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Author Topic: Slight overheating - pump timing?  (Read 5157 times)

January 30, 2012, 05:42:19 am

regcheeseman

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Slight overheating - pump timing?
« on: January 30, 2012, 05:42:19 am »
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?



Reply #1January 30, 2012, 11:34:24 am

R.O.R-2.0

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Re: Slight overheating - pump timing?
« Reply #1 on: January 30, 2012, 11:34:24 am »
retarded timing makes my engine run warmer than normal..
92 Jetta GLI - Black, 1.6D w/ GT2056V turbo..
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Reply #2January 30, 2012, 05:29:41 pm

8v-of-fury

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Re: Slight overheating - pump timing?
« Reply #2 on: January 30, 2012, 05:29:41 pm »
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?

Reply #3January 30, 2012, 06:11:42 pm

regcheeseman

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Re: Slight overheating - pump timing?
« Reply #3 on: January 30, 2012, 06:11:42 pm »
Do you always answer questions with another question?

Are you my wife?


Quote
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.
« Last Edit: January 30, 2012, 06:19:58 pm by regcheeseman »

Reply #4January 30, 2012, 07:36:00 pm

8v-of-fury

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Re: Slight overheating - pump timing?
« Reply #4 on: January 30, 2012, 07:36:00 pm »
I am not your wife?

Yes I generally answer questions with questions. Only to further find out information..

Reply #5January 30, 2012, 10:22:56 pm

Baron VonZeppelin

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Re: Slight overheating - pump timing?
« Reply #5 on: January 30, 2012, 10:22:56 pm »
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.

Reply #6January 31, 2012, 07:56:41 am

Mark(The Miser)UK

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Re: Slight overheating - pump timing?
« Reply #6 on: January 31, 2012, 07:56:41 am »
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 8); 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' ;D


Mark-The-Miser-UK

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Reply #7January 31, 2012, 10:03:11 am

regcheeseman

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Re: Slight overheating - pump timing?
« Reply #7 on: January 31, 2012, 10:03:11 am »
Quote
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.....

Reply #8February 04, 2012, 06:18:58 am

regcheeseman

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Re: Slight overheating - pump timing?
« Reply #8 on: February 04, 2012, 06:18:58 am »
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.

Reply #9February 04, 2012, 08:52:49 am

smutts

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Re: Slight overheating - pump timing?
« Reply #9 on: February 04, 2012, 08:52:49 am »
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. ;)

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« Last Edit: February 04, 2012, 08:58:56 am by smutts »

Reply #10February 04, 2012, 04:03:26 pm

mtrans

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Re: Slight overheating - pump timing?
« Reply #10 on: February 04, 2012, 04:03:26 pm »
If everything else is OK ,than in my case one injector is pissing and I got low mpg so no hard to get.
I`ll improve my English

Reply #11February 04, 2012, 10:34:17 pm

ORCoaster

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Re: Slight overheating - pump timing?
« Reply #11 on: February 04, 2012, 10:34:17 pm »
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. 

Reply #12February 04, 2012, 11:25:55 pm

Baron VonZeppelin

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Re: Slight overheating - pump timing?
« Reply #12 on: February 04, 2012, 11:25:55 pm »
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

Reply #13February 05, 2012, 03:46:55 am

carrizog60

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Re: Slight overheating - pump timing?
« Reply #13 on: February 05, 2012, 03:46:55 am »
could engine timing be off?
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Reply #14February 05, 2012, 09:56:50 am

theman53

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Re: Slight overheating - pump timing?
« Reply #14 on: February 05, 2012, 09:56:50 am »
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.