420R (S3) Radiator design issue, regular failures???

[TomB]

It’s a kit car at the end if the day, some modifying with an angle grinder should never be ruled out! 

[7 wonders of the world]

Mark, 

Understand your wish to keep it 'Factory' however having the car function correctly is far more important, and 'Factory' isn't always the best solution - there are many many examples of that, sadly new owners of new cars are used as an extended R&D facility.

Many members have had to angle grind the DeDion tube for clearence too......

Hope you get things sorted for the chippy run

[David aka Blue7]

Mark #51, Good decision 

[Jonathan Kay]

What is the bobbin connected to?

Jonathan

[ChrisC]

If I was faced with the same situation,  I wouldn't grind the classic bracket, I would enlarge the hole in the replaceable drop bracket, lifting the bobbin, therefore lifting the rad.  A guess you would also need to enlarge the bottom bobbin hole.  That would be reversible when you get a radiator replacement, with a cheap drop bracket. 

[David aka Blue7]

Jonathan, it is shown in second photo in 1st post, it connects between radiator and drop bracket.  It has always intrigued me as to why a bobbin is necessary, I don't recall seeing them on my CSR but I will take a closer look next time the nose cone is removed.

[ScottR400D]

#54 The bobbin's connected to the aluminium bracket welded to the side of the rad and to the drop extension of the chassis bracket. 

#55 Chris, I think the whole purpose of the drop extension was to lower the rad to get the nose to fit. What you suggest might work as long as the rad can be lifted without fouling the nose. 

Another option might be a slightly different extension that would move the rad sideways, but we don't know how tight a fit everything is under the nose. 

If the rad has to be exactly there, then the only choice seems to be to grind the bracket. 

[Jonathan Kay]

"#54 The bobbin's connected to the aluminium bracket welded to the side of the rad and to the drop extension of the chassis bracket."

Thankyou.

Is there a fixed connection above that as well as as the bobbin connection?

Jonathan

[David aka Blue7]

The fixed connection above is to the top of the drop bracket and not the radiator.  In essence the drop bracket does exactly as described, it drops the radiator down but still uses the same connection points on chassis and radiator,  A neat solution apart from the design fault.

[Jonathan Kay]

Thankyou.

I know that I'm repeating myself but why not fix it this way?

Keep the existing position of the radiator and... 

"... how about cutting off the upturned end of the hanger, inverting it and welding or bolting it back so that it engages the bobbin directly?" 

And discarding the drop bracket. (And adding lightness!)

Jonathan

 

[David aka Blue7]

GM is an Accountant, your solution would work but would be more expensive in man  hours cutting and welding.  However, I think the main reason for the drop bracket is that it is an easy solution for the customer who would have a set of spanners but not hacksaw and welding equipment.  I know which option I would prefer

1. insert and bolt up the enclosed drop brackets

2. cut the upturned end off the existing brackets, invert them and weld them back in place, Mark would have to buy welding equipment from Screwfix and take a course in welding ... and not get his fish & chips 

The other problem with your solution Jonathan is that from the photos, it looks like the cut off end of the existing bracket would not be long enough, but I can't be certain.

Of course another solution would be to bend the existing brackets downwards with a big hammer, One of the most famous quotes in car ‘fettling’ - to a mechanic’s apprentice: “Don’t force it lad! Use a bigger hammer!” 

[John Vine]

Re #60:

The S-shaped extension piece has two functions: (a) to lower the rad and (b) to move the rad backwards out of the nosecone.  It simply relocates the mounting point for the bobbin so that the new-style rad fits in the old-style nosecone. For a temporary fix, I think it's quite a neat solution, but it shouldn't be thought of as anything other than temporary. 

JV

[ScottR400D]

I would agree that the best solution for that rad would be that chassis bracket turning downwards and removing the need for the extra bit. But then you do have a significantly modified chassis which Mark won't want, and heavily damaged PC. 

I'd be inclined to try to get CC to supply the original system though I guess they'll resist that strongly because it would be an admission of fault. 

[CtrMint]

Me and welding there's a thought  the mind boggles.

[CtrMint]

In all seriousness, I think I'll just cut down the top of the hanger to increase the gap.  As it's been said earlier in the post, it's not possible to raise the rad due to clearance on the nose cone.  Of course I might be able to obtain a greater horizontal gap with a new rad  

Long term, I like the idea of taking the upright section of the chassis mount clean off, and then placing a 90 degree mount underneath, their with a weld or drilling a vertical hole through an bolt etc. That design would require very careful measurement and consideration as the proximity to the front ARB bush is also very close.

 

[CtrMint]

First of what will be a couple of blog posts is now available.

https://www.caterham7diaries.com/post/taffia-2021-prep-goes-wrong

[CtrMint]

Well I did it this afternoon, cut the bracket down, gained approximately 12mm in clearance,

[CtrMint]

and the hanger, painted.  Chassis is also painted too.

[ScottR400D]

Well that should solve that issue!

Incidentally, what's the rad set up on your 620? 

[CtrMint]

It's a different design, the upper port is on the driver's side.
Part number is different too, 30C086E

 

[John Vine]

Re #67:

Neat dremeling.

Is that a new hole as well?  If so, presumably the entire rad is now lower, or is that a corresponding new hole in the drop bracket?

JV

 

[CtrMint]

Hi JV, 

The radiator (should - not hung it yet) be in exactly the same location.  I've drilled a hole lower down in the bracket and chassis, and then cut the old hole / top off.  The 12mm or so of the old bracket is what's I've gained in terms of clearance with the inlet port. 

[CtrMint]

This the end result, all being loose.  So the hole into which the radiator bobbin goes (below) is in exactly the same location.

[Jonathan Kay]

Well done.

Jonathan

[John Vine]

Good solution!

JV