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Author Topic: Amc 360 cooling advice.  (Read 3549 times)

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djrr6

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Amc 360 cooling advice.
« on: January 20, 2021, 06:27:36 PM »

Evening all.
Just looking ahead and my engine runs hot without any hammer therefore looking towards summer what have people added to theirs.

I know bulldog had endless work on his ( not sure if he is still on here) but having spoken with Dave the spark I think I can sort the power for it and planned on leaving the viscous fan on and adding twin electric fans in front of the radiator to force air through but it’s a power drag keeping the viscous in place.

Appreciate people advise putting on the radiator shroud and trying to source one but if anyone had any joy with this be great to hear.
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JamesH

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Re: Amc 360 cooling advice.
« Reply #1 on: January 20, 2021, 11:03:24 PM »

This is o my from hearing other people talk about the same issue and could be wrong but if it’s and auto then a big gearbox oil cooler can help.
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Brynjaminjones

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Re: Amc 360 cooling advice.
« Reply #2 on: January 21, 2021, 09:39:24 AM »

I've had problems with mine keeping cool since it was rebuilt. I completely renewed my cooling system after my first proper overheat which means it's now fine in normal driving, but if I sit at 80mph+ in summer or get stuck in traffic, then it starts to creep.

Things I've done since:
-Spent a long time getting timing set correctly.
-Set idle speed to factory specs. Previously it was a little low and coolant wasn't flowing so well.
-Upgraded fan clutch. I can find out what I've used if you like. It's still quiet, but you hear it roar when it gets warmer.
-Fan shroud. This was hard to find! I had an original shipped from the US. BJs Offroad also sells them, but I expect shipping will be dreadful. There was a guy breaking an older Wagoneer on eBay a while ago - I remember him saying he had a broken one which would have been fixable. Maybe worth getting in touch if you can find it. There's also another guy on there selling used FSJ parts. He's got some breakers so might be worth asking: https://www.ebay.co.uk/usr/sharpesoffroad2014?_trksid=p2047675.l2559

I've now got it to a level where I'm comfortable with it. I put several thousand miles on it over the summer and didn't at any point hit a worrying temperature, although I still wouldn't say it's perfect so I'm thinking of what else I can do.

My transmission cooler has a lot of fins hanging off, so I will probably replace that soon too. I assume these transmissions get hotter when cruising than the one in my XJ/ZJ, based on the fact that it doesn't have a lock up torque converter.

Edit: I've just realised that your 360 is in a CJ, so my fan shroud comments for a FSJ probably weren't helpful!


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wildwood

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Re: Amc 360 cooling advice.
« Reply #3 on: January 21, 2021, 04:14:08 PM »

Some people have fitted electric water pumps.....at idle they can run faster and circulate more coolant..
Used successfully on a few Mustangs I know of....
Otherwise an ally rad with extra capacity... the US has loads of ‘go to’ people but over here ...???

None of the above are cheap ....but they work.....

But as Abe says check all timings and stuff first ....

I know someone on here was having overheating probs on a TH400 v8 when running 35s but was ok on narrower 33s.

This ties in with what James says re a larger trans cooler ....with fan as well.

Seems like you are manual so maybe not so serious re tyres....
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djrr6

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Re: Amc 360 cooling advice.
« Reply #4 on: January 21, 2021, 09:05:02 PM »

Thanks for the feedback everyone.
Sorry should have said my set up to give some clarity.

It’s an AMC 360 mated via 4.0flywheel to Ax15 manual box and Dana 300 with a factory viscous fan.

The engine is virtually new as rebuilt for me and breaking in with royal purple oil.

The carb and timing set up is probably the first of many checks as it was the old carb from bulldogs 401 and seems to have lots of fuel running through it and as it’s a 4 point mixing set up may leave to professional to sort.
Timing was really odd as couldn’t get it to start from the mark at -5 so I went old fashioned and worked out TDC manually then reset where mark was so timing wise it seems to be running well but might be out and increasing the heat.

I’ll get that side looked at and brand new radiator and hoses abs seemed to be firing around and might be it needs the extra fans to boost the cooling as well.
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Dave69

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Re: Amc 360 cooling advice.
« Reply #5 on: January 26, 2021, 12:08:52 PM »



getting the cooling right on a big engine can be a nightmare and the points highlighted above will help.

if the engine is running sweet then timing is the minor issue especially on a big V8
Bulldogs issue was a cracked block which required a strip down to identify but once fixed cooling wasn't an issue.
If you have done a conversion to the V8 then you can use the original rad from the 4.2 which is quite obvious, you can go the aluminium high capacity 4 core route which in turn gives you a strong more durable item, but the old style copper tube and fin give you the best thermal efficiency for heat displacement at the cost of being more fragile in regards to fin damage etc.

With the durable choice of a bigger capacity rad (Ally) the viscous fan will need a shroud which normally covers the whole of the rear of the rad so that it maximises the air drawn through and pulls the heat out of the system, the downside is knowing what temperature the viscous fan "locks" which is not good when you are driving around at low speeds since the fan will not be drawing the air through the radiator fast enough to dissipate the heat generated.

Another option is the water pump, the standard pump can be acceptable for normal driving but constant low speed activities, the water is not flowing fast enough as it would be at road speeds, a high flow water pump is an option or swapping to a stand alone electrical pump which is not engine speed reliant. The pump can be controlled by a separate control box (additional cost to the pump) which can allow for the pump to still flow coolant after the engine has stopped with a consistent high flow rate to match cooling fan flow.

With cooling fans a twin electrical fan setup is a normal and preferred choice with two fans used to pull the air through the radiator. One or both of the fans could be a two speed type where one is constantly running and increases speed at a preset temperature, with the second being normally a high speed fan to kick in when the temperature hits a higher temp and only runs to prevent the temp exceeding 100.
 With this setup and increased water flow cooling shouldn't then be an issue.

On the front of the radiator larger heat exchangers can be added for gearbox, aircon, power steering and so on. There should be no reason for adding fans to the front of a radiator in addition to the rear fans in the engine bay.


The biggest mistake people make when a car overheats is to switch off the engine, stopping an engine results in heat soak which increases the temperature of the coolant prior to cooling, whereas leaving the engine running results in the coolant flowing around the engine with the cooling fan working as intended.
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