DIY top mounts

I can draw something up and make it a dxf or whatever file if it helps. Ill also offer to make a demo set FOC for discussion with possible vendors too.

Just an offer, that all, hope this helps,

Brian,

edit, tools to hand, lathes, cnc, laser, etc.

 

I like the idea of the shared files, i could sketch some up, in commen file formats as long as people can supply the diemsions (or a part for me to measure - would send it back then) for what they are after - would this only be availible to members? seems like it should be a members only privilage.

 

If someone makes a demo set (hopefully something that could be used across a couple of different models, and ideally top-mounted - Mk1 and Mk2 aren't that far apart) then I know a couple of jobbing machine shops who I could ask for quotes to make a batch of them. One of them makes custom shafts for Hewland gearboxes most of the time. I've chatted to him before about small batch stuff, and he's up for that sort of work.

I think there are potential advantages to opening this out wider than just the paid members. If we run a group buy, then having more people involved gets the price down for everyone.

I don't really want to administer a group buy right now though. I've got a lot else on my plate. Maybe we can find a 'volunteer'?


BTW, IIRC, Danster's top mounts were based on some spare ones from a Mk1 or Mk2 Escort, because they were available. Essentially a lot of these are quite similar, but shapes of turrets, strut pin dimensions, etc. could vary a bit.

 

I'd be interested, but I'm not an engineer so not sure how I could help. I have some powerful PCs to convert files maybe?

 

Thanks for the offers of help guys.

I was hoping to steer away from the group buy scenario Mike.... More like a group design!
Then make that design downloadable. If people then choose to get a batch made up (regional/local) to get prices down, then that is up to them. Likewise, if you just want to get one made by a pal round the corner, he has the design to work from.....
... that kind of thing. Open source'ish.
We just need people to be willing to share their ideas to improve the design.

What do people want from a mk1 golf top mount? Then we could design from that brief maybe?
I'll start...

- Top mounted
- drop ride height by 50mm - Could have spacer 'rings' to drop less/more
- Adjustable camber and Caster if possible
- Top quality bearings that will accept a short'ish thread on top of the damper (reduced sleeve or something?)
- Bolt-on, not weld-in..... hmmm, not sure, maybe weld-in?
- No need to cut the shell to fit.
- Possibly designed to accept a strut brace design...?

It seems like the adjustable ones have 2 main components: One that bolts to the top of the damper, and one that bolts to the shell, and they slide to adjust camber, and move on bolts to adjust caster?

 

In getting from design to working component, it gets a lot less risky if you have a prototype and test fit that. We can do that remotely, but if it's one blokes interpretation, who knows if the others will be close enough to that original, if it's machined by someone else.

In theory, CNC machines should be capable of producing the same result from different machines, using the same drawing file, but every process has variability built in, and every machine is slightly different, needs calibration, maintenance, etc.

If someone can get a drawing done and maybe even make a prototype, then let's take it from there and see if we can get a group buy organised. If folks have a contact and want to go their own way, there's no issue with that. a group buy is a lot cheaper for people who don't have a mate with a CNC lathe and milling machine though. It might also be cheaper to get the bearings in a bulk buy.

In terms of the design, if it mounts on top of the strut tower it should drop ride height about 15mm I reckon, depending on design. if you go for 50mm then that might work for some applications, but you'll need to work on the suspension geometry - ball joint extenders maybe - to avoid any unwanted effects. A lower 'standard' drop and spacer rings/plates would probably be better in terms of making it configurable to different setups. For example, if folk already have shorter Leda / other struts, then they won't want another 50mm drop, and won't want to buy new struts.

The slider design looks good, although it's not essential. The Compbrake ones just use an asymmetric ring design to achieve a similar result of camber and castor adjustment.

 

This is a great idea, I`m in, mk2 platform, however this progresses, I don`t have any pet cnc contacts to offer though....

 

Right, great.

All we need is the design. I have a good friend who can do the CAD drawings (thanks to those who have offered too).
I can fit it to my car and go 10 seconds a lap quicker around Brands.

That design can be open source and shared to the world, and maybe improved if needed.

Others can pick that up and do a group buy if they please. If you go to a company who cannot make it to spec, then don't pay them. Whatever we come up with should be pretty straight forward. Others will have mates in machine shops, can make it themselves from the design, or can get a single pair made - whatever suits.
I think we should aim for as little machining as possible, and rely on laser cutting. Machine only the bearing interfaces that need the accuracy.... ? The two main components and the stackable shims (if we go down that route) can be laser cut from sheet.
I have some compbrake ones that need new bearings, but they are not perfect.

I could come up with a design myself, get a batch made and try and sell them to cover my costs... but I think we could come up with a better design collectively. And sharing is what forums are made for, no?

Aluminium or steel plate?
Any other ideas?

If we make provisions to bolt a brace between the top mounts. Then people can get their own bars made to fit, depending on engine clearance etc. Or something similar.

 

Steel for the biggest bit. It will allow folk to go ahead and bore(or order not bored), or tig to turret.
Everything else aluminum, provided that bolt threads are engaged in alloy 2.5 times diameter of bolt. If 2.5 times cannot be got without excessive alloy/bulk, pull that bit back to steel too.
Id even go as far as helicoiling any alloy that needs threads to get over any stripping issues, galvanic corrosion, seizing, or other. A heli has also greater pullout resistance as the thread cut to insert heli has a rounded top(crest), and not angled/sharp like a normal metric thread. Less stress risers.
Be aware of tolerances should folk want to get alloy bits anodized, a press fit to raw, or anodized will have a different tolerance callout for the spherical bearing.

Everything else should be pretty much abc.
Offering a spacer skirt could be done too, say three different types. Supplied in flat form for easy postage, that the fitter would roll around to form spacer ring. This would be flat ontop, and scribed to turret on the bottom.
Cant remember turret top, but....

Brian,

 

Is the 'plate type' design easier to make than the offset circular ally one? I haven't seen the underside of those types, but from the top it looks like a flat plate with slots cut in it, and the machining work on the top part is all in one plane (if that's the right term - been a few years since I was hanging around in machine shops for a living).

Bottom part needs to hold the bearing, and have a boss to locate to the top plate.

Disadvantage of those type is you need to remove the top lip from the turret.

http://www.clubgti.com/showthread.php?246942-Ground-control-top-mounts

 

Is the 'plate type' design easier to make than the offset circular ally one? I haven't seen the underside of those types, but from the top it looks like a flat plate with slots cut in it, and the machining work on the top part is all in one plane (if that's the right term - been a few years since I was hanging around in machine shops for a living).

Bottom part needs to hold the bearing, and have a boss to locate to the top plate.

Disadvantage of those type is you need to remove the top lip from the turret.

http://www.clubgti.com/showthread.php?246942-Ground-control-top-mounts

 

Mk2 over here as well. If any dimensions/pics required, let me know.

 

Thanks for the input Brian. Great stuff.
I see what you mean Mike.
I wouldn't really mind cutting the turret about I suppose, but we could do with some input from potential users. What do people want? Then we can design something people want, instead of just something I want. Haha.

 

Maybe you could design around the lip - cut a groove in the bottom plate to suit, if the strut is bolted to the top plate and moves with it. Not sure if the existing designs do that or if it's the bottom plate that moves.

Meanwhile, do we need to start collecting dimensions for various cars - it would be interesting to see if we can develop a design that does more than one model.

Useful dimensions (initial design parameters?) would be:

- Circumference of the top of the turret, and the hole in it.
- Clearance from top of turret to inside of bonnet.
- Height of any lip on the top of the turret.
- Height between the top of the turret (not the lip) and the top of the strut - lip where the bearing sits.
- Size of strut top pin inside diameter of bearing insert.

Pics for comparison...

Do we start with Mk1, Mk2, Mk3 Golfs, and Mk1&2 Scirocco? Mk1 Scirocco is the same as Mk1 golf I think, but the turret top on the Mk2 is different. Enough interest in a Mk4 golf too?

If we can come up with a design that works for all the above (maybe with a different insert in the bearing if needed), then that's a big win and expands the benefit to a lot of people, when you add in the various Seats and other models that use the same designs. Maybe there need to be two designs or more, but it's worth a try.

 

mk1 interest here

 

I have a local machine shop who is up for small jobs, I`ll have a word with him.

I looked at trying to get a set of these made a while ago, but not having any to measure meant I was struggling TBH.

 

one for the mix

 

So are they camber adjustable only, Razzer?

Might be a start point to make a camber-castor adjustable one though. Flat plate, so relatively simple to make I'd think.

 

Ray! That's the stuff! Piece of cake to make if we have the dimensions.

How do we get a ride height drop with that. Stackable spacers. Caster with slotted bolt holes?

 

Would they be strong enough if they were mounted on top of the turret on a spacer? Removal of the standard top mount and just mounting them on the top would probably get about a 20mm drop, I reckon.

Are they about 5mm thick, Razzer?