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Solid rack mounts - Fan belt removal


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Gents, while rebuilding I realized that If I can skim the blocks of the solid mounts by 3mm, there will be enough clearance to remove the fan belt without resorting to undoing the engine mounts and lift the engine. Question: Is there any contra in doing so ?

Thanks

 

WhatsApp Image 2019-06-11 at 11.56.47.jpeg

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Hi Stef,

Motorsport Mick will tell you better, but I think this will effect bump steer.

If you only need 3mm put a spacer under the engine mount each side.

Cheers

Graeme

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6 hours ago, graeme said:

Hi Stef,

Motorsport Mick will tell you better, but I think this will effect bump steer.

If you only need 3mm put a spacer under the engine mount each side.

Cheers

Graeme

I already have spacers and fitted a thicker front engine plate (6mm) so if I add another spacer I'll be short of thread on the mounts, plus the engine tilt is already more than enough to my liking...

WhatsApp Image 2019-06-11 at 11.59.07.jpeg

Edited by Geko
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Yes it will affect “ bump steer” whether better or worse depends upon whether the solid mount has been measured to minimise the bump steer. If standard tie rods are used they should cope 

However your solution of shortening the block can be easily be remedied with a piece of steel stock ( 3mm will be a standard size offered) which can be made with slots for the holes so it can be slid into place underneath the block afterwards or removed as required to slide a fan belt through the increased gap.The steering rack needs to return to it’s original position ( dowel or spacer piece ?) so as not to compromise tracking.

Mick Richards

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^  I like that removable spacer idea Mick :)

But surely lowering the height of the steering rack by 3mm will make no discernible difference. ? 

Assuming (and I'm just guessing here) the steering's tie rod  (the bit which articulates to accommodate the change in height as the suspension goes up n' down) is 165mm long,  then a 3mm drop in steering rack position (relative to the steering knuckle) equates to a change of angle by just  1.04 degrees.   And the difference in horizontal length (starting from the horizontal)  is a minute 0.0273mm.  Most certainly the original rubber block mountings allowed 100 times this difference !

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1 hour ago, Bfg said:

^  I like that removable spacer idea Mick :)

But surely lowering the height of the steering rack by 3mm will make no discernible difference. ? 

Assuming (and I'm just guessing here) the steering's tie rod  (the bit which articulates to accommodate the change in height as the suspension goes up n' down) is 165mm long,  then a 3mm drop in steering rack position (relative to the steering knuckle) equates to a change of angle by just  1.04 degrees.   And the difference in horizontal length (starting from the horizontal)  is a minute 0.0273mm.  Most certainly the original rubber block mountings allowed 100 times this difference !

Probably no noticeable difference. The point is about the articulation or travel of the tie rods. In a modified set up, there will be no change in the travel of the tie rods upward (compression) or downward (extension). However the academic question is whether a modified setup is allowable and will/not trigger over articulation of the tie rod on compression considering that the original angle (~5 degree) of the tie rod relative to the rack will close and will be reported towards the neck of the tie rod which could hit the flange of the steering rack on full compression. Original rubber mounts do exactly the job of mitigating that risk but here we're talking about solid mounts...

Edited by Geko
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2 hours ago, Bfg said:

^  I like that removable spacer idea Mick :)

But surely lowering the height of the steering rack by 3mm will make no discernible difference. ? 

Assuming (and I'm just guessing here) the steering's tie rod  (the bit which articulates to accommodate the change in height as the suspension goes up n' down) is 165mm long,  then a 3mm drop in steering rack position (relative to the steering knuckle) equates to a change of angle by just  1.04 degrees.   And the difference in horizontal length (starting from the horizontal)  is a minute 0.0273mm.  Most certainly the original rubber block mountings allowed 100 times this difference !

The original rubber mounts are awful, and the steering as standard TRs have a large amount of “ bump steer” akin to a drunken passenger leaning over in the middle of a corner and yanking on the steering wheel. 

Easily fixed by measuring and altering the steering rack height ( TR4/5/6/7) which is normally adding height to the mount. However it’s only ever the last degree or mm of movement which changes a non binding joint into a sheared or broken part so replacing a removed dimension is as important as the previous measurement against bump steer.

Mick Richards

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Mick offers a solution by removing/replacing a 3mm sheet of packing.  However, when the rain is bucketing down, would one really want to be fiddling around loosening/tightening the nuts in order to do this before installing a replacement fan belt?   I think not.

As I said in the 3rd post, the real answer is to swap to narrow belt - much easier and quicker to install because the belt itself is much more flexible.  And a spare can be folded, so it's easy to store in the boot.

The original belt is really a relic from the Vanguard era, when the engine was unlikely ever to spin beyond 4000.

Ian Cornish

Edited by ianc
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19 minutes ago, ianc said:

Mick offers a solution by removing/replacing a 3mm sheet of packing.  However, when the rain is bucketing down, would one really want to be fiddling around loosening/tightening the nuts in order to do this before installing a replacement fan belt?   I think not.

I think Mick's suggestion is a one-off solution to reverse course in case one's not happy with the driving result after skimming the blocks and that can take place anytime. Fan belt replacement isn't relevant here.

 

 

 

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2 hours ago, ianc said:

Mick offers a solution by removing/replacing a 3mm sheet of packing.  However, when the rain is bucketing down, would one really want to be fiddling around loosening/tightening the nuts in order to do this before installing a replacement fan belt?   I think not.

As I said in the 3rd post, the real answer is to swap to narrow belt - much easier and quicker to install because the belt itself is much more flexible.  And a spare can be folded, so it's easy to store in the boot.

The original belt is really a relic from the Vanguard era, when the engine was unlikely ever to spin beyond 4000.

Ian Cornish

Quite right Ian, fan belts only fail in the rain ! Normally on 70 mph road ! 

To that end on the Stag which has similar “ can’t get the belt in between rad and crank nose extension” problems, I have a spare fan belt already affixed around the front of the engine timing cover around the crank, been there last 10 plus years. Held in place with tie locks it’s easily accessible by cutting the tie wraps and then swung forward onto the pulleys.

Of course having the ultimate “ easy fix” in position guarantees it’s never needed ! I’ve been thinking when next rad out ( no cracks about Stags) I’d better replace it with a new one to prevent early age related failure.

Mick Richards

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On 6/16/2019 at 11:55 AM, Motorsport Mickey said:

I have a spare fan belt already affixed around the front of the engine timing cover around the crank, been there last 10 plus years. Held in place with tie locks it’s easily accessible by cutting the tie wraps and then swung forward onto the pulleys. 

Of course having the ultimate “ easy fix” in position guarantees it’s never needed !

Me too on my TR5. Now I have said this I will be scared to go out in the rain cos you know what will happen.Doh.

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