[Tigers] Backing up other cars
Tom Witt
atwittsend at verizon.net
Thu May 21 15:24:08 MDT 2015
I did the fulcrum pin reinforcement on the cross member. The concept
originated from John Logan and I did an adaptation of it
http://www.tigersunited.com/techtips/LoganFulcrum/pt-LoganFulcrum1.asp. The
reinforcement basically parallels the fulcrum pin and at the outer pin
attachment point serves as a more rigid support to side forces. However, if
the pin still broke the anti rotate can help to (notice I didn't say would)
keep the bracing plates from rotating. The anti rotate piece fits snugly at
a 90 degree angle to the square brace. It is also helpful in that it
occupies space and should a pin still break, the A-arm has less distance to
travel - if forces are moving it in that direction. If you look at the full
shot of the car and zoom in on the cross member you can see the bracing
plates. The added steel in the cross member "U" (cross member on blue tarp)
was a reinforcement recommended by John Crawley.
Today most people seem to opt for removing the center steel piece from the
urethane bushings and using the thicker fulcrum pins that are available.
But, before that came about the above was a method of reinforcement.
BTW, I have the fulcrum pins Derek White had made in Africa (the stock
diameter version). I know about 20 or so people got them. Most I believe
were the larger diameter version. Some were predicting doom & gloom with
their use. It has been well over 10+ years now. I was wondering if anyone
ever had a failure?
-----Original Message-----
From: Gary Winblad
Sent: Thursday, May 21, 2015 1:34 PM
To: Tom Witt
Cc: tigers at autox.team.net
Subject: Re: [Tigers] Backing up other cars
Interesting stuff!
What are those "anti rotate" pieces?
Gary
----- Original Message -----
From: Tom Witt via Tigers <tigers at autox.team.net>
To: tigers at autox.team.net
Sent: Thu, 21 May 2015 16:39:19 -0000 (UTC)
Subject: Re: [Tigers] Backing up other cars
I have the MGB arms on my Tiger. They require about a 1/2” spacer on the
front bolt to fill in a gap between the arm and the spindle. The two bolt
holes do not align perfectly. You need to file or mill out one of the holes
a small amount as I believe the spacing is too large on the MGB arm. If you
are searching for every bit of help you can get, my recollection is that the
front hole is filed towards the rear and that positions the arm about a
1/16”-1/8” more forward, rather than 1/16”-1/8” more rearward if you file
the rear hole. I did this over 10 years ago so check by observation for
which hole to file, but the goal is to get the arm as far forward as
possible. The backing plate/shield needs a notch about 1” high and about
1/2” deep as the arm positions in its path and you need the room for the
tie rod end. For the record I have 13” Cosmic wheels (like those on the
Harrington Tiger) and they clear this modification though I believe I have
about a 1/4” spacer under the wheel. Sorry for the vagueness but my car has
been on jack stands for 15 years now and is currently buried in wood for my
daughters Tiny House.
Regarding rack modification; my rack apparently had one of the ends damaged
at some time in its life. Someone did a hack repair by simply welding on an
Alpine section. A very dubious repair. Some here were horrified when I
shortened both rack ends and then cut threads with a die (left and right
threads) as the original threads are rolled. The die was somewhat adjustable
and I made light cuts after the initial cut. I constantly back cut after a
few degrees of rotation of the die. I then lightly chased the threads with a
fine file and did everything I could to remove burrs, tears, etc.. I did the
threads likewise with a grade 8 bolt which attached to the tie rod end. To
couple the two together I used the split tube and clamp that just about
every American car had before struts became popular. They needed to be as
short as possible and 70’s era AMC tubes (Hornet I recall) were used. Both
the adjustable die and the split tube/clamps were helpful because the
diameter of the rack is not consistent. It allows for the incremental
adjustment people desire and frankly I feel a whole lot more comfortable
with this than a welded on Alpine piece. That said, it would be something
that one does at their own risk. I don’t advise cutting up a stock rack,
but in my case it seemed irrelevant.
Notes on the images: I do not have the clamps on the split tube at this
time, for the record I plan on having two clamps per side. Parts for the
modification. Buried Tiger (will it EVER see the road in y lifetime???).
From: Gary via Tigers
Sent: Wednesday, May 20, 2015 7:08 PM
To: Tom Parker
Cc: Tiger's Den
Subject: Re: [Tigers] Backing up other cars
Thanks Tom, but I knew all that..
What I was wondering was what tie rod ends
or machining on the steering arms did you
have to do? The Alpine arms are slightly
longer than the MGB arms and should help
even more, that was part of Doane's race
mods IIRC. I haven' t heard of anyone else
using the stock rack like you. Did you have
to "unbend" the rack arms and did you make
sure you didn't run out of rack ball joint
travel? You should be able to do your own
precision alignment using the "strings"
method, I do.
Gary
Sent from my iPhone
On May 20, 2015, at 6:31 PM, Tom Parker <tkparker1941 at gmail.com> wrote:
Hi Gary, and Buck,
First, Buck's right, and I think I implied that. The MGB arms DO NOT fix
the Ackerman Angle issue in the Tiger. "The best we can hope for is a
steering angle of about zero degrees with the stock crossmember." The
issue is the MGA rack George fitted to the Alpine crossmember is way too far
forward, and it isn't possible to get close to a proper Ackerman Angle. It
isn't, imho, a problem with the rack, it's with the mounting position. For
about $10,000 Dale can "fix" the problem by constructing a new crossmember
with the rack in a straight line with the steering arms. Is it that simple?
No, and I won't begin to try to understand the math involved. See DrMayf's
article.
What the arms do is what we both said earlier: the make the steering a bit
easier, and they reduce the tire scrub a bit. That's all. The MGB arms are
about an inch longer than the stock Tiger arms. It's about as far as you can
go, and it requires 15" or larger wheels.
There are a few "solutions to the problem. I know the redesigned
crossmember works, and I'be seen Alpine spindles reversed (swapped side to
side) with Alpine steering arms to the front, but I don't know how close it
comes to solving anything. And I don't know if that "fix" works with the
Tiger rack.
Now to the MGB steering arms: Randy Willett (willett581 at msn.com) did the
modification. It involved elongating the center mounting hole a bit and
adding a spacer to align the arm "parallel" (more or less) to the spindle. I
torqued it down to Tiger specs, Randy argued for a bit more torque. He
supplied grade 8 bolts. There's maybe an inch of thread left at the tie rod
ends, and less than an inch clearance to the inside of the wheel. I'm not
going to race the car, street or otherwise. The MGB "solution" helps, and
that's all I was looking for. I knew up front it wasn't a "fix."
So... a bit easier (lighter) steering, not as much scrub. With @ 0" toe
the steering is quite sensitive. I used a Toe Alignment Bar; it's close to
zero toe. How close? I dunno; that takes an alignment rack and the local
guys aren't interested in aligning a car without alignment turnbuckles for
less than @ $350.00. That'll keep 'till I get the Kitty back to Georgia.
Tom
'67 Mark 2
On Wed, May 20, 2015 at 6:41 PM, Gary <garywinblad at comcast.net> wrote:
Tom,
Interesting... I bought some MGB arms a
long time ago. How did you connect them?
Gary
Sent from my iPhone
On May 19, 2015, at 7:22 AM, Tom Parker via Tigers
<tigers at autox.team.net> wrote:
MGB steering arms with the stock Tiger rack (since Dale no longer
makes the Midget rack kit...) solves a lot of the wheel scrub issues when
backing up. The steering's lighter, too, by just a bit. DrMayf wrote (imho)
the definitive analysis on Ackerman v Tigers issue. The best we can hope for
is a steering angle of about zero degrees with the stock crossmember.
Tom
'67 Mark 2
On Mon, May 18, 2015 at 10:21 PM, Jay Laifman via Tigers
<tigers at autox.team.net> wrote:
Every time I back up a non-Tiger, my predispostion to not going full
lock on the Tiger seems to always come through and prevents me from doing it
with the non-Tiger too. I get a chuckle out of it each time - but I still
can't bring myself to do it!
Just thought I'd share that thought.
Jay
-------------- next part --------------
A non-text attachment was scrubbed...
Name: bottom crossmember smaller .jpg
Type: image/jpeg
Size: 493038 bytes
Desc: not available
URL: <http://autox.team.net/pipermail/tigers/attachments/20150521/538ca2d5/attachment-0003.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: full shot pass.jpg
Type: image/jpeg
Size: 279164 bytes
Desc: not available
URL: <http://autox.team.net/pipermail/tigers/attachments/20150521/538ca2d5/attachment-0004.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: african pins.jpg
Type: image/jpeg
Size: 185562 bytes
Desc: not available
URL: <http://autox.team.net/pipermail/tigers/attachments/20150521/538ca2d5/attachment-0005.jpg>
More information about the Tigers
mailing list