Hi, had my Roadster for a short time, thinking about rustproofing etc, was having a poke about and checked under the sill plates, the sills appear to have been filled with foam. Is this a recognised mod? Are there any upsides or downsides?
It might float better?
Sounds like a bodge TBH, foam then filler over a rust spot…sorry.
Tell my wife she recently ‘floated’ our 95 across a deep ford, needlessto say while we got it going it is now having a permanent rest.
Doesn’t look like a bodge, both sills are completly filled, very neat job. Car is solid, no apparent structural rust anywhere. Wondered if it was to do with keeping water out?
Hi - Could it be WAXOIL which is rather foam like when you squirt it into the sills. If so then this could have been used instead of DINITROL as a rust inhibitor
Rod
Austin/Morris had a bit of an experiment with this on the Mini in the '60’s with fairly disastrous results. Numerous people have done it again since because it seemed like a good idea after a couple of pints and found the same thing - the foam acts like a sponge, collects water and promotes rust even more than if the interior of the sills had been left in bare metal.
Get it out of there any way you can.
Iain
Quite a common modification in Japan and the US on MX5s (alternative to seam welding). It does work, but the downside is that the foam can crack, and basically soak up water. Only way to remove it is to cut open the sills.
Some time ago, I found a website from Japan, with a Vspec with sills full of foam, and rusting as a result.
The usual product is made by Bellco; this is not the same as regular expanding foam. See this user review:
http://www.miata.net/products/chassis/bellco.html
It was quite a big deal about 10 years ago.
Thanks for that AT, it looks like that mod has been done, i guess a mixture of good and bad news! I’ll take the usual precautions to prevent water getting in and hope for the best as it is here to stay.
Put some new tyres on at the weekend, had a look underneath while on the ramp and it has the powerplant brace fitted. Not sure if this is a common fitment or whether some cars do not have one fitted. What is the current thinking re this? Is it useful or just deadweight? Was thinking of doing the front and rear bottom braces anyway.