Hot but Stable - Clutching at Straws

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nqkjw

nqkjw

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Location
Nth Queensland,Australia
What I have is a mild 318 abt 280hp.
Compression is an accurately measured 9.25:1
New water pump
New 160deg thermostat - tested and checked out OK
Cleaned out radiator
7 blade fan with new clutch
New shroud
New hoses and spring in bottom
Tefba filter
16" thermofan pusher
New temp guage
Heads shaved so they are flat-meaning leaky head gasket very unlikely.

So in short I went overkill to make sure this thing don't run hot.
But it does.

It's not an airflow problem since it runs hot on the highway.
Well,it makes no difference highway or city driving.

It's running around 205 to 215deg but stable.
It won't go above and it won't pull down.

Timing is 16 initial at 700rpm and 35 total all in at 3000rpm and it runs pretty sweet,starts well.No detonation.
I've been pulling some crud out of the Tefba but certainly not enough to block it.
Switching on the big 16" electric makes no difference.

I've just put in a 195deg thermostat and will go for a spin shortly to try that.

Searching older posts gave me a possible idea.
Do you think the screen in the Tefba would cause enough restriction to force too much recirculated water back through the bypass hose?
There was mention of restricting the bypass hose to less flow to overcome too much hot water recirculating.
Has anyone done this with success?

How much total timing do you think this thing can withstand?
I checked with a mate since his engine is pretty similar to mine and his is 16 initial and 36 total.
He runs a tad cooler than mine around town but he's down to 180 on the highway which is where I want to be.

When I pull up the radiator doesn't feel as hot as the guage suggests so it is possible the guage may be reading wrong.
Otherwise maybe the water in the block IS hot but the water in the radiator isn't??

Since I'm pretty good with cooling I don't think this one will be one of the common problems so any left field ideas welcome.
 
Having a very old radiator boiled out rarely helps. Calcium barnicle build up in the tubes limits the gpm flow through them. I too tried everything else first simply because a new radiator cost so much. In the end it did solve the problem.
 
Radiator had tanks removed,cores rodded through and tanks soldered back on.
Not sure about over there but it's a common practice over here.
 
Here's my suggestions:

- Pusher fan may be blocking air flow, try removing it
- Higher temp thermostate (you are already trying this)
- Six blade water pump (8 blades may move water to fast through cooling system)
- Try lower heat range on spark plugs
- Engine running to lean, up jets one size
- Bump timing to 33-34 total

Lastly, new temp gauge or one of those infared heat guns aimed at base of thermostate housing will give you an acurrate reading of actual operating temp.
 
Is the radiator aluminum or copper/brass? If it's the right size for the application it won't matter too much, but an aluminum radiator will cool much more efficiently than a copper/brass of the same size.
What are the dimensions of the radiator?
Rodding out the radiator will help, but there's no way to get it back to 100% efficiency with that method.

Are you SURE the waterpump is the correct unit for the engine?

I would verify the running temp of the engine (perhaps with an IR temp gun) before I did any more troubleshooting. It may not be running hot, but the gauge might be inaccurate.

George
 
195deg thermostat made no real difference.
And out of interest,nailing it to 5500rpm in every gear makes no difference.
Temp reads stable but hot.

Demon 408 said:
Here's my suggestions:

- Pusher fan may be blocking air flow, try removing it
- Higher temp thermostate (you are already trying this)
- Six blade water pump (8 blades may move water to fast through cooling system)
- Try lower heat range on spark plugs
- Engine running to lean, up jets one size
- Bump timing to 33-34 total

Lastly, new temp gauge or one of those infared heat guns aimed at base of thermostate housing will give you an acurrate reading of actual operating temp.
Click to expand...

Thanks for suggestions.
Will try a few tomorrow since it's bed time over this side of the planet.
 
George R said:
Is the radiator aluminum or copper/brass? If it's the right size for the application it won't matter too much, but an aluminum radiator will cool much more efficiently than a copper/brass of the same size.
What are the dimensions of the radiator?
Rodding out the radiator will help, but there's no way to get it back to 100% efficiency with that method.

Are you SURE the waterpump is the correct unit for the engine?

I would verify the running temp of the engine (perhaps with an IR temp gun) before I did any more troubleshooting. It may not be running hot, but the gauge might be inaccurate.

George
Click to expand...

It's a 22" wide copper/brass 2 core so not a big one.
However,the car never ran hot prior to rebuild and it had everthing against it back then.

When you say correct water pump what do you mean?
If you're thinking reverse rotation magnum pump then no.
We only had LA's over here and anything else would need to be ordered from the US.
This pump was just a generic aftermarket unit to suit local LA's.

I do intend to fit another mechanical temp guage as a check.
 
Have you tried running it without your Tefba filter? tmm
 
205-215 is not too hot. It is fine as long as you are running coolant. Don't worry about it. BTW - the purpose of the thermostat is to make sure your engine reaches proper operating temperature. Changing from a 160 to 195 will never lower your upper end temp, it will just make sure that you lower temperature does not drop below that point. Cooler temps increase engine wear and tear.
 
I say get rid of the filter

Putting in a hotter stat to run cooler is BS

Pumping water "too fast" is BS

Suspect the gauge

Eventually, when you can afford it, a new, larger rad can't hurt

If it's stable temp and is not puking out the overflow, I'm not sure I'd worry about it

What is your ambient temps, and how dry is it there? (Hot dry air has less "cooling ability"), IE, lower "specific heat"
 
Check the gauge before you go any further. Get one of those infrared thermometers and check out the actual temperatures, if everything you've put on the car is working well it shouldn't be running hot. I like the infrared thermometers vs another mechanical gauge just because you can check the temperatures at multiple places to identify problems, like checking the radiator vs the hoses to check the thermostat, or even "watching" the radiator to see when the thermostat actually opens. You can even check the water passages at the front and back of the block (by seeing how hot the surface of the engine is where the ports are) to see if the water passages are blocked. The intake manifold where the water ports seal is a good place to check, especially on an aluminum intake because it rapidly becomes the same temperature as the water.

Could be the water pump, "generic aftermarket" parts aren't know for their quality in most situations, could just be that its a dog.

Who put the engine together? It could also be that one of the water ports got plugged, or that a gasket was installed incorrectly and blocked a port. This is one of those "check everything else first" kind of problems, but it does happen.

Keep in mind that even though the system kept the engine cool before the rebuild more power means more heat, so it may be that its time for a larger radiator as well. I wouldn't think so, there's plenty of cars out there running 22" radiators, but its something to consider if you absolutely can't find anything wrong with the system.
 
Hey all.
Haven't been able to log on for a few days due to some sort of site problem.
Anyway,I've tried all the above suggestions plus a few more.
Checked the NewVintage temp guage and sensor with another guage and it's reading true.
Soooo.....there's a new aluminium 4 core 22" rad on it's way over.
Will post back results when I've fitted it.
 
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