Shaker hood temperature.

[janosch]

Hi.

Anyone out there with a Shaker that could might tell me if the temperatur changes on the bubble when the engine is hot?? Does it get colder from the air running through it, or does it get hot by the engine heat??

I hope someone can maybe test this or allready knows the answer.

Thank you

Rasmus Porsager.

[Green Drop Top]

It depends........An original Shaker bubble is made from a RIM plastic material (Reaction Injection Molded). It is comprised of a base 2 componant resin which cures under heat and pressure in the molding process, this material is filled heavily with talc to give it stability and temperature resistance. This material was engineered specifically for automotive under hood environments, heat and chemical resistant, etc. Normal engine opperating temperatures are not going to affect it, heck I've even seen them survive short duration carb fires with no apparent damage!

Now.......Aftermarket bubbles sold today. They are made of fiberglass. NONE of them are made in the RIM process (cost prohibitive tooling, etc.). Fiberglass is pretty decent for automotive use, engine heat won't affect it much in normal use, but you could have problems if it were to get in contact with open flame, it burns/melts pretty easily, especially if coated with gasoline like from a burping carb fire, etc..

I don't know if this answers your question but it might offer some explaination of the materials involved. In my experience the original bubbles seem to stay realatively cool in opperation, the original material does not hold heat very well. Even though its heated from below (radiant engine heat) it's also cooled from moving air above to counter it.

[kudakidd]

Plastic isn't a great conductor, so I'd say that the cool air around the bbble and in it would offset the heat from the engine below. (Scott's answer is definitely more scientific however!  )

[janosch]

That was an excellent answer, and it gave me a good idea of how the shaker bubbles are made and works considering heat.
Now i have no worries for carb backfire since i use EFI, but i would still like to know if someone outhere with a shaker hood could just do a check some time when they are out driving to feel if the shaker is cold / hand warm / hot when engine is at it's operating temperature. Both when idling (not being cooled by wind) and also after driving for a couple of miles at regular speed.

Thank you.

[FM3V6M]

I believe the earliest painted shakers (the ones painted red only on red cars with color-keyed red mirrors and rubber bumpers) were subject to blistering from the engine heat necessitating the change to argent-silver and later to black.

[Green Drop Top]

Actually I've never heard that one and frankly, would find it hard to believe, I've owned several shaker cars with all three types of finish (painted, argent, organosol) and have never felt one too hot to put your hand on, hardly warm enough to blister paint. That change was more likely due to production efficienceis (getting a good paint finish on a glossy color was difficult) or due to reflections in the drivers face off of shiney paint. I've heard it was due to both of these things.

[hotrod98]

If I remember correctly, the actual reason was the excessive amount of time it took to prep the bubble for the smooth finish required for the red paint. They didn't require much prep for the other finishes.

[FM3V6M]

Actually I've never heard that one and frankly, would find it hard to believe, I've owned several shaker cars with all three types of finish (painted, argent, organosol) and have never felt one too hot to put your hand on, hardly warm enough to blister paint. That change was more likely due to production efficienceis (getting a good paint finish on a glossy color was difficult) or due to reflections in the drivers face off of shiney paint. I've heard it was due to both of these things.

Hey, I read it somewhere on the internet...so it must be true, right?

[janosch]

Thanks for the many reply's..

I have a shaker bubble bought from yearone, so if anyone have the same out there that would be the one i would be most interested in hearing about. So maybe in a case of a temperature at 75 degrees F, would the bubble be warmer/colder when engine is at operating temperature and what would it be in idle and after a good drive where the air is cooling it down.