ChrisJ15
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| posted on 2/10/22 at 02:50 PM |
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J15 Metalastic Bushes
I had an MOT advisory: 'Suspension arm pin or bush worn but not resulting in excessive movement Nearside front upper'.
When I had a look there was significant play in the rearmost upper bush. I took the wishbone off and noticed that the bolt (12mm) does not fit snugly
into the inner lining of the bush. StupidlyI didn't measure the internal dimension of the bush or whether the bolt was a tight fit in the
chassis's suspension mount.
What I do know is that the play went away when I did the bolt up 'F' tight and the handling is 100% better. I was always concerned about how
it would jump around on uneven surfaces but not having a kit car before (or driven one for any distance) I had nothing to compare it to. The way it
drives is totally transformed.
So thats the good news but the problem I can see coming is that when I get the wheel geometry reset and then I have to remove a wishbone or even undo
one of the bolts, its going to go out of alignment.
I guess my options are 1) Get a sleeve made which fills the gap which is OK as long as the bolts are a tight fit in the mounts (I suspect the joint
with movement has ovaled slightly)
2) Drill out mounts to the same size as the bush inner and fit bolts of that size (if available). I'm not loving he thought of exposing bare
metal to the elements though.
So two questions for my J15 colleages: 1) Does anyone know what size the metalastic bushes are that came with J15 kits?
2) I've seen Powerflex Poly Bushes on the Riotcars website. Would these make the ride even firmer (Its already very firm!)?
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Sanzomat
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| posted on 2/10/22 at 03:25 PM |
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Just a punt - not a J15 expert. Should they be 1/2" bolts, not M12? My Locost has MK Indy classic front wishbones and the bushes that came with
them are very loose on a M12 but a close clearance fit on 1/2" imperial bolts so that's what I used.
The other thing to check - are the bolts long enough for the unthreaded shank part to go right through the bush sleeves and chassis pick-up clevises?
Some say it doesn't matter if the bolt inside the bush sleeve is threaded but the guy who set mine up (former race engineer) suggested it does
matter and for the small difference in cost it seemed worth buying extra long bolts and cutting them down to length thus having solid metal rather
than threaded metal all the way through.
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ChrisJ15
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| posted on 2/10/22 at 03:31 PM |
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quote:
Originally posted by Sanzomat
Just a punt - not a J15 expert. Should they be 1/2" bolts, not M12? My Locost has MK Indy classic front wishbones and the bushes that came with
them are very loose on a M12 but a close clearance fit on 1/2" imperial bolts so that's what I used.
The other thing to check - are the bolts long enough for the unthreaded shank part to go right through the bush sleeves and chassis pick-up clevises?
Some say it doesn't matter if the bolt inside the bush sleeve is threaded but the guy who set mine up (former race engineer) suggested it does
matter and for the small difference in cost it seemed worth buying extra long bolts and cutting them down to length thus having solid metal rather
than threaded metal all the way through.
I think the bush internal dimension could well have been 1/2" but the bolts and the bushes all came with the kit so it built as designed.
I don't think there was any thread within the bush but didnt specifically look at this so can't be 100% sure.
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adithorp
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| posted on 2/10/22 at 08:45 PM |
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Jeremy had a nasty habit of using g 1/2' bushes with 12mm bracket holes and bolts. Can cause issues with geometry when removing or loosening
bolts when they retightened due to the o.5mm free play in the bolt. Best option is open up the bracket holes to 1/2' and fit 1/2" UNF
bolts.
PS. The bolts should always be tight to hold the crush tube (clue is in the name) and prevent free play.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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ChrisJ15
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| posted on 3/10/22 at 07:58 AM |
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quote:
Originally posted by adithorp
Jeremy had a nasty habit of using g 1/2' bushes with 12mm bracket holes and bolts. Can cause issues with geometry when removing or loosening
bolts when they retightened due to the o.5mm free play in the bolt. Best option is open up the bracket holes to 1/2' and fit 1/2" UNF
bolts.
PS. The bolts should always be tight to hold the crush tube (clue is in the name) and prevent free play.
I think that's the sensible option. That would hopefully remove any ovaling of the mount that wasn't tight enough.
Any thoughts on rust proofing where the powder coat will be removed? Would be fiddly to paint. Grease is an option but don't want to get any on
threads and reduce the effectiveness of the nylocs.
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nickm
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| posted on 3/10/22 at 06:49 PM |
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Hi Chris
Not sure about the 1/2 inch to 12mm metric part of the question as i dont know either way but i cant see how one bush could upset the geometry to much
as all the adjustability is around the rod end/spherical bearing
If somebody said to me what is the toe camber etc i wouldnt have a clue all i know is its symmetrical and handles well ! .
When i asked JP for some base settings his reply was set to 0 and adjust till its right for you so thats sort of what ive done
Hope your still enjoying the car
Nick M
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ChrisJ15
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| posted on 3/10/22 at 06:58 PM |
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quote:
Originally posted by nickm
Hi Chris
Not sure about the 1/2 inch to 12mm metric part of the question as i dont know either way but i cant see how one bush could upset the geometry to much
as all the adjustability is around the rod end/spherical bearing
If somebody said to me what is the toe camber etc i wouldnt have a clue all i know is its symmetrical and handles well ! .
When i asked JP for some base settings his reply was set to 0 and adjust till its right for you so thats sort of what ive done
Hope your still enjoying the car
Nick M
Hi Nick,
Essentially the top wishbone was able to move left to right which would have constantly changed the camber angle.
It always felt 'skittish' especially on uneven surfaces. So much so that I rarely felt confident enough to drive with one hand on the wheel.
Totally different now.
Still enjoying it but don't use it anywhere near enough and still haven't tracked it.
Do you still have yours?
Cheers,
Chris
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adithorp
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| posted on 4/10/22 at 08:22 AM |
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I was lucky that KitCarWorkshop had changes the Fury chassis to 1/2" holes and bolts but many earlier ones weren't and subsequent designs
are 12mm to my knowledge.
I think people have used a taper reamer to open them up to 1/2". I'd just paint to holes or wipe a bit of grease in them. Don't worry
about that affecting the tightness; just aslikely that the paint/powder coat compressing and doing the same... near zero!
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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nickm
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| posted on 4/10/22 at 06:39 PM |
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Hi Chris
Still got it still love it !!
Changed the cams in the spring (said i would never do it didnt want to increase the vibration factor) but i did and gained 15hp but now tuned down a
bit for road use it pulls like a train the torque line is virtually flat fm 2500-6000rpm.
I want to go down to 14" wheels but i cant find any that are lighter than the 15s i have on it (team dynamics) would love to go down to 13"
really but they wont cover the RMD/Audi rear calipers.
Wash it once in a blue moon its to much fun to waste time cleaning it !!!
Hope your enjoying yours have you had any upgraditus yet
Nick M
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bi22le
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| posted on 4/10/22 at 11:26 PM |
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As suggested above it's common to change all of the bolts to 1/2". I did this and it made a massive difference.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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pigeondave
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| posted on 5/10/22 at 12:51 PM |
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Yep, reamed out the holes to 1/2" on the Fury all good now.
I was at BGH when they had the Fury and Chris showed me the difference between the metric and imperial metalistic bushes. The metric one was a lot
looser than the imperial, when using the correct bolts ie metric- metric bush, imperial-imperial bush.
metric in an imperial bush was hot-dog down a hallway.
It'll be a fun winter project.
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ChrisJ15
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| posted on 5/10/22 at 03:21 PM |
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quote:
Originally posted by nickm
Hi Chris
Still got it still love it !!
Changed the cams in the spring (said i would never do it didnt want to increase the vibration factor) but i did and gained 15hp but now tuned down a
bit for road use it pulls like a train the torque line is virtually flat fm 2500-6000rpm.
I want to go down to 14" wheels but i cant find any that are lighter than the 15s i have on it (team dynamics) would love to go down to 13"
really but they wont cover the RMD/Audi rear calipers.
Wash it once in a blue moon its to much fun to waste time cleaning it !!!
Hope your enjoying yours have you had any upgraditus yet
Nick M
Hi Nick,
I went for 14" minilites and even with those I had to grind the fins off the RMD calipers.
I haven't upgraded anything yet. I was lucky enough to get 200bhp with the Duratec when it was initially setup and it still scares the bejabers
out of me most times I drive it! 
Main issue at the mo is replacing the tyres as they are begining to perish but the A048 Yoahamas aren't E rated anymore
(www.locostbuilders.co.uk/forum/viewthread.php?tid=219625).
I'm also strangley unfussy about keeping mine clean and quite like the well used/fly splattered look. It kind of goes with the Elva/race car
styling I think!
Chris
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nickm
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| posted on 5/10/22 at 06:33 PM |
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Hi Chris
Yep you get it out of the garage because its dirty and the weather is dry and then before you know it your 20 miles away. The engine block is cleaner
than the fibreglass.
My upgrades for power are now complete i could gain a few hp with a proper air filter rather than socks but i would have to get shorter injectors to
move the fuel rail back to fit the filter in between the tbs and chassis rail but seeing as i can get it to snake and squirm a bit at 40/50mph with a
downshift alongside flooring it i dont need anymore (the older u get the more mortal you become !!).
I replaced my toyo proxes this year the soft rubber compared with the old hard stuff made quite a difference.
Managed to get a picture of it in Complete kitcar mag but the size of a postage stamp at the Newark show !!
Fantastic toy and fantastic hobby i would only sell to fund another build which i have been considering but i cant get a reply fm Miles Southerton at
Riot Cars ?
200bhp your a braver man than me !!!!!
Nick M
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