Author Topic: Straight Sixers - 12 valve versus 24 valve  (Read 30487 times)

Pedro

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Straight Sixers - 12 valve versus 24 valve
« on: September 20, 2008, 08:19:24 AM »
My take on 12V Versus 24V thing.

OK, so I have a 24V in mine - and I love it. I've not had a 12V engine (apart from the 2.6, but there's no 2.6 24v to set it against!)
I don't really see where the 12v is "stonger" as the only thing that suffered in SOME of the 24v engines was the timing chain set up - yeah, if one went, then the it's gonna cost.

But then so do most cars!

If the chain snapped on a 12V, that would cost aswell (although half as many valves to purchase and grind in though!!)

To me, it's all relative - I mean, if my chain snapped (pray the lord my soul to keep and all that!),  it would only cost me in parts, as I can do the work myself. Others might have to get it done for them.

See where I'm coming from?

It kinda does my swede in, all these 12V people slating the 24Valver!
Not all of them had dodgy chains, and I would imagine that out of all of them still running, then  most of the weak ones would have been weeded out by now.
If you have a 24v with 100,000 miles on the clock and the chain snapped tomorrow (god forbid!), then that would constitute a weak chain, would it?

It's a great engine, and GM should be applauded for it.

Your thoughts?

Whippit

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #1 on: September 20, 2008, 08:49:53 AM »
Good points well made ;)

My point is I have had 24V and 12V........my preference for the 12V is purely due to the smoother power delivery.
Obviously a matter of opinion but when you put your toe down in the 12V it just roars and goes, the 24V has this 2 stage thing going on.........goes, kicks, goes some more. Hard to define why but I just prefer the 12V.
The 24V looks gorgeous of course.

Hear stories of 24V breaking chains and doing CHG's........though never experienced either.

The only reason I recommended the other thread not to change the engine in his 12V was that, in my opinion, the work and hassle involved are not worth any benefit he may get. Its not exactly a straight swap ::)

hazzy

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #2 on: September 20, 2008, 09:00:32 AM »
Its not generally the chains at fault but the guides. Life seems to be between 100,000 to 130,000 before the plastic on the guides starts to crack and fall off. If you are lucky then the bits drop in the sump. If not they get stuck in the chain and jump a cog or two = Bang.

Basically if you have history of the chains/guides being done at some time then you cant better a 24valve. I have run both 12valve and 24valve and 24 valve wins every time for me. Yes 12valve are very much bullet proof having a duplex chain driven one shaft and the plugs are easy to change.

Cost to do Chains and guides on a 24 valve now running at 700 to 800 if you can get all the parts. So that Gsi on E-Bay with 145,000 on the clock with no history is not worth much at all as you can kiss 700 good buy if you want to keep it.

A club car with the history is worth getting as you are aware of what you are buying.

24 valve every time for me.

take care brian
if it makes you smile its been worth while

Pedro

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #3 on: September 20, 2008, 10:25:04 AM »
The only reason I recommended the other thread not to change the engine in his 12V was that, in my opinion, the work and hassle involved are not worth any benefit he may get. Its not exactly a straight swap ::)

Totally agree with that. ;)

Pedro

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #4 on: September 20, 2008, 10:27:08 AM »
Cost to do Chains and guides on a 24 valve now running at 700 to 800 if you can get all the parts. So that Gsi on E-Bay with 145,000 on the clock with no history is not worth much at all as you can kiss 700 good buy if you want to keep it.

A club car with the history is worth getting as you are aware of what you are buying.


That applies to any car, really.

Bottom line is: unless you have pots of cash, then know what you're buying ;D

doz

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #5 on: September 20, 2008, 10:56:28 AM »
I have only had 24v's apart from a 2.6 which I loved as it was a grunty little engine, but for the frill of it all it's got to be 24v. I really do think this chain and guide thing is over subscribed. My first Gsi did 197,000 miles before the bottom end went on orginial chains. It was a one owner car with all the history when I purchased it and yep it never had chains in that engine in fact the guides were so good they went back in when I re-built it new chains were fitted then. I still have this engine waiting to go into my current GSi. However that may all seem good but in the service history at 8k miles from new the chains snapped and a new engine was fitted. I really think that yes there was a rouge batch of chains but unless you come across a very low mileage example the defect chains have been weeded out.
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badgerpoker69

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #6 on: September 20, 2008, 12:01:52 PM »
i have no experience of a 24v engine, but from what i've heard/read is that the 12v is grunty low down and in the mid-range, and the 24v is great at the top end. but the 12v 2.6 seems to be a good combination of them both! it's grunty low down and in the mid-range, and it also flies at the top end thanks to the dual ram system of the 24v! and I refuse to believe that a car weighing over 1500kg (ie, my cdx estate auto!) that will exceed 130mph easily in 3rd gear has only 150bhp (as listed!) what sort of power do these engines generally dyno at? (3.0/2.6 12v/24v)

Pedro

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #7 on: September 20, 2008, 04:55:01 PM »
and I refuse to believe that a car weighing over 1500kg (ie, my cdx estate auto!) that will exceed 130mph easily in 3rd gear has only 150bhp (as listed!)

Beleive it dude!

At higher speeds, it's more than brake horsepower that keeps it going.
To shift alot of resistance, (in this case - wieght), torque is what you need, and all sixers have it in spades! ;)

doz

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #8 on: September 20, 2008, 05:28:53 PM »
Agree my 2.6 wasn't the fastest of the line etc but when speeds started to get silly it would pull like a battle ship. The LC is mind bending for this. You get to fourth and silly speeds it suddenly jumps to light speed  :P As they say Bhp sells engines Torque wins you races and if you have 6 bangs a revalotion then your always have more torque then 150bhp 4 banger.
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badgerpoker69

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #9 on: September 20, 2008, 06:02:13 PM »
it's the way it just sort of relentlessly accelerates above 80mph that gets me! any ideas how much toraue these things have? really want to get it on a r/r (luckily I live 20 mins away from jabbasport!) but not sure how you'd dyno an auto. my sold s12 silvia turbo dyno'd ok even though that was an auto, but if you selected "2" then it would just pull off in 2 and stay there, where as my carlton, if you select "2" it will pull off in 1st then shift and will also kick down.  the 3.0L engines must make hooooge torque!

Scatmancraig

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #10 on: September 20, 2008, 06:54:28 PM »
Well i like the 12v engine, primarily because of the smoother power delivery.  I've yet to have a 24v that doesn't hesitate in some way, i've never had a 12v that hesitated at all!!

After recently dismantling a 24v engine which had replacemnet chains & guides, i found that the guides were cracked to buggery.  There is also the head gasket issue to worry about too, 24v engines do seem more prone to this. 

On the other side of the coin, i've yet to drive anything that is as smooth & powerful as a 24v for what they cost!

I'm probably one of the few people (if not the only person) to have converted a 24v GSi to 12v power, but i used a later 12v from a Senator.  The later 3.0 12v was never fitted to UK spec Carltons.  The main reason why i did this was because a) i'd  gone though 2 24v engines in a matter of months, the 2nd one costing me a whole track day as it failed after just 5 laps, and b) because i have built this car to be ragged senseless & i don't want the worry of head gaskets and timing chains, and c) because i could - so there!!!

Whippit

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #11 on: September 21, 2008, 10:05:43 PM »
i have no experience of a 24v engine, but from what i've heard/read is that the 12v is grunty low down and in the mid-range, and the 24v is great at the top end. but the 12v 2.6 seems to be a good combination of them both! it's grunty low down and in the mid-range, and it also flies at the top end thanks to the dual ram system of the 24v! and I refuse to believe that a car weighing over 1500kg (ie, my cdx estate auto!) that will exceed 130mph easily in 3rd gear has only 150bhp (as listed!) what sort of power do these engines generally dyno at? (3.0/2.6 12v/24v)
2.6i (2594cc) Cat generating 150 PS (110kW) @ 5600 rpm and 162.3 lb.ft. (220Nm) of torque @ 3600 rpm
3.0i 24V (2969cc) Cat generating 204 PS (150kW) @ 6000 rpm and 199.2 lb.ft. (270Nm) of torque @ 3600 rpm.
3.0i 12V(2969cc) Cat producing 177PS (130kW) @ 5800 rpm and 177.0 lb.ft. (240Nm) of torque @ 4200 rpm
3.0i 12V (2969cc) producing 180PS  @ 5800 rpm and 182.9 lb.ft.  of torque @ 4200 rpm

Nicked the numbers off ABS

doz

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #12 on: September 21, 2008, 10:41:54 PM »
Well I'll be. You would of never thought a 24v would make it's peak torque lower than a 12v.
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bstardchild

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #13 on: September 22, 2008, 08:49:10 AM »
Both are fantastic engines - very underated

Both have advantages and dissadvantages - most detailed above

The real difference is that the 24V is a little more tunable - ie you can eek a bit more power out for very little expenditure where the 12V is harder to get a little extra out of it

Bottom line is nothing beats the scream of a straight six on full chat be it a 12V or a 24V
Cheers

BC

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badgerpoker69

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #14 on: September 22, 2008, 10:07:17 AM »
i like those figures! can't beat an engine that makes more torque than it does bhp! there is a very similar argument going on with the mk2 ibiza gti! 16v owners will hark on about them and slate the 8v as underpowered, and yet the 8v owners (like myself) will hark on about the fact that the 16v makes book bhp (150) and the 8v will usually make 10-15bhp more than book as standard (standard is 115, but even a worn in standard one will push out 130!). and then there's the 8v's party piece! a well modded 16v will just about get 140 lb/ft of torque up in the 6k rpm region, and yet my 8v ibiza made 150 lb/ft @ 1750 rpm! and the 8v's are generally around 50kg lighter! (16v has half leather/abs/t.c ect) so on the road, it's actually the 8v that will get you there quickest! (especially mine with it's lack of ANY interior and a sub 950kg weight!)

Johnraka

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #15 on: September 22, 2008, 10:16:25 AM »
Both are fantastic engines - very underated

Both have advantages and dissadvantages - most detailed above

The real difference is that the 24V is a little more tunable - ie you can eek a bit more power out for very little expenditure where the 12V is harder to get a little extra out of it

Bottom line is nothing beats the scream of a straight six on full chat be it a 12V or a 24V

Yeh, gotta say my old 12v (now owned by Tetley) just delivered power, power and more power, phenomenal acceleration, no pauses, no hesitation, it just flew...
Sheer poetry in motion.... ;D ;D ;D
Regards

JD

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doz

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #16 on: September 22, 2008, 02:45:21 PM »
Well there ws me harpin on about the guides and chains being overrated and I've just removed the ones from the LC and yep you guessed it. The curved one is cracked ant the staight one at the bottom had a bit broken off.
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flash911

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #17 on: September 22, 2008, 03:00:22 PM »
i have both and love em equally, even tho 12v is auto  ;)
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vauxhalljohn

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #18 on: October 02, 2008, 12:59:09 PM »
although im used to the poor old 8v which is a good strong engine  . My experiance with the 24v was a eye openner to me and i enjoyed every thrill it gave me , so untill i drive an 12v  i only have the 8valves  to compare it to .

So my answere is 24v every time , i think it sounds nicer aswell .But i have not heard the 12v so .... :-\
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Johnraka

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #19 on: October 02, 2008, 07:01:22 PM »
12 valve, knackered gearbox and she still gave me a 142 run!

Bl**dy good I say... ;D ;D ;D
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JD

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Elwood

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #20 on: October 02, 2008, 07:54:46 PM »
12 valve, knackered gearbox and she still gave me a 142 run!

Bl**dy good I say... ;D ;D ;D
That's interesting! I have a 12v Gold Top which runs as sweet as a nut with power aplenty, but at about 115mph it seems to run out of breath. Although it would cruise all day at this, it seems reluctant to go any faster (all on privately owned runways, of course). Any ideas why this might be?

bstardchild

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #21 on: October 02, 2008, 10:21:20 PM »
12 valve, knackered gearbox and she still gave me a 142 run!

Bl**dy good I say... ;D ;D ;D
That's interesting! I have a 12v Gold Top which runs as sweet as a nut with power aplenty, but at about 115mph it seems to run out of breath. Although it would cruise all day at this, it seems reluctant to go any faster (all on privately owned runways, of course). Any ideas why this might be?

Something isn't right a good gold top in a senny will do 140 all day!!!

If you've checked all the obvious stuff I'd be looking at the daft stuff - blocked rear box or mids - air intake occluded etc etc
Cheers

BC

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badgerpoker69

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #22 on: October 03, 2008, 07:59:37 AM »
12 valve, knackered gearbox and she still gave me a 142 run!

Bl**dy good I say... ;D ;D ;D
That's interesting! I have a 12v Gold Top which runs as sweet as a nut with power aplenty, but at about 115mph it seems to run out of breath. Although it would cruise all day at this, it seems reluctant to go any faster (all on privately owned runways, of course). Any ideas why this might be?

is it an auto? cos one thing i noticed was that you have to be clever with an auto to get to top speed! in my 2.6 auto,if you just kinda put your foot down it will accelerate well up to about 110mph then it would shift to 4th (only about 3.5Krpm) and not pull any further, but if I switch on sports mode, floor it so it pushes that button in on the floor, it will scream it's way to 130mph then shift to 4th and carry on pulling well up to 140mph (felt like it had more to be honest, but whose to say my speedo is correct at that speed!)

Scatmancraig

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #23 on: October 03, 2008, 05:15:48 PM »
12 valve, knackered gearbox and she still gave me a 142 run!

Bl**dy good I say... ;D ;D ;D
That's interesting! I have a 12v Gold Top which runs as sweet as a nut with power aplenty, but at about 115mph it seems to run out of breath. Although it would cruise all day at this, it seems reluctant to go any faster (all on privately owned runways, of course). Any ideas why this might be?

Something isn't right a good gold top in a senny will do 140 all day!!!

If you've checked all the obvious stuff I'd be looking at the daft stuff - blocked rear box or mids - air intake occluded etc etc
I'd definately agree with that.  I had a blocked back box on a 24v & it really struggled past 100mph.  The same car has now got a gold-top 12v in it & it goes like stink, hand an indicated 151mph at 6200rpm so there can't be a lot wrong!!

P.S.  If it does turn out to be the exhaust, i have a complete gold-top Senator exhaust for sale.  It's in in excellent condition & in the way!  I keep tripping up over in my shed!!!!

Whippit

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Re: Straight Sixers - 12 valve versus 24 valve
« Reply #24 on: October 03, 2008, 05:35:09 PM »
Ow much craig?
Got an Omega one on the senny but its a bit raspy for my liking