nose lift systems? anyone have experience?

Seymour Snerd

Lifetime Supporter
I always thought a ram to pre-load the front ARB would be far neater, simpler and cheaper.

That's a really good idea; has anyone ever done that? Coupled through a lever at the center of the ARB, the ram could be entirely within the front compartment, or at the rear mounted up on the upper crossmember, and varying the length of the lever would allow some choice about ram force vs travel. Plus without the space constraints inherent with the concentric rams you could choose a lower cost general-purpose ram. You could even use a worm drive gearmotor. Effective travel (lift height) is constrained only by the geoetry of the ARB and suspension travel. In fact the ram's job gets easier as it extends.

The only downside I see is you need a way to decouple the ram when not in use rather than simply retract it as in the concentric case, but I can imagine some fairly simple solenoid-operated clutch mechanisms that would work. Also, for what it's worth, with the lift in place you have no anti-roll; the effective spring rates are much higher, but you still probably don't want to take any high speed corners in that configuration.

David, quick, file a patent!
 
No need to decouple, either make it a simple fixed ram with a roller onto a lever arm. Or have a slotted arm and pivot the ram. Either way make sure the off position would be 'below' your normal usage and you're good!
 

Seymour Snerd

Lifetime Supporter
No need to decouple, either make it a simple fixed ram with a roller onto a lever arm. Or have a slotted arm and pivot the ram. Either way make sure the off position would be 'below' your normal usage and you're good!
Yeah you're right; you only need decoupling in one direction. Even better!
 
I recon your sway bar would have to be fairly heavy to overcome the weight of the front of a 40.
You would be trying to lift 5-600kg.

I made skid blocks on the front of my car ,made out of nylon ,over time I throw new ones on.
They work excellent on steep entry drives .

Jim
 

Seymour Snerd

Lifetime Supporter
I recon your sway bar would have to be fairly heavy to overcome the weight of the front of a 40.
You would be trying to lift 5-600kg.
The car still has its springs. If the combined wheel rate at one end is (say) 600 lb/in, then that's what you have to supply for each inch you raise the car. Or to put it more simply the force supplied by the ARB needs to equal the spring rate if the ARB attaches near the bottom of the spring. Regardless of ARB diameter, up to the point where the ARB fails from being twisted too far you can raise as much weight as you want by twisting it further.

If anyone knows their ARB dimensions you can use Puhn's formula to calculate the rate

http://www.paragon-products.com/kb_results.asp?ID=37

Knowing that and knowing your spring rates the ARB is just "over-twisted" by the ratio of the spring rates.

Also re: sliders don't forget there are also speed bumps out there that are >4" high. Scraping the underside of the front is one thing; getting high-centered on a speed bump or striking the front corner of an aluminum oil pan would be quite another.
 
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Alan that is how it would work,the front springs will not have any effect or aid in lifting the car.
The car is supported by the front springs and you are trying to raise the car of the springs by rotating the ARB then you will be lifting 600kg on the bar and I thing it would need a lot of bar and strong links and bracketry.
Once it starts to bend the bar it will stop lifting the car.
It would need to be tried ,I get the feeling modifying the bar in size ect ect will compromise its real purpose.
Sometimes the only way to find out is do it.

GJ no photos but here is a cad drawing.
It mounts to the front chassis under the radiator,there is one on each corner,I used the chopping board material(white plastic).
When I come into a drive I move in slow the corner skid will touch the ground instead of the frame.

The raised section sits against the frame so the screws are not taking the load.

Jim
 

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Seymour Snerd

Lifetime Supporter
,the front springs will not have any effect or aid in lifting the car.
The car is supported by the front springs and you are trying to raise the car of the springs by rotating the ARB then you will be lifting 600kg on the bar and I thing it would need a lot of bar and strong links and bracketry.
Once it starts to bend the bar it will stop lifting the car.
1. You've noticed, I bet, that you can lift the front of your car by hand a little bit (say, 1/8"-1/4"), right? Does that mean with your hand you are lifiting 600KG? If so you're a lot stronger than any human I know or have ever heard of. If not, how do you explain your ability to do that while that end of the car weighs 600 kg?

2. The bar will not bend if it has bushings on either side of the lever; it will only twist. Just like the bushings it now has at the ends that keep it from bending when the suspension arms twist it. The links and bracketry are not fundamentally different from those that allow the ARB to do what it does today. Why would they need to be any different?
The ARB is already doing this when you corner hard and it keeps the car from leaning as much (like, say an inch or two); otherwise there would be no point in having an ARB.

3. There is no experimenting needed. This is all covered by high-school-physics.
 
One thing you need to be careful of when using any system like this is that at full extension of the ram and full droop you are not binding your Ball Joints.
Also with the suspension at full droop and the hydraulics fully retracted that the springs are still tight on their seats.
Also if using these to work on the top spring mount the ram should be able to be locked in its retracted position.

This is probably common sence to most of you but these things do get forgotten at times.

I saw a case recently where the ball joint had gone solid and had bent the ball joint spindle.

Easy to check. If you have the ram extended and the suspension at full droop. then disconnect one end of the shock and see if you still have more droop movement available.
 
Alan

David was tossing an idea around and I thought it was open for discussion,that is what these forums are for.
You seem to be defending the idea as if it were your baby.

It comes across that you are mocking me.

You look like a dick head

I could defend all off your comments and give tech reasons but I would not give it the time of day know.

Jim
 
Forgot to add, skid blocks are not a bad idea at all on a low car like the GT40 even *with* a lift system, certainly when its a choice between a (replaceable) block and de-heading half the rivets or taking the bottom off the sump I know which I'd prefer! :)

I must admit I'd be tempted to go all old school F1 and use Ti blocks, if nothing else if you *do* touch down the sparks will be very pretty :D, should be able to make some out of some scrap Ti which isn't *that* expensive (although a bitch to machine).
 

Seymour Snerd

Lifetime Supporter
Alan

David was tossing an idea around and I thought it was open for discussion,that is what these forums are for.
You seem to be defending the idea as if it were your baby.

It comes across that you are mocking me.

You look like a dick head

I could defend all off your comments and give tech reasons but I would not give it the time of day know.

Jim
I have no idea where that's coming from. I'm explaining my understanding of the technical situation according to my training and in a writing style you would find in any technical article or book. There are no personal remarks in my posting, and no criticism of you or anything you said.

If you'd like to point to a specific piece of text and explain precisely how it's offensive I'll be glad to listen. You are the first to do any namecalling.

You've said some things that are simply inconsistent with basic mechanical engineering, and you've stated them as fact. I'm just trying to establish the truth in the context of a rather simple mechanical system about which there are no mysteries using physics that have been know for hundreds of years. Professional engineers do this all day every day; there is nothing out of the ordinary with David's concept. I'm not possessive of anything but the truth; the technical truth IS my and other people's baby. That's the only reason I participate in this forum at all.

I think it's bad for the forum, as a body of technical knowledge, to have simple mechanical devices portrayed as mysterious and debatable when in fact they are not; that just intimidates people from relying on their education and reasoning power to create these things for themselves. This is science, not art.

Please feel free to explain your understanding of the mechanical system in precise technical terms like I have, and like David and others continue to do in this thread, and we can have a perfectly rational discussion.
 
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