbo supra engine and be done with it.
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doz

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #33 on: November 17, 2008, 10:04:18 PM »
Now. I've had the pleasure of having a nice 2.6 dual ram 12v. It's got me thinking on putting the dual ram gubbins on a a late gold top would be interesting.
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Dougywales

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #34 on: April 24, 2009, 07:11:58 PM »
Hi Guys,

Just asked this very question on the VODC forum.

Whats involved in fitting a Gold top with a dual ram.

What ECU, what loom etc. I would have thought it would be best to start with a 2.6 and swap the engine. If the 3.0L injectors flow 20% more than the 2.6 and you used a 24V intake to match, then, like irmscher did with the 4.0L, the ECU shouldn't know the difference and should adjust for the extra capacity as its a closed loop system?

Any ideas?


Pedro

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #35 on: April 24, 2009, 10:15:51 PM »
I was told by a guy that he fitted a 24V engine in a 12V car and kept the 12V ECU and it ran as well as an original 24V.

I don't know to what exetent a 24V ECU differs from a 12V, but I'm sure the ECU must have the capability to work the DR atthe right time, whereas the 12V ECU wouldn't, unless it's the same ECU on both the 12V 2.6 and 3.0 litre.
So, following on from that, why would the 12V 3 litres have the DR settings in their ECUs? Unless it has absolutely no effect on a non-DR engine and GM thought it would be cheaper to produce the one type fits all ECU for the 12V range?

Pedro

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #36 on: April 24, 2009, 10:17:47 PM »

24v has a cast block and alloy head - which react to heat in different ways and with the addition of the engine's length will increase the risk of HG failure (12v will always be better in this respect as they are fully cast iron)


GM V6 engines are iron block/ally head - and the CHG rarely go on them (usually the heat exchangers inside).

turbojo

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #37 on: May 24, 2009, 03:02:05 PM »
Well, I managed to find this data:

30NE - LE2 Jetronic
C30NE Pre-1990 - Motronic ML4.1
C30NE Post-1990 - Motronic M1.5
C30LE - Motronic ML4.1
C30SE - Motronic M1.5

So in theory a late 12v M1.5 ECU might have the Dual Ram pins.......

Jimmy

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #38 on: August 04, 2009, 02:39:57 PM »
24 all the way, but i did always prefer the 8v thn the 16 in my old astras, thy just seemed to kick abit more, but whn it comes to bigger engines, i think more valves the better....
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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #39 on: October 24, 2009, 07:49:41 PM »
For me, i prefer the 12v - less to go wrong. The 2.6 must have the simplelist management system know to man!
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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #40 on: October 24, 2009, 08:21:31 PM »
But it uses the same system as the 24 valves being a dual ram engine.
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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #41 on: February 17, 2010, 07:14:58 PM »
Although nowing little about any of the engines, I can comment on the guides. Basicaly the more complex the routing of the chain the more likely you are going to have trouble.ie lots of wheels, rollers and guides etc the more trouble.

Dont forget that motor companies dont always get components from one supplier. They can be held to ransom. All components have to go through extensive testing and I would suggest that 100,000 miles was the target in the 80's. Its more now. It can be that one supplier has components that last 100 thou and another might last considerably more. What you guys should be looking at is any identification marks on the guides and materials. You may find different markings and if you pool the results you may find the best supplier. Lots of components have the suppliers part no.,motif & date code on them.

As some of you guys say they last & some dont, then there may be more than one supplier but extremes of usage can bugger this observation.

About 10 years ago at Ricardo in Shoreham I was working on the Ford Mondeo/Jaguar diesel. After 2 years of development when I left they were still tearing up chain guides. At that time Ford decided to delete the balancing shafts to reduce the complexity of the chain routing. Dont know if they actually did it. If so there are two bulges with empty cavities in the casting, one each side going down the side of the block. Its very difficult to predict the action of a chain on complex runs even with CAE. If they didn't solve it they probably changed the block casting as it would be embarrasing supplying engines with strange cavities. Anybody got the 2.0-2.5 litre Mondeo diesel who can comment?

Autos will always be less harsh on chains & guides for obvious reasons. Slower acceleration of the masses and less shock loads.

Molybdenum(?) disulphide oils (molyslip) would reduce friction but its expensive.

The less the components the less the trouble. 12V for me every time. I dont mind being last away from the lights.! 12V is much better than 8V.

Am I boring you guys?
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Jimmy

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #42 on: February 18, 2010, 09:58:18 AM »
nah, not boring us Kieth, a useful bit of information there mate. Just tht by the end of reading tht, i was wondering if you remembered the question - 12 or 24? ha ha ha

iv only ever had a 24v, so my decision is abit bias.

My dad had the Senny 3.0i 12v,  bought brand new and in the 10+ years he had it, nothing, and mean nothing,,, ever went wrong. what killed it was my mum, she wrote it off on the ice abt 10years ago. she was fine, but the senny was buckeled and twisted, nice one mum!! killed a classic, imagine how pissed my dad was. lol!!!!

but the straight 6 engines in general by GM (12v and 24v), i think are one of the best engines ever made, up there with the Rover V8 ;)
« Last Edit: August 23, 2010, 09:22:16 PM by Jimmy »
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Jimmy

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #43 on: April 21, 2010, 04:43:19 PM »
just adding to my comment, when i was thinking if i ever wanted to do a engine conversion in my 2.0 '8v' i think i would do it with the 3.0 '12V' engine as appose to the 24v, if i wanted a one, id buy one,.
Saying all this, iv only owned a 24V senny, so im abit bias to this, but like i sed, il have the 12V for my engine conversion, tho never driven one.lol
And now i want another Senny, and i think i would get the 24V. LOL
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kevinfourlegs

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #44 on: March 20, 2011, 09:12:29 AM »
Never had the 12v or 24v so I can't comment.

However, regarding the power figures, I wonder if they are on the low side? I know of a Feb 92 Senator 3.0 24v that had the top end rebuilt, after head gasket went, using standard parts to standard tolerances, in other words, bog standard. Said lump has no catalytic converters and on a rolling road made 232 bhp at the wheels. Had the car up to 150 mph, clocks said so, so may not be 100% accurate, and it felt like there was more to come. Car is an auto. The owner says he loves the 3.0 24v.

Me, just buy a Countach Quattrovalvole, with 48v V12 lump. Have it tuned, the engine note is better than anything out of Maranello, and it will scare modern exotica easily. Bottomless money pit required. Sorry to digress.
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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #45 on: March 20, 2011, 09:34:58 AM »
Never had the 12v or 24v so I can't comment.

However, regarding the power figures, I wonder if they are on the low side? I know of a Feb 92 Senator 3.0 24v that had the top end rebuilt, after head gasket went, using standard parts to standard tolerances, in other words, bog standard. Said lump has no catalytic converters and on a rolling road made 232 bhp at the wheels.

Rolling roads struggle with autos and I wouldn't mind betting that was a extraperlated crank number rather than wheels - to be wheels and accurate it would have to be banging out best part of 260 bhp
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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #46 on: March 21, 2011, 09:11:53 PM »
I'm planning on building a 3.0 12v with the dual ram and engine management from a 2.6.
It would be alot easier if the 12v was a gold top but unfortunately my gold top engine got stolen (along with the senny it was in).

So... I'm going to use the timing cover from the 2.6 so that I have a mounting point for the crank sensor, then use the loom from the 2.6 with a 24v ECU.

12 or 24v? a bit of both for me! :D

MisterSIR

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #47 on: August 21, 2011, 01:18:59 PM »
hello carlton'ers :) im new here only just signed up :) just thought i would share a little history here of when i was a kid and my mother owned a carlton, so grab a cuppa tea, a few custard creams, and a comfy chair coz this wont be short :L.

when i was about 10 years old, my mother drove a 1.6L Vauxhall cavalier expression, she had been saving up for ages and she kept banging on about this new car she really wanted, my dad and me thought nothing of it and we just thought she was being her typical boy racer self again :L. but when she ought it and brought it home....i saw why she wanted one so bad, she bought one in black, so it looked like the lotus counterpart. she bought the lotus kit, wheels, you name it, it looked the real thing, except it had  "Vauxhall Carlton GSI 3000" on the boot. it was the 24v 3.0 version, about 200bhp? correct me if im wrong. i loved that car, it was awesome! it was quick as hell, and was reasonably comfy, and it would even get the back end out if you gave it a bloody good hiding ;) for me, i would go for the 24v, but i never have been in the 12v. bit of a shame though that as my mother was struggling to  keep up with the tax and insurance on such a big car, she started putting remould tyres on it, thats never a good thing on a 200bhp car....rear tyres stripped the entire tread from the tyre casing, lost control, slammed into the centre reservation at 120mph+ she was ok, walked away from it, but the car sadly didnt, the car aint so good not one bit, i still have the car to this day all smashed to pieces, must show pics soon of her, i havent touched it since we had it towed back, ill never let go of the car, i will rebuild when i feel the time comes :) but 24v all the way ;)

Cosmo D

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #48 on: August 21, 2011, 06:31:02 PM »
120 mph+? ;D You're mother must be a maniac behind the wheel...
Upload those pics please, it would be fun to see how badly damaged it is :P
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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #49 on: September 02, 2011, 07:34:07 PM »
oh yes she was freakin mental honestly :L she had the thing on the limiter many a time :L yeahh sure i will upload some pics tomorrow when i find sopme freakin drivers for my camera -_- i have them on a CD somewhere, its a matter of finding that CD :L, it is willing to get going this carlton, but i just need the bloody parts LOL