MG Sports Cars

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

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limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: limey222
Date: October 08, 2015 09:16AM

Now that the conversion is in place I want to take make another attempt at slightly improving th clearance between my steering rack and my crankshaft pulley rim. I currently have about a 1/8" clearance which is working OK for running the engine. (no matter what just couldn't improve on that at time of installation). However it makes changing the serpentine belt really challenging and I would hate to have to attempt to change belts on the roadside if it ever became necessary.
I realized that I won't increase the clearance by the shim thickness since the rack is mounted at an angle but if I can achieve a 1/16" increase it will do the job.
I don't think it will adversely affect steering as long as i do it equally on both sides since shimming is normally used to align the two parts of the steering shaft.
What do you all think?


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5830 posts)

Registered:
10/23/2007 12:59PM

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

authors avatar
Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: BlownMGB-V8
Date: October 08, 2015 09:25AM

Wouldn't that raise the rack?

Jim


limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: limey222
Date: October 08, 2015 02:32PM

I just took another look at it and yes it would raise it to much and not give me much of a forward movement away from the crankshaft pulley so forget that idea.
I did buy a smaller diameter pulley but that impacts the rpm of the water pump and alternator too much so that's ut of the question too.

Someone on the MGExperience site had the same problem and had little material shaved of the face of the pulley but I don't fancy doing that either. Guess I will just have to leave it as it is. I'll just should go ahead and put a new belt on and forget about it.


MGBV8
Carl Floyd
Kingsport, TN
(3789 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB, Buick 215

authors avatar
Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: MGBV8
Date: October 08, 2015 05:02PM

Great idea. Install a quality new belt & forget about it for a loooong time. The serpentine belt on my Maxima is 12+ years old with 265,000 miles on it.


88v8
Ivor Duarte
Gloucestershire UK
(702 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: 88v8
Date: October 09, 2015 04:21AM

I did buy a smaller diameter pulley but that impacts the rpm of the water pump and alternator too much so that's out of the question too.

Not if you fit a correspondingly smaller pulley to the water pump.

Ivor


limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: limey222
Date: October 09, 2015 09:18AM

On the face of it you are correct however the problem is that it causes interference problems too. By going to a smaller crankshaft pulley the belt comes either too close or actually touches other components. In addition the wrap contact with the water pump pulley is reduced and it wasn't much in the first place.


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

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Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: Moderator
Date: October 09, 2015 09:32AM

Would it help to shim the motor mounts 1/16" inch?



ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1085 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

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Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: ex-tyke
Date: October 09, 2015 09:37AM

A RB front crossmember will get the rack lowered 1" - spacers under the rack can be used to re-orient the steering shaft.....
......or you could try spacers or castor reduction wedges under the existing front crossmember to gain some clearance.


limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: limey222
Date: October 09, 2015 02:39PM

Curtis,

I could shim the motor up by a 1/16" it might help a little. I would have to put the shims under the Guzman engine mounts which is not too desirable.
Of course it would be easiest if I could just use the jam nuts on the vertical Guzman studs to raise the engine a 1/16" however I am right at the highest point I can be and still have full thread engagement of the top jam nut. I used Loctite Blue as it is just to be safe.

To fit a belt right now I have to slacken off the 4 bolts holding the rack in place and oh-so-gently use a crowbar to slightly open up the gap, the main give appears to be when the pulley rim deflects a little but not enough to cause permanent distortion. Obviously not the best solution if I ever had to replace the belt on the side of the road.

I rely don't want to disturb the crossmember at this point.

On original rack and pinions (not the Moss replacements) the larger diameter tube on the rack starts farther out so it wouldn't impinge in the area close to the pulley rim. It would still be very tight but it would be doable.


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: Moderator
Date: October 10, 2015 10:51AM

So isn't the easiest solution is to source an original rack from a breaker?


limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: limey222
Date: October 10, 2015 12:59PM

Curtis,
Not in my book, from my perspective why would I scrap a 1 year old rack and install one that is 35 to 53 years old in its place, i know they were well manufactured but it would surely have some undesirable wear. On my car a PO had welded the lower half of the upper Hardy Spice joint to the shaft instead of using the clamping bolt. I had nightmares of the shaft fractioning at high speed due to it being hardened by the welding. When you don't know the history on a critical component, why take the risk, I got rid of it as soon as I could afford to. I'm fanatical about the safety of brakes and steering on my car, especially now I have 170+ hp to throw around.



Edited 1 time(s). Last edit at 10/10/2015 02:07PM by limey222.


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: Moderator
Date: October 10, 2015 05:59PM

Since your previous owner goofed up your original rack, you were undoubtedly right to change it out. But your aftermarket rack is evidently the cause of your clearance problem. (Other GM V6 installs haven't reported this issue.) I expect a good original MGB rack will be easy to find, for cheap, because so many people around here have installed Fast Cars front ends. Why not post a free "wanted" ad in this forum's classified section? Then, I'd probably sell the barely-used aftermarket rack to someone who doesn't have a clearance issue.


limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: limey222
Date: October 10, 2015 10:09PM

Actually I've had couple of members contact me with very close to the same problem, minimal clearance between the rack and pulley.

But moving on I still prefer to keep the new rack. I can attempt to address the problem by making multiple small revisions in order to gain just enough clearance to more easily change belts. If I have to change out the crankshaft pulley for a slightly smaller one (which I already have) and switch out the alternator pulley for a smaller one (which I already have) then so be it, It will mean some changes to the belt alignment so that it misses some components but it does seem possible if I have to go that far. Alternately I could have a small amount machined off the side of the existing pulley without complete removing then out lip as another member has done successfully.


DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

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Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: DiDueColpi
Date: October 13, 2015 01:52AM

Why not just do some body work on the rack?
There is a considerable amount of room between the rack tube and the actual rack gear.
You can filet the tube and lay the section back in upside down.
Gaining 3/8 to a 1/2" is probably realistic.

Cheers
Fred


classic conversions
bill guzman

(294 posts)

Registered:
01/09/2008 01:58AM

Main British Car:


Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: classic conversions
Date: November 12, 2015 01:08AM

Would it help to shim the motor mounts 1/16" inch?

The V6 motor mount are adjustable for height. I think you are creating a problem.

How thick is the belt? How much space do you need to change a belt? How often are you planning n changing the belt?

You need more room? adjust the height on the mount stud.



limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: limey222
Date: November 12, 2015 07:38PM

Bill, I would but the lock nuts are right at the top of the studs as it is. They are on the stud threads their full thickness but I used Blue Loctite just in case.
I have about 1/8" clearance but the belt is closer to 3/16" thick. That's why I had to slacken off the 4 steering rack bolts and gently used a thin crowbar to lightly stress the rim of the crankshaft pulley to squeeze the belt past the pinch point. Pretty easy to do i my garage but if ever lose a belt on the road I'm in trouble.


Charles
Charles Long
McDonald, TN
(177 posts)

Registered:
09/15/2013 08:54AM

Main British Car:
1966 MGB V6 1994 Camaro 3.4L 60V6

authors avatar
Re: Any detrimental effect of installing 1/8" shims under steering rack mounting bolts on both sides
Posted by: Charles
Date: November 12, 2015 08:12PM

I am with some of the other guys, install a good quality belt. I have not had a good belt break in over 20 years.

On my 66B I only have maybe 5/32 between the rack and damper pully, even today I was able to remove/replace the belt.

Drive and enjoy. Get a good travel insurance, credit card, and cell phone and go any where.


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