6 pot petrol detox

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BikerB

BikerB

Well-Known Member
Posts
6,409
Location
Far up North
My 6 pot is a detox version but the air pump is missing and some of the parts are knackered. Other than a different comp ratio are there any differences between the earlier toxed and the later detox versions of this engine?
There is a bit f a dearth of info because of the rarity and I was intending to just eliminate the detox equipment and maybe improve the engine a little during the rebuild if I can.
Anybody know where I can find tech info about this engine?
 
It is basically the same engine and I have been in touch with a place that I can probably buy some new parts from P4's but they are not identical, there are apparently at least three different versions and capacities.
Still trying to work out what I can use and what I can't.
I do want the six but its quite difficult to get proper info on the LR version, even the parts manual is not a great deal of help other than saying there are two LR versions of the engine!
 
would the detox version perhaps be for export ? eliminating the bits might be a simple solution . Some American engines used an air pump to reduce emissions but not sure if they actually did anything other than tick some boxes for the clean air folk . first thing that usually went was the smog stuff and on went a bigger carb , they run fine .. I appreciate that doesnt answer your question on the Rover engine though..
 
The air injection system is just an air pump, a valve and a manifold on the six, there may be a gulp valve but its not clear because half the system is missing on mine. It is a UK thing as well as export and few were exported to the US in any case.
I am not going to reinstall it but I am still trying to work out from the parts manual if there are any other differences, it looks like the comp ration is lower but not sure why, its only 7.8 to 1 to start with which ain't exactly high. If there are simple upgrades while rebuilding that will improve economy/power I may as well do them.
The problem seems to be that there are at least three capacities of this engine and at least two versions in the Landy, all of which have slight differences between them and make parts non intercghangeable.
What I am trying to do just now is get to the bottom of the seized issue although I would have to say that so far the engine is in much better condition than I was expecting. Once I know what is wrong I will start gathering bits while I complete the axle and chassis build up ready for the engine but since it will take some time to find parts I am just getting a head start.
The problem seems to be that rarity makes finding out about them not so easy:D plus it has to be the largest and heaviest engine I have ever rebuilt, all the ones t I have done in the past have been various motorcycles, MGB's, MG Midgets and 70's Ford Crossflow engines which are all significantly lighter and more compact.
Plus I was a lot younger when I did most of these......o_O
 
To the best of my knowledge no P4 variant had a de-tox version.
The LR was the same 2625cc 7 bearing engine used in the P4 100 model, but with a Stromberg carb instead of a SU.
You may be interested in my previous post on this sub-forum ref. transplanting the more powerful 3litre P5 block, a task I undertook way back in 1989/90.
nb. yes they are very heavy, I damaged a garage loaned engine hoist whilst doing the above :oops:
 
I am awaiting the heritage cert but I am convinced that this is the original engine, that being so I intend to keep it and not change it. I reckon I now have, or know where to get, all the parts needed for the rebuild but they cost a fortune!
Its going to take some time to gather the cash to buy everything needed but I am working on it.
 
Good for you !
You'll have a rare example of the breed at the end of your project.
A problem with these engines lies in their heritage, smooth & reliable in the P4 saloons they were designed for, but not really up to the job in a working 4x4.
 
BruceB said:
Do you still have a six pot? I could do with a measurement off the gearbox crossmember to fit the tie rod.
Click to expand...

Sorry, it was written off after some moron tried to kill himself by driving into the back of the LR whilst it was parked.
Sadly he didn't quite succeed :mad:
I often wondered what happened to it as I heard though the grapevine that it had been repaired, but there's no record with the DVLA.

If I can help with any information (that I can remember after all these years) feel free to PM me.
 
This might be of interest to you Bruce if you haven't seen it already
IMG_20210701_012309.jpg

That appears to be all there is to it, hope its clear enough to read, I can email you the pdf if not.

My engine is not the detox version so has none of these parts - mine's a 1978. The spare lump is not detox either, I think that came from a P4 but I'm not sure, certainly it is older, has a dynamo rather than an alternator.

By the way, I'm not sure if this is the norm but my engine number is almost the same as the chassis number, iirc only the last couple of digits are different from the chassis. If yours is like that too I would hazard a guess that it's the original block.
 
I have that and the only change inside the engine seems to be a slightly higher compression ratio. I am probably going to put the high (7.8-1) pistons in anyway as the vehicle will be fairly low mileage and the petrol it used will be OK, its derated for poor fuel.
My engine number is the same, just a few digits out from the chassis, unfortunately there is no factory record for the engine number. I am trying to get V5 info from DVLA to see if the number has ever changed on the V5 which i suspect it has not as the vehicle was taken off the road a long time ago and the current number is on the V5. It is not likely in the prevailing circumstances at the time that the engine was replaced as back then a blown 6 pot meant it was changed out to something else usually
 
It would be interesting to hear if the DVLA can provide any info. which confirms your engine being original although I would suspect that it is. As you say failed 6's were often swapped out for something else and that has partly lead to their rarity now.

By chance I was speaking the other day to someone who claimed to be a former owner of my Landy and he seemed to think the engine had been changed in the past. Although he did know of it being sold to the person I got it from and therefore seemed genuine, some of the things he said seemed wrong so I was wondering if he might be thinking of a different vehicle. It's got me wondering about confirming if the engine is original or not.
 
To effectively eliminate the de-tox equipment you will need to do at least the following:

Remove the SAI gear if it is still on there
Replace the distributor with one from a P4 or Landrover, 1967 - 1975.
Replace the carburetor with a bottom adjust CD175

Those are the tree main items. You may or may not have an electric idle solenoid as well. If so, ditch it when you change the carb.
 
No real progress as I was building the gearbox and overdrive, however I have gathered more of the necessary parts including a NOS air pump still in the box. So I have just about everything to rebuild it as original with the detox equipment.
I am just looking for pistons at the moment but struggling to find a decent set at +10 or +20 with the correct CR.
There are some available but they seem to have a fairly poor reputation for weight and quality, the good repros I found are £1600 a set of six!
Anybody know anything about or can recommend decent Hi CR pistons for this engine? I know it would be cheaper to swop it out but I want to keep the original block in the vehicle.
Alternatively I know where I can get a set of OE LC pistons but not sure just how many issues fitting these would cause!
 
As far as I'm aware there was no detox equipment on these engines, the air pump & associated equipment was introduced very late in production to reduce exhaust valve temperature.
My '79 Safari didn't have it.

Find yourself a good P5 unit (see my post #7 on the subject) & you won't regret it as it's the unit the 6 pot should have had :rolleyes:
The late HM the Queen had one in a 10 seater.
 
Last edited:
I want to keep it as original as possible, including the motor. The lump will not have a hard life so don't really need extra power and I am willing to spend the money and time keeping the original block. Mine is a 78 109 and it definitely had the detox equipment from new, although bits were missing. However I have managed to get all the bits, including a new boxed air pump, to reinstate it as it was.
I can get replacement +20 pistons but they are the cheap ones and I would rather get a decent quality set, I only want to do this once;)
 
It's to your credit that you are determined to keep the engine original, though from my past experience the only attributes of the 'six' are smooth running, nice exhaust note & peak torque at 1500 revs .. ideal for off-roading. They use more fuel & oil than a 2.25 'four' & are not noticeably better when it comes to real world performance.

The P5 unit (same block, longer stroke) transforms a S3 & returns about the same fuel consumption, due to the much improved power to weight ratio. My conversion was a Mk11 with Weslake head & SU carb.
 
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