Side Vents - GMCMh

[bartz paul]

Fred:

Just wondering what difference you see if it takes longer to cool the engine
compartment area after engine shut down without vs. with same side vents?
I've found that if you open the front access doors after shut down, you'll
feel a significant amount of rising hot air escaping for a short while. But
if it takes longer without facilitating the venting process, so what?

I too, share your reluctance vs. the unsubstantiated benefits, particularly
after I've installed ceramic coated headers.

Paul Bartz

From: FBHUDSPETH [mailto:FBHUDSPETH]
Sent: Monday, November 23, 1998 12:29 PM
Subject: GMC: Side Vents - GMCMh

Has anyone done an analysis of the benefits of the side vents? By this I
mean before installing the vents, document the engine compartment
temperatures after engine shutdown over time; then for the same conditions
document the temperatures after installing. Without a forced air system (as
in a boat), I am reluctant to cut holes in the body for the vents unless the
benefits have been documented and demonstrated to be worthwhile.

 

[chuck will]

Mine were alaready there. If they were not there I would not have put them
there. The answere to heat is two fold. Heraders, Thornly with Ceramic coating
and air vents in the inner fender well where the heat could actually be extracted
from. At least that is where I think they should be. My temperature is not hot
any more. I can put my hands on the engine compartment when running for a few
hours it never gets hot now. Befor the dog would not sit on it. Given the time
to open the compartment up and put it back where you can get into the comaprtment
the headers are almos cool enough to touch. Five minutes or so. Chuck

> Has anyone done an analysis of the benefits of the side vents? By this I mean
> before installing the vents, document the engine compartment temperatures
> after engine shutdown over time; then for the same conditions document the
> temperatures after installing. Without a forced air system (as in a boat), I
> am reluctant to cut holes in the body for the vents unless the benefits have
> been documented and demonstrated to be worthwhile.
>
> Thanks for any input anyone may have.
>
> Fred Hudspeth
> '78 Royale

 

[john wright]

The auxiliary vent that most GMC owners have on their coaches have
several benifits.
1. Permit more hot air to be forced out of the engine compartment by the
raiator cooling fan.
2. The fuel system is kept cooler, reducing possible vapor lock.
3. The transmission operating temp is measurably reduced by the
addtitional air flow.
4. I have noticed that my engine cover does not get as warm than in the past.

The GMC Club that I belong to, very few coaches do not have the vents
installed, they seem to work in lowering temperature.

J.R. Wright
77 Eleganza II

>
> Has anyone done an analysis of the benefits of the side vents? By this I mean
> before installing the vents, document the engine compartment temperatures
> after engine shutdown over time; then for the same conditions document the
> temperatures after installing. Without a forced air system (as in a boat), I
> am reluctant to cut holes in the body for the vents unless the benefits have
> been documented and demonstrated to be worthwhile.
>
> Thanks for any input anyone may have.
>
> Fred Hudspeth
> '78 Royale

 

[chuck will]

Thanks for bringing some more light to the GRAY matter, didn't think about the
slush. I don't have any here but that don't mean I might not get to where there
is some. Maybe a better idea would be to some how over-presureize the complete
engine compartment with the addition of a fan. I am really amazed just how cool
the compartment is after the addedition of the ceramic headers. Chuck

>
> > The answere to heat is two fold. Heraders, Thornly with Ceramic coating
> > and air vents in the inner fender well where the heat could actually be
> > extracted
> > from. At least that is where I think they should be.
>
> Will,
> PMFJI, but I'd advise NOT to cut holes or vents in the inner fender wells,
> at least not near/towards the engine. Aside from the obvious risk of
> soaking/shorting your spark plugs, secondary wires, and distributor, you DO
> NOT want cold water or slush splashing on your hot (occasionally red hot)
> exhaust manifolds. Unless of course you're looking for a good excuse to get
> some new headers, or you want to see what a cracked manifold or header (yes,
> they crack too, usually at welds) sounds like.
> I agree getting the heat out is a worthy goal; I open my cowl vents after a
> run, and am trying to design some side vents to my liking. Just my .02.
>
> Happy trails,
> Rick Staples
> '75 Eleganza
> Louisville, CO