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Front Rocker Arm Assembly

Posted: Mon Dec 08, 2008 6:31 pm
by Antnicuk
As mentioned in my rebuild thread, i have discovered that my drivers side rocker arm has forward/backward play between the brackets.

I havent tried taking it to bits yet but was wondering how its assembled. I have a nut at each end of the pivot, is that because studding was used and not a nut and bolt? Is it just a case of packing it with a washer so its tight (both bolts are tight)

Re: Front Rocker Arm Assembly

Posted: Mon Dec 08, 2008 7:20 pm
by stylussprinter
Antnicuk wrote:As mentioned in my rebuild thread, i have discovered that my drivers side rocker arm has forward/backward play between the brackets.

I havent tried taking it to bits yet but was wondering how its assembled. I have a nut at each end of the pivot, is that because studding was used and not a nut and bolt? Is it just a case of packing it with a washer so its tight (both bolts are tight)
The rocker arm assembly kit should have a sixty's ' mini ' spindle & nuts / bearings for each end / washers-scored / locating oval plate&nuts bolts. If assembled correctly :?: and greased -- this arm shouldn't move .
There's just a possibility that your previous owner didn't put the front washer / scored in , either trapped on one edge or not there at all . Apart from that , it all just gets bolted up very tight. No way of telling until you've taken it apart Tony :roll:
You certainly don't want any extra washers put in :shock:

While you're measuring , you could put a straight edge tight against the two rocker towers over the width of the car THEN check the distances from that straight edge to left and right rockers at their outer points plus inner points . ie. where the shocks fit and where the uprights fit. If these are not equal , this could be the reason your axle seems '' twisted '' as you put it :wink: This is the problem I was eluding to regarding who made the chassis . SO ---- if you then mistakingly re-set the axle to suit the front , the car will ' crab ' :roll:

So before you start altering things towards perfection you need to know WHY things appear ' out ' . Most people wont bother checking but unless needing the very last ounce of track performance , they wont notice it.

I found all these little imperfections way back in 1999 and had great disagreement with P.Powell over it . I actually had the towers cut off and relocated . My eye just picked it up on assembly although P.P. said he couldn't see it. To prove the point I measured each side of the car ---- wheel centre to wheel centre ----- they where 10mm out :shock:

Very few people have mentioned it so it obviously hasn't affected the driving experience enough to get noticed. I told everybody I knew personally at the time though .

Re: Front Rocker Arm Assembly

Posted: Mon Dec 08, 2008 7:44 pm
by Antnicuk
thanks for that rob, i will have to take it to bits and check things out.

I think i understand what you mean about the rocker arms, are you saying that one rocker arm could be further forward than the other or that the rocker itself isnt at right angles with the chassis?,

What I'm saying Tony is in answer to you saying '' there's play in the rocker '' ---- Then , that while you're at it '' check that the towers are equally angled '' . Your other suppositions are best ignored till you define the trueness of the chassis/suspension . Even then , an answer on here in words is too easily misunderstood :wink:

If its the former, am i right in thinking that this would also alter the caster?

YES --- but that's easily sorted :wink:

Also, if one front wheel is more forward than the other, the toe could still be set straight with the car? YES

if it is the former, the measurement from the centre points between the front and back wheels would be different each side? but if its the latter, then the centre points wouldnt change too much? is that right?

So, when my car was on the digital 4 wheel alignment thingy, it showed that one rear wheel was toe out and the other toe in. I assume that the machine isnt measuring the distance to the front wheel but actually measuring the angle of the rear wheels compared to the angle of the front (rear toe) so means my axle is slightly twisted??

POSSIBLY ---- but more likely the arms OR chassis pick-ups aren't 100 % true which is probably the same for most kit cars DEPENDING on how much . I don't believe many ' kits ' are F1 true plus most will never notice anyway :roll:

This is very difficult to explain in writing :? BEST discussed verbally.

Re: Front Rocker Arm Assembly

Posted: Tue Dec 09, 2008 10:18 am
by Bikenuts
"To prove the point I measured each side of the car ---- wheel centre to wheel centre ----- they where 10mm out” That’s not as bad as it sounds - most of the manufactures I've worked for have had a tolerance of around 5mm - and a number of cars have been designed with different wheel bases on each side and any car with a phanard rod will inevitably have the axle offset slightly to one side or the other most of the time. What is important is to get all 4 wheels pointing in the same direction then add toe in or out – the old fashioned Gunsons trackright is actually very good for this.

Re: Front Rocker Arm Assembly

Posted: Tue Dec 09, 2008 10:47 am
by stylussprinter
Bikenuts wrote:"To prove the point I measured each side of the car ---- wheel centre to wheel centre ----- they where 10mm out” That’s not as bad as it sounds - most of the manufactures I've worked for have had a tolerance of around 5mm - and a number of cars have been designed with different wheel bases on each side and any car with a phanard rod will inevitably have the axle offset slightly to one side or the other most of the time. What is important is to get all 4 wheels pointing in the same direction then add toe in or out – the old fashioned Gunsons trackright is actually very good for this.
I knew myself , without measuring wheel centres , that the drivers side tower was welded onto the chassis with a clockwise twist unequal to the passenger side .(just by eye) Peter P couldn't see it , so that was a way of showing him. I take your point about manufacturers in general not worrying about it ---- the P . 205 GTI was built with the drivers side rear wheel 10mm or so further back . I did emphasize that most wouldn't notice :wink:

Re: Front Rocker Arm Assembly

Posted: Fri Jan 02, 2009 7:34 pm
by Antnicuk
Right,

I have removed the rocker arms tonight, the passenger one moved 2-3 mm and the drivers moved about 5mm front to back on the spindles. Both were done up tight and had nice easy movement with no play but when levered, would slide as mentioned above.

Now they are off I can only just turn the spindle by hand as its stiff but when it was bolted up in place, it was easy to move the arm, i'm not sure if this is down to the extra leverage or not.

Both sides were the same with a thick 'washer' to the front and a thinner one at the back. Both washers had a groove machined in but this groove is off centre so i dont see how this can locate anything?

Tomorrow i am going to fix rose joints to the lower wishbone and then re assemble it all but i want to make sure the rockers are ok and not going to slide as this will bugger up my caster

I also want to replace the upper ball joint that seems to be screwed into the top of the upright, what is it from?, and does it just unscrew?

see pic for washers/spacers

Image

Re: Front Rocker Arm Assembly

Posted: Fri Jan 02, 2009 8:41 pm
by kevp
Top swivel joint as listed on web site QSJ 1060S

Re: Front Rocker Arm Assembly

Posted: Fri Jan 02, 2009 9:02 pm
by Antnicuk
thanks for that, are they like these?


http://cgi.ebay.co.uk/MGF-TF-MG-METRO-M ... 1|240:1318

If so, i cant seem to see any thread at the bottom, do they screw in to the upright?

Re: Front Rocker Arm Assembly

Posted: Fri Jan 02, 2009 10:47 pm
by stylussprinter
Antnicuk wrote:thanks for that, are they like these?


http://cgi.ebay.co.uk/MGF-TF-MG-METRO-M ... 1|240:1318

If so, i cant seem to see any thread at the bottom, do they screw in to the upright?
They are 'old Mini' swinging arm from memory. The cut off macpherson strut gets a threaded outer welded on as part of the ' new kit ' supply when buying a Stylus kit from ssc . I believe Fury's and Striker's copied this idea from Neville Powell's developement of the ssc chassis when P.Powell bought SSC in 1996. This means you'll be able to get them from both those places if you can't find them elsewhere :roll: All Sylva's originally had Chevette top swivels but it was possible to fit them back to front causing crazy camber :shock: , hence Neville's change to ' mini ' swivels :wink:
Amazingly MGF's still use this joint --- I've seen them on my son's car when he was sorting the brakes last time he borrowed my jacks etc :o

Re: Front Rocker Arm Assembly

Posted: Fri Jan 02, 2009 11:59 pm
by Antnicuk
the ones in the ebay link says for metros and mgfs but not for minis. Can i just bend the safety tab and unscrew the joint?

I have finally figured out the bearings. The shaft has 2 raised steps, 1 at each end of the tube sticking out just proud of the tube end, The idea is that the two washers clamp against the steps holding the spindle clamped between the 2 brackets on the chassis, thus allowing the rocker arm to rock on the bearings inside the tube. The edges of the tube should be as close to the inside face of the washers without binding so the tube doesnt slide along the spindle. The tubes on mine are a couple of mm shorter than they should be so when clamped the tube in the rocker is able to slide along the spindle between the clamping washers. I will machine the centre of one of the washers a little more (0.5mm ish) so it gets closer to the tube once clamped.

Thats what i think anyway!

Re: Front Rocker Arm Assembly

Posted: Sat Jan 03, 2009 12:25 am
by Antnicuk
the ones in the ebay link dont seem to have the hex at the base of the ball to scre it into the upright.

here is the picture

http://six.ebid.net/upload_big/3/8/1/12 ... -859-0.jpg

I have found these which seem to have the hex bit

http://www.southwalesprops.co.uk/images/qsj1060.jpg

Re: Front Rocker Arm Assembly

Posted: Sat Jan 03, 2009 2:09 am
by Bikenuts
You need the second type, the first are the joints from the bottom of the suspension cones. Before you buy new take the old ones apart they should have shims under the washer to adjust them- if there not worn or rusty.

See here;http://cgi.ebay.co.uk/MINI-BALL-JOINT-K ... 240%3A1318

Matt

Re: Front Rocker Arm Assembly

Posted: Sat Jan 03, 2009 2:27 am
by Antnicuk
They are not rusty but are a little loose, and i need new rubbers, i thought for the sake of £15 i would put new ones in. Didnt know they would come apart. I will have to have another look. If i have to assemble new ones then i may just refurbish mine.

Re: Front Rocker Arm Assembly

Posted: Sat Jan 03, 2009 10:28 am
by MattD
Plenty of replacement rocker arm pivot's on Ebay for a tenner each too.

They are just Metro rear radius arm pivot bearings... :?
632f_1.jpg

Re: Front Rocker Arm Assembly

Posted: Sat Jan 03, 2009 11:49 am
by Antnicuk
cheers matt. my bearings dont look like that, they look like a conventional bearing rather than a needle bearing. I'm going to have a better look today, i think with a bit of lube.