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Slight overheating - pump timing?
by
regcheeseman
on 30 Jan, 2012 05:42
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My recently AAZ has a tendancy to run a bit hot, not overheating,just warmer than expected. Could this be a symptom of a slightly mis timed pump?
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#1
by
R.O.R-2.0
on 30 Jan, 2012 11:34
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retarded timing makes my engine run warmer than normal..
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#2
by
8v-of-fury
on 30 Jan, 2012 17:29
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My recently AAZ has a tendancy to run a bit hot, not overheating,just warmer than expected. Could this be a symptom of a slightly mis timed pump?
Have you adjusted the timing to suspect a mistimed pump?
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#3
by
regcheeseman
on 30 Jan, 2012 18:11
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Do you always answer questions with another question?
Are you my wife?
retarded timing makes my engine run warmer than normal..
Thanks for that, confirms my suspicions.
It's a new built engine and I suspect that my pump is a bit retarded from optimum, however I advanced it a touch and it suddenly ran awful and wouldn't rev past 2000 rpm, so I put it back how it was and it still ran awful. I later found what was causing the poor running. (A coincidental fault)
The car went for it's first decent run (200 mile round trip) and just ran a bit hot all day - I suspected the timing may not be helping.
That's why my question was left open so as not to influence any replies.
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#4
by
8v-of-fury
on 30 Jan, 2012 19:36
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I am not your wife?
Yes I generally answer questions with questions. Only to further find out information..
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#5
by
Baron VonZeppelin
on 30 Jan, 2012 22:22
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If you put brand new everything with close tolerances it could just be the extra friction from that. Will probably subside some with further break-in.
Could also go for a lower temp Tstat/Fan switch if its getting warm enough to make you nervous. And of course theres always the chance of loose tension on water pump belt sometimes too.
Hope it gives you good service for a long time.
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#6
by
Mark(The Miser)UK
on 31 Jan, 2012 07:56
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My recently AAZ has a tendancy to run a bit hot, not overheating,just warmer than expected. Could this be a symptom of a slightly mis timed pump?
My take on this is that it could just be that the engine is burning more fuel than the 1.6 for much of the time, but your cooling system is unchanged.
My thoughts on the timing v heating effect, is that out on the extremes of 'running' either retarded or advanced will waste more fuel, to get the same work done and heat the cooling and exhaust system more.
However, when operating around the 'correct' operating region advancing gives more heat to the cooling system, and retarding means slight raising of post exhaust valve heating, and so can be seen with slightly earlier turbo boosting.
There is a research paper on the internet that points to about 10 degrees ATDC as being the ideal place of peak chamber pressure, for work out [kind of makes sense f you think in terms of leverage ; so I would think that at this point, the product of coolant losses and exhaust losses is a minimum; or is it the 'sum of'
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#7
by
regcheeseman
on 31 Jan, 2012 10:03
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My take on this is that it could just be that the engine is burning more fuel than the 1.6 for much of the time, but your cooling system is unchanged.
Yes, I'd thought about this, however a mate on exactly the same run with the same engine / radiator setup was running cooler.
He also has problems with the temp rocketing when the engine is worked hard - but that's just the case of the heat output of the engine exceeding the capacity of the radiator.
I've bought a new much bigger ally rad - hopefully that will sort it.....
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#8
by
regcheeseman
on 04 Feb, 2012 06:18
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I checked the pump timing and surprisingly it was not a bit retarded as assumed but running 1.20 lift, I knocked it back to factory 0.95 setting and it struggled to start, coughing and spluttering even with cold advance pulled.
I've set it back to around 1.2 again.
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#9
by
smutts
on 04 Feb, 2012 08:52
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Both of my GTD's are as steady as a rock at 5/8ths on the guages. Seems VW never bothered getting them to sit at midway. Just a thought.
If a man speaks in a forest and there is no woman around to hear him is he still wrong?
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#10
by
mtrans
on 04 Feb, 2012 16:03
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If everything else is OK ,than in my case one injector is pissing and I got low mpg so no hard to get.
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#11
by
ORCoaster
on 04 Feb, 2012 22:34
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1.2 seems a bit large. Maybe if that one injector was doing it's job the way it should your timing could bounce back to mid 90s and your starting issues would go away.
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#12
by
Baron VonZeppelin
on 04 Feb, 2012 23:25
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yeh those timing numbers / results are odd.
If you rotate engine by the Inj Pump instead of Crankshaft you get an inflated number. But its only about .05 - .08 higher than actual.
I tested this before and posted results -
its somewhere in that range. iirc
Belt tension being too loose and using Inj Pump nut - those combined - could produce that much variation perhaps.
1.05'ish is supposed safe max on TD.
If you're rotating by crankshaft, and everything is dead on the button -
there are issues at hand.
I'd have the injectors spray tested and pop verified. imho
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#13
by
carrizog60
on 05 Feb, 2012 03:46
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could engine timing be off?
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#14
by
theman53
on 05 Feb, 2012 09:56
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At 1.2mm you maybe stressing the engine some, but it probably has tons of snap. I think running the cummins pump on mine at 1.28mm was the thing that was hard enough on the precups to make them want to fall out and one did. I would bump it up to 1.05 or so instead of the 1.2 and see if that helps. Your pump could be worn and not advancing like it should. I would suspect that the little hot you are running is from the 1.2 timing. When it was back a .95 it wasn't starting well, but did it run hot?
What is exactly hot? If you are going by the VW gauge I wouldn't worry, but if you have an aftermarket gauge that tells you exactly what you are running what is that number. 205F and under running it hard and I wouldn't be concerned.