Conflagration avoidance - close call with S1 air filter....
Discussion
A simple air filter change uncovered a curious growth in my air box......
Being pretty sure that shouldn't be there I started to dig a bit deeper and whipped off the whole assembly - I reckon I dodged a fiery bullet here. LH exhaust header is clearly too close / touching the air box and resulted in some impressive melting.
In the interests of making a proper job of it, what vehicle were the air boxes on 2.8 S1's fitted to - Granada? Sierra? Capri? I'll see if I can find another one to replace this crispy one before I go too far and I clearly need to look at the routing of the exhaust headers too.... Has anyone seen an air box scorched like this before? Is this a normal S1 ailment?
I've been toying with changing the whole exhaust anyway (it's pretty battered underneath, as they all seem to be) so where would be the right place to obtain an original style or stainless system? are they available off the shelf or do I need to get one made?
Being pretty sure that shouldn't be there I started to dig a bit deeper and whipped off the whole assembly - I reckon I dodged a fiery bullet here. LH exhaust header is clearly too close / touching the air box and resulted in some impressive melting.
In the interests of making a proper job of it, what vehicle were the air boxes on 2.8 S1's fitted to - Granada? Sierra? Capri? I'll see if I can find another one to replace this crispy one before I go too far and I clearly need to look at the routing of the exhaust headers too.... Has anyone seen an air box scorched like this before? Is this a normal S1 ailment?
I've been toying with changing the whole exhaust anyway (it's pretty battered underneath, as they all seem to be) so where would be the right place to obtain an original style or stainless system? are they available off the shelf or do I need to get one made?
Wow,not good! My exhaust is well clear of the air filter box, looks like your exhaust is not fitted right.
These air boxes are now hens teeth to find I am afraid. Another S1 owner was after one for a long time. I can confirm they are not Capri 2.8, we found one from the Capri club but it wasn't right. I also believe they are Granada, the air valve assembly matches the Granada number.
I suggest you salvage that one.
Good time to draw all S1 owners attention to one issue you may not all be aware of. Your picture nicely shows the rivets that attach a stiffening plate to the inside of the air box, or at least it shows a couple of corroded rivets and a couple missing! Those are alloy rivets holding a steel plate to the plastic, and nicely exposed but out of sight under the airbox. The rivets corrode very nicely! When they do they come loose or drop out, that lets in air onto the downstream side of the filter. Air and dust gets sucked in. The mixture is upset because the air pressure at the air meter plate changes. The mixture is upset because dust accumulates on and around the meter valve and lever and even a small amount affects it. If you are unlucky a rivet gets sucked in and causes damage to the meter valve plate or throttle body. Take the airbox off, replace all the old pip rivets, make sure the new rivets are sealed (sometimes the centre part of a pop rivet comes out allowing air to get through the centre of the rivet)
To salvage it, I think it should be possible to cut out the damaged bit, make a new and larger plate for inside the airbox which goes beyond the hole, rivet and seal it in place. Good sealant like Sikoflex. Alternatively a body shop which has the gear to repair modern plastic panels might be able to put a piece in. Looks like you are going to have to make a new mounting which bolts through the casing, again well sealed. Bolt from inside the casing with a lock nut on then fasten the bracket to that?
These air boxes are now hens teeth to find I am afraid. Another S1 owner was after one for a long time. I can confirm they are not Capri 2.8, we found one from the Capri club but it wasn't right. I also believe they are Granada, the air valve assembly matches the Granada number.
I suggest you salvage that one.
Good time to draw all S1 owners attention to one issue you may not all be aware of. Your picture nicely shows the rivets that attach a stiffening plate to the inside of the air box, or at least it shows a couple of corroded rivets and a couple missing! Those are alloy rivets holding a steel plate to the plastic, and nicely exposed but out of sight under the airbox. The rivets corrode very nicely! When they do they come loose or drop out, that lets in air onto the downstream side of the filter. Air and dust gets sucked in. The mixture is upset because the air pressure at the air meter plate changes. The mixture is upset because dust accumulates on and around the meter valve and lever and even a small amount affects it. If you are unlucky a rivet gets sucked in and causes damage to the meter valve plate or throttle body. Take the airbox off, replace all the old pip rivets, make sure the new rivets are sealed (sometimes the centre part of a pop rivet comes out allowing air to get through the centre of the rivet)
To salvage it, I think it should be possible to cut out the damaged bit, make a new and larger plate for inside the airbox which goes beyond the hole, rivet and seal it in place. Good sealant like Sikoflex. Alternatively a body shop which has the gear to repair modern plastic panels might be able to put a piece in. Looks like you are going to have to make a new mounting which bolts through the casing, again well sealed. Bolt from inside the casing with a lock nut on then fasten the bracket to that?
Thanks for the reply - yes, they do appear to be scarce! From what I can gather the part number is 78 TF-9600-DA / 78TF9600DA and possibly 6052498.
I think I am stuck with having to rebuild my current one .... JB Weld to the rescue!
Thanks for the heads up on the rivets issue. I had heard of this before, it's a very valid point and one I'll be addressing in the air box rebuild. I am planning to do as you say - cut out the scorched part and replace, make a larger plate to cover the repaired area, remove all the rivets entirely and replace with self tapping screws - screws won't suffer the same corrosion issues, are unlikely to loosen and fall out over time and can't get sucked through the engine even if they do, so it seems sensible.
Such are the joys of working on old cars! A little recommissioning job is rapidly snow-balling into a huge heap of work! I can see I'm going to end up with a load of 'while you're in there' jobs too, now that the front clam is off and more and more bits are coming off.....
I think I am stuck with having to rebuild my current one .... JB Weld to the rescue!
Thanks for the heads up on the rivets issue. I had heard of this before, it's a very valid point and one I'll be addressing in the air box rebuild. I am planning to do as you say - cut out the scorched part and replace, make a larger plate to cover the repaired area, remove all the rivets entirely and replace with self tapping screws - screws won't suffer the same corrosion issues, are unlikely to loosen and fall out over time and can't get sucked through the engine even if they do, so it seems sensible.
Such are the joys of working on old cars! A little recommissioning job is rapidly snow-balling into a huge heap of work! I can see I'm going to end up with a load of 'while you're in there' jobs too, now that the front clam is off and more and more bits are coming off.....
Thanks for posting this. I think I'll be adding some heat protection as well as replacing those rivets. On checking mine I found that one rivet had corroded off and the head of it was just sitting at the bottom of the filter housing. Self tappers in stainless I think, maybe with some glue!
Fixed.
Just to round this off, I spent some time scouring the internet looking for a replacement for my scorched air box.... but nothing was found at a sensible price. Consequently I've repaired the old one, as below. Scorched areas and mountings chopped out, cut edges keyed, new pieces of heat resistant plastic (cut from an engine shroud off something else) shaped to fit, then JB Weld to glue it all together. As good as new again. I've also made a new plate (not yet fitted in the photo) to go inside the air box which is bigger than the old one and extends over the repaired area, hence the extra 'rivet' hole. The new one being secured by stainless self-tapping screws to eradicate the potential corroded rivets problem.
All I have to do now is fix the source of the problem, the exhaust header.... Looking more closely at that it looks like my header has been modified in the past and the pipe runs too far forward before curving down to meet the main exhaust pipe run. Doesn't seem to be any other solution to that other than remove and re-make.
Just to round this off, I spent some time scouring the internet looking for a replacement for my scorched air box.... but nothing was found at a sensible price. Consequently I've repaired the old one, as below. Scorched areas and mountings chopped out, cut edges keyed, new pieces of heat resistant plastic (cut from an engine shroud off something else) shaped to fit, then JB Weld to glue it all together. As good as new again. I've also made a new plate (not yet fitted in the photo) to go inside the air box which is bigger than the old one and extends over the repaired area, hence the extra 'rivet' hole. The new one being secured by stainless self-tapping screws to eradicate the potential corroded rivets problem.
All I have to do now is fix the source of the problem, the exhaust header.... Looking more closely at that it looks like my header has been modified in the past and the pipe runs too far forward before curving down to meet the main exhaust pipe run. Doesn't seem to be any other solution to that other than remove and re-make.
Hi Larrylamb,
Well done!
Here is a link for info on the correct original exhaust manifold for the S1:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Hope this is of some help to you.
Edit: and another thread to peruse:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Well done!
Here is a link for info on the correct original exhaust manifold for the S1:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Hope this is of some help to you.
Edit: and another thread to peruse:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Edited by glenrobbo on Thursday 7th February 13:45
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