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1981 u1300L, 1998 s280
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Discussion Starter #1
I've just purchased an m180 high compression engine, with twin carbs, manifolds the lot.

I've a 404 doka with 10.5 tyres on, also has a brand new zenith twin choke carb.
I've also a 404 flat bed with 12.5 tyres on, the planned use for this is a tow wagon.


I've been told that for offroading the twin carb set up isn't ideal due to them not being able to handle the extremes of angles?

If this is the case, am I best to swap the head over to the doka, keeping the current twin choke. The doka does get used offroad.

Then bolting the twin carbs to the flat bed to overcome the torque lost through stepping up the tyre size?

Or are the twin carbs OK off road?


Many thanks :bowdown:
 

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Options....F.I., Propane, Stock carb, LPI. You can spend 0-$2500bucks..Theres alot of search information. If you are trying to maximize the perfomance of your M180...You can go electronic ignition, larger air cleaner, have the cam reground to #2 Euro cam spec which will give you better performance. Twin Fuel setup...like a Multi-fuel engine. Let's just say you have options.
 

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85' U1300L Holset Turbo VA A/C, 66' Propane 404.1 rock mog, 1975 416 Doka, G500, Volvo C303
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If you are running carbs offroad, you should be running zenith 32ndix carbs. Anything else is going to act up. The NDIX carbs will work fine in a dual carb setup. Not sure what your twi. Choke job is, but it's not an NDIX carb.
 

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1981 u1300L, 1998 s280
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Discussion Starter #4
I don't see how propane would increase power, rather than decrease. LPG (propane) is very common this side of the atlantic, and a basic single point (which the m180 would need unless it's moved across to electronic ignition and the fitting of a lambda sensor) system usually causes a loss of power by about 10%. This is the system which I've fitted to my Jeep ZJ, and although it halves the fuel cost (LPG is far cheaper than petrol over here) there is a significant drop in performance. With a multipoint system (seperate propane injection to each cylinder) then performance on par with petrol can be gained.

I'm wondering which combination of head and carbs to use for a reliable truck to be used offroad whilst also providing a power increase? Can the twin carbs be used, and is are the limits of the angles which they can be rotated too known?
 

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1981 u1300L, 1998 s280
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Discussion Starter #5
If you are running carbs offroad, you should be running zenith 32ndix carbs. Anything else is going to act up. The NDIX carbs will work fine in a dual carb setup. Not sure what your twi. Choke job is, but it's not an NDIX carb.

Sorry my bad on the O.P.

I currently have a twin carb zenith set up on the doka (standard 404 carb). The new engine has the standard twin carbs from the Mercedes car 2.2 m180, it looks to be 2 totally seperate carbs, one for the front 3 and one for the rear.

You're suggesting running the high compression head with the standard 404 carb though?
 

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85' U1300L Holset Turbo VA A/C, 66' Propane 404.1 rock mog, 1975 416 Doka, G500, Volvo C303
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Uhgh, your loosing me.

First, Propane typically does increase power over the stock Zenith 32NDIX carbs that came stock on the 404. The reason is poor tuneability and efficiency of the zentih carb. But I will never make this a 100% claim. Although 100% of the trucks I have converted report gains in power.

Now, on to your junk.
So, your doka has the 404.0 setup consisting of two Zenith 32NDIX or 36NDIX carbs on a factory mog dual carb manifold found on the 2.8L?

The engine you have purchased is a high compression M180 with factory car dual carbs that look like regular carbs found on say a chevy or ford V8?

If the last statement is true, go ahead and dump those carbs in the trash if you plan on going offroad. You may or may not be able to fit the NDIX carbs to that manifold. I have seen at least two different car manifolds. One will accept the mog carb with a bolt pattern change, and the other will not or is just not suitable.

Anyways, I am running a a 2.3 M180 with a 9:1 HC head with a modded dual carb manifold and dual propane carbs. This setup will outlast a cockroach or twinkie with ease. It has been dead reliable with zero issues. I spent a little over $1000USD to rebuild the HC head with all new valves etc.
 

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1981 u1300L, 1998 s280
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Discussion Starter #7
The doka is a stock 404.1 with an m180 and a single unit - twin carb (as in one lump of casting with 2 halves, one feeding the front 3 and the other feeding the rear). As far as I'm aware this is totally stock for the motor, and the motor is the 2.2 6 cyl it left the factory with - It's matching numbers on the build certificate.


The engine you have purchased is a high compression M180 with factory car dual carbs that look like regular carbs found on say a chevy or ford V8?
Yes :D

It appears that the manifolds on the new m180 are different from the one currently on the doka so I would have to swap them over if I was to keep the original carb, which is what your suggesting be the better option.

I've though about 'LPG'ing' a couple of times due to the very low cost of the parts over here - I bought a full kit about a year ago for £45, kept the tank and sold the rest on. The only real reason for doing it though would be for the cost of fuel, and the mog doesn't really get used enough to warrent that.

Thanks for persisting with me ;) I think I'm getting the answers I need :D
 

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85' U1300L Holset Turbo VA A/C, 66' Propane 404.1 rock mog, 1975 416 Doka, G500, Volvo C303
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Ok, so your saying you have the factory Zenith 32NDIX TWO BARREL carb. So it has One carb with two ports.

This pic shows the correct DUAL carb manifold to use with the Factory Mog carbs. This setup uses two separate carbs. One to feed the front three cylinders, and one to feed the back 3 cylinders. The manifold pictured has some carb conversion parts bolted on so disregard that.
 

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I have found the dual zenith manifold on an HC head installed in an m180 to be pretty darn underwhelming.

The m130 with that setup is the way to go, or something way more exotic. (m180 w/turbo?)
 

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85' U1300L Holset Turbo VA A/C, 66' Propane 404.1 rock mog, 1975 416 Doka, G500, Volvo C303
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You are correct sir. That setup is not as impressive as you would think. I was disappointed in the end, but what made up for it was that I had a brand spankin new head which made me feel much better about my engine. Turbo all the way in my mind.
 

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LAND ROVER 90 / DISCOVERY BOTH FITTED WITH TWEEKED PERKINS PRIMA ENGINES UNIMOG 404
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not sure of the stud patern on your manifold but would it be posible to fit a pair of zenith carbs as fitted to the 2.25 land rover engine ,these are off road rated as the mog carb and plentifull over here.
 

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404.0 Doka, 404.1 resto-mod
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Webbers (sedan carbs) are not suitable for extreme offroad driving.

You will likely have difficulty mating a M130 (2.8L) head to a M180 block. I think the stud pattern is different and at minimum, the bore fo the quench area would be larger than you cylinder bore.

Also, the exhaust manifolds from a dual carb setup are different from the stock 404.1 manifolds. you can't just swap the intake side and call it done due to the shape of the castings. (The exhaust is designed to warm the intake air for cold weather operation).

actual dual carbs engines (2 of them, not a sinlge 2 barrel carb) were more efficient and made more power. Combined with higher compression and better fuel mixtures, these engines did very well.

Hope some of this helps...
 

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85' U1300L Holset Turbo VA A/C, 66' Propane 404.1 rock mog, 1975 416 Doka, G500, Volvo C303
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Didn't he say he had a HC M180 head/engine.
 

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I actually was saying, replace the entire engine with an m130, not just the head. the m180 is wimpy unless you take heroic measures with it. Not to mention it's only a 5 main bearing engine, while the m130 is a 7.


Webbers (sedan carbs) are not suitable for extreme offroad driving.

You will likely have difficulty mating a M130 (2.8L) head to a M180 block. I think the stud pattern is different and at minimum, the bore fo the quench area would be larger than you cylinder bore.

Also, the exhaust manifolds from a dual carb setup are different from the stock 404.1 manifolds. you can't just swap the intake side and call it done due to the shape of the castings. (The exhaust is designed to warm the intake air for cold weather operation).

actual dual carbs engines (2 of them, not a sinlge 2 barrel carb) were more efficient and made more power. Combined with higher compression and better fuel mixtures, these engines did very well.

Hope some of this helps...
 

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1981 u1300L, 1998 s280
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Discussion Starter #16
Yes, the engine I've purchased is an m180 2.2. The original engine is burning a little oil which I think is the valve stem seals, so rebuilding and swapping in an HC head will mean that the engine will be exposed to the elements for the shortest possible time. Sounds like I'm going to keep the current carbs and manifold and put the sedan twins on the other 404 which will not see much off-road use. Once again, thanks for the advise guys.
 
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