[Samurai]

Originally Posted by dhanushs

Did you change the belt to the smaller pulley?

It is already on the smaller pulley. The largest pulley on the crankshaft is unused.

Originally Posted by oldmonk

On our way to Mangalore yesterday, the wife and I saw your Jeep (she said "Thar?", I said "offroader..") near CR Patna. It looks great, congrats!

Thanks, I saw your grey Vitara and wondered could it be you. But I had no way of calling you, and no way of chasing you down for confirmation.

Yesterday I was zipping away on the 4-lane highway, feeling like a highway king, then I see couple of 100CC bikes passing me. I got confused and looked at the GPS, only to find I was zipping at 65kmph. But it felt lot faster than that. I guess that is what we lose for gaining the offroad advantage, at 1/3rd the price of Thar.

Originally Posted by Samurai

The second niggle was the slight body wobble/vibration starting around 70kmph (GPS) and it gets worse at higher speed. So I kept the speed between 65-70kmph most of the way, and touched 75-78kmph (GPS) occasionally. The speedometer when did work had massive error, it showed 70 when gps was at 60 and showed 83 when gps showed 70. So I didn’t mind much when it stopped working. The body wobble, could it be because wheels were not balanced after mounting the tyres?

I am glad to say this has vanished after changing to alloys and Geolandar AT-S tyres. It must have been the unbalanced steel wheels.

I was able to hit the top speed of 77kmph with AC and the top speed of 82kmph without AC. And absolutely no body wobble unlike last time, and in the same stretch of roads where it happened before. Both are GPS speeds. And in a vehicle without ABS, airbags or crumple zone, I don't care to drive any faster.

[vivekjayasheel]

Isn't 77 kph a tad low for a 550? I thought they can get up to 120...

[Samurai]

Today at noon, I was driving around in Bangalore. My eyes automatically went towards the temp gauge by habit. Except, there was no temp gauge! I was in the i10.

Originally Posted by vivekjayasheel

Isn't 77 kph a tad low for a 550? I thought they can get up to 120...

May be with BA-10 (5 speed) gearbox. With KMT-90 (4 speed), 82kmph could be the limit.

[dhanushs]

Originally Posted by Samurai

It is already on the smaller pulley. The largest pulley on the crankshaft is unused.

Sir, all this time I was pointing out the pulley in the water pump.

As you can see in this picture, the belt is turning the larger pulley. All you need to do is to put the belt into the smaller pulley. If the alternator alignment is right, this job will take only about say.. 2 mins ..

Originally Posted by vivekjayasheel

Isn't 77 kph a tad low for a 550? I thought they can get up to 120...

120?!!.. Saarrr!.. NO. IIRC ~100 is the company said top speed. Maybe with a really good downhill, a mind tuned like a bungee jumper and a truck on your behind carrying luck, you can do 120 on GPS.

[Mpower]

Originally Posted by ex670c

The purpose of the thermostat is to maintain optimum engine temp, and prevent flash heating and hot-spots in the engine head.

How does it prevent hot spots and flash heating

I thought the purpose of a thermostat is to help warm up a cold engine quickly

[Samurai]

Originally Posted by dhanushs

Sir, all this time I was pointing out the pulley in the water pump.

But the answer is the same. Any attempt to move the fan belt forward will make it tangle with the compressor belt. Eventually I have to move the compressor to the left side, and use 3 belts. Better do it in one shot.

[ex670c]

Originally Posted by Mpower

How does it prevent hot spots and flash heating

I thought the purpose of a thermostat is to help warm up a cold engine quickly

Hi Mpower,

The thermostat restricts the water flow to the radiator, till optimum engine/head/block temp is reached, then the valve opens and allow the normal cooling circuit to work.

If there is no thermostat, then the water in the engine head and block will flow into the radiator, and cooled down further, without heating up the engine.

Also the Peugoet engine (XDP4.9 & XD3P) have a aluminium head and cast iron block so there is a difference in thermal expansion, and cooling down.

The thermostat works in maintaining even temp for both the head and block, since the thermostat is in the engine head (Water Pump) this warms up the head and prevents hot spots near the Cylinder walls, where the head gasket usually develops leaks due to thermal shock.

This thermal shock is caused by the difference in temp of the water entering the engine from the radiator vs the temperature of the engine block.

With a thermostat this difference in water temp vs engine block temperature is marginal.

Regards,

Arka

PS - Experts please make necessary corrections.

[headers]

Originally Posted by ex670c

If there is no thermostat, then the water in the engine head and block will flow into the radiator, and cooled down further, without heating up the engine.

It will heat the engine, but take a longer time as the water circulation is perennial

[It should be read as "it takes a longer time to reach optimum engine operating temperature without the thermostat", hence bad for the engine as it is not in its optimal operating temperature zone]

[Sutripta]

Hi,
Some thoughts:

Originally Posted by ex670c

The thermostat restricts the water flow to the radiator, till optimum engine/head/block temp is reached, then the valve opens and allow the normal cooling circuit to work.

OK.

If there is no thermostat, then the water in the engine head and block will flow into the radiator, and cooled down further, without heating up the engine.

I would think water does not heat up the engine. Rather it cools it down, and in turn is heated by the engine.

Also the Peugoet engine (XDP4.9 & XD3P) have a aluminium head and cast iron block so there is a difference in thermal expansion, and cooling down.

OK.

The thermostat works in maintaining even temp for both the head and block, since the thermostat is in the engine head (Water Pump) this warms up the head and prevents hot spots near the Cylinder walls, where the head gasket usually develops leaks due to thermal shock.

See previous thought.
Also most of the heat is generated in the cylinder head, not block.
Look up reverse flow cooling systems/ counter-current heat exchangers.

This thermal shock is caused by the difference in temp of the water entering the engine from the radiator vs the temperature of the engine block.

With a thermostat this difference in water temp vs engine block temperature is marginal.

Unlikely in steady state conditions.
Only during initial warm up, I would say yes, provided there is a bypass connection between engine water outlet and inlet. Water must circulate through the engine if temperature uniformity to any degree is to be attained. (In older Indian cars, the tap off points for the HVAC heater was sometimes shortcircuited with a hose. That would act as a very effective bypass.)

Ergo, don't see how a thermostat prevents hotspots and flash overheating.

Regards
Sutripta

[vivekjayasheel]

I agree with Sutripta.

If anything a thermostat would CAUSE hot-spots (as the temp-sensor that opens the valve may not be very close to the hottest areas of the closed-off water-circuit) and flash overheating (as well as flash cooling, when the valve opens and lets fresh coolant into the previously cut-off coolant circuit).

[Samurai]

I have replaced the radiator cap with..... a new one. That's it. There is nothing written on the cap about the PSI, etc. Even the shop keeper knew nothing except this will work for JEEP.

Damn, just realised that I completed 8 years on Team-BHP today.

Ok, got to pack up for the OTR. I'll see many of you today.

[Samurai]

On the way to the Bangalore OTR, the Jeep had a breakdown. The clutch cable broke and the clutch pedal was moving freely. Fortunately, I was only 2kms away from Vivek's workshop, where this Jeep was rebuilt.

So I called Vivek and told him about the problem. He quickly dispatched couple of mechanics to replace of clutch cable. Now this is a proper After Sales Service with emergency/breakdown service.

While waiting for the mechanics, I thought about the first time this happened to me. It was in my Maruti 800 with only 6000kms on the odometer.

Whoa... wait a minute! There was something wrong there.

This happended in 1998. I was driving along cubbon road and suddenly the clutch pedal became free (or fell flat). So I had to park the car next to Brigade Parade Grounds and take an auto to Mandovi (I think) workshop to request breakdown service. Why didn't I call? Well, we didn't have mobile phones then, at least most of us didn't. They sent a kid mechanic (not more than 16-17) with me back to the car. He looked at it and declared that my clutch plate is gone. He asked me to get the car towed to the workshop. Then I went to Russel Market to hire a matador truck to tow my car. The matador driver wanted me to get couple of cycle tube to use as tow rope. So I bought cycle tubes in a cycle store. Then we towed the car precariously to the workshop, that was less than 2Kms away, at the junction of museum road and St.mark's road.

After two days I got my car back. Some 2K+ for replacing clutch plate and clutch cable. Another 200 for towing truck, some more for cycle tube.

It occurred to me now, while waiting for Vivek's mechanics, that I had been swindled by Maruti mechanics in 1998. How can clutch plate go bad at 6000kms. Now that I think back, it was a clear case of clutch cable break, exact same breakdown as now. But I knew nothing about cars then. So the kid mechanic took me for a ride.

Anyway, back to 2013. The mechanics came, they didn't even look at the pedal, but directly went under the vehicle and then under the hood and removed the clutch cable. Then I had to wait another 30 minutes for them to get the correct replacement from a shop. Another 30 minutes later, the mechanic was done. But he wanted me to come to the workshop to tighten another bolt which needed a 19 size spanner. Then I told him I have a complete tool kit. Then he borrowed my spanner and finished the job.

This was the first time I was driving a XD3P equipped MM550 for an entire OTR. People had told me that it won't be as easy as CJ340, since the body is heavier and longer, with lesser ADR angles.

However, by the end of day one, all my doubts had been swept away. The MM550 had performed marvelously, it had conquered every obstacle in trail 2 and trail 3 in single attempt.

I don't want to discuss the OTR any further, that belongs to the OTR report.

So, here is the damage report:

1) The right side edge of the hardtop was damaged by a tree in a tight turn.
2) The two year old puncture in one of the tyre was leaking again. Got it patched today.
3) The front right leaf is damaged.

After parking the Jeep on Saturday, I never got the time to get back to it until today morning. I wanted to get the water service done.

When I moved the Jeep out of the basement to remove all the stuff from the back, I noticed that the Jeep was listing like a leaky boat.



The rear right tyre was fully flat, but that didn't explain this tilt. So I went around inspecting the suspension and found this.

The front right leaf spring.








The scene under the hood was completely muddy, thanks to the slush pit.



It finally got a 500 rupee bath, the cleaner even got on top of the hard top to do a thorough job.

[Jaggu]

Originally Posted by Samurai

Once I started climbing the 50kms long ghat road, things changed. It started heating faster, AC time reduced.
===============
So, I definitively have a heating problem. I am actually relieved. This heating problem is not because of the additional load of AC. That means, once I fix the heating problem, AC should be able run non-stop.
===================
Ok, but I better wait until the heating problem is solved. Right?

Problem is heating, factor causing the heating are 1) Less airflow due to additional grill in front 2) More load on engine due to compressor.

For 1) The fan compensates, but not enough for slow drives or hot summers. Also there should not be any gap left open "around" inbetween the two radiators. Typically OE arrangement will have foam packed around the edges. Now the best solution is to account for this lower air flow and add a larger radiator (fin area/core etc). This will take care of the issue 99%.

For 2) One is to separate area, second is to keep temp setting at min so that compressor cuts off faster.

And do plug the thermostat back.

FYI almost all gyspys fitted with AC goes through the same heating issue, and in gypsy upgrading to larger radiator is a more daunting task due to space constrains.

[svsantosh]

That shackle reversal should have given you a Nasty feedback in your steering/ride, surprised you caught it (so far) after returning home. It would have happened only in a trail (extreme arti) and no where on the roads.

Just as a good-to-practice habit, after exiting every trail I recomend check for leaks from oil sump, diffs, GB, shackle reversals, steering box loose (you need another person to play the wheel). Would be a safety habit, God forbid that front leaf broke on highway!

So, let me be the first to ask you - What was different (+ & -)'s from CJ days to this hardtop+ac jeep

[dhanushs]

Originally Posted by Samurai

3) The front right leaf is damaged.

Sharath, please beware about this. Its not so simple as it looks. It is not shackle reversal, but the reason for this damage is that the shackle/tyre has hit somewhere so hard that the entire set up is pushed backwards. This is why the leaf spring bent.

The main issue about this damage is that, the entire drivetrain is pushed backwards, and the only area that prevents the movement is the transfer case mounting on the long member.

Please remove and check for cracks and if possible re-inforce, or else, I'm sure it will give up someday. Mine had.. :(

That said: We had a wonderful time at the Bangalore OTR!