Unstable water temp in new built Pinto turbo (cools off when driving)

[therealpinto]

Hi all

I'm having some issues with the new Pinto turbo build (http://www.turbosport.co.uk/showthread.php?t=1142387).

The water temperature is unstable, when the car stationary it will creep up over 100 degrees C (saw 106 today), and when driving it cools off, down to around 80 degrees or less.

I had the same issues when I first started it, using a QH 82 degree thermostat so I swapped in the used 92 degree Ford thermostat I used in the old engine. Same issues.

The only differences in the cooling system from the old engine are;
- engine management coolant temperature moved to the intake flange (used to be in the hose)
- turbo water cooling connected (between the thermostat elbow small takeoff and top of radiator)
- radiator and heater matrix flushed out

The engine itself has higher compression ratio, and I now use Victor Reinz Pinto head gasket, the old engine had a YB head gasket.

The old engine was stable in the coolant temps, it would idle happily without overheating and would drive without overcooling.

The easy test is another, new thermostat. Any recommendations for best brands? I have always used generic ones before...

I can also try plugging the turbo coolant flow, I have made a test with just clipping the hose tight but could not check if it really sealed.

Thankful for any ideas!

Gustaf

[alladdin]

Hi all


- engine management coolant temperature moved to the intake flange (used to be in the hose)

Gustaf

not quite sure what your saying above but it sounds like a possible cause ............

[stevieturbo]

Moving the sensor might cause some differences...

But what you're describing could also be a lack of airflow from whatever fans you are using when stationary, and when you start driving there is adequate airflow to keep it cool.

[MegatronUK]

Just reading through your other thread - what type of radiator have you got? When you say that your turbo water return is to the radiator top tank is that into the rad itself, or an external header tank? The Cossie has a seperate water return for the turbo to the header tank, so it's not direct into the radiator:

[MegatronUK]

Also, are you using a viscous fan or electric? If electric have you tested that the fan switch activates at the correct temperature - on the Cossie it's suppoed to be somewhere around 91-92'c, so it should kick in an then bring the temperature back down again; if it doesn't, then perhaps either the fan or the radiator isn't up to the job (though the overcooling at speed would make me think it was the fan).

[therealpinto]

Moving the EFI temp sender should not matter at all, it is only a 10 cm difference and the instrument cluster follows the same pattern.

I have used the same radiator (Winner Racing alloy radiator) and fan (manually activated) in the old engine with no issues. And I don't see how they could cause over cooling?

The turbo return goes to the top of the radiator;


Regards

Gustaf

[MegatronUK]

I'm wondering if the turbo return direct in to the top of the radiator is part of the overheating problem, not the overcooling problem?

If it's sat with no airflow, then that hot water from the turbo is going direct into the radiator. If your fan isn't powerful enough then that could the cause of the problem. It looks like the radiator is pretty big, so with airflow when driving it's probably fine (as you say, it actually overcools in that situation).

That's just my guess though, other than the turbo water return, it seems like your cooling setup is pretty much as the YB is intended to be.

[therealpinto]

Yes, the turbo cooling circuit may be the root.

What is does, is that it bypasses the thermostat with a flow of water through the turbo. I do see how that could cause over cooling (since even when the thermostat is fully closed, there is coolant flow).

However, I really don't see that it would cause over heating, the amount of heat from the turbo at idle should be quite low. And if I dump it into the lower hose instead, that would add more heat to the engine I feel.

Well, the easiest thing to check is to block the coolant circuit for the turbo completely.

Gustaf

[kliobas]

For turbo cooling I used the return from heater matrix, this means that hot water goes into smaller pump inlet and mixes with cold water from main radiator and goes to the engine. Never had a problem in my driving mode, except when used 82 deg thermostat (from Burton). Temperature rised very quickly on idle or low speed, then swithed to 74deg thermostat and everything is OK.

If you removed heater matrix, you also blanked smaller pump inlet ? So when thermostat is closed, how is water circulating? The pump should be wanting to pump the water, but it's not possible due to closed thermostat. Although not sure if this can be an issue after engine reaches normal temperature.

[therealpinto]

I still have the heater matrix (will not be able to use the car without it...too cold!).

Way back (from 2000 to 2005 or so) I had the turbo cooling in parallell with the heater matrix. That worked fine in the sense that I never had heat problems but I felt most of the flow went through the turbo, the heater was not very efficient.

Gustaf

[therealpinto]

Update; I disconnected the water cooling lines from the turbo and plugged them off.

Now the water temperature behaves much like before, stable at around 82 degrees when cruising and seems to level off at around 92 when stationary (only fan airflow through the radiator).

I would like to be able to run water cooling though so I have to think about alternative connections that does not bypass the thermostat.

Gustaf

[longboy]

Could the routing not be heating the thermostat? Does the heat from the block jacket open up the thermostat. But if routing is from pump to rad and back is it just heating that small volume of water.

[Bart]

Are u sure the sensor is measuring correct?

[caprimentle]

How have you plumbed in the water cooling from the turbo Gustaf? My water cooling to the turbo on my pinto suffers no problems and bypasses the thermostat. Where does the water feed to the turbo come from? And the outlet of the turbo goes into the top of the rad?

[therealpinto]

The sensor should be correct, seems to correspond with the gauge cluster and ambient temperatures.

I have taken the feed to the turbo from the thermostat elbow, the small pipe closest to the head that is fitted to Sierra elbows. That is before the thermostat flow wise. Return is to top of radiator.

Caprimentle, how is yours plumbed?

I am thinking that the thermostat elbow is really the only place where the water pump "pushes" the coolant.

Gustaf

[caprimentle]

I like to think I was a genius in the way I done it ��

I undone the water bung on the block by around no:3 cylinder on the exhaust side, drilled it and brazed in an 8mm copper pipe, I ran that feed to the turbo then out the turbo I fed it into the thermostat housing just after the thermostat, you could plumb it in before the stat like on the sierra manifold, wouldn't of thought that would cause any harm but it might make the stat think the engine is hotter than it really is so it might open it early.

I mainly did it my way because I wanted to utilise the water bung on the block to help the flow around cylinder 3, the hottest cylinder. Also with my feed being at the bottom and the exit being at the top natural convection really helps the flow of water.

[caprimentle]

Double post

[therealpinto]

Ah, of course, that's a nice way.

Should've thought about that when the block was on the stand.

I'll see if I can make a connector for that port now, might be doable. Then I can try returnin either to the top of the radiator, or the thermostat elbow.

Thanks!

Gustaf

[Erikmex]

Youll certainlybe loosing alot of airflow through the rad with that gap between the front panel and intercooler

[therealpinto]

Yes I would, but there is a cover panel that goes there now, it just wasn't fitted when the photo was taken.

There are gaps on the side though but they were there last year too, no issues. And it works when driving :-)

Regards

Gustaf

[MegatronUK]

I still think it could be your electric fan. If it's cooling at speed, then the fan isn't going to come in and the air flow at 50-60mph is going to be far more than an electric fan can provide.

I think standing running with the turbo water circulating through the radiator it's likely getting too hot for the electric fan to compensate for. Sitting idling mine brings the fans in and out all of the time after 10 minutes or so, though the temperature does stabilise.

By stopping the hot water from the turbo you're definitely reducing the amount of heat going in to the cooling system (though probably putting more into the oil), and that's probably why it doesn't get as hot.

You may just need a more powerful fan and a fan stat to control it.

[therealpinto]

It might be so but I doubt that. Actually I ran the same fan (Datsun Stanza, of all things) many years ago, with the standard Capri radiator, and the water cooling on the turbo plumbed in (in parallell with the heater core). It worked fine.

I found connectors last night so I can use the port at the rear of the block, so when I get the time to drain the coolant I will try that.

If I still get the same issues I will have to look at the fan. I know it is not ideally mounted since the shroud does not cover the entire area of the radiator - but it has always been like that.

Thanks for all the input

Gustaf

[Miniliteman]

Hot cooling water from turbo giving vapour lock with subsequent less cooling capacity?

[therealpinto]

I can see that happening if it for some reason would return hot water into the thermostat housing, but not in the header tank of the radiator...?

Anyway, I let the car idle a bit today in the garage (swapped out a muffler and wanted to check the sound) and even with the turbo disconnected it does not seem 100% stable. So I might try another new thermostat too, it's too cheap not to try.

Gustaf

[katana]

Just speculating here but blaming the turbo I believe is a bit bogus! I've run watercooled turbos without watercooling and never had a problem with them by allowing the engine to idle for 15 - 30 seconds before turning off. I've never once managed to really spank the turbo and then turn the engine off immediately - even drag racing! The water is only there to take 'excessive' temp away from the bearings and as idle speeds aren't going to produce excess heat it seems pointless. As a turbo relies on good oil i'd tend toward loosing the water and improving the oil cooling if necessary. I believe there is a capacity problem with the system - don't know what though!

[MegatronUK]

I can see that happening if it for some reason would return hot water into the thermostat housing, but not in the header tank of the radiator...?

Anyway, I let the car idle a bit today in the garage (swapped out a muffler and wanted to check the sound) and even with the turbo disconnected it does not seem 100% stable. So I might try another new thermostat too, it's too cheap not to try.

Gustaf

If it's still not stable with the turbo water cooling disconnected then it can't be that. Perhaps with it connected it just manifests quicker?

Maybe katana's capacity suggestion holds some water (pun intended).

[MK1_Oz]

Left of field, not running way lean at idle?

[Graham]

Left of field, not running way lean at idle?

or retarded? that will get the exhaust valves hot and rocket temps

[therealpinto]

Both AFR and timing is pretty well monitored (running Megasquirt and I have those things logged).

I agree that blaming the turbo itself is probably not correct, but adding the water cooled turbo is the only thing (except for the engine itself, head gasket and thermostat) that has changed in the cooling system. I even run the same water pump as last season. So maybe not the turbo itself, but the way it is connected.

I need to drive it more to see if the problem is still there. If it is, I have to investigate further...

Gustaf

[katana]

Also you noted a H/gasket change which resulted in bit more compression? This is usually opposite to 'normal' turbo practice and I'm wondering if its slightly leaking and pressuring the coolant system, a compression increase will build more temp anyway so with a bit of boost it could have nibbled the gasket?

[therealpinto]

The whole engine is "built", new DP pistons etc. and designed for 8.5:1 compression ratio and that should be no problem at all, especially when the problems started - I only had about 0,6 bar of boost.

Now it is turned up to around 1.3 bar but that should also be fine.

I did a track day yesterday (turbo water cooling still disconnected) and the temperature behaved all day so I don't think there is an issue in the engine itself. Will drain the coolant and try plumbing as Caprimentle did - as soon as I get back from a work trip to Brussels. Again.

Gustaf

[therealpinto]

I gave the engine a good flush of the cooling system for good measure, and connected the coolant feed to the turbo from the block, and return to top tank.

Only had time to idle test in the garage but seems stable so far.

With no fan it will rise towards 95 degrees but as soon as I hit the fan it goes down to a stable 82-83 degrees again.

Gustaf

[therealpinto]

Well, another follow-up.

The solution above, taking the feed from the block and return into the top radiator tank still gave over-cooling when travelling at speed.

The next test was another new thermostat (Gates, 88 degrees) and plumbing the return line from the turbo to the hose from the heater to water pump.

Once again, it seems to work better, engine warms up way quicker at least (logical since the turbo does not bypass the thermostat). I have only had time for a quick road test before going on a track day yesterday but so far, looks pretty good.

Oh, another change is that I made a shroud that covers the area of the radiator that the fan shroud leaves open. The shroud has three rubber slats that at least in theory opens with air flow when the car is running. This should mean that the fan will draw air through the entire radiator (at least after some minor adjustments of the shroud).

Gustaf