Flash Lube Valve Saver

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Originally Posted by PLR

Hello , if it were me i`d do a bit more searching before you remove it .

We have 3.9 with and 4.0 without both in RRCs . The 3.9 has efi and lpg the 4.0 has carbs and lpg .

The one with is not so much a valve lube as a power thing it has more with than without or seems to , never on a dyno .

Ive replaced the exhaust valves on the one without , the valve seats were fine and only need a touch up but the valve faces were pitted beyond reassembly . This motor has both stanless exhast and inlet valves . I have maybe 3 other sets of 3.5 heads that have been on lpg and their valves/seats are fine as well as another set of 10 bolt 3.9-4.6 heads that ran lpg and the seats/valves are fine also .

All these head sets came from engines that have 2 numbers and a letter in there engine number pre-fix . 12D to 86D .

If your mid 70s 3.5 is a 341 . 355 , 359 , 398 etc prefix .
Being 8.25 or .5 or .13 :1 ratio it will have small valve heads and i think you will find that these valve seats are not so lpg friendly and i would keep flash lube etc on these . None of the early V8s had stem seals at all .

Actually when i think on it a bit more if yours is a 398 prefix with 8.13:1 ratio and is at least 76 it should have the bigger valve heads but the only way of knowing is the casting numbers on the heads which if bigger valve will be ERC-0216 , this is the numbers the first of the bigger valved heads had .

Being its age it could have had much done to it over the years you`d need to know what it is before you can be sure .

Cheers

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Thanks for that - unfortunately the 101 3.5s engine numbers all start with 961 - my engine number is 96100684A. These engines would have been built 76 and into 77.

As these engines run on unleaded Ok I have assumed they run on LPG ok - however back in the early 90s when my LPG was fitted, the installer or owner must have had some concerns as they fitted the flash lube. I have has trouble getting the dose right as a slight turn on the dripper screw turns it off and a slight turn the other way provides too much.

Cheers

Garry

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Originally Posted by garrycol

Does each carby just feed fuel air mix to the side of the engine it is on or is there a common chamber at the start of the inlet manifold that then branches to the 8 cylinders.

Thanks

Garry

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IIRC feed from one carby does 1,4,6 &7 and the other does 2,3,5 & 8


Martyn

I play around with LPG a bit for a living.
The life of the valves on LPG has alot to do with engine load as the heat soak factor of the slower burning fuel will destroy a valve quicker than the no lube factor of the fuel.
I personally believe if you are using dual fuel, add two stroke oil to the petrol side of things and use petrol for climbing hills and periods where sustained high power out puts are required.
a 101 pulling say a trailer of 2 tonnes and climbing ...say Mount Ousley with a high power output from the motor on LPG for a lenght of time will do in the valves , harden seats or not........valve lube or not.
For years I drove a old G60 Nissan patrol with a P40 motor with no valve inserts on LPG and did alot of heavy towing and no flash lube.
I never had a problem as i just used to take my time towing up hills etc until i let my father drive it up a mountain one day with a heavy load and valve seat recession was my friend.
Note most fork lifts converted to LPG have no valve seat inserts and survive very well because the motors are governed.
Flash lube will not hurt....but is not a complete answer as the way the motor is driven will matter more.
My under standing the manifold and heads on the 101 were the best rover had at the time and the motor was set up to run on poor fuels(why it has low compression and rich carby needles as standard).
The 101 motor was set up as a truck motor higher output at lower revs and not as a car motor.
I believe the heads are slightly different .
Remember unleaded fuel has little lube effect for valves , but alot of cast iron head motors are still running on the stuff without mods

If I was to fit flash lube to my 101, the way it has been done on garrys 101, would be the best way as the little vacuum port mentioned on the carby is near the butterfly and gives good mixing.
Both carbys need to be done and therefore the tee piece.
the other good spot is at the balance port which joints the vacuum of the two carbys.
The 5\8 UNF metal plug facing forward in the middle of the manifold between the carbys will acess this and will service all of the motor with flash lube.
( the balance port was the way I did my first LPG install with my 101 to supply the motor with gas )
It should also be noted the 101 standard manifold is slightly different to the other early rover V8s because of its army spec.

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Originally Posted by Bushie

IIRC feed from one carby does 1,4,6 &7 and the other does 2,3,5 & 8


Martyn

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Bugger - a visit to the shop to buy little brass connectors is now needed.

Garry

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Originally Posted by 101 Ron

If I was to fit flash lube to my 101, the way it has been done on garrys 101, would be the best way as the little vacuum port mentioned on the carby is near the butterfly and gives good mixing.
Both carbys need to be done and therefore the tee piece.
the other good spot is at the balance port which joints the vacuum of the two carbys.

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I want to run an air line for a vacuum gauge and the only remaining and logical spot is the balance tube between the carbies but this is the flash lube sucker hence the question do I really need the flash lube. On the balance of views it probably doesn't need it but it might do a little good.

So I will get a X piece in so that the carbies still balance, it still sucks the flash lube and the suction will work the vacuum gauge.

Garry

My 101 has been changed slightly fron normal.
If you look at this pic you will see a L shaped pipe going into the centre of the manifold between the carbys.( my LPG inlet).........the standard fitting is a large metal plug which can be drilled and tapped to 1/8 bsp for a hose nipple.
the plug is the balance chamber and is a good vacuum supply and even distribution of flash lube if required.
https://www.aulro.com/afvb/images/im...010/01/412.jpg
https://www.aulro.com/afvb/images/im...010/01/410.jpg

Current set up with the standard black plug in place right hand side centre.


https://www.aulro.com/afvb/images/im...010/01/411.jpg

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Originally Posted by 101 Ron

https://www.aulro.com/afvb/images/im...010/01/410.jpg

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Thanks Ron - I do not have that centre plug drilled, tapped and plugged. You indicted that your gas goes in there - so that chamber must be feed by fuel air mix from both carbies when on petrol - therefore feeds all combustion chambers with common mix.

In your pic, you will note the pipe just to the right on the passenger side side carby - I have this but it is also replicated on the drivers side carby so there is a small balance pipe between the bases of two carbies.

I have changed this so the flash lube goes in the passenger carby in the pipe you have on yours and the vacuum gauge being run off the vacuum off the drivers carb in a hold that is not on yours.

If the chamber under that centre plug is common to both carbs then the flash lube will go to all cylinders, likewise the vacuum off the the drivers carb will also be balanced vacuum and not that from just the drivers side of the engine.

I thought you had "gas" rings under each carb - but I take it your gas just goes into the central chamber.

Garry

The only thing to use "Flashlube" on is your mates car !!! Watch it looooZe power as the crap builds up on the back of the Inlet valve , to the extent you will looze 50% of your inlet Valve port Flow !!! Aint worth two Knobs of goat**** !!!
As someone who races straight LPG engines , pay more attention to the AFR and EGT's if your worried about Valve recession , yes ,never are the seats the problem , its the valve recession that kills your engine.