Body to chassis rubber

Body to chassis rubber

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Discussion

Moto

Original Poster:

1,261 posts

260 months

Monday 7th February 2022
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I'm about tp remount the body onto the chassis following a chassis rebuild. I've been given good sound arguments for both using no rubber between chassis & body and using 6mm rubber.

The 'race' boys argue for the former but just tightening it up really well. But is this realistic for a car used on the road? Anyone tried it and if so what were the results.

Moto

GAjon

3,804 posts

220 months

Monday 7th February 2022
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The rubber is there to compensate for discrepancies in the chassis fabrication and body lay up.

3mm out in either direction is fk all and TVR weren’t exactly precision engineers, the rubber takes up the difference aswell as offering a bit of insulation ( I actually don’t t think anyone would know if a car had the rubber or not).

I would always put it in.

Moto

Original Poster:

1,261 posts

260 months

Monday 7th February 2022
quotequote all
Dollyman1850 said:
You run a rear cage which is bolted directly to the chassis then glassed in around cage foot.
All the noise will transmit through this.
Pointless using rubber on the other mounting points.

I have a theory that best way is most likely to use a polyeurethane sealant on the mounting plates, smear it on to give a good thickness then pull the body down onto it so that it becomse sealed and levelled that way. The key is to ensure that you are pulling down the flat body floor onto the flat chassis plate rather than pulling the chassis corner plate up to meet the body because one side is already bolted up with the other having a gap. Sit it on for a look first.

Occasionally you may resort to rubber packers but only if body is pissed on the chassis and you need to pack it to level it.

Sit it on first and see how level it looks when you pull it down. They can and do twist with age and if they have been off the chassis for a long time.

Also don't forget to use PU sealant on your cage feet when bolting it down. makes a big difference to stiffness.

N.
Edited by Dollyman1850 on Monday 7th February 11:49
Thx Neil. I like the idea of putting a smear of Sikaflex on the chassis plates & then pulling the body down. I think I'll go with that idea once I've sat the body on to see how she sits and what gaps there are, if any.

I didn't use any Sikaflex on the rear cage feet when I originally fitted, it was metal to metal only. I can see this could reduce any noise resonance but surprised that you say it will improve stiffness. How so confused

Moto

tyracious

65 posts

55 months

Monday 7th February 2022
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Sikaflex seems to be a good bonding agent.
"It is suitable for making permanent elastic seals"
Do you really want to glue the body to the chassis?
With something that says "permanent"?

Monkeythree

514 posts

236 months

Monday 7th February 2022
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If you delete the rubber spacers and bolt the body direct to the chassis then be aware you might bottom out of adjustment on the bonnet mounts and find that you need to make modifications to the bonnet frame to get the bonnet to fit properly i.e. low enough.
I have also seen it the other way where a body was packed miles up off the chassis apparently in effort to increase tyre clearance (go figure) and the bonnet adjusters were extended like a pair of stilts AND packed out to try to get the bonnet to fit right.

tyracious

65 posts

55 months

Monday 7th February 2022
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Dollyman1850 said:
The sikaflex will effectively bond both surfaces together in addition to the bolted joint. It all helps with the strength of the joint and will stop any movement of the bolted surfaces on a sliding plane because ultimately the holes are larger than the bolt.. All good race prep smile
Fair enough.
Good point.

Remove the body?
Once in my lifetime. Hopefully. But you never know.

Supposedly it can only be removed thru mechanical means once cured.
Tough stuff - impressive.
Marine Formula by the Debond Corp. claims to work on Sikaflex without damaging fiberglass/gelcoat.

Edited by tyracious on Monday 7th February 22:16

plasticpig1972

203 posts

53 months

Tuesday 8th February 2022
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I would place Body on Chassis with Doors closed and check bonnet.
Then make packing to exact size so no stress or body twisting takes place.
IMHO If you use sikaflex it's a backwards step and you just aswell go back in time and Bond Body to chassis.
The next Custodian in the future who wants to lift the Body will curse you. lol
Personal choice i suppose.
The most important is to assemble it and get back driving it.
Alan

Moto

Original Poster:

1,261 posts

260 months

Wednesday 9th February 2022
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All good things for me to consider. I certainly don't plan to ever take the body off again but ..... scratchchin

Moto