Heat Shield for Duratec Coolant Overflow and Cam Cover Breather Pipes

[aerobod - near CYYC]

As I blew a weakened coolant overflow hose while at a track day this summer (luckily while idling in the paddock), I decided that a heat shield above the exhaust headers is advisable to try and alleviate the problem in the future. A quick look at the side of the head showed 2 unused M10 bosses with 25mm deep threads that could be used to attach a heat shield with no further modification:

 

The hoses also have a tendency to vibrate due to the long run, so I also put a small rubber block to zip tie between the hoses and one of the heat shield mounts, which are made from some scrap 31mm square aluminium tubing:

 

The heat shield itself is a 1mm thick piece of aluminium 100x380mm in size, I have pressed in a number of stiffening ribs with a bead roller to subdue any likely reasonance if it was left as a flat sheet:

Overall it seems to be quite rigid and seems to block the worst of the direct header heat on the underside of the hoses:

[7 wonders of the world]

Hi James,

Nasty blowing a coolant hoses under pressure certainly wakes you up !

you could always sleeve the hoses too, or replace the coolant hose with a metal section in the vunerable area and cap the breather and run the DS as a sealed system which improvesits scavenege performance too.... and saves weight   

 

[graearea]

I'd wrap the primaries.

[aerobod - near CYYC]

I've had problems with wrapped primaries / headers before on other cars, with in one case weld cracking likely due to thermal expansion beyond the design limit, and Lambda sensor heat issues. If needed, the proper way to reduce under-bonnet temperatures would be to do a fully coated exhaust to the catalyst (assuming the welds can take the additional thermal expansion) and re-position the Lambda sensor. Overall the under bonnet temperatures are not excessive on my R400D, just the point where the hoses run 50mm or so above the headers, so a heat shield was the easiest, cheapest and most reversible option for my car and probably lighter than header wrap, too, at 150 grams of additional weight.

[Ian Lummis]

Great idea and a quality piece of fabrication my r400 has wrapped headers would you remove the wrapping. 

[7 wonders of the world]

Interestingly I have run wrapped primaries on a couple of Duratecs now, however the exhaust have been custom ones, peices of art really, which have been TIG welded (fully purged) as opposed to the stock CC ones which arre commercially made MIG versions, which may well support James comments regarding failure when certain products are wrapped.

 

 

 

[timb2117]

Lovely work James, and I concur about the wrapping of primaries, a friend once fully wrapped his exhaust that was going to run inside a glass fibre sill, "just in case" sadly just in case caused a pinhole of superheated gases bursting through a  weld, onto the sill and complete flame out of car, poor guy. I "ceramiced" mine and it seems great, allegedly up to 30% less underbonnet heat.

Only thing I did do once was very similar to your handiwork but made the alloy double thickness with a 5mm air gap, the top piece had very very little heat to it, or another idea is self adhesive turbo wrap (like silvered glassfibre mat) could be applied to bottom of your lovely work.

Then again look what "belt and braces" caused my mate!

Great solution.

[John Vine]

Very neat and workmanlike, James. 

Although I've not encountered problems with the original hoses in over 51K miles, I'll now be examining them very closely for signs of heat damage.  (I do have wrapped primaries, however.)

JV