[Jomz]

Originally Posted by BaCkSeAtDrIVeR

I have not heard of teh 412 variant. Thanks for the info.

But afaik, 680 uses a different block. I have not seen it, only heard of it, and have some boats fitted with that engine. Actually, these are larger boats - 50 feet or longer.

680 is a 12l Engine , Pretty low on power but stupendous torque ~1000Nm. Ther are some applications which demand high torque- which Hino and AL could not give, So 680 caters to that market.

This is an inline 6 with 2 cyl heads- one for first 3 cyls and 2nd for the other 3cylinders. The block, heads, FIP, crankshaft, conrods, bore, stroke etc, everything is different.

This is one example of AL having different products which helps the customer in the market. 6BT,412, or Hino cannot reach the 1000Nm mark.

This engine dates from World war 2, But the last i know AL engineers had this upgraded to Euro 2. Euro 3 and onwards- I don't know.

[ontheroad]

Originally Posted by greatmana2000;2131013[B

The cummins engines give shivers down the spine while idling , I dont know if it is a problem with the engine or the state of tune at various stu.[/b]

Very true.

Recently travelled in a new KeSRTC Tata 1512c LS TT between Kodundallur-Thrissur. The bus was literally shivering in idle. I have observed that most of KeSRTC TATA buses vibrates heavely when idled. But rarely seen a leyland shivering that much.

[BaCkSeAtDrIVeR]

Tata chassis - as far back as I can remember, vibrate heavily, either harmonic vibrations at high speeds, or rattling at idling. It is only rare models which do not vibrate.

[dkamath]

Originally Posted by teamveevee

Even the new KaRTC Rajahamsas are built on 1618, KerRTC yet to procure 1618s.

Travelled from B'lore to M'lore by a Rajahamsa of Tata make, and body built by Prakash, a P8000 x3 or something along these lines. The chassis monogram was missing in the front, and hence do not have an idea on the same. The vibrations within the bus were not obtrusive, and the bus did have a good top speed. The trip time taken was 7.45 hrs, with a 10 minute break at Sakleshpur. Impressive by any count.

[greatmana2000]

[quote=sumitkalindi;2131131]Sorry to contradict you here sir, but the suspension AL uses is a TVS-WILRIDE Air Suspension Systems and are currently being manufactured by Wheels India Limited, in a technical agreement with TRELLEBORG.

It was Dunlop initially , then Dunlop got taken over by Trelleborg .The product was initially known as penuride and now it is known as nuride .

I must also point out here that Tata suspension is supplied by Tata AutoComp, with its joint venture partner Hendrickson USA.

After how many years ?We have air suspension in TATA buses only due to the compulsion of city buses which needed only air suspension .

So both actually do not designed the suspension systems from scratch.

About the weveller system AL has, Tata says it has Rubber ended suspension. Both are basically same thing. So here both are on equal grounds IMHO.

Rubbish . Leyland has longer and thicker leaf coupled with a weveller system . TRY running both buses or trucks on uneven roards . you will understand what a weveller suspension can do.

Also please pardon my ignorance but what is meant by half steering???
Front wheels are not fully steerable . They can be steered only half way trough.

[greatmana2000]

Originally Posted by dkamath

Travelled from B'lore to M'lore by a Rajahamsa of Tata make, and body built by Prakash, a P8000 x3 or something along these lines. The chassis monogram was missing in the front, and hence do not have an idea on the same. The vibrations within the bus were not obtrusive, and the bus did have a good top speed. The trip time taken was 7.45 hrs, with a 10 minute break at Sakleshpur. Impressive by any count.

May be it was a WORLD BUS like the "world truck" from TATA

[greatmana2000]

Originally Posted by Jomz

680 is a 12l Engine , Pretty low on power but stupendous torque ~1000Nm. Ther are some applications which demand high torque- which Hino and AL could not give, So 680 caters to that market.

Somehow i get a feeling that AL looks for torque on its engines than horses .The TN STU drivers are trained to shift gears as soon as the engine barely reaches 1000 rpm ,but the biggest surprise is that the engine happily lugs even with an overloaded bus and i see the drivers change to top gear at speeds of 40-45 km/hr .

[teamveevee]

Originally Posted by greatmana2000

After how many years ?We have air suspension in TATA buses only due to the compulsion of city buses which needed only air suspension .

That is true, Both SRTCs and private operators want to buy the cheaper ones, If the gov regulation did not mandate, i am sure even now nobody will be buying them. Not sure whether TML can be blamed for this?

[BaCkSeAtDrIVeR]

Originally Posted by greatmana2000

Front wheels are not fully steerable . They can be steered only half way trough.

I still do not get what your point is. I have owned AL buses. Others in the family have owned TELCO (that is what TML used to be) buses. Have owned Fargo buses and Bedford lorries.

Have owned Dodge and Buicks, (cars), when I was as tall as their wheels.

Have owned Fiats and ambies and my current WagonR.

None of these vehicles had their froont wheels turning more than approx 30 - 40 deg.

[greatmana2000]

Originally Posted by BaCkSeAtDrIVeR

I still do not get what your point is. I have owned AL buses. Others in the family have owned TELCO (that is what TML used to be) buses. Have owned Fargo buses and Bedford lorries.

Have owned Dodge and Buicks, (cars), when I was as tall as their wheels.

Have owned Fiats and ambies and my current WagonR.

None of these vehicles had their froont wheels turning more than approx 30 - 40 deg.

Nope check the leyland vehicles .. their front wheels turn much more than a tata bus . I have owned leylands , Tatas , Mahindra vans , allwyn nissan vans . The leyland vehicles are known to have "full cutting " as compared to a Tata vehicle in Tamil nadu .

[BaCkSeAtDrIVeR]

gah!!!!

Steerability is measured by turning radius and steering stability. What has wheel turning radius got to do with this?

[greatmana2000]

Originally Posted by Jomz

Well I'm not that much familar with marine engines, But I know they are specific for that application.

THe Exhaust manifold etc are seawater coooled, so that it does not get extremely hot and start a fire in the boat. This feature alone makes it unlikely that an used auto engine can be used as a marine engine.

The market requirement here which I suppose is, ease of maintananace- some engines which are familar to mechanics always are recommeneded. And I believe there are no emission norms for marine engines in India, I might be wrong.

Marine engines are normally coated or treated with anti rust in the insides and the inlets of the engine . A true marine engine is not really there in India , but I might be mistaken with the AL engines .

[BaCkSeAtDrIVeR]

^^ That is a statement I have heard before.

But what exactly is a "true" marine engine??

Somebody (a naval architect) once told me that a marine engine would run even with a piston burnt out. If that is the real test, I can vouch that both my bus and boats have done that - on 2 or 3 occassions each, with piston rights and one or two pistons burnt out.

When this happens, there will be corrission like burnt marks on the piston, and one or more piston rings would be broken.

There would a rattle, distinctive to this kind of damage.

The engine would not stall, and the vehicle / boat can be brought to some place under its own power.

[greatmana2000]

Originally Posted by Ashley2

I feel AL and TML can be attributed to Super Star Rajnikanth and Kamalhasan.
Though the earlier has a excellent crowd pulling capacity and an untammed mass super star(highest paid star in whole of Asia) when it comes to acting and trying new things Kamalhasan scores better.

So Rajnikanth can be attributed to TML and Kamalhasan can be attributed to ALL.
I am not sure this will be understood by all

Well the diff is Kamal takes 2-3 yrs to finish a film . ALL is much faster doing new things

[greatmana2000]

Originally Posted by BaCkSeAtDrIVeR

^^ That is a statement I have heard before.

But what exactly is a "true" marine engine??
Different water pump . Normally a brass impeller water pump is used . More /bigger/better thrust bearings are used for crankshaft .Exhaust manifold is water cooled .To prevent corrosion chemical coating is used( i do not know the process ,but there are a lot of companies in europe that do the marinising . Good example would be DMV-bootsdiesel .

Somebody (a naval architect) once told me that a marine engine would run even with a piston burnt out. If that is the real test, I can vouch that both my bus and boats have done that - on 2 or 3 occassions each, with piston rights and one or two pistons burnt out.

I do not know if that is possible as the fuel will still be injected into the cylinder and there is a very big possibility of the injected diesel getting mixed with oil .


When this happens, there will be corrission like burnt marks on the piston, and one or more piston rings would be broken.

There is a huge possibility of the crankshaft getting broken if the broken pieces of rings make the piston and liner to get stuck .

There would a rattle, distinctive to this kind of damage.

The engine would not stall, and the vehicle / boat can be brought to some place under its own power.

Normally ships and big trawlers have spare engines or engine parts and in case of ships , the ships engineers can even disassemble and reassemble an engine on the high seas or they can even perform emergency repairs and safely reach the nearest port .