16 replies to this topic

[johnyj]

Hi and i hope everyone is keeping well in these strange times.

 

My question is on sills and their vents and the use of them. I know it is said that they are for primarily to drain the condensation  that arises in the car from the open structure of the car and most places draining into them. Today while removing the remnants of the old sill i notice that the worst of the corrosion on the inner sill is directly where the vent hole is/was and it is relatively good where it meets the floor. Does the vent hole let more water into the sill if the car is used on a wet day than the condensation effect on the sill. It seems to me that if an outlet is created for water then that outlet becomes an inlet for water when the car is or was used in wet weather and the water does the damage anyway. If a sill without the conventional vents is used and put smaller outlets facing the rear to avoid the  spray from the wheels

or use a sill without the vents what is the likely outcome if they were done that way? What do people think? Or will they rust in spite of whatever is done. Hard to know what to do for the best.

 

 

John

[Ben_O]

I would always recommend sticking with the standard narrow vented sill.

providing the car is well protected and the box section is filled with cavity wax, you shouldn't have any trouble.

 

The non vented sills that are available are too wide as they are designed as a repair panel with them to be fitted over the top of the existing sill.

not only do these trap moisture, they change the structure of the sill making it weaker.

but this is always debated. Not everybody agrees.

[sonikk4]

The vent is designed to let moisture out so any water that gets in should in theory drain out.

 

Now back in the day unless you got your car Ziebarted or Rust Proofed through various companies out there our little cars were onto a hiding to nothing due to the spasmodic quality assurance that was done at the factory.

 

So like Ben and like many others, once you have replaced your standard sill with like for like then flooding the cavity with a Waxoyl based product will improve the rust proofing.

 

Now from a personal point of view i aways paint the inside of the replacement sill with epoxy primer and topcoat. The same applies to the inner sill. Where its welded there will be some minimal damage to the paint. I always try to inject some paint in afterwards then use Dinitrol. 

[mab01uk]

As a point of interest:-

The sills on early 1959 and 1960 Minis were flat and unvented and part of the floorpan, the inner sills were separate panels spot welded to the floor. Because most of the pre-production testing was done during a dry summer it was not until customers started complaining of wet carpets that it was realised there was a problem with the seams on the inside instead of the outside for drainage. As an interim measure the sills were foam filled to prevent water ingress and later the floor/sills were redesigned with separate outer sill panels with vents and the inner sills formed with the floor pan. Around when the Mk3 Mini was introduced the sill vents were increased in size.

 

In my experience some of the most rust free sills I have seen on older Minis after many years use were those that were foam filled at the factory.......however when rust does take a hold they are/were very difficult to repair by welding until the foam is completely removed!

 

All 1959 cars have flat sills as part of a one piece floor pressing with separate inner sill. The inner sill on 59 cars showing the two inner drains to let water into the car:-

(scroll down for photos)

http://1959miniregis...riations-shell/

Edited by mab01uk, 09 August 2020 - 07:03 PM.

[johnyj]

Thats interesting on the older ones they way they did them. I dunno would i be to enamoured with foam if they had to be repaired. I'd say that would be a nightmare to clean up. No i just wondered if there was an alternative way of doing them to give airflow and drainage as well. There has to be a reason as to why they rust as bad as they do because the one im doing has been painted inside and is still as rotten as a pear. A case in point, i have a 1986 Mazda 323 that i use daily and has lived outside for the last 10 years, before that it was garaged but my point is that when i recommissioned it last year it was and still is structurally solid and it didnt have anything but minor repairs on the body to get it right, where as the mini is a few years older but is rotten for a good many years and the Mazda hasnt had any waxoil in the cavities or such treatment on it and i probably should do it. Hard to know what is best practice.

[mab01uk]

Waxoyl in body cavities extends the life of Mini sills, the steel used was sometimes poor quality (it was a budget priced car and expensive to build in later years, compared to modern robot assembly) and concealed areas were rarely painted or protected properly. Modern cars use galvanised/protected steels in vunerable areas. In the Minis design era cars of any make rarely lasted more than 7 years before terminal rust set in.

Plastic shields like modern cars available from Minispares in link below, can be fitted to front under wing areas:-

https://www.minispar...01.aspx|Back to

Edited by mab01uk, 10 August 2020 - 12:57 PM.

[johnyj]

Waxoyl in body cavities extends the life of Mini sills, the steel used was sometimes poor quality (it was a budget priced car and expensive to build in later years, compared to modern robot assembly) and concealed areas were rarely painted or protected properly. Modern cars use galvanised/protected steels in vunerable areas. In the Minis design era cars of any make rarely lasted more than 7 years before terminal rust set in.

Plastic shields like modern cars available from Minispares in link below, can be fitted to front under wing areas:-

https://www.minispar...01.aspx|Back to

Yes , what you say is true about the life span. My father had a 1960 mk1 morris mini that he bought when it was 2 or 3 years old and by the late 60's the floor was gone rotten and had timber boards for a floor until he sold it in 1969 for scrap. I had a 1976 mk 3 in 1985 and that was rusty enough then as well. I remember patching the rear valance with filler and getting the front subframe mount welded by an uncle who was a mechanic when it broke, same went for a 1975 clubman i had after. All had a life span of 7 to 10 years depending on its treatment and whether it had a garage or not.

[Ben_O]

I restore mini's for my job and one of the cars I restored almost 4 years ago has been back a few times between then and now for additional work unrelated to the original resto.

 

During the original restoration, I replaced the floors and sills and protected them with paint, stone guard and waxoil.

Having the car back since then has given me the opportunity to inspect the sills and keep an eye on how they are holding up.

The latest visit was only last week and after more than 30,000 miles since the floor and will replacement, there is absolutely no sihmgn of corrosion whatsoever.

bare in mind this car is used regularly and lives outside.

 

I believe that with care and attention during the fitting of these panels, paint protection afterwards and keeping the underbody clean is all you need to do to ensure longevity.

 

Cheers

Ben

[Cooperman]

The foam-filled sills on the early cars were indeed a problem.

I did hear that a guy doing some welding to repair a badly dented sill was overcome by fumes and hospitalised.

[johnyj]

Thats good to know Ben that a car that is used as a normal car in normal conditions is holding its own. The waxoil and paint is a big help then if maintenance is kept up.

[Ben_O]

Thats good to know Ben that a car that is used as a normal car in normal conditions is holding its own. The waxoil and paint is a big help then if maintenance is kept up.

I believe so. It's very important to use a creeping wax in these areas so that it can flow down between the vents in the sill protecting there as with the best will in the world, it's difficult to paint that area well and keep the paint there when welding.

[gaspen]

Hello

 

I recently fitted the outer sills to the floor. Before I spot welded it, I primed the surfaces with 2K epoxi. I don't know where the car will be painted but it takes months I think.

 

Should I spray waxoil into the sill BEFORE final painting ?

[sonscar]

I wouldn't as it may contaminate the final paint.Steve..

[sonikk4]

Hello

 

I recently fitted the outer sills to the floor. Before I spot welded it, I primed the surfaces with 2K epoxi. I don't know where the car will be painted but it takes months I think.

 

Should I spray waxoil into the sill BEFORE final painting ?

 

Nope as mentioned you are likely to contaminate things, however i would force more epoxy primer in there. The more the merrier.

[johnyj]

 

Thats good to know Ben that a car that is used as a normal car in normal conditions is holding its own. The waxoil and paint is a big help then if maintenance is kept up.

I believe so. It's very important to use a creeping wax in these areas so that it can flow down between the vents in the sill protecting there as with the best will in the world, it's difficult to paint that area well and keep the paint there when welding.

 

What is the best wax to use Ben or should i put as which one do you use in the day to day operations of the garage? I will understand if you prefer not to advocate one brand over the other however. just interested to know what you use?

 

John.