[Sudarshan]

Originally Posted by Samurai

Thanks for the info.

Ahh nope , as you have mentioned its a family sort of vehicle , so for safety concern --- otherwise its learn & let learn for me .

But this Jeep was recently rebuilt by Vivek (papaboost), so I can safely assume U Bolts to be of good quality.

That does not make a difference , base Workshop prepared vehicles do fail after they get hit . Even OE parts fail in such conditions .

Still, I told the mech to inspect them when he takes them off. Also, I told him to look for anything wrong underneath and fix it.

Certainly a good thing .

We offroaders don't give our Jeeps to just any street side mech, but to mechanics who are used to fixing offroad vehicles. The Bangalore Mechanic I am using right now is known and trusted by all the senior offroad Jeepers in Bangalore. So when I told him to look for anything wrong, he knows what damages to look for.

OK , I mean I cant debate this .

As I said before I know that assessing damage visually can be misleading , I had this particular problem with one of my BIL's ( ohh they are too many & thats a long story ) Jeep & know what happens next , so interrupted you .

Sudarshan

[Samurai]

Originally Posted by Samurai

Meanwhile I am intrigued about this part. I see no nut, how does it stay on the pin without slipping. Just by the outward tension of the U shaped bar?

Originally Posted by Jaggu

There would be a nut or bolt that holds the link in place. Must have sheared off and that's why you don't see it.

Originally Posted by Samurai

There is no nut. If you look at the other side, there is no nut. And there is no groove for a nut.

Finally I got my answer when I got the Jeep back from the Workshop. There should have been a pin, and I had lost them on both sides.

Bad photo, thanks to the mobile phone.



Both main leafs were replaced, sway bar bushes were replaced, pins were put, upper water hose replaced since it was looking bad. The bill came to Rs.2470/-

[genesis]

Originally Posted by Samurai

Finally I got my answer when I got the Jeep back from the Workshop. There should have been a pin, and I had lost them on both sides.

Bad photo, thanks to the mobile phone.

Attachment 1045978

Both main leafs were replaced, sway bar bushes were replaced, pins were put, upper water hose replaced since it was looking bad. The bill came to Rs.2470/-

(best hummed to the tune of a certain tv commercial)

We live young...We live chained...
To the mechanic.
We are the jeepers!

[DHABHAR.BEHRAM]

Dear Sharath - please look at the photograph in your post 135 on page 9. You will have to replace the U bolts / nuts as you can see nonsecical nuts fitted all over the place, one nut over the other etc. One of the U bolts is bent also. This is nothing new, it clearly indicates uncontrolled activity. Please also replace the leaf springs as a set. As the front right shackle had reversed, its bush would be badly damaged, so replace shackles also as a set. Please try and procure the original silent block bushes with shackle plates, they will work well. Please ensure to use correct size split pins on the stabilizer bar mountings otherwise they will break again. This joint had a nut, pin was introduced as part of some silly cost reduction exercise in Kandivli in 1995. Bend the ends in opposite directions against the washer face. If correct pins are fitted properly, they will not break.

Only for your information - one of my engineers here in Pune has an MM540, it had very bad death wobble, the Jeep was practically undrivable! When we opened it, we found some idiotic brass spacers in place of the kingpin bearings! The brakes would pull the vehicle 45 degrees off its line, I am dead serious, that's how bad it was! The springs inside the wheel cylinders on one side were missing! The gears would not shift, half a liter of something resembling oil came out. The steering gear box was bone dry! The whole vehicle defied my rationality. It took a herculean effort to sort out but now the same vehicle does Pune / Nasik in just under 4 hours (205 kms). We have systematically done what is correct, so it works. These things happen, mechanics are like that only, this is your second experience, so welcome to the club once again!

Best regards,

Behram Dhabhar

[Jerrycan]

Originally Posted by dhanushs

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!

Originally Posted by dhanushs

I think, with the main leaf bent that way, you cannot just knock the shackle down.

btw, please do check for damages of the transfer case mounting to the chassis.

The star and Yoke on the Front wheel drive universal joint will compensate for the drive train being pushed backwards, if that's what you meant. Usually the star and yoke on the front wheel joint can slide up to 4 inches (100mm) to compensate for the articulation of the leaf spring. In fact the bend on the leaf has acted as a crumple zone. Even a slight change in alignment of the drive from the TC to the front Pumpkin would be noticeable.
My thoughts, Gurus may be decisive.

[svsantosh]

Dear Behram Sir,

I have a question for you regd the kingpin bearing/bushes. I assume all the old jeeps till somewhere in late 80's came with top and bottom bearings with shims for adjustments? Right?

From which year onwards did the top bearing was replaced by a polyurethane bush? My AG has one with a OE part# on it, i had a pic in my thread IIRC of it. If you agree it was a OE part, why was it introduced?

From your field experience, when did the market start using the brass bushes? What do you think or learn from the users of the necessity of these widely used UNIPAK brand brass bushes?

In my CJ, at some point of time, I used this bush IIRC at the top (top used to fail due to jumps, tyres, -ve offset rims, etc etc). Currently in my Armada Grand, the current setup is top has the unique Poly bush on top and I replaced the bottom bearing with this brass bush (my necessity was to increase steering feedback) I felt the stock steering was over-servo-ed and I hardly had any control. I needed to make it a bit tighter and the results for me are satisfactory.

[svsantosh]

Samu - Just for your reference, this is how the base plate on my AG looks, front right, thread type.

[ex670c]

Originally Posted by Sutripta

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

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.

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

Originally Posted by 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).

Hi Sutripta,

How about looking at the cooling system as

1) In an engine assy with Radiator and with out Thermostat the water cools the engine down.

or

2) In an engine assy with radiator and with a thermostat, the water heats up the engine and the Radiator cools the water down so as not to overheat the engine.

I have blown the head gasket of my XD3P twice, both instance the compression leaked into the water jacket and superheated the water.

June-July 2009 without thermostat in summer, and water, in an OEM 3 core Radiator

April-July2010 without thermostat in summer, with coolant + water mixture, in a Custom 4 core Radiator.

Post 2007, I used to remove the thermostat, in summer (Palar Challenge Recce's) and fit it back around August-Sept.

Since 2010 October,I'm running the Thermostat through summer & cooler months.

A Thermostat prevent Flash Heating and Hotspots because it allows the engine head and block to reach optimum operating temp i.e 80Degrees.(Peugeot XDP4.9/XD3P). But the Thermostat Valve opens at 68Degrees (Printed on the Thermostat).

This is achieved because the the coolant/water first circulates in the block and head, heating up the engine and then thermostat to allow maximum flow into the radiator, thereby cooling the water. A small amount is allowed to Bypass the Thermostat, to prevent pressure and heat build up in the water pump.

http://carsite.lk/2011/10/how-car-co...do-we-need-it/

http://www.youtube.com/watch?feature...hTOQD3VDI&NR=1

Regards,

Arka

PS - Please make necessary corrections. How about a new thread on cooling systems?

[Sutripta]

Originally Posted by ex670c

I have blown the head gasket of my XD3P twice, both instance the compression leaked into the water jacket and superheated the water.

June-July 2009 without thermostat in summer, and water, in an OEM 3 core Radiator

April-July2010 without thermostat in summer, with coolant + water mixture, in a Custom 4 core Radiator.

Post 2007, I used to remove the thermostat, in summer (Palar Challenge Recce's) and fit it back around August-Sept.

Since 2010 October,I'm running the Thermostat through summer & cooler months.

Relevance?

http://carsite.lk/2011/10/how-car-co...do-we-need-it/

http://www.Youtube.com/watch?feature...hTOQD3VDI&NR=1

Once again, really elementary stuff, and I would think entirely irrelevant to our current discussion.
BTW, did you check out reverse flow cooling systems, and counter flow heat exchangers?

Originally Posted by ex670c

How about looking at the cooling system as

1) In an engine assy with Radiator and with out Thermostat the water cools the engine down.
OK
or

2) In an engine assy with radiator and with a thermostat, the water heats up the engine and the Radiator cools the water down so as not to overheat the engine.
And what heats the water?

When the thermostat has opened, it has no further role to play. It might as well not be there anymore. As such, that case can be ignored.

Thermostat closed case:
In the initial warmup phase (ie cold engine), as I have said, if there is a proper bypass, temp distribution across the engine will be more even. Should we worry about 'hotspots' in a cold engine? For arguments sake assume that there is a hot spot. Are we to assume that cold(er) water from the radiator will not cool it down, but hot(ter) water recirculating in the engine will?

Regards
Sutripta

[ex670c]

Originally Posted by Sutripta

Relevance?

When the thermostat has opened, it has no further role to play. It might as well not be there anymore. As such, that case can be ignored.

Thermostat closed case:
In the initial warmup phase (ie cold engine), as I have said, if there is a proper bypass, temp distribution across the engine will be more even. Should we worry about 'hotspots' in a cold engine? For arguments sake assume that there is a hot spot. Are we to assume that cold(er) water from the radiator will not cool it down, but hot(ter) water recirculating in the engine will?

Hi Sutripta,

I don't know the relevance just that I have blown the head gasket twice, in summers, without the thermostat, and 3 summers while running the thermostat, no damage or overheating affected problem have occurred.

Why do you think the head gasket blew in my case or in the case of most M&M XDP4.9 & XD3P engines.

In a Cooling system there can be 3 flow rates.

1) No Thermostat - Maximum Flow

2) Thermostat Closed =Bypass Circuit Minimum Flow

3) Thermostat Open - Average Flow (because even with the Thermostat open the aperture is reduced with the thermostat body, hence it will not be as much as a system without a thermostat.

Regards,

Arka

PS - Will read up on cross flow and reverse flow system when I get a bit free,

[Samurai]

Since the purchase of the Jeep, I have been experiencing sticky accelerator once in a while. When I let go the A-pedal, it doesn't come back sometimes, for a second or two. While changing gears, the Jeep howls loudly if this happens. So I have been wondering whether I should get the accelerator cable changed.

But today I was able to do a thorough diagnosis and have decided against any cable change.

As the accelerator got sticky again, I quickly pulled my foot back and looked at the A-pedal. And this is what I saw:



Now I am looking for a thick foot mat that doesn't fold.

[Sutripta]

Originally Posted by ex670c

Hi Sutripta,

I don't know the relevance just that I have blown the head gasket twice, in summers, without the thermostat, and 3 summers while running the thermostat, no damage or overheating affected problem have occurred.

Why do you think the head gasket blew in my case or in the case of most M&M XDP4.9 & XD3P engines.

I wouldn't give the thermostat magical powers.
As to why, no idea!

In a Cooling system there can be 3 flow rates.

1) No Thermostat - Maximum Flow

2) Thermostat Closed =Bypass Circuit Minimum Flow

3) Thermostat Open - Average Flow (because even with the Thermostat open the aperture is reduced with the thermostat body, hence it will not be as much as a system without a thermostat.

I don't think there is much of a difference in flow between thermostat open, and no thermostat.

Case 2. In case there is a bypass, more than the flow, the circuit is different.

Regards
Sutripta

[DHABHAR.BEHRAM]

Dear Arka / Sutripta - your cooling system comments clearly make out a case for equipping the vehicle with a degassing tank. I would also like to have a separate thread on cooling systems architecture. Kindly start the same in the technical section.

Best regards,

Behram Dhabhar

[Sutripta]

Originally Posted by DHABHAR.BEHRAM

I would also like to have a separate thread on cooling systems architecture. Kindly start the same in the technical section.

Sir, I think you are the best person to kickstart such a thread/ tutorial. Would benefit all of us.

Regards
Sutripta

[Samurai]

Had a Founder's Day offroad meet today in Udupi: http://www.team-bhp.com/forum/team-b...ml#post3037764