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twentyover Dork
3/8/21 9:38 p.m.

Generally with kits of this ilk the oil is drained from the lever, rendering it inop. Maybe contact Peter Caldwell @ Worldwide if you want to run the levers for a better than original rebuild (it's true)



AxeHealey Dork
3/9/21 8:26 a.m.

In reply to Robbie (Forum Supporter) :

Doubly shock absorbed. That's got to make it handle better, right??

TurnerX19 UltraDork
3/9/21 8:32 a.m.

When I have installed these type kits I removed the valve from the lever shock and refilled the oil. I think the control arm bushings prefer it. The only worn out bushings I saw were on Morris Minors in hundreds of beat up lever shock cars.

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
3/9/21 11:43 a.m.

Yeah, I'm aware that the bolt on tube shock conversions are definitely not guaranteed to be 'better' than a good-functioning lever shock, and I'm vaguely aware that lever shocks can be rebuilt and re-tuned to do many different things. Long term I'll look into those options, especially because I think the shortness of the tube shocks needed for this conversion means you end up with a shock that is really not meant for the MGB application. For example, I think I've heard that Chevy 3/4 van rear shocks are often used simply because they are short enough to physically fit. Nice... 

TurnerX19 UltraDork
3/9/21 4:23 p.m.

In reply to Robbie (Forum Supporter) :

I liked the results I got on the conversions I did. The motion ratio is so great that the 3/4 ton Chevy shock may be the perfect solution. That said, the kits I installed (30 years ago) were all Moss Motors sourced.

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
3/10/21 12:22 p.m.

So, I need to be ordering some motor mounts soon here. The ones I have are 'useable' but I want to fab stuff with fresh mounts so that I'm not fabricating based on the position of sagging old rubber. 

Anyone have miata mount experience? Options are:

  1. Aftermarket - $30ish each
  2. Mazda stock - $60ish each
  3. Mazda motorsport (40% stiffer than stock) - $55ish each

I guess I'm leaning toward the motorsport ones, any reason not to?


Carl Heideman
Carl Heideman
3/10/21 3:05 p.m.

I like the motorsport ones.  They reduce engine shake but don't seem to cause any NVH.  We run them on our Miatas and our swapped cars.


cmcgregor (Forum Supporter)
cmcgregor (Forum Supporter) SuperDork
3/10/21 3:53 p.m.

Seconded on the Mazda Motorsport ones. They last longer than the stock ones but aren't annoying.

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
3/11/21 9:39 a.m.

Thanks guys!

In other news I did a bit of a parts run last night. 

A few days ago, I found an ad on fb for bumpers and a dashboard, for $25. I responded since I'm a nut, but the woman said the parts were her dad's and he had a ton more in the garage. So I called him and agreed to drive out.

Turns out, he did have a lot more. He handed me this page and asked me if there was anything I wanted.

I thought I knew what I needed, but as we started looking through his stuff for things I was interested in (radiator, fans, taillights), I started noticing most of the parts were really nice. Great chrome, good shape, everything wrapped up nicely in packing paper. I started to wonder if I could remember if my door handles were as nice, for example. I stopped him and asked if he was looking to sell it all. He told me he realized the other day that this stuff had been sitting untouched in his garage for 15 years, so yes, it was all for sale.

I made him an offer of $150 for everything except the trans and zenith carbs. He accepted. Here's what I came home with - oops.

Next, I had been invited by a guy on the mgb exp forum to a 'wednesday night mg club' meeting that was pretty local to me. So I swing by, and meet some good guys who are all mg nuts.

I was able to stay and chat for a while, which was nice, and when I mentioned I was looking for an RB crossmember, the guy that owned the place pointed to one under his bench and said "That one's yours. Next time you come by, bring me a case of Miller light in glass bottles". 

So, all in all a good trade. A crossmember and some new friends for 12 beers (and by the way, it's really only 10 or maybe even less because I drank 2 of his while I was there!)

And now I've got the "parts car" I was looking for, without even having to drag a parts car home, disassemble it, and get rid of the husk.


Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
3/11/21 9:55 a.m.

I didn't have much time to work after unloading everything, but I did throw a tape measure at the crossmembers. I think the RB crossmember puts the steering rack in a different location relative to the wheels. Looks to be about an inch forward, haven't measured the height yet.

bentwrench SuperDork
3/11/21 12:26 p.m.

Why did they move it?

Bump steer fix, ackerman fix, or making room for motor?

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
3/11/21 12:41 p.m.
bentwrench said:

Why did they move it?

Bump steer fix, ackerman fix, or making room for motor?

Great question. I think 3 is the primary reason - I think it was done to fit the v8s and it is the reason I'm doing it - but I don't actually know if bumpsteer got better or worse. 

I thought ackerman was mostly controlled by the relationship between the point where the outer ball joint connects to the wheel hub and the direction of wheel travel (ie basically controlled by the length and shape of the steering arm)?

TVR Scott (Forum Supporter)
TVR Scott (Forum Supporter) SuperDork
3/11/21 1:56 p.m.

Good haul on all those parts!  What a deal!

Ackerman, to my understanding, can be controlled by moving the rack out of the line drawn through the steering arm mounts where the outer tie rods join it. Front steer, move rack forward for more Ackerman. That is not to contradict what you said, just finally had something to say.

Following, and enjoying,

Carl Heideman
Carl Heideman
3/11/21 8:03 p.m.

Great score!  You just saved yourself a lot of time.  Did you get the fans?  They work much better than aftermarket fans that zip-tie to the radiator.

Here are a couple of tips I can offer about mounting the engine/gearbox.

  1. I wouldn't recommend building a cradle for the engine mounts like we do it at Eclectic.  We've done them that way because we've planned on making bolt-in kits to sell and wanted to offer a fairly reversible mount setup that doesn't require welding.  If I were doing a one-off like yours, I'd just weld more simple mounts to the subframe.  (By the way, we still haven't gone the extra distance to make production versions of the cradle, don't know if we'll ever find time to do that, and maybe the next swap we do will get simple, weld-in mounts.)
  2. Remember that the shifter isn't centered on the stock MGB gearbox and the hole in the tunnel isn't either--it's offset roughly 1/2-1" to the driver side.  So when you position the Miata shifter, don't center it in the hole or your engine/gearbox won't be installed straight.  This will give you mis-matched U-joint angles in the plan view and likely cause a driveshaft vibration.  When I install and engine for a swap, I run a string down the centerline of the car and then use a plumb bob on the center of the crank pulley and the center of the rear output of the gearbox to make sure the engine/gearbox is straight and centered.


Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
3/12/21 10:16 a.m.

I did get the fans and even the guards. 

About the motor mounts - yeah I will have to do some work to center everything up side to side and up and down. And I was thinking of just welding straight to the car or subframe too, wherever is closer. I figure the original engine mounts aren't unboltable so I wasn't too worried about returning mine to stock.

Interestingly I think my pinion angle may be messed up currently. I did some rolling around with an angle finder, and with the car level and weight on the rear springs, the pinion of the diff seemed to be angled up 2 degrees (this was with the trim strip above front and rear tires equidistant from the ground). Pinion angle up = no good.

Now, my "leveling" technique could probably be improved since I'm not sure the trim strip is a great reference point, so I need to look into that more.

In other news, I went through my parts haul. Turns out I actually did get a stromberg carb as well as the intake and the giant intake/exhaust manifold that goes with it. I separated everything into 3 piles. Stuff I will probably use (chrome: including door handles, side marker lights, cowl grill, headlight ring, and both mirrors; and headlights and a brand new windshield washer system with pump and lines and nozzles), stuff I might use (dashboard, dashboard wiring harness, hvac stuff, interior covers and matts, shift boots, armrests, door pieces, etc), and finally a pile of stuff I definitely will not use (stromberg induction, for example, but also a nice tonneau boot and the matching 2 piece bow and bow carrying felt bag, vent windows for a convertible, windshield frame for a convertible, air pump system, and more). I'll probably work on listing anything that might be valuable from the pile I'm definitely not going to use. I think I can get my $150 back pretty easy.

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
3/14/21 9:32 p.m.

Got one spring out, and took some shots of steering racking.

On the CB subframe, the outer ends are a little forward of the rack. Also, the rack is slightly above the middle of wheel travel.

So, it would appear that moving the rack straight forward might increase ackerman. Also, if you lower the ride height 1 inch to offset the rise of the crossmember mounts, the steering rack is moved "down" closer to the rack center.

I mean, tell me where I'm wrong, but that all seems pretty good to me. 

THEORY WARNING: ASSuming that the hub moves straight up and down during wheel travel (it does not necessarily), having the front-steer rack directly in line with the outer tie rods at ride height means that the wheel tends to toe in during both bump and rebound. If the steering rack is above the outer ends but not in front or behind, then on bump you will toe out but on rebound you toe in. Having the rack in front of or behind the outer ends seems like it would just exacerbate whatever effect you're inducing from the height of the rack. (As well as affecting ackerman, as noted).

In other news removing the steering rack was fun. One of the 4 bolts was siezed in the rack itself (steel bolt and aluminum case, I think). The meant I had to hammer on the bolt HARD to push it down a bit to get a saw in between the rack and the crossmember. Then after the rack was off I tried to hammer the bolt back through but it got tight again so I drilled a hole in the bolt to try and relieve pressure but that didn't work. Finally I had to get the pulversived nut that I had been hammering on back off and then hammer the remains of the bolt back out the original direction.



I'm a bit rusty, and was never an expert anyway, but here goes:

I can't remember if ackerman can be achieved by moving the rack back from a line drawn between outer tie rods. I am certain that by having the rack in front of that line, you can get there. ASSuming the current setup has decent ackerman effect, moving the rack forward would decrease that effect until you have a straight line, after which, as you move further past that straight line, ackerman increases. 

Question: do you want to move the rack for oil pan clearance? I have no idea how any stock MGBs ackerman is, but do know a fair amount of bump steer is present in this suspension design, but it never stopped them from being a fun and competent car to drive. Maybe someone with a better understanding of all this will chime in. 

3/15/21 4:38 p.m.

Removing the springs


just unbolt the 4 shock mount bolts. I know it sounds dangerous, but it is not with the MGB. 

TurnerX19 UltraDork
3/15/21 8:19 p.m.

Ackerman is almost meaningless for engine powered vehicles. It is very important with single horse vehicles, and was discovered when they were the norm. In fact quite a few racing cars have used anti-ackerman on the theory that the outer wheel has more load due to weight transfer, so can work at a greater slip angle. The important consideration here is bump steer. Most particularly you must never toe in  when compressing beyond static ride height. With a system where the tie rod is not exactly in line on all planes with one control arm (this one) zero bump steer will not happen, so move the rack in any direction to produce the best compromise outcome. 

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
3/15/21 9:45 p.m.

Wheelsmithy: moving the rack (by switching crossmembers) because it gives room to actually change the belt on the crank pulley with engine in place.

Nohome: yes, that does sound scary. I'll try it.

Turner: I thought toe OUT on compression was what was bad, because when you hit a bump going to a stable alignment (toe in) is better than going unstable? Am I understanding wrong?

TurnerX19 UltraDork
3/16/21 9:41 p.m.

In reply to Robbie (Forum Supporter) :

When you begin to roll in a corner if the outside wheel toes in the car turns in more than the driver inputs and results in massive oversteer, or at least the need to "unsteer" before your line is set. Toe out on compression requires some more steering input to achieve the intended line, but it feels very natural, and once the line is achieved further road irregularities are more naturally controlled. You seem to be addressing bump steer related to straight line driving, where it is far less important then cornering behavior. Bump steer has to be very bad before the effect in straight line operation is a serious concern.  

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
3/17/21 11:43 a.m.

Yeah, I'm reading and re-reading the passages in how to make your car handle and tune to win and prepare to win books on bump steer, and the part I don't understand is that they all seem to measure bump steer only where the wheel is basically straight. Which sort of makes sense, because when you move away from dead straight is when you start the transient conditions. 

But it really does seem to me that bump steer is really a 3d graph, not a 2d one. It's really steering angle error vs wheel travel vs steering angle rather than just steering angle error vs wheel travel. As bump steer could change at different steering angles. 

Regardless, all of this is mostly academic for now, as I plan to just use the RB crossmemeber and live with whatever that gives me, unless it is awful, and I wont know that till I get down the road. This is why Carl recommends using the crossmember - just save the time and assume the MG engineers at least sort of looked at it for you. I can always make adjustments later if needed. 

stafford1500 Dork
3/17/21 12:27 p.m.

In reply to Robbie (Forum Supporter) :

The toe response is a 3D surface and gets more complicated when you add in the fact that it is sort of connected to the other side of the axle, which can allow for differential travels (roll) and the ackerman effects that are part of the steering angle.

Your plan of build it first and then see what it does makes the most sense. When I was on the road 4-5days a week, I would use my evenings in the hotel to tweak on suspension design for my Spitfire. I wound up spending most of a year with a "good" design, then promptly hacked together a suspension using existing parts. The results are not as good as my calculations, but it holds the car up and doesnot drive itself into a ditch. Next round is custom uprights to get what I really want.

autocomman New Reader
3/17/21 7:22 p.m.

I've just been through all of this crossmembe nonsense with the 70 GT and the 3800.  The RB cars had the rosie height raised so the bumper met impact regulations.  They did this by raising the stands on which the xmember bolts to the frame.  Then I don't remember why the rack was relocated other than to correct for the extra height of the body in relation to the xmember.  I'm pretty sure that was it.  That way none of the suspension geometry changed. 


For me I'd push the engine back more to get it behind the rack and deal with a shifter lever that's bent.  I wouldn't want the RB xmember is it raise the car quite a bit, and it sounds like you won't be nice to it, that extra height does nothing for handeling.  


I'm a tube shock guy, with that said my bugeye has stock levers that are HD rebuilds.  They are ok, but I prefer how the tube shock setup rides.  I would have done that on my bug eye but I couldn't make the frontline kit fit.  My car has positive caster issues from the wonderful quality control at BMC in the 50s.  But anyway...I'd keep the CB xmember and move the motor back.  

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