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overheating and scalded face !!!!

Valtra - 9/6/13 at 06:13 PM

Had my first drive and couldn't get it running smoothly using speed density so tried Alpha N and instantly the car started running properly and not chucking out black smoke. But this time squealing like a kettle from the header tank. Waited a few minutes until it had settled before removing the pressure cap.....not long enough it seems as boiling water/antifreeze gushed out all over the engine and into my face.....now watching the Grand Prix wearing a bit of sunburn sensation but at least I can see..

Now have to work out why I'm overheating any suggestions gratefully received. wondering if I either had some sort of airlock or the thermostat has seized shut , but I only drove a very short distance on a cool day would that cause overheating?

Slimy38 - 9/6/13 at 06:30 PM

The last time I opened the header tank on a hot car, it did pretty much what you describe although my face wasn't in the way. There was nothing wrong with that car, apart from an owner who didn't listen to the warnings about opening the coolant cap on a hot car. At least the engine got steam cleaned...

Or is that not the reason why you think the car overheated? What did the temperature gauge say?

dave_424 - 9/6/13 at 07:05 PM

Also, sometimes there is a delay between raking the cap off and it spewing out coolant that's hotter than a Mcdonalds apple pie

Just a warning so people don't put their eye over the hole after nothing seems to happen as they take the cap off.

britishtrident - 9/6/13 at 08:21 PM

It sounds like the coolant isn't circulating, I don't know how you have the car plumbed but you need a by-pass hose ie a hose that takes coolant back from the hot side of the thermostat back to the water pump inlet. This allows coolant to circulate when the thermostat is closed and this continuous coolant flow stops hot spots forming in the engine and allows the thermostat to open.

In modern tintops the by-pass is formed by continuous water flow through the heater but if you have old fashioned heater with a water valve you controlling the heat must fit an additional by-pass hose.

In addition you should drill one or no more that two holes in the thermostat valve plate the holes should be 2mm to 25.mm dia this helps air bleed and allows the thermostat to respond more quickly.

I would also check you have enough ignition advance through thee whole rpm range.

Valtra - 9/6/13 at 08:35 PM

quote:
Originally posted by Slimy38
The last time I opened the header tank on a hot car, it did pretty much what you describe although my face wasn't in the way. There was nothing wrong with that car, apart from an owner who didn't listen to the warnings about opening the coolant cap on a hot car. At least the engine got steam cleaned...

Or is that not the reason why you think the car overheated? What did the temperature gauge say?

Not sure what the guage(s) were saying about temps as I was concentrating on the header cap squealing , I wonder now if I had the header tank too full so that as the water heated up the header tank got too full hence the plastic (with rubber valve) causing such a row. I took that cap off first with no issues . Removed the actual pressure cap slowly but turned it too far.... ouch. So could be simply too much water ?

Valtra - 9/6/13 at 08:53 PM

quote:
Originally posted by britishtrident
It sounds like the coolant isn't circulating, I don't know how you have the car plumbed but you need a by-pass hose ie a hose that takes coolant back from the hot side of the thermostat back to the water pump inlet. This allows coolant to circulate when the thermostat is closed and this continuous coolant flow stops hot spots forming in the engine and allows the thermostat to open.

In modern tintops the by-pass is formed by continuous water flow through the heater but if you have old fashioned heater with a water valve you controlling the heat must fit an additional by-pass hose.

In addition you should drill one or no more that two holes in the thermostat valve plate the holes should be 2mm to 25.mm dia this helps air bleed and allows the thermostat to respond more quickly.

I would also check you have enough ignition advance through thee whole rpm range.

Car is plumbed just as it was before the engine rebuild and for that mater just as the Fiat 131 was plumbed when I ripped out the engine 18 years ago. that is not to say for definite that the thermostat is not knackered. however the radiator was hot top and bottom.

Would an engine at correct operating temperature spurt like Vesuvius a few minutes after stopping?

Valtra - 9/6/13 at 09:22 PM

Lean running causes overheating but I'd probably driven less than 5 miles in total and certainly less than 2 miles on Alfa N (i.e not way too rich) Thinking about it now the heater valve was stuck open when I drained the system prior to re-build but closed when I refilled the system so could have caused an air lock ?

Valtra - 13/6/13 at 10:40 PM

Carefully filled up the water system I have a vent at the highest point to purge all the air . tried running again and again it got very hot very quickly . I had issues with the engine leaning right out to stall So have to assume this is causing extreme overheating over and above the likely similar tendancy to run leaner than twin 40's whilst using fuel injection. will see if I can encourage it to run a little on the rich side to see if it helps cooling

britishtrident - 14/6/13 at 07:10 AM

Is the ignition getting enough advance ? nothing causes overheating faster than retarded ignition.

Not Anumber - 14/6/13 at 10:35 AM

Try running it without the thermostat in and the pressure cap off for a while from cold to get rid of air leaks. Top up the coolant and take it for a drive. If all is well it would then be worth checking the thermostats operating by dropping it into a heatproof glass jar full of boiling water.

Valtra - 14/6/13 at 12:26 PM

quote:
Originally posted by Not Anumber
Try running it without the thermostat in and the pressure cap off for a while from cold to get rid of air leaks. Top up the coolant and take it for a drive. If all is well it would then be worth checking the thermostats operating by dropping it into a heatproof glass jar full of boiling water.

Thanks

I'm pretty sure the Thermostat is opening as the rad is getting hot ( the switch for the fan is in the rad and the fan is working) and in any case it is not easily removable as it sits in a sealed canister separate from the engine . As for ignition advance I'll try to post up the standard tuner studio map that it's been using, it may be that there could be a cause there if I haven't got my advance curves right (or even got them disabled somehow )

dave_424 - 14/6/13 at 12:53 PM

You aren't still running on the fixed 10deg timing are you?

You should be able to see on your ignition advance gauge in tunerstudio weather or not it is staying at 10 deg or is following your ignition curve.

Dave

Valtra - 14/6/13 at 09:14 PM

quote:
Originally posted by dave_424
You aren't still running on the fixed 10deg timing are you?

You should be able to see on your ignition advance gauge in tunerstudio weather or not it is staying at 10 deg or is following your ignition curve.

Dave

Pretty sure I'm not but will check as I had a major ecu failure due to stupidity early on so it may have reverted back to static advance

Valtra - 15/6/13 at 08:20 PM

Description

this is the inbuilt spark advance table in microsquirt . can anybody see a problem ?

dave_424 - 15/6/13 at 08:24 PM

I'm no expert, but I thought that full ignition should be around 32-36 degrees. Was the trigger wheel tooth offset set up correctly with a timing light?

Valtra - 15/6/13 at 09:01 PM

quote:
Originally posted by dave_424
I'm no expert, but I thought that full ignition should be around 32-36 degrees. Was the trigger wheel tooth offset set up correctly with a timing light?

When you say "full " ignition, where is that on the table bearing in mind my car is running in and won't be revving much over 6000 even when it is .

I've not checked the "static " timing since whipping the head back off following the water leak , which means I had to remove the vr sensor to change the cam belt , but it can't be far out (was absolutely spot on initially

dave_424 - 15/6/13 at 09:07 PM

As in your maximum ignition advance in the table. I don't know how your bracket is made and how well it would return to its position, if you have a tonight light then it would be worth a check.

Other than spark and fuel being lean I don't really know what the problem is. Seems as though you have ruled out the possibility of it being in the coolant system

Valtra - 15/6/13 at 09:53 PM

Thanks I'll re check the static timing just to make sure but the bracket is pretty stiff and secure so I doubt it is far wrong . Have wondered if the thermostat could be stuck partially open and thus not circulating properly , may be worth investing in a new one to rule out the possibility

Dusty - 15/6/13 at 11:42 PM

quote:

....header...... I took that cap off first with no issues . Removed the actual pressure cap slowly but turned it too far.... ouch. So could be simply too much water ?

Odd! With the header tank cap removed surely the whole cooling system should be depressurised.
Subsequently getting sprayed when removing the pressure cap (from where and why two caps?) suggests a plumbing fault. Not sure I understand your system! Heat soak plus air in the system could possibly explain a delayed eruption but it doesn't quite sound right.

[Edited on 15/6/13 by Dusty]

Valtra - 16/6/13 at 12:25 AM

quote:
Originally posted by Dusty

quote:

....header...... I took that cap off first with no issues . Removed the actual pressure cap slowly but turned it too far.... ouch. So could be simply too much water ?

Odd! With the header tank cap removed surely the whole cooling system should be depressurised.
Subsequently getting sprayed when removing the pressure cap (from where and why two caps?) suggests a plumbing fault. Not sure I understand your system! Heat soak plus air in the system could possibly explain a delayed eruption but it doesn't quite sound right.

[Edited on 15/6/13 by Dusty]

Hi

I plumbed the cooling system using all the components of the Fiat the engine came from With the exception that the Rad sits lower than the engine so I put a tight plain cap on the rad and made a filling point with the original pressure cap at the front of the engine where the top hose enters . this also has an overflow hose going up to the header tank as high as I could get it on the scuttle. the system is designed so that as the water in the engine expands it forces past the pressure cap into the expansion(header) tank, which is hot but not under pressure as the air escapes through a rubber valve in the plastic header tank cap . As the engine cools it sucks water back from the header tank .

If this is plumbed wrong then it worked fine before with carbs so I'm a little perplexed

Description

[Edited on 16/6/13 by Valtra]

britishtrident - 16/6/13 at 06:51 AM

Looks way to retarded to me, with an old fashioned purely centrifugal advance max advance was reached around 3,500 RPM -- note this is driven by crank rpm not load.
On most engine there is no gain in adding more ignition advance over this crankshaft speed.

Try setting the full load ignition advance to 15 degrees at 1200 rpm and 36 degrees at 3,500 rpm with a straight line in between.

Because they of the poor combustion chamber shape which gives slow combustion because of the long flame path and lack of turbulence two valve twin cam engines with hemi combustion chambers need a lot of advance so you may find using more advance at the high end is required. 40 degrees advance at full throttle is pretty well the limit.

[Edited on 16/6/13 by britishtrident]

Valtra - 16/6/13 at 09:32 AM

Thanks I'll look into that . I'm also wondering if the Innovate LC1 is calibrated quite right in tuner studio as I have a G5 gauge that reads a bit different to the Tuner studio gauge from memory so it could be fooling the ecu into leaning back too much . I'll do a free air calibration and see if there is a correlation .

Valtra - 16/6/13 at 09:45 AM

quote:
Originally posted by britishtrident
Looks way to retarded to me, with an old fashioned purely centrifugal advance max advance was reached around 3,500 RPM -- note this is driven by crank rpm not load.
On most engine there is no gain in adding more ignition advance over this crankshaft speed.

Try setting the full load ignition advance to 15 degrees at 1200 rpm and 36 degrees at 3,500 rpm with a straight line in between.

Because they of the poor combustion chamber shape which gives slow combustion because of the long flame path and lack of turbulence two valve twin cam engines with hemi combustion chambers need a lot of advance so you may find using more advance at the high end is required. 40 degrees advance at full throttle is pretty well the limit.

[Edited on 16/6/13 by britishtrident]

Also excuse my ignorance but when you say full load you mean the top line of the table should read with those figures ? what about lower down at lower load ? Have you some suggested figures for the bottom line and how they should progress up the load and rev range ?

dave_424 - 16/6/13 at 09:54 AM

This is a megasquirt map that I downloaded to get something to work off, lower RPM area might have a degree or two too much advance for your engine.

Also note that it is for a bike engine so the RPM's would have to be bought down to match your engine's rev range.

Valtra - 16/6/13 at 12:23 PM

Thanks Dave

I'll nudge my advance up a little towards these figures and see if I can make a difference , if I self tune in tuner studio will it change the advance anyway? or does it concentrate on fuel load only

dave_424 - 16/6/13 at 12:33 PM

Self tune shouldn't change your ignition table unless you have knock input. The tuner studio self tune is really only used when you have a good tune already, so I've been told anyway. Also needs careful setting up to determine how much and how frequent it makes changes. If you are using self tune, and your ECU isn't getting a correct AFR when compared against your gauge, it might be adjusting everything too lean or rich but the ECU thinks it's correct. I would possibly turn self tune off and see if you still overheat

Dave

Valtra - 16/6/13 at 05:54 PM

ok been scratching my head all day and this is where i am

Description

any comments ?

Valtra - 16/6/13 at 06:19 PM

Just taken it for a quick run and can't get the revs to die back , constantly running above 1500 rpm and only very slow to die back to there . I'm guessing too much advance low down ?

also car is still boiling up so will have to get a new thermostat and try again . it shouldn't be hitting the danger paint while running under light load on a cool evening . like I say the rad is hot as the fan is running but it can't be circulating properly

Valtra - 16/6/13 at 06:20 PM

oh and it's not cutting out today. I started by tightening the injection pump contacts so maybe it was that

BaileyPerformance - 16/6/13 at 06:26 PM

fast idle or revs not returning is a throttle body problem or air leak, check the balance of your throttles at idle AND light throttle.

Make sure your throttles SNAP shut when you blip the throttle peddle

Incorrect timing will not make the engine rev at idle IF the throttles are setup correctly, up to a point more timing will bring the idle up by a small amount but thats it.

Incorrect fuelling and timing plus overheating = knackered engine, be careful.

Valtra - 16/6/13 at 06:32 PM

quote:
Originally posted by BaileyPerformance
fast idle or revs not returning is a throttle body problem or air leak, check the balance of your throttles at idle AND light throttle.

Make sure your throttles SNAP shut when you blip the throttle peddle

Incorrect timing will not make the engine rev at idle IF the throttles are setup correctly, up to a point more timing will bring the idle up by a small amount but thats it.

Incorrect fuelling and timing plus overheating = knackered engine, be careful.

checked the balance last week and it was fine , will see if the bodies have dislodged due to vibration thanks

and yes trying to be careful........ fuelling seems better now but will be better once I get the overheating sorted as it must be something fundamental in the cooling system .

thanks

Valtra - 16/6/13 at 06:43 PM

No obvious air leaks and TBs nice and firm so that's a baffler

BaileyPerformance - 16/6/13 at 06:48 PM

have you checked the throttle for balance at idle and at light throttle?

if you are using motorbike TBs the link springs can do funny things causing the TBs to go out of balance at light throttle.

Just to get you up and running aim for 13AFR everywhere, you can lean off when you have the cooling system sorted.

Your advance table is wrong but not that far off to cause overheating, its normally far too much retard that causes overheating and also a hot exhaust.

dave_424 - 16/6/13 at 07:19 PM

You need to change the AFR table load on the left hand side to 0-100%, looks like it still has the scale for speed density.

What are your afr's like? On your gauge not in megasquirt. Are they around where your AFR table wants it? Can't you just remove the thermostat and try that?

Dave

Valtra - 16/6/13 at 09:56 PM

quote:
Originally posted by dave_424
You need to change the AFR table load on the left hand side to 0-100%, looks like it still has the scale for speed density.

What are your afr's like? On your gauge not in megasquirt. Are they around where your AFR table wants it? Can't you just remove the thermostat and try that?

Dave

Hi Dave

Ever the font of practical advice , thanks.

Yes I noticed the discrepancy after I posted the picture and adjusted the scale on the left to similar values to the vr and spark tables .

I took some time to calibrate the LC1 and did find an anomaly in the scale i'd set at 1-5 volts instead of 0-5 and the gauge reads very similar values to the Tuner studio gauge. as to actually following the afr table ....loosely .

Thermostat is sealed (AFAIK) into a canister separate from the engine with three outlets

dave_424 - 16/6/13 at 10:11 PM

I know that you have had this engine together and running fine, but are the 3 outlets connected to the right places in the cooling system? If so, then can't you remove it and use some pipe and clamps to connect the respectable pipes?

If your engine is getting boiling hot, then so should your radiator. It should be very very hot. If it is just warm/hot then possible that the thermostat isn't opening all the way or not at all.

Dave

Valtra - 16/6/13 at 10:20 PM

quote:
Originally posted by BaileyPerformance
have you checked the throttle for balance at idle and at light throttle?

if you are using motorbike TBs the link springs can do funny things causing the TBs to go out of balance at light throttle.

Just to get you up and running aim for 13AFR everywhere, you can lean off when you have the cooling system sorted.

Your advance table is wrong but not that far off to cause overheating, its normally far too much retard that causes overheating and also a hot exhaust.

thanks

I checked the balance at low idle , I could screw the stopper in and try it then

britishtrident - 18/6/13 at 02:40 PM

This thread in another Forum might help with the ignition curve.

http://www.guy-croft.com/viewtopic.php?f=11&t=2443

DarrenW - 18/6/13 at 03:07 PM

Ref idle rpm and speed to drop - i had issues with bike carbs. 2 causes;
1. butterfly wasnt closing properly due to dirt in the body and varnish type deposit around the butterfly,
2. return springs too week. New spring made a big difference.

(Interestingly i also had issues with the throttle body butterfly on tin top some time later, this time the varnish type deposits were sealing the throttle body too well and causing engine to die at junctions. RAC man told me how to fix it when i had a flat battery at an airport once.)

I also had issues with carb tops not being sealed but i guess that wont affect you.

Re mapping - i was kindly given a map be somebody with a similarish set up and it got me started.

Valtra - 18/6/13 at 11:12 PM

quote:
Originally posted by britishtrident
This thread in another Forum might help with the ignition curve.

http://www.guy-croft.com/viewtopic.php?f=11&t=2443

Thanks , yes Guy knows all there is to know about the twink , and has given me free advice recently . Those advance figures are likely to be spot on

Valtra - 18/6/13 at 11:21 PM

quote:
Originally posted by DarrenW
Ref idle rpm and speed to drop - i had issues with bike carbs. 2 causes;
1. butterfly wasnt closing properly due to dirt in the body and varnish type deposit around the butterfly,
2. return springs too week. New spring made a big difference.

(Interestingly i also had issues with the throttle body butterfly on tin top some time later, this time the varnish type deposits were sealing the throttle body too well and causing engine to die at junctions. RAC man told me how to fix it when i had a flat battery at an airport once.)

I also had issues with carb tops not being sealed but i guess that wont affect you.

Re mapping - i was kindly given a map be somebody with a similarish set up and it got me started.

yes could be the butterflies sticking a tad; the bike the tbs came from had open and close cables working together . they seemed free enough but I'll check they are closing sharply

Valtra - 19/6/13 at 10:14 PM

Got my new Thermostat canister today and fitted it . started up and brought it up to thermostat opening temp , this should now have released any air trapped in the bottom hose so that once cold tomorrow I can top it up again and it should be good to go . Incidentally the car idled happily once I'd tickled it to start and settle The afr gauge sat at about 13 settling back around 14 once warm . The problem I had with the revs not dying back seems to be down to the throttle not slapping shut properly every time , progress at least

snapper - 20/6/13 at 05:40 AM

A while back in the thread you said you had changed timing belt
Is your cam timing correct?

Valtra - 20/6/13 at 07:42 AM

quote:
Originally posted by snapper
A while back in the thread you said you had changed timing belt
Is your cam timing correct?

Yes seems to be, all the markers line up correctly and the engine idles as sweet as a nut once it's properly awake .

Thanks .

Valtra - 8/7/13 at 05:09 PM

Quick update

Thermostat fitted and carefully bled ....but despite it being fairly cool here today due to cloud round the wash (not a euphemism) had to stop for 10 mins on the way to MOT to let it cool down . Passed MOT and now taxed and legal , my friend at MOT station suggested the water pump impeller could be slipping on the shaft so another �15 to ebay for a new one to eliminate that possibility.

On a good note car ran ok on Microsquirt with occasional drops to lean on closed throttle but picked back up without cutting out . Pulls well on open throttle and sounds very crisp , just need another spring to close the butterflies as revs keep running away (bike had a closer cable as well as opener)