Lightweight

[Guest gdc]

update

 

the mods are complete , the car has had some new carpet and the seats refitted , all the bits that were removed

have been put back .

its not quite finnished but tis close .

 

back on its wheels , always a nice sight .

 

 

graham

 

testing time ??????????????

[peter_m7uk]

so the prob i have fought to ovoid has today happened ,

i have spun my diff , my highly moddified lightweight has indeed spun its diff .

we went out for a run in the sun today , dan and i and i got approx 1.5 miles , i had just filled up with juce

went approx another 300 meters and then heard a noise under accelration , i backed off and a simmaler noise .

tried it a couple of more times to be sure and , had to limp home .

on inspection in gear and rocking back and forth the nose of the diff is moving about an inch in each direction

up and down indicating the tear in the fabric of the diff support .

the car has been stripped this afternoon and i have a bit of a plan to sort it .

first thought was to add a match to the new fuel !

but i fought off the thought and tried to think positive , not easy .

i think the way is to add the rear support that was on the sierra orioganly .

add a u section from below the tunnel to support the nose of the diff and plate it to the floor in steel .

also further side supports for the other 2 suppot bolts .

i have said in the past that about 150 bhp is prob the limit for the ally supports .

so nearly 200 is asking a bit much i spose .

silly me .

but to me its a challenge and i hope still to have the car at detling , we will see .

so a message to the lightweight guys !

 

it might happen to you also , if you are still building then add some strength .

 

graham

ps very very p ssedf off

 

 

Graham,

 

Oh dear, sorry to hear about that!! I know you've sorted it now, but if you have any

further troubles, how about one of my strengthening mods? I made up these Diff Brackets and attached like this.

It was a bit fiddly, but I did it as a retro fit with the tank in and the wheels on. Just wondering, how is it possible

for the diff to come lose only at the front mounts without knackering the other mounting points?

Anyway, hope she stands up to the ST!!

 

Cheers,

Pete

[Guest gdc]

Graham,

 

Oh dear, sorry to hear about that!! I know you've sorted it now, but if you have any

further troubles, how about one of my strengthening mods? I made up these Diff Brackets and attached like this.

It was a bit fiddly, but I did it as a retro fit with the tank in and the wheels on. Just wondering, how is it possible

for the diff to come lose only at the front mounts without knackering the other mounting points?

Anyway, hope she stands up to the ST!!

 

Cheers,

Pete

[Guest gdc]

Graham,

 

Oh dear, sorry to hear about that!! I know you've sorted it now, but if you have any

further troubles, how about one of my strengthening mods? I made up these Diff Brackets and attached like this.

It was a bit fiddly, but I did it as a retro fit with the tank in and the wheels on. Just wondering, how is it possible

for the diff to come lose only at the front mounts without knackering the other mounting points?

Anyway, hope she stands up to the ST!!

 

Cheers,

Pete

hi pete

re the mounting to the rear i have done much the same as you , but i have braced the mounting to the boot floor up to the roll bar , the front is connected to the floor of the tunnel and braced together with the hand brake cable retainer .

i think the front and rear mounts are poss the most important , as the centre ones are not as loaded as the others .

i have not tried it as yet but i will report when i have .

 

i do think the damage was done on the rolling road 17 hours is a long time time to be strapped down and to be performing

 

ask the wife if you dont believe me !!!!!!!!!

sorry didnt read all the post

the front holes were elongated , the holes more towards the middle wernt as bad , as you would expect cos the movement isnt as exagerated in the middle .

graham

[Guest gdc]

hi pete

re the holes

the front ones were slots

the centre ones not as bad but the movement under load was enough to bu**er another speed sensor at £53

i have always had probs with the speed sensors , i have fitted 4 so far and all have had their heads cut off .

so the movement has prob been arround for some time but it has been made worse by the extra power of the st and the extended rolling road session . with no clutch cable and ramming it into gear , and starting it under load

i have always had in excess of 150 horses in the car so i may have expected the worse but i thought the car was better than it was ?

 

it needs extensive mods to make it work , i thought mine were working but obviously not .

i have made further mods and i hope this is the end of the journey .

 

 

graham

[Guest ScotMac]

Sorry to hear about all the problems Graham. In general, i would think if we use thick enough alluminum it should hold (6000 or 7000 series for the strengthening). The analogy i come up w/ is wheels. Aluminum obviously has no problem for wheels. However, they use pretty thick ally. Also, re your enlongated holes, one area we may not be considering is that ally wheels use *steel* *sleeves* in order to protect the soft ally from elongating around the lugs. Since our bolting is not like lug nuts, i would say that steel plating on both sides, w/ the ally in the middle, would serve a similar purpose as the sleeves.

 

But this gives me another idea. A lug nut style bolting, w/ the mentioned steal sleaves, might give us better protection from this elongation. It would be difficult to setup the bevelling of the normal acorn style conical lug, but we might be able to do something like the concentric approach of a mag seat style lug.

Edited April 8, 2009 by ScotMac

[Guest gdc]

hi scott nice to see you back

re the diff

after the work to reinforce it i gave it some real stress over the weekend

and its all still there

an elise thought that he was better than he was , and was upset at the out come .

it is staying together , i have picked up the rear 2 bolts and transmitted the force through to the upper boot floor from there

the forces are transmitted up to the roll bar .

on the front

the bottom bolts are collected by a piece of 5 mm steel in a u shape

its inserted through the thick underside of the car up and under so to speak

this in tern is sandwitched to the underside with another 5mm plate with weded nuts on it to capture the piece of 5mm

under it .

it seems to work !

i did a lot of real work with the car on sun and all is still intact .

i love the st power , wow

graham

[Guest ScotMac]

Glad to hear youre back on the road, and that you have some power now!

[Guest gdc]

the curse returns !

 

dans lightweight diff is on the move !

he said that on the way back from detling he thought he had heard something a bit odd .

we checked to day and rocking back and forth in gear there is a distinct noise clunk clunk .

so stripped it tonight and repairs under way ,

not long to do it as stonleigh next week ?

should be done though .

graham

ps i am not even anoyed its just another lightweight issue to sort .

does p s you of though

[peter_m7uk]

the curse returns !

 

dans lightweight diff is on the move !

he said that on the way back from detling he thought he had heard something a bit odd .

we checked to day and rocking back and forth in gear there is a distinct noise clunk clunk .

so stripped it tonight and repairs under way ,

not long to do it as stonleigh next week ?

should be done though .

graham

ps i am not even anoyed its just another lightweight issue to sort .

does p s you of though

 

Hi Graham,

 

Just wondering what engine Dan is running with?? I have often thought that the Lightweight should not be overpowered, given its known problem with diff mounting. My Pinto should give about 130bhp, but I would be wary of putting more in than that.

Diyer has been using a standard Zetec for the last couple of years since he got on the road, but reports no diff problems.

If you tell me Dan has a modestly powered car then I will be worried!! Since you have had these problems, I'm thinking of strengthening the front diff mount a bit. I suppose if I just take a few washers out (the ones recommended in the original instructions) and put a decent thickness of steel in there, bolted to the rest of the chassis, that will give me a solid mounting. I also used the holes on the back of the diff to tie it to the boot floor, so those two mods would give plenty of torque resistance at the extreme mounting points.

 

Apart from diff mounting, no one has actually reported bending or failure anywhere else on a Lightweight, have they?

 

Cheers,

Pete

[Guest ScotMac]

Hi Graham,

 

Just wondering what engine Dan is running with?? I have often thought that the Lightweight should not be overpowered, given its known problem with diff mounting. My Pinto should give about 130bhp, but I would be wary of putting more in than that.

Diyer has been using a standard Zetec for the last couple of years since he got on the road, but reports no diff problems.

If you tell me Dan has a modestly powered car then I will be worried!! Since you have had these problems, I'm thinking of strengthening the front diff mount a bit. I suppose if I just take a few washers out (the ones recommended in the original instructions) and put a decent thickness of steel in there, bolted to the rest of the chassis, that will give me a solid mounting. I also used the holes on the back of the diff to tie it to the boot floor, so those two mods would give plenty of torque resistance at the extreme mounting points.

 

Apart from diff mounting, no one has actually reported bending or failure anywhere else on a Lightweight, have they?

 

Cheers,

Pete

 

Yep, Pete, i had the same thought. I REALLY beef'd it up where the rear 4 diff bolts are, but didn't much at all on the front ones. I think i'll simply get some nice thick angled ally and glue it into there and the tunnel bottom, and also see about getting a "sleaved" bolt...ie, to get something to fit w/ minimal space between it and the hole cut in the ally (like my l idea about the mag seated lug nut).

[Guest gdc]

so to report the issues

my lightweight has now 201 bhp as rolling roaded at stonleigh .

my latest speed sensor mounted at the diff has been eaten by the prop , despite all the efforts to stop it .

i can only assume the diff is on the move again .i have added so much to the car to stop the movement . but top no avail .

i can only sumise that 150bhp is the max for a fully strengthened lightweight . dans is ok at the mo its been strengthened

and appoeares ok . mine is a different thing ..

i have recently purchaced a locost chassis and converted it to accept the lightweight wishbones and sierra diff

it is a variant of my daughters lightweight that i have just scrapped , it will i think be my new car .

a locost clad in lightweight panals . giving the appearance of a lightweight but with a steel chassis .

i have had to alter the wishbone mounts to the rear to suit the lightweight bones and the front are also an issue to be sorted i am fortunate that i have the remaining panals from rhsc to complete the build .

i will keep you up to date with the build .

graham

[Guest zoomzoom]

Hi

Its amazing that its still moving, but good luck with the hybrid build cant wait to see it.

Of course it will be ready by newark !!

 

marcus

[Guest gdc]

hi marcus

i thought you would be in le mon ?

newark ? no not going .

 

graham

[Guest zoomzoom]

The man at the DVLA he say NO