S1 Sump Mod

S1 Sump Mod

Author
Discussion

theprof

Original Poster:

51 posts

94 months

Thursday 4th July 2019
quotequote all
Does anyone know the wall thickness of the chassis rails that the cross member is welded to, the one that blocks the sump from being removed on my S1. It is leaking on the rear right corner so needs to come off and the seal replaced mad . I plan to do the bolted rail modification eek. For anyone who has had it done or had it done for them, does anyone have the bolts only through into the rail, or does anyone have bolts through the entire rail. I am also interested in thread types, metric/imperial, coarse or fine. I know phillpot has a photo, anymore out there?spin

88S1

715 posts

60 months

Thursday 4th July 2019
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I wouldn’t have thought the main chassis is thick enough to thread. You may be better using a blind rivnut, like a big pop rivet that leaves you with an internal thread, like the ones in the photo below. There’s loads of different manufacturers.


theprof

Original Poster:

51 posts

94 months

Friday 5th July 2019
quotequote all
The rivnut solution is one idea I have considered but it is more work to have the backing plate sit flush against the chassis rail. A very shallow counter bore may solve that problem though. More to consider.

GreenV8S

30,150 posts

283 months

Friday 5th July 2019
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Some of the ones I've seen done had a stub welded to the chassis rail so the removable bar could be bolted to a flange rather than directly to the rail - that seems like a good way to avoid these issues.

88S1

715 posts

60 months

Friday 5th July 2019
quotequote all
Could always weld a couple of tubes bigger than the bolt diameter into the chassis, grind flush and bolt straight through. I’ve got to do mine, so have an interest in this.

You can be the guinea pig laugh

Edited by 88S1 on Friday 5th July 18:22

DamianS3

1,803 posts

181 months

Friday 5th July 2019
quotequote all
88S1 said:
Could always weld a couple of tubes bigger than the bolt diameter into the chassis, grind flush and bolt straight through. I’ve got to do mine, so have an interest in this.

You can be the guinea pig laugh

Edited by 88S1 on Friday 5th July 18:22
Thats how mine is.. otherwise you could crush the chassis rail when bolting up.

Thanks

Damian

theprof

Original Poster:

51 posts

94 months

Friday 5th July 2019
quotequote all
All of these ideas are worthy of merit gentlemen smile. I have been looking at rivnut technology and the tools seemed to have changed a bit. A two handed tool, like bolt croppers, would cope with an 8mm steel rivnut. Seen em on fleabay for about a pony. The chassis is balk standard mild steel .2% I would have thought, so any welding should be relatively easy if welding on, or in, any type of tubes or fastener. AC is a must though as it greatly increases the pull out/through strength which limits the welder to mig. TiG carbon steels and you will fight porosity a lot. Things to muse over!


theprof

Original Poster:

51 posts

94 months

Friday 5th July 2019
quotequote all
Is the outrigger return rail pushed through the chassis rail, i.e. is the main chassis rail drilled to receive the pushed through outrigger, then welded, does anyone no??ears

Adrian@

4,290 posts

281 months

Friday 5th July 2019
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Yes, it is one piece pushed through. A@

88S1

715 posts

60 months

Friday 5th July 2019
quotequote all
DamianS3 said:
88S1 said:
Could always weld a couple of tubes bigger than the bolt diameter into the chassis, grind flush and bolt straight through. I’ve got to do mine, so have an interest in this.

You can be the guinea pig laugh

Edited by 88S1 on Friday 5th July 18:22
Thats how mine is.. otherwise you could crush the chassis rail when bolting up.

Thanks

Damian
Upload a photo, be nice to exactly how it works in reality.

theprof

Original Poster:

51 posts

94 months

Friday 5th July 2019
quotequote all
Drilling through and keeping it straight is the key I would of thought. Never easy at the best of times when passing through a void, a pre-fabricated drill guide would defo help if there is room for the drill and bit.

88S1

715 posts

60 months

Friday 5th July 2019
quotequote all
theprof said:
Drilling through and keeping it straight is the key I would of thought. Never easy at the best of times when passing through a void, a pre-fabricated drill guide would defo help if there is room for the drill and bit.
Just mark it out both sides and use a centre punch, can’t go wrong. No need for anything fancy, just tried and tested engineering methods. Check twice, drill once.

greymrj

3,316 posts

203 months

Monday 8th July 2019
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This needs to be done properly with a knowledge of the stresses involved. It has been discussed before. This is one thread on the subject: https://www.pistonheads.com/gassing/topic.asp?h=0&...

88S1

715 posts

60 months

Monday 8th July 2019
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greymrj said:
This needs to be done properly with a knowledge of the stresses involved. It has been discussed before. This is one thread on the subject: https://www.pistonheads.com/gassing/topic.asp?h=0&...
What’s proposed is a metal to metal spacer, something like the sketch below, box section could be replaced with original size tube. Any thoughts anyone????


greymrj

3,316 posts

203 months

Monday 15th July 2019
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Essentially as strong in tension and compression but not in bending (vertical plane) or in torsion. Increased torsional flex in chassis would be my principal concern but whether it would be significant??? Someone has mounted with 3 smaller bolts in a triangle, that is better. Your two bolts in plane allow flex at 90 degrees to that plane.

88S1

715 posts

60 months

Monday 15th July 2019
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There can’t be torsion, the two main RHS chassis sections are not going to have any rotation, the lattice truss arrangement of the space frame ensures that.

A 5mm plate with a welded section in the middle would be rock solid, plus as the transom is in line with the outriggers tube, a triangular plate wouldn’t work.

I guess the transom is to prevent crabbing of the chassis (surprised it’s not diagonal plan bracing which would be much more effective) so a web plate (like the ones at the corners of the outriggers) could be introduce to make it a belt and braces design. Or the box section could be replaced with a RSC (U shape channel section) with the fixing plate welded inside of the flange.

Open to arguments on this subject, it’s got to be right.

Edited by 88S1 on Tuesday 16th July 06:43


Edited by 88S1 on Tuesday 16th July 08:37

88S1

715 posts

60 months

Tuesday 16th July 2019
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So, having a look at a few images on PH and Southways site, it looks like some models do have diagonal bracing (maybe it’s just the V8), whereas the S1 just have a straight crossmember and no diagonal bracing.

Due to the exhaust down pipes it doesn’t look like diagonal members can be introduced, and there doesn’t look to be enough space for a C section to go either side of the outriggers without clashing with sump and keeping the plate internal, so would still require the fixing plate similar to my original sketch.

I need to drop my engine back in and have another good look.

88S1

715 posts

60 months

Tuesday 16th July 2019
quotequote all
This seems a good option that ticks all the boxes.

https://www.pistonheads.com/gassing/topic.asp?h=0&...

Adrian@

4,290 posts

281 months

Tuesday 16th July 2019
quotequote all
There may be an issue with that piece of tube, because the tube is one piece across the car and it has a central bend IF the outriggers have failed in the past, water collects there and the tube tends to be rotten..just a thought. A@

88S1

715 posts

60 months

Tuesday 16th July 2019
quotequote all
Adrian@ said:
There may be an issue with that piece of tube, because the tube is one piece across the car and it has a central bend IF the outriggers have failed in the past, water collects there and the tube tends to be rotten..just a thought. A@
Adrian. So I assume the outriggers rise slightly to the outside edge in that case, 20mm is in my head but would have to check my notes again. If the mid tube is rotten when you cut it out then that could be replaced, that would actually be better than having a rotten tube and not knowing about it don’t you think.

So if they are a continuous tube from the outside to outside, when outriggers are replaced I assume that the tube is cut outside of the main chassis, sleeved at a solid un-corroded section and replaced. Not the full continuous tube replaced which would mean the sections going through the chassis needed to be ground out (which would be much more time consuming).