| Author |
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Randall Smith
| | Posted on Friday, January 03, 2003 - 06:52 pm: | 
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Trying to determine the true cause of exhaust valve fouling in the 4.0 V8 engine. My thought is that it is actually caused by the programing of the ECU(fuel injection computer). And that this bad program is isolated to certain markets, like North America. You can go to any LR dealer here in North Carolina(USA) and see Discoveries that "need a valve job". But I suspect that in some countries fouled exhaust valves is unheard of.
If you live outside of North America could you please relate experiences with exhuast valve fouling. Example: What country your 4.0 LR was shipped to, and wheather or not the engine stopped working because of exhaust valve problems.
Randall |
Ron
| | Posted on Friday, January 03, 2003 - 08:36 pm: |
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It is going to be really hard because the only 4.0 outside North America are either bosch disco IIs or range rovers. All series I discos had 3.9s in the rest of the world
Ron |
Randall Smith
| | Posted on Friday, January 03, 2003 - 09:02 pm: |
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Not to dispute your word, but it seems unlikely that LR made the the 4.0 and the GEMS fuel injection system exclusively for NA market for five years. This might require two seperate assembly plants. Surely thay would have sold the GEMS Discoverys in the UK if nowhere else.
I could probably create plenty of circumstantial evidence that the valve train of the 4.0 is not really at fault.
Randall |
John Moore (Jmoore)
| | Posted on Friday, January 03, 2003 - 09:05 pm: |
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Randall, I too have heard of your theory. I will watch this thread.
Surely the guys in the UK aren't watching the Fiesta Bowl.
-John |
Ron
| | Posted on Friday, January 03, 2003 - 09:08 pm: |
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Hey Randall I know I am right on this one. LR made the 4.0 for the 95 range rover when the US mandated OBD II for 96 LR decided it was cheaper to only use the one engine, the GEMS 4.0 rather than make the dizzy trucks OBD II compliant.
So the only other GEMS 4.0 trucks outside north america (not sure but I think Japan may have got 4.0s but it is such a small # of trucks) are 95-99 range rovers and a very few limited edition 98ish D90s.
Ron |
John Moore (Jmoore)
| | Posted on Friday, January 03, 2003 - 09:21 pm: |
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Though not as severe, don't NAS 3.9's also foul early? Other countries had the 3.9. |
Randall smith
| | Posted on Friday, January 03, 2003 - 10:03 pm: |
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Ron you are right(I went and checked after your post). The history of the Discovery is not my thing. 4.0 Discovery was exclusive to NA market. However the RR did have this GEMS system with the 4.0 from 95-98.
And it is unlikely that an a RR owner from overseas will respond to this thread. But a foreigner would surely have heard that RR with 4.0 have ex valve problems.
Which shows that my observation is correct. Only Americans are having this problem. There has to be an explination for this.
Every car engine made has valves and valve guides in them. They are just dumb pieces of metal cut to specific dimensions. Why doesn't someone just change the dimensions and sell parts that work correctly? How hard can it be to check the parts with a micrometer and bore gages?
The reason why your ex valves are fouling(I suspect) is the ECU is causing them to foul.
Randall |
Ron
| | Posted on Friday, January 03, 2003 - 10:16 pm: |
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"Why doesn't someone just change the dimensions and sell parts that work correctly? How hard can it be to check the parts with a micrometer and bore gages? "
LOL you are batting 500% now.
Randall, the latest and greatest fix is, get this, ream out the valve guides when doing a valve job, seems they are a bit tight (just to see I measured on a head and they are indeed a smidge too tight).
It is a bunch of factors, not just the ecu programing. And as far as any info on 4.0 ROW RRs there are very few of them out there so how would we know. Maybe a UK main dealer would know, but beyond that I doubt any enthusiast would have a clue.
Ron |
Todd W. McLain (Ganryu)
| | Posted on Saturday, January 04, 2003 - 06:23 am: |
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aahhhhhhheeeeemmmm .... not to disagree with everybody (actually Ron is correct), but I have a late model (read November) '95 Disco with the 4.0 and have had no carbon fouling problems.
Todd, in Japan |
Randall Smith
| | Posted on Saturday, January 04, 2003 - 10:49 am: |
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Not sure by reading the post, but Todd may have a 7 year old 4.0 with no problems.
Look at it this way: There is probably no significant difference between the ex valve stems/guides in the 4.0 and the ex valve stem/guides that are in any other car engine. These dimensions could be easily measured, and any LR parts vendor could easily supply correctly dimensioned parts.
It is interesting that this problem coincided with the introduction of the 4.0, and allegedly continues with the latest models. But you could also say that the problem started with the introduction of the GEMS fuel injection system.
The CUX and the GEMS are probably licensed technology purchased from Bosch. And once Lucas got there hands on this system, someone at LR introduced a few faults into the programing of the ECU. So now you are dealing with a wheel barrel load of Lucas electronics, featuring a Lucas programmed computer at it's core.
I personally feel that Lucas is a name brand that I trust more than most off-brand auto electronics. But this ECU program about 1000 times more suspect to me than valve stems.
Maybe I'll call some of the LR dealers in the UK. Wonder how their Parts & Service departments compare to American.
Randall |
Dean Chrismon (Chrismonda)
| | Posted on Saturday, January 04, 2003 - 02:35 pm: |
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Randall what part of NC are you from? I had put a post several months ago about having to replace my valves. It all started by my accelerating onto I-40 when it started missing. I brought it to LR Cary and the tech knew what it was before he even did a compression test. Later that week after selling a kidney to pay for the work. He told me that this problem is very common on these engines. If you find out anything let me know because in my opinion this should be a recall.
lndrvr72@earthlink.net |
streak
| | Posted on Saturday, January 04, 2003 - 03:47 pm: |
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In South Africa the 4.0 V8 only came out in the Disco II about 3 1/2 years ago. Before that it was the 3.9 V8. The Range Rover came out with both the 4.0 and 4.6 before the Disco II was launched.
As you know there are lists upon lists of problems with both the Di and DII but AFAIK valve problems were not one of them.
Also, up until recently we could only get leaded fuel 93 octane inland and 98 octane at the coast. Over the last 4 or 5 years unleaded has become available lower in octane at first but now up to 93.
Having said this the Disco II has no Oxygen sensor and a fake catalytic converter filled with bakelite. The DII here can thus accomodate both leaded and unleaded fuel which is necessary when travelling in neighboring countries.
The leaded fuel destroys the expensive platinum sparg plugs very quickly.
Hope this helps and may give you some clues as to the valve problems in NA.
www.worst4x4.freeservers.com |
Carter Simcoe (Carter)
| | Posted on Saturday, January 04, 2003 - 04:52 pm: |
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I think Kyle, Ho, or Axle should make a big string of these: •••••• come up everytime this: "www.worst4x4.freeservers.com" is typed. What a waste. |
Randall Smith
| | Posted on Saturday, January 04, 2003 - 05:17 pm: |
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Dean: I live and work 3 miles from LR Cary. Might go by there this week and ask them if they ever reprogram the GEMS computers. There may be a $ motive in not recalling and rechipping. More money to be made in a routine head job.
Isn't the internet cool!! Sometime in the past I think I went after Streak in S.A. like a mama bear defending her cubs. Now he is telling me just what I suspected. That plenty of 4.0s have been shipped around the world with ECU programs that do not cause the ex valves to foul. I'm certain Streak would tell the whole world if this was happening in S.A. too.
Randall |
Alex Moore (Alexmoore)
| | Posted on Saturday, January 04, 2003 - 10:06 pm: |
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I just replaced an exhaust valve in a '97 disco but because the stem began galling in the guide and would hang up once warmed up, not cold.
Learned alot though with talking to the extended warranty folks. They definetly did not want to pay if it had carbon build up on valves. There is indeed a problem with the valves sticking due to carbon build up and should be taken care of with a "MotorVac" service. Worse case scenario is remove intake, loosen rocker bars and chip it off!!
The thought I had after reading the thread is perhaps the environmentalists or ??? have forced the inclusion or exclusion of some sort of additive in U.S. fuels!?!? What is it....MTBE? Could that be it?
Alex |
Ron
| | Posted on Saturday, January 04, 2003 - 10:50 pm: |
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Well I have a July 95, 4.0 96 disco with no valve problems ever and I am in the US. There is no way to get enough data to be signifigent.
Also based on my informal impression, in the US, 4.0 RRs are no where near as prone to valve issues as 4.0 discos (why I dunno).
I am fairly sure there was some updated GEMS programing available. I am kinda vague but I think it was just proms, but I could be mistaken.
In no way let me disuade you from your quest Randall, keep at it!
Ron |
Jaco de Klerk (Biltongvreter)
| | Posted on Sunday, January 05, 2003 - 06:50 am: |
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I read this with interest as non-US discoteers appears to be 'in demand' today. :-)
Streak explained the SA situation. Can add that to date I've not heard of Disco exhaust valve fouling in South Africa.
Jaco
'97 Disco 3.9L V8 ES |
OLIVER CLOTHSOFF (Everythingleaks)
| | Posted on Monday, January 06, 2003 - 10:58 pm: |
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The current fix is shorter valve guides and black nitrile valves. This is the fix Ford currently uses in the new reman exchange program at the dealerships.
Another thing that is different between 14CUX, GEMS, and Bosch is the cam profile. |
streak
| | Posted on Thursday, January 16, 2003 - 06:56 am: |
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Randall,
One more point I just remembered.
There are 2 4.0 engines, a low and a high compression.
We get the low compression unit here in South Africa. This coupled with the other factors in my earlier post may give you some answers.
www.worst4x4.freeservers.com |
Paul Long
| | Posted on Thursday, January 16, 2003 - 08:25 am: |
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Oliver,
I think you mean black nitriTe coated. Black nitrile is a synthetic rubber. Nitrite has been used in racing applications and carbon simply doesn't stick to them. Also improves heat transfer. I was told by the dealership (about a year ago) that my 99 DII should have the new style "carbon cutter valves", and in the same breath they said it didn't always cure the problem. Maybe they have changed to the new coated ones since then? Any idea when Ford introduced this type, and if replacement valves sold over the counter are the coated version? That sounds like the best fix so far. I would assume they would go to them in the latest production to eleviate the problem entirely. I couldn't bring myself to tear mine down just to ream the guides and wire wheel the valves for fear it would happen again. The replacement with these valves would make it worthwile.
I worked at a Subaru dealership back in the late 70's and we replaced valves with sodium filled to improve heat transfer in tons of vehicles under a service action. A recall is safety related, but when enough complaints are registered about a product, a "service action" was instituted by mfg. to cure the problem. Could be a matter of time that LR has to do something about it. Can't someone with big bucks get a law suit going? Everone stateside sues for a lot less than a $2,500 valve job! With some mfg. boasting no tune ups for the first 100,000 mi. I wouldn't think the public would put up with a vehicle that requires major head work at HALF that mileage. Thanks for the insight. |
OLIVER CLOTHSOFF (Everythingleaks)
| | Posted on Thursday, January 16, 2003 - 08:34 pm: |
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Nitrite, nitrile - whatever it takes.
The new nitrite valves were introduced about 7-8 months ago. If you have a good machine shop they could probably just shorten the current guide you have. We had a machine shop that was cutting the guides down years before LR started this and it prolonged the time between valve jobs. The "carbon clutter" valves did not work and actually seemed to make them stick sooner ( did one set at 6740 miles )
If you don't want to do the machine work LR currently has a remanufacturing program (Fords FQR) which offers the updates. I personally think their machine work sucks and have had problems with 2 sets of their heads so far but it would have a 12/12 warranty on the part. Just a thought. |
Ron
| | Posted on Thursday, January 16, 2003 - 08:53 pm: |
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And the new valves are expensive. $50 a pop retail.
FWIW
Ron |
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