24v V6 Alfa stripdown in this month's Car Mechanics

[Gary H]

Hi,

To anyone that's interested, the latest issue of Car Mechanics has a 3 page article on stripping down a 24v Alfa V6. There are about 25 colour photos. Should be useful to 24v engine owners.

BTW do people have a preference for 12 or 24v Alfa V6's ? When I visited Hawk Cars, Gerry seemed to suggest that the older 12 valve engines were simpler and would also probably not require a CAT. Any thoughts or advantages/disadvantages of each engine type would be very useful.

Cheers - Gary

[David May]

I've tried a 12V (2L turbo) and a 24V in my Corse I and cannot find any reasons to want a 12V motor (if not for extreme penny-pinching.) The only disadvantages I can find are the slight weight penalty and an even tighter fit in the chassis around the heads.
But once its fired up, the 24V is in a class of its own - loads more power (up to 231hp std.), more revs, more torque, lower fuel consumption, less maintenance, ..
If its a case of avoiding catalysts, there must be some uncatalysed (pre-1993?) 24V cars to choose from. (I've gone the full catalyst route.)

Dave M

[JohnB_SPY8808053]

I don't think that magazine available here in the USA. I could pay for it through PayPal if someone was willing to buy & mail me a copy. (Hint, Hint)

John B.

[Gary H]

Hi John,

If you mail me your details I'm sure I can arrange to send you a copy.

Cheers - Gary

P.S It's the 3.0l Alfa 12v/24v V6 I was considering.

[CorseChris]

Gary,

Apart from the size issue, the only other thing that might be worth a mention on the 24V engine is that they seem to be a little susceptible to cambelt slippage if not correctly serviced and treated harshly when cold. I follow the 164 forum and there are endless threads about this subject. Most frequent problem is that the exhaust cam on the rear head skips one or two teeth, causing a very erratic idle. Any more than 2 teeth and it's time for new valves. Perceived wisdom is that the belt tension needs to be re-checked at around 5k miles after belt replacement and NEVER thrash it when it's cold.

Should say that this is all third hand - I have no personal experience of the 24V motor as my two Alfas run 12V.

Cheers


Chris

[Gary H]

Chris,

Thanks. I'd read about the cam belt slippage on the 24v V6 / no thrashing when cold ( not sensible on any motor ) somewhere as well.

BTW are both your engines V6s ?

Cheers - Gary

[CorseChris]

Gary,

Yep - a 164 3l manual (engine donor for when I can afford to go V6 in my Corse) and a 155 with a 2.5l V6 12V.

The 24V is certainly a sweet engine and apart from a couple of things that proper handling and servicing can prevent, the only other issue is probably cost of obtaining and maybe more importantly, servicing the 24V. It's the electronics side of the 24V that would worry me a little. The coil-per-plug ignition is going to cost £100 per cylinder of you have trouble and there have been some cases of persistent problems with cam angle sensors (which sort of suggests to me that it isn't that at all, just that the ECU can't pin it down and just makes a best-guess).

Other than that, it's all positive I should think. In a couple of years the 24V motor is going to be a lot more commonly available as all the later 164s start to die and therefore cheaper with luck. How would you fancy the 3.2 out of the new GTA!!

Chris

[Gary H]

Chris,

Your concerns about the electronic complexity of the later 24V Alfa V6 are exactly what I thought when I saw the stripdown pictute sequence in Car Mechanics. Until you told me I didn't know how much the coil packs were, but when I realised they were individual to each cylinder I knew they'd be pricey ! I assume the 12v just have a single coil ?

Put simply I thought that the 12v V6 would be simpler and almost certainly cheaper to maintain without all that extra complexity.

Cheers - Gary

[CorseChris]

Gary,

The 12V 164 is indeed a single coil/distributer setup. My 155 is slightly different in that it has a 6 pole coil and no dizzy which is sort of halfway between the two.

Having expressed concern over the cost and complexity of the 24V, it wouldn't put me off fitting one though.

If you can get one for the right price - go for it. The gearboxes are a bit more robust as well apparently.

[chris.richard]

What exactly are the rules about catalytic converters in kit cars? What determines when you have to fit them?

[mogul_x]

David,

Saw your post about the full catalyst exhaust you're using on your car. Is there any way I could get a photo or two showing the installation?

I'm using a 12 valve engine in my car (24v engines are extremely rare and very expensive in the 'States) but emissions regulations where I live require the use of both catalysts and lambda probe.

The Hawk exhaust system makes provision for neither (or so I'm told) so I need to do a custom made exhaust. There's a shop nearby that does custom Stainless exhausts, but I need to tell the shop how & where to route the pipes & catalysts. Any information you can supply would be very helpful.

Thanks,

[mogul_x]

All,

I don't know if European spec cars were available with different engines than the US spec cars, but all 91-93 v-6 models in the 'States were 12 valve. We had the 164L with around 180 or 190 horsepower, and the 164S with 210 Horsepower. All US models were catalyst equipped.

In '94 and '95 we got a very small quantity (something like 700) of 24 valve equipped cars. They were the LS model (210 horsepower) and the Quadrifoglio (230 horses).

[Gary H]

Chris,

I asked Gerry this ( quite a while ago now ) and I 'think' ( if I remember correctly ) that it depends on the age of the engine you use. ie if you use an engine that did not originally require a CAT then you don't need one.

On kit cars whose chassis are based on 'donor' cars I think the age of the original donor chassis has a bearing, but this obviously doesn't apply to the Stratos replicas which all have a custom built chassis.

Cheers - Gary

P.S Willing to be corrected on the above points ( enough disclaimers already ! )

[roger001]

Given a choice if all other factors were equal, I'm sure most of us would choose a 24V the extra complications would be more than made up for by the advantages of the 24V, however availability and cost are still important factors ( I think minor "penny pinching " is an underestimate) In a few years time the later 164s, and early 156s and GTVs should be biting the dust which will certainly see me trying to switch, - untill then I'll just have to put up with a 12V

PS its not such a bad unit after all!

[Stratos]

I had a 12v 164 road car, and now have a 24v 164 road car. When I got the 24v, it was noticeably more powerful. Neither of the 2 cars have been the Cloverleaf version.

BUT, it was also very noticeable that the power came in at a higher rev range on the 24v. At about 4000rpm, it really picks up and then shoots all the way up to 7000. I'm not saying that the 24v has no power below 4000, but the 12v doesn't seem as cammy as the 24v.

The point about cam belt slippage has also been mentioned to me, although you might find that it is not the belt which slips, but the actual cam, as it is only held in place by a taper, and does not have a keyway.

Another consideration is that the 24v has hydraulic lifters, so for a high performance version, you will need to change to solid lifters.

Also, if you are building a performance version, you are probably going to need 24 new valves instead of 12, and 4 cams instead of 2 - which all adds to the cost of the build.

[roger001]

unless of course you are going for a "production" class - Anyone got a 24v going for around £500??????

pigs might fly

[Gary H]

During my ( limited ) research into Alfa 3.0 V6 engine ( as installed in the 164 ) I think I read that when it changed from 12v to 24v it got the more aggressive cams from the Alfa SZ.

Cheers - Gary

[chris.richard]

this site has some data that might be of interest

http://carpoint.msn.com/Vip/Engines/Alfa%20Romeo/164/1995.asp

[David May]

Here are a couple of (poor) shots of my 24V catalysed system.
The two front-pipes join up under the oil filter, pass over the rear chassis, through the catalyser and back round to the Fiat Ducato Diesel Van silencer. I'm not pretending to be a real Stratos so I only have a single tailpipe.
Its not as neat as the original 4-catalyser twin-bore Q4 system but then the car is a bit smaller!

Dave M

[David May]

Heres a better top -view of the plumbing.

[David May]

Just a few more thoughts on 24V motors:
1) Many cam-belt slippages are actually caused by the belt tensioner which gets stuck if not used (under oil pressure) for long periods or is incorrectly adjusted. You hear a clattering sound when cold if that's the case.
2) The 24V actually has more power throughout the range than the 12V, it just feels cammy since it really starts to pull over 5000rpm just when the 12V is dying.
3) The hydraulic tappets are good for at least 7750 rpm (which is more than can be said for the 12Vs ironwork!)
4) Yes, all the electric components are expensive, but then who buys a used engine without all the ancillaries? I've nevery heard of coils burning out and its nice to only have to change the plugs at 100,000kms (once in a life-time - just as well, as they are well buried and cost a bomb!)
5) How much does it cost to get a 12V up to a reliable 231hp (my Q4s rated output in USA 164 4WD spec)?? Yes, soon there will be some crashed 155 GTVs with 250hp and more torque to be had...


Dave M

[David May]

I paid £600 for my 24V complete with all ancillaries!! There is no kit-car market in Italy and the law severly limits tuning, so the breakers can't get rid of the things!! They didn't build many but they don't get easily broken either.

Dave M

[roger001]

got any good contacts ? I cant imagine picking up a 24v in this country for that sort of money

[chris.richard]

[The gearboxes are a bit more robust as well apparently. [/B][/QUOTE]

The gear ratios are a bit shorrter and the final drive ratio lower, giving better acceleration too. - more use than top speed in this country. (UK)

[Matt P]

hi all

after having carried out a 24v conversion on jery baily's car i would say that it is no more difficult than fitting a 12v in a once fiat/lancia powerd car. the engine wiring loom comes out of the 164 in one piece and all you have to do is find the posative's (inc the ignition switched live) the earth's and the tacho drive.

As for the room the engine takes up in the bay. the 24v has a narrower valve angle and there for narrower heads. this gives a little more room at the back of the engine bay.

cam belt slipages happen on both the 12v and 24v if thrashed from cold. the main reason for the 24v belt problems can be the plastic idler bearings geting tight or locking up all together. belt changes are also hamperd by the fact you need the proper cam timing block from alfa to get it perferct. there are no timing marks on the cams you see.
if you want to know any more please get in touch
matt.p

[Matt P]

just another quick note. i have run many alfa v6 powerd cars, and the last three have been tuned by Tony Favarin at road and race developments my first being a 2.5 on carbs that made 210bhp at 7000rpm. the second being a 3.0 with gasflowed heads making about the same with much better torque. the third was as the last but with some of tonys special cams that made 240 bhp and 220 ibft of torque the last motor cost in the region of £2500 and that was four years ago. so it is possable but at a price.

[rutthenut]

Originally posted by mogul_x
The Hawk exhaust system makes provision for neither (or so I'm told) so I need to do a custom made exhaust

I thought Gerry was now doing cat-equipped exhaust systems, but I may be wrong on that - perhaps he was just looking into it as there will be some demand for these as time goes on.


As for 12v versus 24v engines, there is another benefit on installing the better (24v) engine, in that the plumbing arrangements are much neater since the main pipework comes out above the gearbox, so is nearer the centre spine of the car.

On Jerry's car, he didn't need to modify the fuel tank nor move the small chassis brace to fit the 24v engine, whereas the 12v engine needs these mods (on a 2-litre Hawk chassis, at least) to get clearance for the thermostat housing and associated plumbing.

Also agree with Dave's comment about cost of parts going up as you get more valves per cylinder. I did however get the camshafts reground for a decent price on my part-built 24v engine, so didn't need to pay for new blanks. This is apparently quite a good setup, with not too mild a camshaft angle and lift range. That's coupled with new valves, springs, caps and shims though, which does put the price back up again.

It would be possible to use this cam grind with hydraulic tappets, but AHM recommend removing those, especially where compression is raised and revs are likely to be higher.

For road use, it might be quite an improvement to try this camshaft on otherwise standard settings, but the ecu would need remapping or replacing. And having the coil-per-plug arrangement requires a more clever ecu, rather than the more simple ones that work with a distributor. Back to the cost issues again!

[rutthenut]

I've now got a copy of the magazine and I see that it has a box listing 'V6 mods' and prices to be considered, as sourced from AHM. Summary of these is as follows:

Camshafts - around £1,000 for fast road, hydraulic tappet setup.

Valves - stainless from £23.50 each, larger sizes available.

Exhausts - tubular manifolds £350 upwards.

Throttle bodies - around £2,350 for system with ecu et al.

Head work - gas flowing, porting, standard sized valves, around £940 per pair.

[mogul_x]

John,

You're right, Gerry does offer a catalyst equipped exhaust option. It's not on his price list - I inquired about it when I found out my car would require Cats to pass inspection. I was probably repressing that memory due to the shock of the expense involved.

Gerry quoted me something like 1418 Pounds for it last year.:eek: That's just shy of what I paid for my Alfa 164 donor vehicle. I'm sure it's gone up since then. I couldn't afford it at the time I ordered my car, and shipping expenses at this point would make a bad situation worse.

I think Gerry's system also retains the cast iron exhast manifolds from the donor car, and didn't make provision for the Lambda probe. (my memory might be a little fuzzy on this point) The shop I mentioned in an earlier post is fairly sure they could do an all stainless system, including cats and tubular headers in stainless, for about half of what Gerry quoted.

I was looking for photographs, dimensions, and other specifics of a catalyst exhaust system so I could give them to the shop and have them do a more exact quote. I'd make up my mind about whose system to buy once I had a better idea of what it would really cost to do from scratch.

Cheers

[chris.richard]

AHM quoted me "V6 24VALVE ON THROTTLE BODIES 300 BHP £7000 APPROX" -gulp! Cost and performance cause me knee tremors.

I've been offered a 24v from a 164 write-off for £1200, but I've yet to find out if it is a cloverleaf or not. There seems to be two 24valve 3.0 V6s, one a cloverleaf at 230bhp, and another non-cloverleaf at 210 bhp. Any comments on the non-cloverleaf version?

[chris.richard]

[QUOTE]Originally posted by rutthenut
[B]


On Jerry's car, he didn't need to modify the fuel tank nor move the small chassis brace to fit the 24v engine, whereas the 12v engine needs these mods (on a 2-litre Hawk chassis, at least)


Is it true that I won't have to reweld this strut for a 24v engine? Can anybody who has done this conversion confirm it?

[chris.richard]

Another thought on this topic: In a previous thread Roger001 posted a photo of his adaptation of the Hawk four cylinder stainless system for his V6 engine - basically a graft of the mild steel Alfa manifolds onto the stainless system. He says it works fine, and it saves £££££
Must go to bed!

[Stratos]

Originally posted by chris.richard
I've been offered a 24v from a 164 write-off for £1200, but I've yet to find out if it is a cloverleaf or not. There seems to be two 24valve 3.0 V6s, one a cloverleaf at 230bhp, and another non-cloverleaf at 210 bhp. Any comments on the non-cloverleaf version?

My road car is a non-cloverleaf, and I noticed the difference between it and the 12v that I had previously.

Depends on what you want the car for.

If it's a road car, then I would have thought that 210bhp from a standard 24v would be more than adequate.

If it's a competition car - well, you can never get enough power!!!

[GMC]

What ? two version in the 24V, What is the difference between the cloverleaf and non cloverleaf ?:confused:

[David May]

I was told by the factory that the only diiference betwen the various 210 and 231hp (cloverleaf) 24V engines was the engine management. The higher-power units use a Bosch sequential ECU with a different mapping (although I didn't think the other would have been non-sequential). The 231hp is a tax-break figure - its usually a bit more!

Dave M

[Stratos]

David,

I was always under the impression that the Cloverleaf had hotter cams (certainly as far as the 12v was concerned), but I may have been given incorrect information.

If it's only the ECU that's different, then fitting an aftermarket mappable ECU should be a good engine upgrade.

[Gary H]

That's definately what I've read ( 12v Cloverleaf has more aggressive cams from the Alfa SZ ). Unfortunately I don't have any info about the 24v Cloverleaf, so would be very interested to find out :-)

Cheers - Gary

[GMC]

Is there any external difference or different engine number ? How would I know which one without opening the engine ? or is it only certain cars/ models that had the more powerful version ?

[mogul_x]

In the '91-'93 cars, the cloverleaf engines were in the 164 S models only. In the '94-'95 cars (the last ones we saw on our side of the pond) the Quadrifoglio model had the cloverleaf engine.

I don't know how to tell a cloverleaf engine from a non-cloverleaf once they're removed from the car. I can't seem to find where the engine code would be marked to provide positive I.D. If somebody else out there knows, please post!

Also, I mis-stated the horsepower figures for 12 valve cars in my earlier post. My earlier numbers were told to me by a friend. According to the owner's manual, output is as follows for North American models:

91-93 164L - 180 horse DIN
91-93 164S - 200 horse DIN

The figures for the 24 valve cars were:

1994+ 164LS - 210 horse
1994+ 164 Q - 230 horse.

[GMC]

Another question to try and help understand the 24V. Why is it called a "cloverleaf" engine ? The only cloverleaf I know is the one that grows out of the ground and we call it a Shamrock and use it for St, Patrick's day !!:D

[JohnB_SPY8808053]

This is a really interesting thread.

'Quadrifoglio' or 'Cloverleaf' is the special designation that Alfa Romeo gives to its high performance cars & engines. I have some interesting information on the Alfa V6's at home that I can post later. I'm pretty sure I have the engine codes.

John B.

[mogul_x]

I think they're called cloverleaf engines because Alfa Romeo uses a shamrock to signify one of its higher performance models. I have no idea why. Maybe they're superstitious? :confused:

In some of the literature for the 164, I've seen the letters 164 followed by a little shamrock. This sometimes refers to the "S" model from '91-'93 literature and to the Quadrifoglio model in the later brochures. The Italian word "quadrifoglio" translates into English as "four-leaf clover".

If all quadrifoglio models had 4 valves per cylinder, I might venture a guess that the cloverleaf came from the shape of the combustion chamber in the cylinder head. Unfortunately, it is also applied to the 164 S, which only has 2 valves per cylinder.

My 164 S engine has a four leafed clover embossed on the head of the dipstick. I'm not sure if this is typical to all Alfa Romeo engines, or only the performance models. I've never taken a close look at a 164 L to see if it's the same.

[chris.richard]

They had the equivalent of the 164 S there as Quadrifoglio single cam.Then
came Quadrifoglio dual cam same model as here and then Q4, dual cam awd.
the weight that they call "curb weight " is with full tank.Notice however that
tank capacities are different.
0-100 km/h is not exactly 0-60 MPH but 0-62.something
In the latest brochure, the one for 156 they even say how they measure that (
2 people + 20 Kg load in the car)
for the 164 L, it never existed there as a model but putting all the options
on a 164 base would make one up.Since weight is important i will mention
what's not given in the car that has it's performances shown
Another thing quite commonly shown in EU tests is that the speed indication
that one reads is not identical with the real speed.Untill like 60 mph the
truth is more and over is less (not a specific Alfa info).

164 3.0 V6
No: fog lights,sunblinds,power mirrors,power rear seats,heated,
leather,washers,alloys,sunroof;

184 HP (with cat) /5600
max torque 132Kw/5600
Kurbweight 1400 kg
Standing Kilometer 28,2 sec
max speed 230km/h
fuel tank 70litres/9reserve
consumption:
6,8 litres/100 km @ 90 km/h
8,9...........................120
12,5..........................in town

A quick figure-out i think is that 29MPG is around 8litres/100km

164 Q (single-cam =Sport)

200 HP/5800
max torque 145/5800
Kurbweight 1430 Kg (without sunblinds, heated seats, headlight washers,
recaros or sunroof)
max speed 237 Km/h
Standing kilometer 27.8 sec
Consumption
7,3 l/100km @ 90 Km/h
9,3 120
13 in town

164 Super V6 24V (= 164 LS)
210hp/6300
torque 28 Kgm/5000 rpm (sorry that's what they chose as units)
max speed 240Km/h
standing km 28 sec

164 quadrifoglio (dual cam= quadrifoglio here)
230 hp/6300
29/5000
max speed "over 245 km/h"
standing kilometer 27,8 sec

164 Q4 (allweheeldrive *there is your SUV (lol))

230hp/6300
29/5000
max speed 240
standing km 27,9

form "auto motor und sport" there are some 0-100 km/h
164 v6 7.9 sec; LS 8.0; Q4 7.5


Engine
Type 3.0-liter, 24-valve, DOHC V6
Horsepower
-- 164LS (hp/kw) 210/152 @ 6300 rpm
-- Quadrifoglio (hp/kw) 230/168 @ 6300 rpm
Torque
-- 164LS (lb-ft/Nm) 198/270 @ 5000 rpm
-- Quadrifoglio 202/280 @ 5000 rpm
Fuel system Bosch Motronic multipoint fuel injection
Engine block Aluminum alloy with cast-iron cylinder liners
Cylinder head Aluminum alloy

[chris.richard]

http://www.digest.net/alfa/FAQ/164/pb87/pb87-10.htm

http://www.digest.net/alfa/FAQ/164/modid.htm

http://www.digest.net/alfa/FAQ/164/modid.htm

[rutthenut]

The cloverleaf designation has been used for many years by Alfa Romeo and does not relate to specific engine types. I think it was also used on their early race cars, a bit like the 'HF' designations on Lancia's.

[rwd]

Can any of you chaps tell me if there is a 2.5 ltr 24 valve V6 Alfa engine available?

The reason is that for UK rallying the capacity limit for 4 valves per cylinder is 2.5ltrs, otherwise I will have to use a 12V 3ltr V6 in my 6R4 rally car project.

Thanks,

Martin Fox

[Stratos]

Originally posted by rwd
Can any of you chaps tell me if there is a 2.5 ltr 24 valve V6 Alfa engine available?



Yes, there is. The Alfa 156 has a 2.5 V6.

Originally posted by rwd
The reason is that for UK rallying the capacity limit for 4 valves per cylinder is 2.5ltrs, otherwise I will have to use a 12V 3ltr V6 in my 6R4 rally car project.

Thanks,

Martin Fox

Martin,

That's what I thought too, but on the British Rally Forum, Colin Salkeld, who is an RAC Scrutineer said otherwise. If you search for a thread entitled "Maximum Capacity" you will find his responses, but basically he said that if your car is a category 1 car, then engine capacity and valves per cylinder is completely free.

He mentioned looking in the Blue Book at K37.1.1 for cat. 1 cars, K37.1.2 for cat. 2 cars, and K37.1.3 for cat. 3 cars.

Hope this is of help to you.

Are you thinking of replacing the Rovaru?

[rwd]

Thanks David,

Yes, Im looking for a new project!

See my comments regarding your reply on the other thread I started regarding the 6R4 project. Sorry it's not a Stratos!

Martin

[Stratos]

Originally posted by rwd
Thanks David,

Yes, Im looking for a new project!

Sorry it's not a Stratos!

Martin

Even though it's not a Stratos, it sounds interesting.

Will it be 4wd or 2wd?

[rwd]

I think it will have to be 4Wd this time!