heat shield thread

[gtgt_bangbang]

gawd after looking at those threads where Your Truck Does the Slinky, I feel like a neanderthal duffer with my lil av snips & rivets, but nevertheless, heat transfer gets me hotter than Toroweap at noon.

In a nutshell, I'd like to reduce the heat transfer from the exhaust manifold to the head, and specifically the head gasket line.

Looks to me like the bulge on the driver's exhaust manifold / collector (in very near proximity to the rearmost driver side cylinder) is a prime place to protect. That shows the closest approach, and I can't even get one of my sausage fingers in between there.

I haven't mastered the Sunday comic running photos plus caption, so I have to break this up in multiple posts. Bear with me and thanks for staying off this thread until I am done for the sake of posterior ity.

 

[gtgt_bangbang]

First thoughts on a heat shield

I had a spare exhaust gasket, and it really looked like a section of it would do the job with minimal fitting. It might have, and it's a reasonable fix to install with the engine insitu, but its hard as hell to cut neatly, it may of stayed on, it may have dropped off at the first sidewalk.

Shown is a small section of scrap exhaust manifold gasket, intended to be attached using a stainless tie wrap around the manifold down spout. It would place an extra shield at the worst spot but nowhere else.

That may also have been a damned lie about doing it with the engine in-situ, since I had to drill a hole in the manifold web to create a simple planer path for the tie wrap. You could take just that manifold off ?

 

[gtgt_bangbang]

Heat shield phase 2

The basic idea was to make a larger radiation shield, using old license plates. To get really fancy, I was going to sandwich some muffler wrap between a couple sheets.

I had full access to the motor, which helped greatly. It could be done with the motor installed.

A few comments;

1) one standard license plate cut in half is plenty adequate material to fit in there.

2) make your initial pattern with thin card stock, it's much easier to shape, the transfer your finished shape to the metal.

3) note that the flat plate is further shaped (wrapping around downspout) to provide extra shielding to the oil cooler hose. Don't rivet the entire plate initially, as the rivets will tear out due to bending mismatch; instead place a couple rivets, make the next bend, rivet that, then proceed.

4) it occurred to me there is a lot of plastic artwork on the plate, and this would be a nasty place for a small fire.
So sacrificing looks, I baked the finished shield in a 400F oven. Yes it stunk. Horribly. Revolting smell. Fair warning.

5) with careful fitting, you can find a location to rivet the shield directly to the exhaust manifold gasket that will not interfere with the exhaust manifold.

6) notice that OE heat shield works well with the new shield, thus the exhaust manifold downspout has a fairly complete jacket around it until well away from the motor.

 

[gtgt_bangbang]

Further shielding on the crossover

But wait, There's more! near-approach between the crossover and the head.

Wrapping the entire crossover would be a messy waste and possibly counterproductive. I just want to slow down radiation heat transfer at the most direct path.

Most of the crossover is already encased with stainless heat shield jacketing. The flat flange of that jacket is easily notched with a cut off disc, in order to securely locate stainless wraps or wire, not unlike a guitar nut.

Carefully cutting the notch width will allow it to prevent the slippery tie wrap from simply spinning when drawing it tight. Getting those tight should make a durable and neat installation.

A strip of muffler wrap (folded to a loop to protect the frayed ends from further unraveling) has been attached the crossover , again only at the most direct path from crossover to head. Band-Aid my ass. The rest of the crossover remains unshielded to improve cooling

 

[gtgt_bangbang]

Now I'm done

I'd like to find one of those cheap IR meters check the results.