mushroom inserts

[georgenewman1]

hi again, bought a set of mushroom inserts off of ebay for cheap, the only problem is that they have the hole in the middle, is this a problem as the book ststes that you need it offset toward the front, any ideas???

[alga]

AFAIU shifting the pivot point forward changes the effective length of steering arms, which in turn adjusts (I think) the front axis turn radius. If the mushrooms are centered, the axes of front wheels will intersect at the Sierra's standard wheelbase -- 2608 mm, whereas the Haynes Roadster's wheelbase is 2300 mm.

[frankie boy]

HI
The offset mushroom is for the caster. This mushroom is needed to maintain the correct geometry. Before SVA I had the centre hold mushroom but it didn’t self centre very well. I have noticed on some cars with the sierra upright haven’t used the offset mushroom or have the angle on the top wishbone not sore what affect this would have on the ride of the car.

[alga]

Frankie, I used to think so too, but consider this: the hub will rotate around the axis going between the top and bottom ball joints. Caster is the slant of this axis. The offset, or position, of the mushroom insert will not shift this axis at all.

[RAYLEE29]

I am no suspension expert but I beleive it has something to do with kingpin inclination.
the suspension is designed to use an offset mushroom so if you want your car to handle properly use one thats offset.
Ray:)

[squbti]

hi all, does anyone know if it would be ok to use ali mushrooms ?
cheers
Samy

[londonsean69]

hi all, does anyone know if it would be ok to use ali mushrooms ?
cheers
Samy

No idea if it is OK, but mine are going to be Ally, when I get my lathe sorted.

I guess it also depends on what you are using for power, and how you are using it.

BEC vs Car engine
Road vs Track
etc.

Sean

[squbti]

yeh i think it should be ok too, i know there are some uprights made of ali so i cant think of any reason why ali mushrooms wont work .
Samy

[londonsean69]

MNR do theirs in HE30 ally (same as me), so no reason not to use ally.

Although I am sure someone will be along to tell us why not:D

As an aside, what are the 3GE inserts made from?

Sean

[Spikehaus]

Offset mushrooms are building an unstable pivot into the geometry. A grub screw may help any correct any movement for the IVA. I am yet to here of any calculations to backup this geometry. I have run this item past all the local precision engineers and yet to receive any feedback to the contrary.

I challenge some geometry based calculations or drawings to prove this? Ally is acceptable, but I recommend that that the stem is extended to fill the hub counter bore.

[londonsean69]

Spike, you've lost me there!!

I think that for the IVA they need a secondary fixing such as a bolt tapped into the mushroom, through the cast upright.

As far as calculations to back up the geometry, surely Ford 'must' have done some work on this. Although obviously the Ford upright is being used in a different situation.

And what item have you run past the local precision engineers?? The insert, the upright??

Also, what do you mean by "the stem is extended to fill the hub counter bore"??

Sean

[squbti]

hey guys , kinda lost me there too. anyone have a picture or drawing of how the inserts should look for them to sitt corectly in the uprights .how long should they be & whats the best way to fasten them ?
Samy

[RAYLEE29]

take a look at this
its the pdf somone posted before the big post loss
its not my drawing I take no responsibility for it but it may be usefull to you
ive made my mushrooms from ali theyre offset made close to this drg but i may have altered them
if someone can give me a valid reason then ill remake them in some stainless i have but for now they are ali
hope this helps
Ray:)

[Bonzo]

That's the one I posted many moons ago :)

Kindly drawn by my Nephew

I believe I still have them on my desktop system somewhere & have been meaning to rake it out and have a look :o
Since I have had my laptop, my poor old system has been packed up & put away.

Just as well the wife is blissfully unaware of how much that system cost me to build :eek: :D

[RAYLEE29]

hi ronnie i have the other two if you wat ill post them up too?

[Bonzo]

Cheers Ray :) :)

It'll be nice to have some of the lost posts back :cool:

EDIT

I can see no reason as to why alloy wouldn't be suitable for the inserts & a darn site easier to machine too ;)

[RAYLEE29]

ok heres the other two:)

[squbti]

hey guys , great drawings, thanks for the help.actualy i think i have them from before but its good to know i can make them out of ali but there´s one thing i dont realy understand & thats what the notches are for? & do i have to do anything else so that they dont pop out?
Cheers

[Bonzo]

The notches were put there to allow the use of a C spanner to help locate accurately if they are a little tight in the upright.
They can be left out if not needed.

In the UK some IVA stations require a secondary fixing point for the mushroom adapter.

A simple grub screw will do.
Personally I think the reason for a secondary fixing is to eliminate the risk of the insert lifting out of the upright if the pinch bolt becomes loose or snaps.

[AshG]

mine are made from ali.

[sirtommy]

Just wanted to make sure that before i make the mushrooms that the drawings above are correct. Anyone made them using these drawings.
regards, Tom

[Bonzo]

Hi Tom

I have those very mushrooms fitted to my build at the moment & have found no issues.

Have a nice pair of Red anodised alloy ones to go on the build when it goes on the Road ( Thanks Kev :) )

The pair currently on my build were CNC machined & were specifically designed for the Sierra front upright.

The drawings on this forum were kindly drawn up by my Nephew, a post graduate mechanical design engineer :)

I hope that this is of some help.

[sirtommy]

Yeah made one today. Did it the old fashioned way on a lathe and milling machine. Considered making mine out of ali but decided not to as aluminium and cast iron/steel hate eat each other.

[fabbyglass]

Could always add a bit of garlic which is supposed to improve mushrooms:rolleyes: