tr7triumph.com

Guys,
I have my spare set of rear axle arms, blasted and ready to be hot zinc dipped and then black powder coated

- but I was thinking of putting a lid on those crud traps. And I'd like to hear your views on this: to box or not to box?

Hi Odd,

I'd say yes to the extra strength and rust protection so long as the drainage remains.

A V8 needs all its strength around the rear axle. I cracked the rear floorpan / rear passenger bulkhead area shortly after converting mine.

Adam

TR7 V8 DHC Jaguar Solent Blue. 9.35cr Range Rover V8, Holley 390cfm, JWR Dual Port, 214 Cam, Lumention, Tubular Manifolds, Single Pipe Exh, 3.08 Rear, 200lb Spax & Solid Bushes, Anti- Dive, Granada Vented Discs & Calipers, Braided Hoses, Green Stuff, 4 Speed Rear Cylinders, Uprated Master Cylinder & Servo, AllyCat 5 Spokes and Cruise Lights. No Door Stickers. Mine since July 1986, V8 from 1991

Nooo, less weight/go faster! LOL j.k....

Sound like a good idea, but like Adam said; make sure water can be able to drain out.

Looks good.

Johnny

Drain is no problem - there's several holes in the bottom of the arm.
This is regarding putting a 'lid' on the thing so (most) crud will stay outside, not assemble/pile up inside...

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Odd</i>

Drain is no problem - there's several holes in the bottom of the arm.
This is regarding putting a 'lid' on the thing so (most) crud will stay outside, not assemble/pile up inside...
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

V-good idea!

Johnny

What would Colin Chapman do? Probably drill more holes in it.

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I wouldn't bother, leaving the lid of makes it easier to blow out dirt from the trailing arms a few times a year. Just make sure they get coated properly.

Think it won't ad much stiffness to the arms, only weight …


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<font color="blue"><i>1981 TR7 FHC Sprint (better known as 't Kreng)
1981 TR7 DHC (not very well known yet, but back on the road)
Also a 1980 TR7 DHC, 1980 TR7 DHC FI, 1981 TR7 FHC</font id="blue">
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Box'em Odd,then liberally coat them with wax oil/underseal and forget
about them for a while.How much weight penalty to be had?Take the
cd player out and the passenger seat etc.if you wanna'go down that road!

See ya. Paul

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[url="http://www.triumphcars.com/"]Huw's Website[/url]

OK, so I'm a worrywart, but I am a bit concerned with the high local
stress points this boxing builds into these arms.

From full compression to full extension, of the rear suspension,
from side to side, [inside wheel off ground], there must be between
8, & 10 degrees of twisting in these arms. The stock rubber
suspension bushes would have absorbed much of this.

Now we fit urethane bushes, & the mounting points, & the arms must
absorb this twisting, mostly the arms. The open arm has no trouble
doing this, in fact it would not even notice it, but the boxed arm
has to do it, in a very short, localised area. Roll on stress cracks.

If I was going to do this, in a road car, I would use rubber bushes
in the front mount, & keep an eye on the mounting point, & the arm,
where the boxing ends.

For a competition car, with beefed up mounting points, using
urethane all round, I would still keep an eye on the same things, &
change the arms after a couple of thousand Km.

In defence of my careful attitude, I did race an aging Lotus open
wheeler, which taught me to expect stress cracking, EVERYWHERE.

Hasbeen

<font face="Comic Sans MS"><font size="2">The questions you have to ask yourself before reinforcing any component are:
1/ Has there been any history of these components failing?

2/ Do I expect to be putting increased loading or stress on these components?

3/ By stiffening this component am I transferring the load the flex this component used to adsorb in to another component?

4/ Will that other component be able to take it?

5/ Is there a proven improvement in modifying these components?

6/ What improvement do I hope to gain from this modification?

If the answers to the above questions are:
1/ No, 2/ No, 3/Don't know, 4/ Don't know, 5/ No, 6/ Don't know.
Don't bother your efforts could be better applied elsewhere!

</font id="size2"></font id="Comic Sans MS">

80'Triumph TR7, , 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
85'Alfa 90, 69'Ford F250.
76' Ford F100

Well,
I think you guys have given me the arguments I was looking for. Both pros and cons...

Since I'm not contemplating this to 'strengthen' the arm mechanicly (not needed for the type of use
my car gets) but only to prevent unwanted road muck to pile up inside the arm, I think Hasbeen and
Cobber have hit the nail: I definitely don't want to start chasing stress cracks here - there - and every-
where in the future.

In order to keep the crud out I think I'll affix a 'roof' over the ditch in the arm using (the slightly elastic)
black aquarium silikon cement (after <u>all</u> the zinc/powder coat work is done). This solution should be
more elastic as compared to permanently welding the roof in place.
Thanks guys!

fyi
I'm off and on chasing stress cracks in the 25+ years old (= very vibration prone) snow blower I've got
- so I know what it is, and I don't like it one little bit!