Is filler heat-sensitive?

[droopsnoot]

I've done some repairs to the bulkhead on my project car, and I intend to use a bit of body filler to get the surface as good as I can, then paint as normal. Only thing is, the exhaust manifold runs very close to the bulkhead (around 1" away, maybe a little less) on this side. Am I going to have trouble with the filler, or will it be OK on the basis that the paint is OK on other car?

 

[optima21]

depends on how hot you're getting it, I've used a thin skim of it it on the camshaft cover on one of my cars and its been fine.

if you get epoxy resin adhesives (or chemical metal etc) they have a operating temperature of about 100c, but if you only need to do a small bit of filling, you can use jb weld, which can operate upto 250c

and I used the JB weld to reduce the inlet port size on my other car and thats been ok for the last 6 or 7 years

 

[rich the mechanic]

It depends on what you use if I have to make a quick repair using filler or stopper and want to get it off at a later date I run the blow tourch over it and give it a tap and off it falls off quick wire brush and it's all gone

 

[rich the mechanic]

and I used the JB weld to reduce the inlet port size on my other car and thats been ok for the last 6 or 7 years

Out of interest is the JB Weld on a manifold ot the head itself?

 

[optima21]

no jb weld was only used on the induction side on both the cylinder head and inlet manifold. it wouldnt be able to stand up to the temperature of the exhaust manifold.

 

[Rig Pig]

You could make a heat sheld for the pipe to protect the bulkhead.

 

[Daz1968]

Or you could use heat wrap on the manifold

 

[grim_d]

That air filter cover is just about the coolest thing i've ever seen.

 

[brightspark]

no jb weld was only used on the induction side on both the cylinder head and inlet manifold. it wouldnt be able to stand up to the temperature of the exhaust manifold.

out of curiosity why have u reduced the bore of the inlet manifold

 

[droopsnoot]

Thanks, I suspect I'm over-thinking it. I wouldn't know how to start guessing what temp the exhaust manifold gets up to - it's not a turbocharged car so not excessive. Sounds like I might need to get a handheld thermometer and measure the other one.

 

[optima21]

out of curiosity why have u reduced the bore of the inlet manifold

you can flow more air through the ports by making them smaller and reshaping them and get more power across the rev range too.

the top inlet port is the standard one and the bottom one is an early version of the reprofiled one

 

[brightspark]

rite

 

[langy]

Filler won't like the heat off an exhaust manifold and paint won't either.

 

[rich the mechanic]

no jb weld was only used on the induction side on both the cylinder head and inlet manifold. it wouldnt be able to stand up to the temperature of the exhaust manifold.

I was only meaning the inlet manifold, the steel can just about take the heat from exhaust gasses which to give a idea of the temp achived it is not uncommon to see the first few inches at least of a tubular exhaust glowing dull red however I can't remember what temp that is though.

 

[zzr1200]

hth

 

[droopsnoot]

Filler won't like the heat off an exhaust manifold and paint won't either.

So turning that around, if the paint on the bulkhead area that I'm worried about hasn't come to any harm after years of being next to the manifold, then I should be OK?

Thanks for that temperature chart, the exhaust manifold doesn't change colour at all, or not to my eyes anyway.

 

[zzr1200]

Thanks for that temperature chart, the exhaust manifold doesn't change colour at all, or not to my eyes anyway.

If you don't have Superman's temperature sensitive eye's, you'll have to use a heat test/temperature gun like the rest of us mortals.....

 

[droopsnoot]

Oh OK - I thought the chart was showing temp vs. colour of manifold when hot - I know some turbo manifolds glow red when hot.

I'll have to keep a look out for a temperature gun.

 

[zzr1200]

Oh OK - I thought the chart was showing temp vs. colour of manifold when hot -

I'll have to keep a look out for a temperature gun.

The chart is just a general temperature colour chart for steel of the web.


Heat gun......DT8550 is the higher temp reading model....

 

[rich the mechanic]

Cast iron exhaust manifolds don't tend to glow as there is a bit more mass to heat and a lot of tube manifolds that are a standard fit are twin skinned but my srx-6 headers would glow faint red to blood red depending on how much it was thrashed and it was only at night it was clearly visable.