poorlysick thor 4.0

Hi
I've had one problem after another, most likely down to poor maintenance from the previous owner(s)
I replaced the headgaskets to cure gas in the coolant, a simple if not long winded job! But the result was a fully functional V8, as it should be!! Also replaced the thermostat because it was running cool, previous owner had drilled 2 decent sized holes, not sure why, but this was allowing enough flow to the radiator for it to never get hot.
Then I had running issues which got worse over time and I eventually traced to a wornout exhaust cam on no4.
One camshaft later and its still running badly - the cylinder that had the worn cam (no4) and its coil mate, no6. II replaced the injector on no4 because it was all black as a result of the exhaust gases escaping into the intake. All other plugs and injectors are a nice colour.
I'm pretty sure there are no air/vacuum leaks and the MAF sensor appears to be functioning properly.
I've changed the plugs and checked the gap is 1mm, the coils are new and the leads appear to be good ( get a good
When I took the plugs out, 6 was quite sooted and 4 was quite dark in colour but no soot deposits and slightly damp (not wet, dripping etc), edging toward oil rather than petrol as it didnt smell or evaporate.
I've no smoke etc from the exhaust and nothing noticable from the oil filler cap.
Cleaned the plugs up, checked the resistance (as you do..) and put them back in, quick run to get up to temperature, some pops/chuffs from the exhaust and I've attached the state of the plugs as of now.
Any ideas where I should be starting to look, before I take the offending head off and start from scratch? (can only think of a valve issue)

Many thanks

Swap the plug from a duff cylinder over to a good one to check if the fault follows the plug
Do the same with a lead.
Compression test.

I've tried doing plugs into no 4 before I realised 6 was poorly too, no difference.

If it's not too cold out tomorrow after work then I'll set to and swap the coils over, then swap some leads. I'll keep you updated, thanks!

It was that easy!! I replaced 2 plug leads, job done!!

The engine hadn't given in though!! Decided to get an air lock and over pressurise!! Noticed a tiny drip under one of the hoses and thought it was ok. Given past experience I'll probably end up draining completely and starting again, once it gets air in, I've never been able to get it out

There's a sequence/Procedure to filling a P38 to avoid airlocks..
It is in RAVE I think.

Yea, I've followed RAVE to the letter, parked on hills, etc etc. But no joy once there's an airlock

kermit_rr said:

Yea, I've followed RAVE to the letter, parked on hills, etc etc. But no joy once there's an airlock

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OK. Be radical. Find the lowest point (bottom of RAD?) and fill from that point till the expansion tank is 1/2 full, start and rev it, rinse/repeat until the tank is full.
Then let some out to the MAX-Fill mark on the tank?

But then again, someone sensible will be along in a minute.

I've not tried that particular one!!
But I'm really so very happy that I've got the engine running right, I really don't mind draining and starting again. It's a minor detail that doesn't take that long!!
I really don't see how they can get airlocks so easily!! Every time I've had the slightest leak, I've ended up with an airlock leading to coolant being dumped out of the cap.
The trick is, never have a leak!! The bleed pipe that goes from the top of the radiator to the cap is obviously the issue, getting blocked too easily with an air bubble

Ok. I officially dispair! Drained and refilled the coolant just now, in preparation for MOT in the morning. Pressurised the system to check for leaks and it's decided to wee from the back of the engine. I'm assuming it's the valley gasket. Again!! The number of times I've had to strip the top end the last few months is a joke!!
Is there any alternative to the britpart offering and is it worth it? That's all folks seem to sell

I've just found a rubber coated valley gasket, rather than the one i have at the moment which is described as composite and certainly didn't look or feel rubber coated! Part Number: LKJ500020
Would this do a better job? It's still britpart and about the same price

The valley gaskets are either the bare metal type or the later type which is the metal covered with a rubbery sort of material.
I used the latter when I did the top end of my 3.5EFi RRC last year & - so far - no trouble.
It was LKJ500020G - the G is normally used to signify genuine. It didn't come in a blue wrapper. Whether they're all made in the same factory & just packaged & sold as whatever by whoever I don't know!
Use new end seals & don't forget the small blobs of sealant that need to be applied where the cylinder head to block join is. My manual instructs to use silicon grease on both sides of the rubber seals used at each end under the gasket & I did but not in the immediate vicinity of the blobs of sealant.

Thanks. I found a genuine one so I'm going to go with that! Hopefully it does a better job than the composite.

To late now but for any one reading this thread in the future this a statement by Rimmer Bros about the composite gasket supplied by Land Rover with Part Number: LKJ500020.

Product Description

Note: The improved composite inlet manifold gasket was first introduced on engines from 1992 approx. onwards, but is often used as a sensible upgrade on earlier engines originally fitted with the tin item. The composite gasket type end seals ERR7283 may in fact be used with either a tin or composite manifold gasket, but whichever the case they must be used with their matching ERR7282 clamps.

Specifications and additional product information
Defender 83-06 - All V8 carb and EFi petrol models - Composite type - Quantity Required - 1
Discovery 1 - All V8 carb and EFi petrol models - Composite type - Quantity Required - 1
Discovery 2 - All V8 EFi petrol models - Composite type - Quantity Required - 1
RR Classic - All V8 carb and EFi petrol models - Composite type - Quantity Required - 1
RR P38 - All V8 EFi petrol models - Composite type - Quantity Required - 1
Series III 109 - All V8 carb petrol models - Composite type - Quantity Required - 1

Thanks for pointing out about the seals and clamps!! I've not had chance to order anything yet so not too late
However in even more confused now! Rimmers sell 3 different valley gaskets, Genuine, OEM and aftermarket. Genuine always used to mean OEM!
The end seals are all rubber and must all be the same shape because they all need to fit a standard block. As stated they are interchangeable, so why would you need different clamps? Sounds like sales talk to me.
Lastly, does the tin gasket (ERC3990) work any better than LKJ500020? I assume it fits as the blocks are all the same from that perspective.

Right, I thinki have found the bigger issue, the rear-most manifold-to-head bolt wasn't tight, I tried tightening and didn't seem to get any tighter!! So I'm guessing the thread has gone.
Next question, does anyone know how to work out which size helicoil is the right one, or how to work it out? I've never used one before so I've not got any unused ones to go off to find the right size for the existing bolt

I've used helicoil & timeserts & I'd say the latter is the better but they're a lot more expensive. Order by the size of the original thread.
LRcat says that the bolts for the Thor manifold are:
http://new.lrcat.com/#!/1234/90127/90555/7181/90790
LYG101440 which comes up as https://www.brit-car.co.uk/product.php/87245/2626/bolt_3_8_unc_x_1_375_inl_manifold_v8
and
LYG101450 - BOLT-FLANGED HEAD 3/8UNC X 1 7/8 [ (V)XA410482 - ]
One is shorter than the other & it should be apparent which goes where but I'd suggest measuring the hole depth with the manifold in place as you remove each one & the length of the bolt that comes out so the right one goes back in the right hole.
Bit of cardboard with holes (use a screwdriver to make the holes) to put each one in as it comes out saves a lot of headscratching later!

kermit_rr said:

Thanks for pointing out about the seals and clamps!! I've not had chance to order anything yet so not too late
However in even more confused now! Rimmers sell 3 different valley gaskets, Genuine, OEM and aftermarket. Genuine always used to mean OEM!
The end seals are all rubber and must all be the same shape because they all need to fit a standard block. As stated they are interchangeable, so why would you need different clamps? Sounds like sales talk to me.
Lastly, does the tin gasket (ERC3990) work any better than LKJ500020? I assume it fits as the blocks are all the same from that perspective.

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There's been much discussion on various forums as to genuine,oem & aftermarket & it's a bit of a minefield. It's difficult to know whether the part is made by one manufacturer & simply sold as whatever by whoever.
If I want to be absolutely sure that the item is as currently used by the car manufacturer then I buy from the franchised dealer parts dept. This should see the latest evolution of the part in question. As an example Peugeot 306 1.6TU head gasket. Replaced one a few years ago & all the factors were selling composites but the dealer part was now a mls. Even as trade I get b.all discount 10% not being unusual.
OEM should be a part as originally supplied by its manufacturer to the vehicle manufacturer. As an example - again Peugeot - 307 clutch kit from the dealer comes in a box with Peugeot all over it. The parts are marked Valeo but Valeo also sell the same items to the general market & the boxes will have Valeo on them - as will the parts. BUT these may not be the latest evolution.
Aftermarket or pattern might have been made on original tooling thrown out by the genuine/oem maker or tooling made up by the pattern part maker. Some are very good, some are awful. In the 70s we sold Mini wings. The genuine BL item was 3 times the price of the aftermarket one. The aftermarket ones were made on press tools thrown out by BL due to wear. The BL ones fitted perfectly. The aftermarket ones fitted where they touched but usually needed a fair bit of work.


Discool is correct. The clamps are different & I used the later ones when I used the composite gasket on mine - which originally had the tin type.

wow, many thanks for such extensive replies!! very much appreciated I've found a 3/8 UNC helicoil kit online, so I'll be ordering that later today if I can't get anything locally. I'm now feeling excited with anticipation! Gleeful in the knowledge I've found a black and white issue with a solid fix
Thanks again everyone for all your help I just hope I'll be able to offer similar levels of assistance to others in the future!

kermit_rr said:

wow, many thanks for such extensive replies!! very much appreciated I've found a 3/8 UNC helicoil kit online, so I'll be ordering that later today if I can't get anything locally. I'm now feeling excited with anticipation! Gleeful in the knowledge I've found a black and white issue with a solid fix
Thanks again everyone for all your help I just hope I'll be able to offer similar levels of assistance to others in the future!

Click to expand...

Let's not tempt providence just yet.......

Let's just hope I can reach at the right angle with a regular drill That is something that will have to wait for the weekend