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Beat the heat: some theory behind the problem.

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Beat the heat: some theory behind the problem.
#1
NOHOME P P
O, ON, Canada   CAN
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1967 MG MGB GT "Maggie (GT From Hell)"
Found some good reading from a poster over on the Miata V8 board. Those guys have very similar temperature issues with big engines in small cars.

http://www.autospeed.com/A_2159/cms/article.html
http://www.autospeed.com/A_2160/cms/article.html
http://www.autospeed.com/cms/A_2162/article.html

may be old stuff or basic for some of you, but it is a good article on what we are figthing when it comes to cooling these engines.


Pete

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Re: Beat the heat: some theory behind the problem.
#2
dhen Avatar
dhen Darian Henderson
San Antonio, TX, USA   USA
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1962 MG MGA Conversion "Mater"
Thanks,

Darian

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Re: Beat the heat: some theory behind the problem.
#3
BritishV8 Avatar
BritishV8 Curtis Jacobson
Portland, OR, USA   USA
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The articles talk about using a Dwyer Magnehelic differential pressure gauge to assess pressures in various locations so that sensible decisions can be made about cooling vents, spoilers, trays, etc. This topic was previously discussed (along with actual measurements taken on an MGB-GT) in this British V8 article: http://www.britishv8.org/Articles/MGB-Cold-Air-Induction.htm

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Re: Beat the heat: some theory behind the problem.
#4
V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kingsport, TN, USA   USA
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Okay, y'all have thoroughly convinced me that I should have made those inner fender louvers that I was thinking about when I installed the V8. I never pursued it since I don't have overheating issues.

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Re: Beat the heat: some theory behind the problem.
#5
NOHOME P P
O, ON, Canada   CAN
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1967 MG MGB GT "Maggie (GT From Hell)"
Carl:

If you had made the louvers in the inner fenders, which way would they point? Open side to the front of the car or to the rear.

Intuition and aesthetics dictate rear facing. Not so sure if this is a good assumption. The wheel well is a low pressure area, so it will pull air out regardless is what I am thinking. One direction will pull the air from the rear of the compartment, and the other will allow the hot air from the rad to go out the front facing openings.

Pete

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Re: Beat the heat: some theory behind the problem.
#6
V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kingsport, TN, USA   USA
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Pete,

I would face them to the rear & I would have the louver protrude into the wheelwell instead of into the engine compartment. I think this would provide good flow & help keep "splashings" out.

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Re: Beat the heat: some theory behind the problem.
#7
NOHOME P P
O, ON, Canada   CAN
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1967 MG MGB GT "Maggie (GT From Hell)"
Carl:

I like the idea. The only way I can see to do the louvers is to cut out the piece of inner fender, run the piece through a bead roller with a set of slitting dies to make the louver, and then weld the piece back in.

Just patching in a vent with louvers would fail the eye appeal test.

Pete

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Re: Beat the heat: some theory behind the problem.
#8
Jim Blackwood Avatar
Jim Blackwood * BlownMGB-V8
Gunpowder Rd, Florence, KY, USA   USA
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That hood vent test was pretty impressive, maybe you should pursue that. (Wonder what a big hood vent does when it has a blower sticking through it?)

Jim

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Re: Beat the heat: some theory behind the problem.
#9
rficalora Avatar
rficalora ROB FICALORA
Willis, TX, USA   USA
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1976 MG MGB V8 Conversion "MG MUTT"

I read the articles on the plane, but it all talks about air flow at speed. Who has problems with that in their B? Seems like the more interesting topic is getting sufficient air flow when the car is sitting still or crawling in a traffic jam. I believe Curtis' article may have mentioned that but I did't get to re-read it because my printer ran out of ink before I got to that one (I printed the articles to read on the plane)

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Re: Beat the heat: some theory behind the problem.
#10
V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kingsport, TN, USA   USA
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NOHOME Wrote:
Quote: Carl:
I like the idea. The only way I can see to do the louvers is to cut out the piece of inner fender, run the piece through a bead roller with a set of slitting dies to make the louver, and then weld the piece back in.
Just patching in a vent with louvers would fail the eye appeal test.
Pete

I was actually looking into making the louvers without removing the metal. I was thinking there should be a tool similar to a hydraulic knockout pucnh that would make the louver on the car. Drill a small hole at each end, make a cut from one hole to the other, then assemble a two piece mandrel, & use the hydraulic pump to form the louver. I haven't been able to find such a tool.

Kurt Schley sent me an old article years ago on making homemade louvers. I think the technique they used would be very difficult to do on the car instead of on a workbench. Removing a patch from the car, then welding it back in after the louvers are punched would probably be the easiest.




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Re: Beat the heat: some theory behind the problem.
#11
Duncan Avatar
Duncan Duncan Cowen
Delta, Vancouver, Canada   CAN
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1956 MG MGA 1500
1969 Triumph GT6+ (MkII)
I think the louvers would have to face down, as tires bring up road slop and fling it forward. Think back to riding a bicycle with no fenders in the rain.

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Re: Beat the heat: some theory behind the problem.
#12
V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kingsport, TN, USA   USA
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I think tires would sling the water straight up into the engine compartment if the louvers faced down. It may do it regardless of orientation. I'm counting on the airflow out of the engine compartment to get most of the water out. Besides, I really, really try to avoid driving my MG in the rain! winking smiley


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Re: Beat the heat: some theory behind the problem.
#13
bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
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1956 MG MGA
1958 MG MGA Twin-Cam
1962 MG MGA MkII Coupe
1965 Jensen CV8    & more
The MGA Twin Cam had removable inner fender panels (the lower part only, behind the shock position) with louvers in them.

I don't see why someone couldn't come up with a similar panel they could sell, along with a template for cutting out the stock MGB inner fender, and for drilling for small Dzus fasteners to fit the replacement panels.

Here is a pic of the MGA panels.




Bill Spohn www.rhodo.citymax.com/carstuff.html
Current: 1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1957 Jamaican MGA (200 bhp)1965 1971 Jensen Interceptor (350 bhp)
2009 Pontiac Solstice GXP Coupe (375 bhp)
2007 BMW Z4M coupe (340 bhp)
Recent: 1969 MGC roadster (175 bhp),Jensen CV8 (375 bhp),
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
North Vancouver BC


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Re: Beat the heat: some theory behind the problem.
#14
Jim Blackwood Avatar
Jim Blackwood * BlownMGB-V8
Gunpowder Rd, Florence, KY, USA   USA
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bills Wrote:
Quote: The MGA Twin Cam had removable inner fender panels (the lower part only, behind the shock position) with louvers in them.

Using that in the B would compromise the body strength forward of the firewall, requiring reinforcement in some other way. Otherwise you are very likely to develop cracks in the inner fender along the forward corners of the cutout. Using RV8 cutouts for vents like Kurt did makes more sense and the expanded metal covers he used looked just fine. He said he didn't have much trouble at all with water coming in there.

Jim

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Re: Beat the heat: some theory behind the problem.
#15
302V8 Avatar
302V8 Platinum Member Pete Mantell
Sidney, IL, USA   USA
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1969 MG MGB V8 Conversion "Xenia"
1969 MG MGC GT
1969 MG MGC GT "Foxy"
1978 MG MGB V8 Conversion "Lucky Lady"    & more
V8MGBV8 Wrote:
Quote: I think tires would sling the water straight up into the engine compartment if the louvers faced down. It may do it regardless of orientation. I'm counting on the airflow out of the engine compartment to get most of the water out. Besides, I really, really try to avoid driving my MG in the rain!

I was worried about the same thing myself when I cut mine similiar to RV8 openings.

As the inner fenders are negative pressure zones (mentioned above), at speed hardly any road debris/water will enter the engine compartment as it is forced out under the car.

I think more dust/bugs/rain enter through the grille!!




Cheers

Pete

69 B 302 V8 - 78 B 215 V8 - 80 B 302 V8 - 58 ZB Magnette - 69 CGT 9004 - 69 CGT 7666

http://www.mantellmotorsport.com/


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