Thread: Gav's 101.

Originally Posted by garrycol

The previous owner claimed to get 19l/100km when cruising along and it was maintained by a local mechanic - maybe use that mechanic to check it over.

My carbs have only had the diaphrams replaced and mixture/idle setup once and seems about right. My Jag has four of these carbs and I purchased the car in late 1982 - the carbs have never been touched since I have had the car - the car was laid up in about 2003 and I fired it up for the first time earlier in the year and it still ran smoothly and idled fine at 500rpm after nearly 10 years not having run - so the carbies once setup they stay in tune and run well,

Vacuum leaks around the inlet manifold of the 3.5 can be an issue and I have had this problem - plays up with carby tune.

You do have an issue with your speedo if your speedo is reading fast on your XZLs - given their size your speedo should read slow so that you could be cop bait. With 9.00x16 (34.7") your speedo should read very slighlt fast and the odometer should be about right. If I remember, your tyres are about 36.5" so your speedo should read slow by up to 10%. i have 315/75x16 (about 34.1") and my speedo reads 10% fast.

If on standard tyres and your revs are 3000rpm at 100kph, with bigger tyres at 3000rpm you will be going faster than 100kph even though your speedo shows 100kph, likewise with smaller tyres at 3000rpm your speedo will show 100kph but actual speed will be less than 100kph - but you already know that and I am telling how to suck eggs - sorry.

Cheers

Garry

I would have thought 19/100 was stretching it a bit. That's what the Rangie does when I'm being kind to it. Based on my very inaccurate calculations I was thinking more along the lines of 25/100 but once the speedo is sorted I'll start running some calcs to see what it really is. I did get warned not to rely on the speedo with these tyres on it as it reads about 10 k's out and I'll get done before I know it...

Even though it looks a bit naff, I'll probably keep the GPS in there to cross reference.

If you have an iPhone there is an app called SpeedBox that will give you speed and distance.

The O/D will leak oil from the selector rod and the end of the countershaft where it comes though the housing at the back of the O/D.
The oil leaks are a design feature of the O/D as to stop the rear X member and diff housing from rusting and it was very thoughtful of Mr Fairly to provide that feature.
I have stopped the oil leak on the countershaft on my O/D by making a screw on end cap.
The leak on the selector shaft I need to remove the O/D to fix and I was thinking of machining a O ring groove on the shaft or in the housing......too much work involved to warrant to do it while it is working OK.

My 101 does 2800 rpm at 100 kph with tyres that are about the same OD as the ZRLs ???? , transfercase ratios fitted make a slight difference to these figures, mine is running the highest one 0.996 ????? using the standard compression motor.

Head winds do make a difference if you use the O/D or not and shows how much that box shaped front end takes to push around.

As for pinging

The first thing to try is check the ignition timing


The second thing to try is changing the sparkplugs to a colder range as colder plugs will reduce pinging.

The Third thing to try is increasing the size of the main jet.

The fourth thing to try is ensure enough fuel flow is getting to the carbies.

mine would get 12mpg ( 19.5 l/100)

fitted elec fans. ( dont bother)


12mpg



fitted overdrive ( dont bother)

12mpg


electronic assist ign ( great mod by the way)

I went with the assist so I could revert to points in an emergency

12mpg but smoother idle.


after a year when changing down for a junction overdrive let go. spit case in two.managed to still drive home abeit very smelly. Also bent fork selector for second gear.

the fairly o/d are not strong enough...
sure its quieter but adds a weak link.

did not change fuel use.

if it still has stombergs I doubt the jetting is off but check dash pots have correct grade oil. Too thin can give a bit pinking.
I found you can tune the carbs like the old SU which had a slide lifter.

remove carb 90. degree manifolds ( Bend a 1/2" spanner to make it easy) then with engine running and a flat blade screwdriver lift slide..if revs rise and continue that is rich if engine slows too lean..the revs should rise a bit then drop.

you will need to have timing set before this and balance carbs with your ear and a bit tube..or a uni-syn if you're posh

I know peoplehave changed carbs from strom to SU ( which doeshelp with fuel) but the stroms stay in tune as long as diaphram is good ( fit new to both as new silicone ones will last the life of vehicle) also stroms have a greater flood angle.


after a few years converted to gas

Originally Posted by drifter

If you have an iPhone there is an app called SpeedBox that will give you speed and distance.

Thanks but I don't have a smart phone, only a work one that makes and receives calls.

Originally Posted by 101 Ron

My 101 does 2800 rpm at 100 kph with tyres that are about the same OD as the ZRLs ???? , transfercase ratios fitted make a slight difference to these figures, mine is running the highest one 0.996 ????? using the standard compression motor.

I think that is about the same for mine with the OD in. It is comfortable at about 2,650 which is 95 on my GPS.

Originally Posted by 101 Ron

Head winds do make a difference if you use the O/D or not and shows how much that box shaped front end takes to push around.

As for pinging

The first thing to try is check the ignition timing


The second thing to try is changing the sparkplugs to a colder range as colder plugs will reduce pinging.

The Third thing to try is increasing the size of the main jet.

The fourth thing to try is ensure enough fuel flow is getting to the carbies.

Thanks - I haven't checked anything on the engine yet, I will start that diagnosis and a tune up next week at some stage.

Originally Posted by amazing

mine would get 12mpg ( 19.5 l/100)

fitted elec fans. ( dont bother)


12mpg



fitted overdrive ( dont bother)

12mpg


electronic assist ign ( great mod by the way)

I went with the assist so I could revert to points in an emergency

12mpg but smoother idle.


after a year when changing down for a junction overdrive let go. spit case in two.managed to still drive home abeit very smelly. Also bent fork selector for second gear.

the fairly o/d are not strong enough...
sure its quieter but adds a weak link.

did not change fuel use.

if it still has stombergs I doubt the jetting is off but check dash pots have correct grade oil. Too thin can give a bit pinking.
I found you can tune the carbs like the old SU which had a slide lifter.

remove carb 90. degree manifolds ( Bend a 1/2" spanner to make it easy) then with engine running and a flat blade screwdriver lift slide..if revs rise and continue that is rich if engine slows too lean..the revs should rise a bit then drop.

you will need to have timing set before this and balance carbs with your ear and a bit tube..or a uni-syn if you're posh

I know peoplehave changed carbs from strom to SU ( which doeshelp with fuel) but the stroms stay in tune as long as diaphram is good ( fit new to both as new silicone ones will last the life of vehicle) also stroms have a greater flood angle.


after a few years converted to gas

Thanks. The carbys do seem to be out of tune a bit - my Rangie had the same setup a while back and I could feel them coming out of tune. I used to have a guy that could tune these in minutes by ear (an ex Land Rover mechanic who cut his teeth on early Rangies) but he is in his late 70's now and for some reason doesn't want to do them any more...

As for fuel usage, I'm not fussed what the figure is as long as it is running well. If I wanted good economy I'd buy a Prius...

Cheers - Gav.

Ok, a quick question. What are the pros and cons of driving around with the front prop shaft removed and the centre diff lock permanently in?

The noise the front drive shaft makes on over run drives me nuts and 99% of my driving is on the bitumen...

Thinking long term I will get the diff rotated if I can find someone I trust to do it, but in the mean time...

Thoughts/comments welcomed.