MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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Brownwood
Keith Montague

(176 posts)

Registered:
01/25/2014 08:08PM

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Steering tube mods to get V8 lower in the car
Posted by: Brownwood
Date: June 12, 2015 11:18AM

I got my blown up motor out of my MGB V8 on Wednesday. While I wait on my new 5.0 crate motor, I am fixing some things that weren't quite right with my original swap. One thing I want to do is get the motor sitting lower in the car. I now know that I can grind the lip off the bottom of the timing chain cover and get almost 1/4 inch. Can the steering tube that connects the two wheels be ground enough at the center where the engine wants to sit to make a difference or is it to thin?


rficalora
Rob Ficalora
Willis, TX
(2626 posts)

Registered:
10/24/2007 02:46PM

Main British Car:
'76 MGB w/CB front, Sebring rear, early metal dash Ford 302

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Re: Steering tube mods to get V8 lower in the car
Posted by: rficalora
Date: June 15, 2015 12:21AM

Not sure, but I think the steering rack tube is pretty thin Keith.


Jim Stabe
Jim Stabe
San Diego, Ca
(720 posts)

Registered:
02/28/2009 10:01AM

Main British Car:
1966 MGB Roadster 350 LT1 Chevy

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Re: Steering tube mods to get V8 lower in the car
Posted by: Jim Stabe
Date: June 15, 2015 01:26AM

It is about the thickness of exhaust tubing


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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Re: Steering tube mods to get V8 lower in the car
Posted by: BlownMGB-V8
Date: June 15, 2015 10:34AM

You can look at the end of the rack by popping off the boot to get an idea of how much possible gain is there. Because it contains gear oil you'll want to seal the opening. Probably not worth the effort, lowering the rack gives better results.

Jim


waterbucket
Philip Waterman
England
(79 posts)

Registered:
07/30/2011 01:08PM

Main British Car:
1978 MGB GT

Re: Steering tube mods to get V8 lower in the car
Posted by: waterbucket
Date: July 02, 2015 02:25PM

Please can someone explain to me the disadvantages of lowering the steering rack. I have always assumed that if you draw a line from the top to lower inboard suspension pivots then the centres of the spherical joint on the ends of the steering rack should pass through this line when the steering is in the straight ahead position. The above answer suggests that this is not the case. If the rack can be lowered then what is the maximum amount? I would ideally want to lower the rack so it is level with the top of the cross member.
From a response on an earlier posting I got the impression that bump steer would be increased making the car unpleasant (unsafe?) to drive on any thing other than perfect road surfaces.
Philip



Edited 1 time(s). Last edit at 07/02/2015 02:28PM by waterbucket.


MGBV8
Carl Floyd
Kingsport, TN
(3749 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

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Re: Steering tube mods to get V8 lower in the car
Posted by: MGBV8
Date: July 02, 2015 06:11PM

Philip,

Try it and see. It may be okay. IMO bumpsteer on a lowered MGB is mostly a myth/urban legend. My RB MGB has been lowered about 2". The bumpsteer people say that it should be horrible to drive. Personally, I barely notice it & correct on the fly. As they say, YMMV (Your mileage may vary).


Jim Stabe
Jim Stabe
San Diego, Ca
(720 posts)

Registered:
02/28/2009 10:01AM

Main British Car:
1966 MGB Roadster 350 LT1 Chevy

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Re: Steering tube mods to get V8 lower in the car
Posted by: Jim Stabe
Date: July 02, 2015 06:26PM

When my B was stock width I lowered and narrowed the rack. I was swapping out the N/A 215 Buick for an Olds Jetfire and the turbo wouldn't clear the hood so I needed to lower the engine about 2". I felt the geometry was bad enough with the rack in the stock position and lowering it only made things worse. I never checked the bump steer before but after there was only a few thousandths change in toe through 4" of suspension travel. IMHO definitely worth doing, I noticed a significant difference in the handling of the car after the mods.



BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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Re: Steering tube mods to get V8 lower in the car
Posted by: BlownMGB-V8
Date: July 03, 2015 11:05AM

Several factors involved. I lowered the rack on my car and we did the same on the Roadmaster (did that one first actually). So far nobody has complained about the steering on the RM and a lot of drivers including Hap Waldrop have driven it (at Road Atlanta).

The stock rack is slightly longer than optimum. Did you know that? Doesn't seem to matter. Since the angle of inclination of the inner A arm pivots is outward at the top this will be slightly exacerbated when it is moved down, just something to be aware of but in real world terms not noticeable. (Maybe for Jim S) The real concern is to put the spindle arms at the same height as the rack with the car at your final ride height. If you do not do this you will have bump steer. It also should make a straight line across the car front to back from spindle, through the rack to the other side at final ride height. These two things will minimize bump steer. You can bend the spindle arms, they are forgings. Hot bending is probably better but cold bending also works. If it makes you feel safer, magnaflux them afterwards.

Shortening the rack to the ideal distance for the height it is mounted at could be done I would think but I'm guessing it would not be more than 3/4" max and not worth the effort for most people. Jim, how much did you take out of your rack, and how far did you lower it? I'm guessing there was enough plain shaft at one end or the other to cut and splice?

Jim


Jim Stabe
Jim Stabe
San Diego, Ca
(720 posts)

Registered:
02/28/2009 10:01AM

Main British Car:
1966 MGB Roadster 350 LT1 Chevy

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Re: Steering tube mods to get V8 lower in the car
Posted by: Jim Stabe
Date: July 04, 2015 01:20AM

I'm trying to remember how much I shortened the rack (It was 40 years ago) and it seems that it was at least 2". I don't have any old pictures that show it. I agree that you don't really notice the bump steer that much in a stock car but what you do notice is the difference once you correct the issue, it sharpened up the turn in and corner grip noticeably. Is it worth the effort? I would have probably said no before I did it but I was young and idealistic back then and I had lowered the steering rack a lot more than most have done here on the forum.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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Re: Steering tube mods to get V8 lower in the car
Posted by: BlownMGB-V8
Date: July 04, 2015 11:31AM

Interesting. 2" sounds like a lot, and the RM and my car have the racks lowered so far that lower control arm mods were required. Looks like it'll be hard to measure accurately but since my car is on the rack maybe I could eyeball it at least.

Edit: I just had a quick look and on my car it would apparently take a good 3" decrease in length to line the inner ball joints up with the inner control arm pivot axis. However, a quick check looks like the outer pivot is close to 1-3/4" outside of the king pin pivot axis.

This tells me that the rack should not be shortened, and that there may be some room for moving the outer pivots in a bit to accommodate non-stock wheel/brake combinations. Am I wrong?

Jim



Edited 1 time(s). Last edit at 07/04/2015 11:54AM by BlownMGB-V8.


Jim Stabe
Jim Stabe
San Diego, Ca
(720 posts)

Registered:
02/28/2009 10:01AM

Main British Car:
1966 MGB Roadster 350 LT1 Chevy

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Re: Steering tube mods to get V8 lower in the car
Posted by: Jim Stabe
Date: July 04, 2015 12:26PM

I forgot to mention that I took out the Ackerman at the same time I lowered the rack and that could have also contributed to the increase in grip. Hard to say since I did both at the same time. The bump steer may not have been that bad had I left the Ackerman in. I wouldn't recommend ditching the Ackerman on a pure street car since it makes low speed tight turns on slippery surfaces interesting


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Steering tube mods to get V8 lower in the car
Posted by: BlownMGB-V8
Date: July 04, 2015 01:40PM

Ah yes, the Ackerman. Of course. That does complicate the issues.
Anyway it seems to work pretty darned well as is. The length of the tie rods may not be a perfect match to the control arms and moving the rack changes that of course, especially since moving the rack down also moves it left a bit.

But I think any bump steer complaints I've heard involved lowering the rack without bending the spindle arms, something that is easy to address. (a length of pipe slipped over the end comes to mind) I recommend checking your rack boots with the steering at lock and the suspension fully compressed before finalizing the rack height. Don't want to slice your boots open.

Then there's always Carl's credo: Done beats Perfect.


Anarchy99
Jim Purdy
Memphis, TN
(118 posts)

Registered:
12/06/2013 03:54PM

Main British Car:
61 austin healey sprite LS6

Re: Steering tube mods to get V8 lower in the car
Posted by: Anarchy99
Date: July 06, 2015 10:09AM

I ended up moving my steering rack forward to get the clearance needed for a blower pulley. In the end, I got the most clearance by going with a much lower profile intake and a drop base aircleaner with a lower profile. I still had to run a 429 cobra jet hood scoop to keep everything below the hood.


pspeaks
Paul Speaks
Dallas, Texas
(698 posts)

Registered:
07/20/2009 06:40PM

Main British Car:
1972 MGB-GT 1979 Ford 302

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Re: Steering tube mods to get V8 lower in the car
Posted by: pspeaks
Date: July 06, 2015 06:25PM

Problems with my legs (doctors say I need to have both knees replaced) are still keeping me from driving the car so I'm doing some mods I should have done to begin with. Like changing the front motor mounts because I'm not comfortable with the head mounts on my new aluminum heads. The RV8 hood helped a lot but I'm never satisfied and think things could be a little better so I'm also seriously considering lowering the steering rack so I can lower the front of the motor a bit. The rack is out right now so I can replace the boots and worn out tie rod ends, so this is a great thread for me. Thanks for the info.



Paul


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