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sgiitk

Nostalgia: Lost art of engine starting

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With the demise of carburetter cars we are fast losing the art of starting engines. One still recalls fondly the number of times the good old Fiat 1100 engine was a pain in the a.. since it was flooded.

Now of course you just remember not to touch the gas pedal, switch on, wait for the system to prime itself and crank. However, this does lead to people being totally unaware of how to handle the gas pedal when you push start (i.e. when electrics are alive, but there is not enough juice to crank)  !!

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But the bad habit carryover from dynamo days of revving the engine before turning off doesn't go away in India, from stupid Taxiwallahs, truck drivers, mechanics, average people all do the heinous crime of revving a cold engine to death after starting up and then they finally kill it before turning it off. Imagine, when you start an engine, there is only a remnant film of oil in the cylinder liner, valve train etc. If you take a look at oil pressure gauges which themselves are sadly extinct nowadays, you will see how slowly it rises up after cold start, when temps are low, its even slower. For revving up a turbo engine after a cold start or shutting it down with a hefty dose of throttle means apparent death knell for the turbo. The turbo spins at over 150,000 rpm, the oil near the alloy turbo bearings get exceptionally hot, when you turn on or shut off the engine with a good dose of throttle, you basically shut off the oil supply and the high RPM heats up the thin film of oil to coke it on the bearings leading to premature turbo failure. Of course, all this makes your mind happy to hear the vrooom vroom from your engine and keeps your mechanic nice and rich. Remember folks, revving a standing engine is a crime no matter what. If you like to rev it, do so with gear engaged on an empty piece of highway. Revving a hot engine and then shutting it down puts destructive carbon on your rings and leads to premature engine failure.

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Agreed. Only I never had the habit of revving at either start or shut down, so it never came to mind.

It is nice of  you to point out that a Turbo should be held at idle for a few seconds before shutting down, to permit the heat to dissipate from the bearings, etc.

As for the oil pressure gauge behavior in cold engines,  the slow response may also have something to do with the cold (high viscosity) oil taking its own time to come up the capillary to the Bourdon tube. 

I also regret the demise of the oil pressure gauge, being replaced by the i***t light. In the 70's the Ferrari's had the oil pressure gauge in the middle of the cluster, and it was the largest gauge.

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Yep, the slow oil pressure response is due to heavier viscocity and also tells you how slow the oil reaches critical areas when its cold, a grim reminded that all you have at the moment is metal to metal contact. Another important point to watch here is viscocity and cold pumping. There are thicker oils and thinner oils, today's cars, specially Honda, Toyota etc. are made to run on 5W-30 and yet, most India workshops keep putting heavier 15W-40, in case of these vehicles, thick is not better protection, rather its poorer mileage and in some cases, poorer protection. Also any diesel rated superior HDEO oils can be used on petrol engines as all exceed petrol's highest requirment my miles, opposite is not true, most, even synthetic petrol oils are only rated at max of CG which is antiquated for modern diesel engines, bear that in mind.Gurkha2007-11-16 17:34:24

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gurkha, you have made a very informative post.. congrads... smiley32.gif

by the way, i heard that, with petrol engines, it is better to keep the engine idling before stopping, if the cooling fan is working. is it true..? why..?

then is there any benefit, if we idle the petrol engine to warm up, on cold staring..? smiley5.gifcarispassion2007-11-16 17:54:59

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Thank you. For any engine, its advisable to pull over and let the engine fast idle if it overheats or fan malfunctions, this is done to keep the coolant circulating through the engine core to dissipate heat, in case you shut down the engine, the hot coolant standing still on the engine hot spots would boil over and cause even more disaster. As for warm up, I had a long chat with MB Germany engineers as well as Honda engineers, their conclusion was that its harmful to idle cold engine, it builds up carbon and does more damage, today's fuel injected vehicles can be started and driven in under a minute as long as the oil has reached the critical areas. The trick to long engine life is gentle gradual warm up. Don't flog the cold engine, stay in lower gears and let the rpm build up gradually and let the temp come to operating range and only then put full load on engine. Also change your thermostat every five years to make sure that the engine reaches operating temperatures quickly, a stuck thermostat will make your engine reach operating temp slowly causing more damage. LASTLY, please never ever remove your thermostat, no matter what, a very nasty and stupid desi mechanic practice along with removing radiator cap. If the vehicle is overheating, there are causes for that and removing thermostat is not a solution, its a temporary patch job which is very bad on the long term life of your engine.

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Ha ha, no, nothing that interesting, have had plenty of exposure to automobile world in past including racing, building etc when in college in US, I am just a mundane boring math professor now here in India.

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hehe.. doent feel so...

you should have tried automobile engineering... really..

any way.. it is better to be a maths prof and love cars.. than being an automobile engineer, who has no real interest on automobiles....congrads again....

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it is better to be a maths prof and love cars.. than being an automobile engineer' date=' who has no real interest on automobiles....congrads again....[/quote']

So very true.......most who are in this field here are not enthusiasts like us in any sense, one trip to auto expo and you will know their depth on auto within few minutes of talking to them.

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YThere are thicker oils and thinner oils' date=' today's cars, specially Honda, Toyota etc. are made to run on 5W-30 and yet, most India workshops keep putting heavier 15W-40, in case of these vehicles, thick is not better protection, rather its poorer mileage and in some cases, poorer protection. Also any diesel rated superior HDEO oils can be used on petrol engines as all exceed petrol's highest requirment my miles, opposite is not true, most, even synthetic petrol oils are only rated at max of CG which is antiquated for modern diesel engines, bear that in mind.[/quote']

Some cars still specify SAE 40 for operating temperatures above 40C, as in the plains. So using 5W-30 may not be really on.

As for HDEO in petrol engines, and the reverse. A Diesel engine oil has a higher detergent content, hence petrol oils may not be suitable for diesels to the same extent. It is true that most petrol engines specify API-SG which most premium diesel oils also conform to. I have been partial to Castrol and my favourite is Magnatec, an API-SJ oil. I have used synthetics in the past but once this came on teh market I switched to it.

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YThere are thicker oils and thinner oils' date=' today's cars, specially Honda, Toyota etc. are made to run on 5W-30 and yet, most India workshops keep putting heavier 15W-40, in case of these vehicles, thick is not better protection, rather its poorer mileage and in some cases, poorer protection. Also any diesel rated superior HDEO oils can be used on petrol engines as all exceed petrol's highest requirment my miles, opposite is not true, most, even synthetic petrol oils are only rated at max of CG which is antiquated for modern diesel engines, bear that in mind.[/quote']Some cars still specify SAE 40 for operating temperatures above 40C, as in the plains. So using 5W-30 may not be really on.As for HDEO in petrol engines, and the reverse. A Diesel engine oil has a higher detergent content, hence petrol oils may not be suitable for diesels to the same extent. It is true that most petrol engines specify API-SG which most premium diesel oils also conform to. I have been partial to Castrol and my favourite is Magnatec, an API-SJ oil. I have used synthetics in the past but once this came on teh market I switched to it.

None of the modern day cars at least from Japanese or Germans do anymore, you can check Honda's or MB's lube chart and you will see even in hotter region, 5W-30 or 10W-30 is max recommended. This includes hot regions in US like AZ, NM etc. In Arizona, its normal for temps to hit close to 50C with dust. The problem is that today's engines are made to close tolerance and thicker oils can't really get into every nook and corner that easily as thinner oils will and today's thinner oils are engineered for high shear strength so its no hitch there. For a much better product than Castrol Magantec or any other Castol oil, check HDEO oil like Chevron Delo 400 or Mobil Delvac MX. Both are commercial HDEO diesel oil with highest rating for diesels, passes the toughest on field Mack rating and also exceeds SJ requirements for petrol engines. They are the only two oil to meet million mile OEM warranty certification. Apart from costly synthetics, these are the best value on the market but they are a bit hard to find. Delo 400 is hydro-cracked ISO-SYN oil which performs like a synthetic due to its design. Check out used oil analysis done with these oils on various engines from gensets, motorcycles to modern passenger cars, diesel and petrol at www.bobistheoilguy.com/forums

In big rigs, they are routinely used and changed at 25000 miles interval.

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Thanks very much for the valuable info, Gurkha.  I wondered why it was mentioned not to idle in cold starting and just to drive away normally in my Vauxhall Astra's manual, now I know why!  Cheers, mate!

 

Jitz

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If they demand SAE40 you can use 15W-40 Delo 400 with full confidence.

Thanks. May switch over the next time ZI change oils. Incidentally Delo being a Caltex-Chevron brand,  will it be available at (select)  HP outlets (I think HP was once upon a time Caltex).

sgiitk2007-11-19 09:55:00

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If they demand SAE40 you can use 15W-40 Delo 400 with full confidence.
Thanks. May switch over the next time ZI change oils. Incidentally Delo being a Caltex-Chevron brand' date='? will it be available at (select)? HP outlets (I think HP was once upon a time Caltex).[/quote']

HP wont' carry specialized oils Delo 400, Indianoil was stocking Mobil Delvac initially but that too stopped. Problem with Delo 400 is that only comes in 15L or 20L containers so you have to buy in bulk. I use it on my petrol, diesel and 2 wheelers as well as my genset so I pick up 40L every six months.

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Thanks. That will not be such a problem. Both my cars are serviced at about the same time. So that takes care of half of the 15L. The balance can go into my Genset! Incidentally of late I have seen Mobil 1 at Indian Oil. have they changed horses?

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