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A. W.
| | Posted on Sunday, April 21, 2002 - 07:16 pm: | 
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Hi Everyone, I was wondering if someone can help me with a spark plugs question. I have a 95 disco 3.9 v8i, and I had an outside mechanic take the engine apart to fix a problem, and he's in the final stage of putting it back together. He has a small problem though, he can't figure out the correct order for reinstalling the spark plugs because the sheet by the engine that tells you how to do it is torn. He told me that he believes the correct organization is 15 36 42 78 and he asked me to check if I could. Anyone knows for sure? Thanks much. |
JMcD
| | Posted on Sunday, April 21, 2002 - 08:31 pm: |
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Reinstalling the spark plugs? Do you mean the firing order?
I would worry about a mechanic who 'took apart' your engine but does not know the firing order. Scary. Could you clarify a little?
JMcD |
A. W.
| | Posted on Sunday, April 21, 2002 - 09:06 pm: |
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I know JMcD! But it's a little too late now to change mechanics, he already finished almost everything. It could be the firing order, is this the only thing that makes sense when talking about "Spark plugs organization or division"? If so, does anyone know the correct firing order?
Thanks. |
A. W.
| | Posted on Sunday, April 21, 2002 - 10:48 pm: |
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Hi, I found this info on a Land Rover Website, it says that all LR V8 engines (Discovery and Range rover) firing order is: 1, 8, 4, 3, 6, 5, 7, 2
Cylinders 1, 3, 5, 7 - LH side of engine
Cylinders 2, 4, 6, 8 - RH side of engine
Does this sound right? URL is
http://www.landrover.inc.pl/4x4xfunEnglish/techdata/V8ENGINEDATA.html
Thanks. |
Steve H
| | Posted on Sunday, April 21, 2002 - 10:57 pm: |
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Ask your mechanic where he/she got the torque values for the heads, mains, rod caps etc.. not to mention things like ring gap,and bearing clearance. I would think that the firing order would be in the same reference. Like JMcD said, scary! |
Norm
| | Posted on Monday, April 22, 2002 - 12:40 am: |
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AW --
You had the motor that was making a loud ticking sound, right? What did your mechanic say was the culprit?
If he's had the heads off, make sure he uses new head bolts on reassembly.
---Norm |
A. W.
| | Posted on Monday, April 22, 2002 - 01:35 am: |
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Thanks for the help guys, I will check these things out. Norm, the mechanic said that the oil pump went bad reducing the oil flow considerably. That in turn damaged a metal part (I forgot its name) so we had to replace that metal part with a new one, as well as the oil pump.
P.S. Why do we HAVE to use new head bolts on reassembly, just wondering. |
PerroneFord
| | Posted on Monday, April 22, 2002 - 02:04 am: |
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The bolts are designed to stretch as they are brought to proper torque. Unfortunately, they only do that once. So if you try to reuse them and torque them down again, they won't stretch the proper amount giving an improper fit.
Use new head bolts.
-P |
A. W.
| | Posted on Monday, April 22, 2002 - 02:43 am: |
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Thanks man. |
Norm
| | Posted on Monday, April 22, 2002 - 03:40 am: |
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AW-
Does your motor have a serpentine belt and is there a "B" at the end of your engine serial number? If so, assuming the oil pump was the cause of your problems, your mechanic should be replacing the entire front cover/oil pump assembly (@ $350 for the part) as LR does not recommend trying to rebuild these.
If I were you, I'd invest in a factory service manual as well as a factory OVERHAUL manual, which is a lot harder to find (I got one from the 4x4 Connection). Your mechanic should be checking the specs of all the components he's tearing down -- that's where the factory manuals are essential. This is particularly important since you say the motor has been overheated in addition to the oil pump failure.
You should also check the RPi website, especially the section on V8 problems -- very informative. Pay particular attention to priming the oil pump the first time the motor is started.
Find out what parts your mechanic is replacing -- rocker arms, cam bearings, whatever. I've been through this before so I think I can help.
Good Luck!!!
---Norm |
doug james (Dgj95lwb)
| | Posted on Monday, April 22, 2002 - 04:01 pm: |
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You need to have him remove the oil pan-sump-and clean/confirm that pan's clean. The tube attaches to the pump so that will be fine. But the'grunge' in the pan you do not want going back thru your new bits. The other comments on this thread are good as well. cheers- doug, recent oil pan and gasket man. |
PerroneFord
| | Posted on Monday, April 22, 2002 - 04:08 pm: |
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Hey Doug,
Did you actually use an oil pan gasket or did you use RTV/Right Stuff?
I did mine 2 weekends ago and used the RTV. So far its working well.
-P |
doug james (Dgj95lwb)
| | Posted on Monday, April 22, 2002 - 05:10 pm: |
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P:
Kinda ol' fashioned on this one. Like the old 80-90 v. new school, I did the cork gasket. doug |
A. W.
| | Posted on Monday, April 22, 2002 - 06:26 pm: |
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Thanks again for your input guys. I talked to the mechanic today about everything mentioned in the above posts and he assured me that he applied all the correct settings, he was only missing the firing order. He also cleaned everything in the engine thouroughly, including the oil pan, primed the oip pump (as Norm mentioned). He told me though that he didn't change the head bolts because he thinks that they fit well and that their torque setting was going to be alright. After this talk, he was ready to start the car for me for the first time since I took it to him, and I must say the engine sounded very good. I will actually take it home in a couple of days, I will let you know then how it turns out. Thanks again for all your support. |
muskyman
| | Posted on Monday, April 22, 2002 - 07:04 pm: |
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AW
if he reused the same head bolts he should check the torque on them and retorque them if they dont stay in spec after 100 to 500 miles also replacing them if they dont hold the torque
the problem is that on aluminum motors you often dont get a chance to retorque them
they just blow the head gasket puke coolent into everything and your back at square one...in need of a rebuild
but that will be on his nickle if he's any kind of mechanic |
Norm
| | Posted on Monday, April 22, 2002 - 07:39 pm: |
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AW -- new head bolts don't cost that much and they're probably in stock at your local dealer (or can be Fed Exed from Atlantic British if necessary). By the time this truck has been driven a few hundred miles and he removes the valve covers (along with the plenum chamber on the right hand side) re-torques the old bolts and replaces any bad ones he'll have spent 10 times the time and expense of putting new ones on in the first place. If he has any bad ones at all, he'll probably have to take them all out and start over -- by that time damage to the heads will probably have been done. Reusing old head bolts is false economy and the mark of a mechanic too lazy to get on the phone and order new ones. It pays to get critical (and relatively inexpensive) parts like headbolts new instead of having a mechanic eye ball old parts. The problem is (on top of everything else) if one or more of the head bolts is faulty you may end up warping your fragile aluminum heads and you may end up with even more problems than you started out with.
Good Luck!!!
---Norm |
A. W.
| | Posted on Monday, April 22, 2002 - 07:41 pm: |
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Thanks for your concern Muskyman, I will definitely check into that. |
A. W.
| | Posted on Monday, April 22, 2002 - 10:02 pm: |
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Norm, thanks much for your detailed explanation. I will call the mechanic and ask him to install new ones, I appreciate it. |
Norm
| | Posted on Tuesday, April 23, 2002 - 12:16 am: |
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AW --
Make sure you get the correct head bolts -- there are head bolts for the early 3.9 (total of 14 for each head) and there are head bolts for the later 3.9 "B" suffix motor (total of 10 for each head) and they are not interchangeable. As memory serves, the "B" motor came on mid-year '95 Discoveries.
Check your engine serial number, which is located on the left side cylinder bank (as you're sitting in the truck) in the middle just below the cylinder head and behind the exhaust manifold. If you have a "B" at the end of your serial number, you have a "B" suffix engine.
Also, the 3.9 and 3.9 "B" motors use different head gaskets, among other things, so it's important to get the right parts. The factory OVERHAUL manual which covers all LR V8s (as opposed to the Discovery service manual) has all this information in detail.
---Norm |
A. W.
| | Posted on Tuesday, April 23, 2002 - 12:33 am: |
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Norm, thanks much, you're really a wealth of information. |
A. W.
| | Posted on Tuesday, April 23, 2002 - 01:32 am: |
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Hi again, this is for Norm or anyone familiar with differences between the regular 3.9 and the 3.9B engines. You mentioned in your last post that the head gaskets are different in the 2 models. How different are they? Is it in thickness?
I'm asking this because I bought the gaskets from the dealer and when I compared the new gaskets with the old ones in the car, the newer ones were a bit thinner, did I buy the wrong gaskets? Thanks. |
A. W.
| | Posted on Tuesday, April 23, 2002 - 01:40 am: |
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I was also wondering if the B model's head bolts were the newer "Torque-to-Yield Head Bolts" or the conventional type bolts. I wanna buy the correct bolts this time! How confusing. In times like these I wish I had the factory manual, I think I'm gonna get one soon. |
Ron
| | Posted on Tuesday, April 23, 2002 - 02:23 am: |
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Just relax. They are scaring you.
There are two types of head gaskets. Composite and metal. metal is earlier. Heads and bolts are determined by gasket type.
The bolts can be reused ONCE without much chance of issue, especially on the earlier ones. YOu should replace them but you do not have to.
You either trust your mechanic or not.
Ron |
A.W. (A_W_Disco)
| | Posted on Tuesday, April 23, 2002 - 02:57 am: |
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Thanks Ron. I did some research on the Net and found out that only the newer 3.9 "B" engine uses the "Torque-to-Yield Head Bolts". The gasket issue is still unresolved so far though, I bought the metal type by the way, could this be why it's thinner? |
Ron
| | Posted on Tuesday, April 23, 2002 - 03:15 am: |
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Is your old one black and has little metal rings around the holes? Is so that is composite and you would need a new composite gasket.
If your old one is metal and the one you bought is metal then it is fine.
Ron |
A.W. (A_W_Disco)
| | Posted on Tuesday, April 23, 2002 - 03:28 am: |
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Ron, The old gasket was composite but I bought the metal type. My mechanic said that they are pretty much the same. Is it going to be a problem? Thanks again. |
Ron
| | Posted on Tuesday, April 23, 2002 - 05:01 am: |
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YES!!!!
You need to go buy the composite type. Also given that you have the composite type I would buy new head bolts as they are not reuseable
If it has already been put back together with the metal gaskets you will have three major issues.
1. The compression will be boosted (enough to be bad I dunno)
2. The metal type was not designed to work with the head bolts used on the composite type as the metal type uses an extra row of head bolts.
3. Metal gaskets suck, they are more prone to blowing than composite
Ron
You know people knock dealers but there is no way a dealer would do something like this. |
PerroneFord
| | Posted on Tuesday, April 23, 2002 - 09:31 am: |
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Ron,
I've got to agree there. This guys sounds like a real hack. The dealer would have been more money, but these are the kinds of mistakes that can costs thousands of dollars down the road...
-P |
Kingfish (Kingfish)
| | Posted on Tuesday, April 23, 2002 - 11:29 am: |
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I think all this advice is a little late for AW.(His car is already running) A "hack" mechanic, as Perrone put it, would probably swear everythings peachy in order to avoid spending hours on something he already did. AW, did your mechanic say he would put in the new gasket and bolts? If so, great! Also, using new headbolts is very much the standard way. It goes without say. You should avoid that guy next time you need some work. |
Norm
| | Posted on Tuesday, April 23, 2002 - 02:09 pm: |
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Gosh, Ron, and you were accusing ME of trying to scare AW? This from a guy who drives around with his right hand on the emergency brake at all times??? LOL
AW, get your engine serial #, determine if its a "B" suffix or not and order parts according to the serial #. In fact, give me your whole engine serial # -- if this is a used truck, you never know if they might have stuck an old Range Rover motor in there.
What exactly has your mechanic replaced? Did he do anything with the oil pump?
If you have your parts invoices, you may be able to determine if he has the right parts in there or not for your engine serial # from the dealer.
Get yourself the service manual and especially the overhaul manual ASAP and read it yourself (it's not that long) and make sure your mechanic reads it and understands it, especially all the warnings and cautions.
---Norm |
A.W. (A_W_Disco)
| | Posted on Tuesday, April 23, 2002 - 07:33 pm: |
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Hi Norm, I think Ron was joking when he said you were scaring me  Anyway, I believe my engine is the newer 1995 engine because each gasket requires only 10 bolts not 14 (the older engine required 14 bolts per gasket). The metal gasket I installed by the way requires only 10 also.
As far as the serial # is concerned, I found a number at the location you described and it ends with the letter 'C' not 'B'. And no he didn't give me any invoices, but he did give me a warranty on his work. Anyway, I will let you know how the engine is doing in a couple of weeks, thanks. |
Norm
| | Posted on Tuesday, April 23, 2002 - 11:46 pm: |
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A "C", huh? Now that's weird. I am assuming you have a North American market Discovery?
As far as I can tell, there were never any "C" suffix factory 3.9s, at least not in the US. It may be that you have a rebuilt motor or a new replacement that came from an aftermarket supplier who stamped on their own serial #. If you have the original '95 motor in there, it should show the compression ratio above the serial number (9.35:1) and the serial # should start with either a "35D" (for a 5-speed) or a "36D" (for an automatic) -- although some suppliers like RPi use the same serial # prefixes as LR. Just proves you can't take anything for granted on a Rover V8!!!
Anyway, if still possible, while your heads are torn down you should make sure you have the newer "carbon break" exhaust valves in there -- they are identified by a notch around the lower end of the valve stem that's designed to prevent sticking. If you don't already have them, now would be an excellent opportunity to have them installed. Also, this would be an excellent opportunity to put in a new thermostat and change out the coolant hoses.
---Norm |
A.W. (A_W_Disco)
| | Posted on Thursday, April 25, 2002 - 01:40 am: |
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Norm I had no idea that US discos are different than overseas ones (unless it's a diesel one of course). I'm not in the US, so that should clear the confusion. After your last post I contacted the dealer and he told me that the US models are built to different enviromental standards, but that for the most part they are the same. One notable difference though is the lack of Oxygen sensors in my disco. So that explains the 'C' suffix I guess. Anyway, I did drive the car for the first time today and it drives like a dream again, I hope it stays this way. Thanks. |
weespeed
| | Posted on Thursday, April 25, 2002 - 04:35 am: |
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Don't worry about the head gasket. I build race motors for a living, and composite gaskets suck, they blow alot. The only time I have ever seen a metal gasket blow, was when we were boosting 30+ lbs of boost and the head lifted, becuase the factory head bolts couldn't take it. Composite gaskets on the other hand, any excessive kind of heat and pressure can cause them to blow. Metal ones if used correcty (making sure the block and heads are flat using a laser cut straight edge is how I check our motors) are very strong..there is a reason, why many if not all automotive manufacturers went to metal gaskets on newer cars and did away with composite gaskets. And I'm sure Land Rover did the same if you ordered a new gasket and it is metal instead of composite. |
A.W. (A_W_Disco)
| | Posted on Thursday, April 25, 2002 - 08:32 pm: |
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Thanks man, I feel better now |
Ron
| | Posted on Friday, April 26, 2002 - 02:12 am: |
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Sorry I have been late in responding.
It is hard to say for sure what you have, but so long as the metal gaskets were made for a 10 bolt head I think you should be ok. I have never heard of such a thing but who knows.
The compression boost will not be that much from a thinner gasket. While weespeed I am sure is telling the truth, the composite gaskets are much more forgiving than the metal ones. Any slight warpage will blow a metal gasket. If it runs and continues to do so then good.
You have no O2 sensors? That can't be right. No cats was possible (not sure about a 3.9 disco but a 3.5 disco for sure). anywho
Ron |
A.W. (A_W_Disco)
| | Posted on Friday, April 26, 2002 - 07:01 pm: |
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Hi Ron, I guess since everything is installed, I can only wait and see how the car will act, so far it's pretty good, I hope it stays this way, thanks. |
Norm
| | Posted on Saturday, April 27, 2002 - 03:25 am: |
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AW --
Sounds like your mechanic probably got it right -- unlike my first one (who will remain unnamed, lest he be found floating down the river face down).
Did your guy ever replace the oil pump? If he didn't, I sure hope he did a pressure test when he finished repairs, especially since he said it was having problems in that area -- should be making 40 psi at 2500 rpm.
Anyway, make sure you keep your oil & coolant levels up. I check mine at every fill up.
Good Luck!!! Out of curiosity -- where are you located?
---Norm |
PerroneFord
| | Posted on Saturday, April 27, 2002 - 10:39 am: |
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40psi@2500 rpm?? Where did you get that figure? Mine is never that high and my factory manual (3.9l) doesn't indicate that it should ever get that high. Generally 10psi per 1000 rpm is the norm with pressure between 12-20 psi at idle.
-P |
Norm
| | Posted on Saturday, April 27, 2002 - 01:24 pm: |
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This from the 1995 Discovery factory Workshop manual, Section 12. ENGINE, V8i subsection, FAULT DIAGNOSIS, Page 1, "Engine Oil Pressure Test" Item 7, and I quote:
"At a steady engine speed of 2500 rev/min - engine oil pressure reading should be - 2.75 bar (40 lbf/in2)."
This is for a "B" suffix 3.9 with the oil pump/front cover, whether or not that makes any difference.
---Norm |
PerroneFord
| | Posted on Saturday, April 27, 2002 - 01:34 pm: |
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Damn,
I was thinking about this today as I drove in to my office. My low idle oil pressure is overing around 24psi. At 2500 rpm, I am seeing about 35psi. When I ran 10w-40 I never saw anything near that high. Before I dropped the oil pan a couple weeks ago, I was seeing 12-15 psi at idle.
I'd like to see what others are getting for oil pressure. I know some of the D90 guys have oil pressure gauges and when I installed mine last year they told me my pressures were quite similar to what they were seeing. I wonder what's different about your motors... Is the oil pump changed or something between the new block and the old block (and yes I realize you said 3.9B).
-P |
Norm
| | Posted on Saturday, April 27, 2002 - 02:58 pm: |
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As far as I can tell, the major differences between the 3.9 and the 3.9 "B" is that the "B" has a different oil pump -- integral with the front cover -- and has the 10 bolt heads. Both motors use a distributor, the "B" uses a 14CUX ECU, not sure about the old 3.9. There are some other internal differences -- like the "B" has a camshaft thrust plate to eliminate cam walk -- that are noted in the overhaul manual. Seems like I read somewhere that the "B" block has bigger cooling galleries. Other than that, the two motors seem to be essentially the same.
My old 3.9B was making about 40 - 42 psi at 2500 rpm, even when it was getting noisy. Have never tested the 4.6.
---Norm |
PerroneFord
| | Posted on Saturday, April 27, 2002 - 03:42 pm: |
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Terrific info... I guess that new oil pump really makes a difference.. What are you running now with a 4.6? A NBS Rangie?
-P |
Norm
| | Posted on Sunday, April 28, 2002 - 03:34 am: |
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It's a '95 Disco with an RPi 4.6 motor. Basically, it uses the same front cover/oil pump, distributor and other ancillaries from the 3.9 "B", as well as a "Tornado" chip on the 14CUX ECU.
---Norm |
PerroneFord
| | Posted on Sunday, April 28, 2002 - 10:25 am: |
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Sweet! I bet that thing gets up and gets out of its own way! Where's the pics? Actually, I've got a question I'd like to ask.. could you email me privately?
-P |
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