Running hot

[Richie-Van-GTi 70 2 Cars]

My 8v runs very hot which I suspect is the mapping but I want to be sure i cover the basics first. I've already changed thermostat and fan switch to ensure they are working correctly and are the correct temperatures. All the pipework is new, heater matrix is new and functional and the engine was freshly built a few years including liners, seals etc so I am confident it hasn't silted up. It also has a large aluminium rad as I originally suspected the standard rad.

Previously looked at water pumps but never been able to get a new old stock OE with the metal impellers. There was a comment around the number of holes in the plastic impellers restricting flow. Does anyone know any more on this or has even added extra holes?

Next job is to swap the water pump so want it to be correct before i commit yo another days mapping.

Edited May 12 by Richie-Van-GTi

[PhilNW 43]

What are you using to establish the temp?

 

 

[Richie-Van-GTi 70 2 Cars]

I am going on how quickly and frequently the fan kicks in, so its the fan switch which is brand new, old one was the same.

[PhilNW 43]

3 things

 

How frequent does the fan kick in and out?

 

Can you get your hands on an infrared thermometer (sort that heating engineers use) to check actual temps?

 

Is the fan running at slow or high speed?

Edited May 13 by PhilNW

[Richie-Van-GTi 70 2 Cars]

I am more interested in info on the water pumps, I have done my due diligence on the other parts and I am confident that it runs hot and gets up to temp faster than is considered normal.

[welshpug 1,629]

never had a water pump cause this unless it was pissing coolant out or the impeller has come off, which I've only ever seen once.

 

running lean or incorrect ignition timing can make it run hot.

[Richie-Van-GTi 70 2 Cars]

4 hours ago, welshpug said:

never had a water pump cause this unless it was pissing coolant out or the impeller has come off, which I've only ever seen once.

 

running lean or incorrect ignition timing can make it run hot.

This is my thinking as well, it runs rich so I am suspecting ignition timing although the tables suggest its fairly sensible. 

My plan is to change the pump anyway so I know its not that, I have then ruled everything out bar the mapping.

Also gives me more confidence in the car when it inevitably goes for more mapping.

[PhilNW 43]

Dont know much about mapping in detail but has it always been hot since it was first mapped or has it happened since then?

 

 

[Richie-Van-GTi 70 2 Cars]

Always ran hot since mapping, before that it was off the road since 2009 and not in my possession so cant testify to it.

[Richie-Van-GTi 70 2 Cars]

Old pump, new pump.

I believe the metal impeller is the OE style pump, but are they better, worse or the same?

Certainly not slipping and no signs of it having any issues.

[welshpug 1,629]

fitted loads of the type on the left without issue.

[PhilNW 43]

Can you just clarify In what order did things happened?

since 2009?, back on the road? came into your possession? Engine rebuild, mapping? etc, 

[Richie-Van-GTi 70 2 Cars]

Phil 

I bought it in bits as a project. I rebuilt the whole car from a bare shell up and in process moved to mappable ECU, raised CR, big cam, 4 branch exhaust, TTV flywheel etc. It was built, partially mapped, taken away and given bigger injectors and a slightly milder cam because they were not right, then mapped again.

In all the time ive had it running its always ran hot, but that is literally no time at all in terms of hours ran and miles covered.

 

[PhilNW 43]

Thanks for that Ritchie, bit clearer now, Well done on building it from a pile of bits!! Dont think I would  have taken it on. Rebuilt most of 2 205's bit by bit as time and money allowed.

 

So the engine has "run hot" ever since the initial engine build and initial mapping, and not changed since the new cam, injectors and remap, thermostat and fan switch.

 

Rather than delve into new pump, still think you need to get some real numbers as to the level of heat the engine and cooling system has been/is dealing with, and an infrared thermometer is one way to go. Especially as it is a modified engine.

 

Presumably the fan can deal with the heat and it does not boil over?  

 

It will answer some of the questions re how effective the fan system is when it is off and on, the same for the heater, block and head temps, rad temps top and botton, hotspots, temp on the rad where the switch is and what temp it goes on and off etc etc ... It will also feed into the re mapping to see what effect it has.

 

 

 

[Richie-Van-GTi 70 2 Cars]

It didn't run much after the first map as it was never completed, it was left safe to move about which is pretty much all it done so I cant really say how much mapping changed it.

Its fine if its moving, the fan doesn't come on much, after a hard drive it kicks in and if i stop it will keep running for a long time. If its in traffic it will be on most the time. Its never boiled over. The issue is more the speed it gets that hot and how long it takes the fans to cool it. 

Pump is swapped now anyway with a new belt etc. got a few jobs to do tomorrow then i will bleed it up and test it all again.

[DamirGTI 329]

Might need to match thermostat deg. rating to the fan thermoswitch .. if temp. rating of the two are too close you'll get more frequent cooling fan activation and longer running too .

 

Water pump efficiency , if you really looking for a better one , it's not so much about the impeller shape/design ... it's about the clearance between the pump body and the impeller which makes most difference ie. the less clearance there is in-between the impeller and the pump body the better/stronger/more efficient it'll be in shifting coolant around the system .

 

How much CR are you running ?

 

I'd say it's mainly the rise in the CR which makes it behave like so ... especially if combined with a little retarded ignition map .

 

I had (still have .. "experimenting" ) wide range of CR's during the years .. from around 10.8 , 11.3 up to 12.5 ... the higher the CR the more pressure in the combustion chambers and that = heat !

From you're description , my engines in those ranges of CR behaved kinda identical - warming up sharpish from cold start and just a minute or so left idling kicks the fan in , good whilst driving , but idle and town/traffic stop-and-go regime same thing fan mostly always on especially during the summer time ... but the coolant temp. never went past 90/95C not even in the hottest summer day and stuck in a traffic jam neither did it ever overheat , however oil temp. was/is regularly to the maxi mark especially when speeding on a motorway (running oil-air cooler) .

 

D

[Tom Fenton 1,528]

How much water flow have you got on the self bleed legs from the thermostat housing and the top of the rad back to the header tank? (Easier to see on the earlier round bottle).

 

If there is a lot then you can make a hot car run cooler by restricting the flow. A lump of something with a small hole in will do the job. All those pipes really need to do is allow air back to the header tank so the system self bleeds. Which on a 205 is does do very well compared to many other cars by the way.

[petert 556]

Let's go to the ignition.

 

Have you locked the timing at 10º BTDC and confirmed with a timing light?

 

Please post a pic of the ignition table.

 

[Richie-Van-GTi 70 2 Cars]

Tom, I am on the process of putting it back together so will check that flow later today.

Peter, I will plug in later and get the ignition table.

[Richie-Van-GTi 70 2 Cars]

Ignition table to follow, left my laptop at work

Its back together, twin fan set up wired in, all bled etc and the fans work as expected. Also seemed to warm up a touch slower and fan ran less time than before so I suspect this water pump is circulating better.

[petert 556]

You didn't answer this question:

"Have you locked the timing at 10º BTDC and confirmed with a timing light? "

[Richie-Van-GTi 70 2 Cars]

On 5/15/2024 at 11:49 AM, petert said:

You didn't answer this question:

"Have you locked the timing at 10º BTDC and confirmed with a timing light? "

Sorry, yes I have confirmed the timing is correct with a strobe.

Sorry hope this photo shows clear enough as my mapping laptop doesnt do internet things.

Left column in kpa is 6,13,20,26,33,40,46,53,60,66,73,80,86,93,100

 

Edited May 16 by Richie-Van-GTi

[petert 556]

Definitely not enough light load advance, although I'm not sure that would make it overheat. Cruising along at 80-110km/h, ie 2500-3300 RPM, it should have around 36-38º. ie replicating the 9º of advance the vacuum module pulls on. I'll find a table as an example.

[Richie-Van-GTi 70 2 Cars]

On 5/16/2024 at 11:04 PM, petert said:

Definitely not enough light load advance, although I'm not sure that would make it overheat. Cruising along at 80-110km/h, ie 2500-3300 RPM, it should have around 36-38º. ie replicating the 9º of advance the vacuum module pulls on. I'll find a table as an example.

Did you ever find a table Peter?

Thanks

[petert 556]

Sorry, I forgot for a while. The map says 205, but it's actually from my XU10J4 race car. An 8V will probably need 2-3 degrees more at full load. Obviously the axis differ between ECU's. In my case, 0kPa equals wide open throttle, ie atmospheric pressure. I'm sure you'll work it out.