over heating

V8 Rail · Post by **V8 Rail** » Sun May 11, 2008 7:30 am

Hi, am running a 3.5 rover engine in the back of a rail the engine temp gets into the high 90s within 10 miles when I pull over and let the engine idle the temp drops to 80 with the fan running in 5mins and hold steady running with a 390cfm holley with an offenhauser manifold 40%antifreeze mix landrover desert spec rad in the back above engine with a 16" pacet fan blowing have fitted a temporary perspex heat shield to stop heat from engine being drawn into rad have taken plugs out mixture seems ok any ideas[/img]

Ian Anderson · Post by **Ian Anderson** » Sun May 11, 2008 10:46 am

Hi

Couple of things to look at well a few would be more accurate
1) Thermostat - is it sticking to nt let flow intil it get really hot?
2) Got an air bubble somewhere and just needs bled if the engine is nose down try jacking the nose up about 2 foot and then re bleed
3) Your heater flow and return pipes (pump out) and wherever in - is it a full flow or blanked off? If it is a full flow does the circuit mean not enough flow through the rad? - Sounds crazy but I did some reading recently and this was a known [roblem on MGB V8 when the heater valve was open they overheared as too much flow went that way and not enough through the rad.
4) When running is the rad in a good air flow.
5) Check which way the fan is blowing - it has been known that they force the air against the natural flow (forwards) and hence cause a high pressure no air flow zone.

Let us know what fixes the problem or even give some feedback and more people will chime in

Ian

V8 Rail · Post by **V8 Rail** » Mon May 12, 2008 8:56 pm

Thanks for response, stat working ok. 3 An offenhauser thermostat housing with a 2nd 3/4 outlet with a short hose on to the back of the waterpump from the rear of the manifold a hose runs to the connection on the water pump return from the radiator is this correct should i put some sort of restiction on have spent hours venting rad will try tommorrow pm and see if its any better have got lots of air out but had engine boiling hope it holds together [/img]

ian.stewart · Post by **ian.stewart** » Mon May 12, 2008 9:28 pm

Can we see a pic of your engine bay and rad area, pictures speak a thousand words.

V8 Rail · Post by **V8 Rail** » Mon May 12, 2008 9:30 pm

can some one give me an idiots guide to uploading pictures thanks mark

ian.stewart · Post by **ian.stewart** » Mon May 12, 2008 10:06 pm

open a Photobucket acount and cut and paste from there.

V8 Rail · Post by **V8 Rail** » Mon May 12, 2008 10:27 pm

hope this helps, the perspex shield has been removed, cheers mark

[/img]

V8 Rail · Post by **V8 Rail** » Tue May 13, 2008 7:06 pm

more pictures of manifold waterpump rad hoses I am going to replace the ribbed hose

[/img]

Post by **katanaman** » Tue May 13, 2008 8:15 pm

From what I can see it looks to be connected ok but I just cant see enough air getting through the radiator. Looks like you have fuel tanks and seat backs in front of it that will either stall the air in a vortex over the engine or just plain block any air. I dont think a fan on its own is capable of getting rid of all the heat from an engine under power. This might explain why it recovers stopped on idle which is what the fan is meant to do. I cant really spot any easy way for you to duct air to the rad and it doesn't look like an easy job to mount the the rad up front. Maybe look into some of the desert racers. I think they have their rads mounted in the back but horizontal. Maybe they can get some suction up through the radiator or something?

Ian Anderson · Post by **Ian Anderson** » Tue May 13, 2008 8:22 pm

In Pic number 2 (big picture) you have a small pipe coming back in next to the pump

Where does that go? It looks about the size of the heater matrix pipe and this should be restricted to next to mothing (or blocked if you are brave but you could get trapped air) or the flow is from pump and bacl to pump without going through the rad

Think about it in the winter you would be running the heater full inside the car removing the heat from the system so no problem but in the heat woth no restriction you are just moving the hot water atound until enough manages to get through the rad to cool it.

Cheers
Ian

Post by **katanaman** » Tue May 13, 2008 8:55 pm

Not in this application Ian. That pipe goes into the stat housing and is meant to and has to be like that or you get problems. Its a different system to the injection and aids coolant to circulate while the stat is closed saving hotspots in the engine. Coolant flows all the way through these manifolds and not just the front like injection manifolds.

V8 Rail · Post by **V8 Rail** » Wed May 14, 2008 6:33 am

thanks for the help, large picture 1&4 shows small pipe from thermostat housing connecting onto back of water pump, large picture 2 shows return from rear of manifold connecting onto water pump return, would it be worth while fitting an adjustable valve to restrict the flow on the return pipe

Post by **katanaman** » Wed May 14, 2008 9:00 am

it already is restricted to a point its just a smallish hole under the housing.

andyv8van · Post by **andyv8van** » Wed May 14, 2008 6:39 pm

Hi,

the pictures help,

i would try removing the bottom part of your plastic cover ,the rad is not in a direct air flow,you may also have to build a cover/shroud to direct the air into the radiator.

Andy

kiwicar · Post by **kiwicar** » Wed May 14, 2008 7:07 pm

If you moved the radiator up and forward so the bottom of it sat on the cross bar and angled it forward to about 45 deg and made a duct around it to enclose the whole thing. using the existing pannel as the bottom of the duct. With the opening at the front verticle you should get good flow thwough the rad from air comming in over the drivers head. It will get in the way of the view from behind but i suspect you won't care much about what is behind you, after all you will have just passed them and they are going slower than you. If you flair the front out a bit then this will help too.
Mike