intake manifold

[braganjackson11]

just got the engine stripped down to almost the plain block and head this afternoon and noticed that the intake manifold and the exhaust manifold are connected. Can anyone explain why these two are togethor? I always thought that you wanted air in the intake manifold as cool as possible, aren't exhaust fumes generally hot?

Also, is there anybody out there that has set up an electric fan on the radiator? I'd heard that it can help with over heating. Is overheating really a problem with the 2.25 petrol?

[Bogatyr]

braganjackson11,
I won't pretend to know why the two manifolds were attached together.

If your cooling system is running properly, you should have no need for an electric fan. My truck almost runs too cool, with just the stock system, I look forward to summer when I can take the radiator muff off, even then it takes her a while to warm up. The good thing is that she can idle all day in traffic or on a trail and not get warm. The other nice thing is that the temp gauge actually works as opposed to a modern vehicle. If I'm running on a long stretch of tarmac, you can see the temp needle run a little higher, come back from speed and she'll ease down...

Bogatyr

[pickuprover]

The two manifolds are bolted together to allow heat from the exhaust manifold to warm the intake which in turn is supposed to keep the carb warm and prevent icing in the carb. However anyone that regularily runs their 2.25 petrol in the winter (especially with the weber) will know that the transfer of heat is not enough.
As for the overheating issue. There is something going on in your engine if the temperature is climbing. Either your rad is getting plugged, or you have the wrong thermostat (usually more an issue in the summer than winter) or you are severly out of tune. If your timing is too far retarded the engine will run hot, as well if the carb is too lean it will run hot.
As for the electric fan you should not need it, however it is not a hard thing to do. You just have to mount it (either infront of it or behind it. To install it behind it you usually have to remove the viscous fan,but still not a big deal) Run wiring to it. Usually there is a seleniod that is temperature controled off the rad fluid to be installed. Alternatively you can hook it up to the ignition switch so that it is always on when the key is turned, however that would make it warm up slower in the winter.
Having said all this I would definately look into why it is running hot and fix that first. Test your thermostat and make sure that you are running one with the right temperature rating. And do a complete tune up. If this still does not solve the overheating issue than get your rad flushed and engine flushed. You might have a partial blockage and installing the fan might help but might do damage if the engine is running hot for another reason..

[Muddy Oval]

Electric fans are less reliable than old fashioned stock fans. If you mount an electric in front of the radiator, often it blocks enough airflow that it causes problems having it there. The stock setup works just fine.
As for the intake and exhaust setup- common on Brit 4 bangers. I'm not sure they thought it out too well since most non-Brit companies put them on separate sides. Makes for nice big fires if your carb malfunctions or leaks and dumps gas.

[braganjackson11]

are there any alternatives that can be installed to separate the two manifolds? or would the separation cause a problem with the carbs icing, which to my understanding is why they were designed that way. Is the Zenith carb the best way to go?

[pickuprover]

The carb debate is a long and involved one. Basically I think that it comes down to personal preference. I personally like the weber carb as it gives you a little lee way if it is not setup just right and supossedly give a little more horse power. However that being said, they do tend to ice up more. I beleive that the older Zenith carbs actually have a heater built into them. But it has been my experience that the zenithcarbs are a bugger to get set right (but that might just be me).
As for seperating the manifolds, I see no advantages. The air cambers already are seperated, so you would have to have raw gas flowing down the side to ignite when it hits the exhaust manifold. I believe that would only happen if you really did not do any maintence. A gas leak out of a card is usually pretty evident by the discoloration on the side of the carb.

[braganjackson11]

i had read that the weber carbs were just so much harder to get adjusted and to keep adjusted.

[pickuprover]

As long as they are jetted properly and the float level is correct they are a cinch to set up. All you do is set the idle to about 800 rpms and then turn the idle mixture screw till you hit max rpms. Then you turn the idle screw back to 800 and repeat. When you can't raise the rpms using the idle mixture screw again, you just turn the idle mixture screw to get about 500 rpms. Then you are finished. The only tricky part about them is setting the float level as that determines your mixture when the throttle is applied. However there are very good instructions included in the carb box for setting the float level.

[Muddy Oval]

I like SU carbs... but that's beside the point I suppose.

Why are you trying to re-engineer the engine? You could have a custom cross-flow head made for it and it would be cool. You'd still have 68HP.

[bamarover]

Since we are going to the trouble of doing a frame swap for a galvanized frame (ours was shot) and decided to rebuild the 140K engine to keep from having to do it later, as we plan to keep this for a loooong time, we want to do reasonable things while we are at it to make highway driving a bit easier without sacrificing the off road capabilities of the Series. From what we can tell, highway driving is tenuous, and we plan to drive it both on the highway and off-raod. This is not going to be an off-road farm truck. From all we can read from multiple sources, a Turner HO engine (http://www.turner-engineering.co.uk/...ticleoff1.html) makes the Series a bit more road friendly without altering off-road low speed and torque by changing the valves for unleaded fuel and gas flowing the head. Turner recommends the Zenith carb over all others. Since we are interested in having our original engine rebuilt locally, and keeping the vehicle as original as possible, we are seeking as much info as possible so we can make wise decisions that will work for the long haul. Our Series has a Weber carb, so I do not think it is original. The head work may not be worth the money (about $1000 if you buy the Turner head, ready to install), but available info seems to indicate that people who have that set-up like it better than the original engine status.
East Coast Rover in Maine (www.eastcoastrover.com) takes it one step further and mates the Turner HO with a 5-speed conversion using Land Rover parts for what they describe as a Series vehicle that is a joy to drive at highway speeds. We want to use the original gear box and transfer case, at least for now.
We are really learning as we go and know little about all of this, but are having fun getting our hands dirty and are glad for this forum.
I am taking the engine to the machine shop in the morning, so we will see what they say and I will post what I find out after they evaluate it and we talk about the head ideas.
Thanks for the replys. Keep them coming!

[Muddy Oval]

Fit an overdrive-
You know- you could do a V8 in there and still run all period Land Rover bits. You may end up liking the truck a lot better. There's nothing Turner does that is magic or that any other engine builder can't do. Same for ECR. You're doing exactly the right thing by collecting methods and ideas, then extracting what fits your needs.