My CMC has a bump, outcropping on the engine bay firewall where the fan on the doghouse is. Am I supposed to cut this out?
Thanks
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My CMC has a bump, outcropping on the engine bay firewall where the fan on the doghouse is. Am I supposed to cut this out?
Thanks
Thanks
If it's the big sorta mouse hole thing, mine is cut out. Guess it allows another path for air to the fan.
Bill
Bill
Looks like a natural extention to the air intake. Seems to me that it wold allow hot air to enter from below. Isn't the idea to seal the top half from the bottom half like in a bug?
Yup....I think the theory was that when the car is moving the hot air would be exhausted out the back from under the car and relativly cool air be available through the 'mouse hole'. I've blocked mine off for test purposes and it didn't seem to make any real big difference - at least based on oil temps. I believe George has used, or suggested, running a large diameter hose (dryer vent hose?) mounted in the area of the mouse hole and run down and under the car with the open end facing forward to 'scoop' up cooler air and dump it into the engine room. This should eliminate sucking up the majority of the engine generated heat. Probably want to use an 'owl strainer' (wire mesh) to filter out the big hunks that may come up the hose.
Bill
Bill
Check out the circa 1984 CMC build manual in the on-line library.
On page IV-18 it tells you to cut out the surface of that "shroud area" to get fresh air to the engine cooling intake. I installed a sound deadening material onto the firewall and made it to snugly fit the entire firewall area, including below that opening and down to the horizontal air shields at the heads, effectively isolating the engine compartment and making that open air inlet more important. The air comes in under the body and up into the area between the firewall and the rear seat back (a pretty big area) so I never saw the need for any kind of additional ducting. The incoming coolong air comes either from that opening or from the engine cover grill and the engine runs reasonably cool at highway speeds on really hot days so I'm happy.
gn
On page IV-18 it tells you to cut out the surface of that "shroud area" to get fresh air to the engine cooling intake. I installed a sound deadening material onto the firewall and made it to snugly fit the entire firewall area, including below that opening and down to the horizontal air shields at the heads, effectively isolating the engine compartment and making that open air inlet more important. The air comes in under the body and up into the area between the firewall and the rear seat back (a pretty big area) so I never saw the need for any kind of additional ducting. The incoming coolong air comes either from that opening or from the engine cover grill and the engine runs reasonably cool at highway speeds on really hot days so I'm happy.
gn
The "bump" on the engine firewall is to be cut out leaving a 1" horizontal surface "lip" The lip is to affix a piece of stair tread rubber or similar item to extend over to the engine shroud intake . This is the engines cool air source......Alan
Thanks for the info. So Is there still a need to seperate the bottom from the top? I noticed in some pictures posted here that some do and some don't.
Don't know what you mean by "separating the bottom from the top". Can you give a little more detail?
gn
gn
Whoops! Just looked a bit higher in the thread.
Yes, you should separate and seal the bottom of the engine from the top......that's why original VW's had all those shrouds and seals to seal up the engine compartment and keep the hot air from below (from the heads and exhaust pipes) away from the cool air intake. VW Beetles got all of their cooling air from the engine cover louvers, hence a lot of folks used spacer hinges at the top of the rear hood to push the hood up and get more cooling air in there, especially in hotter climates.
Take a look at the 1984 CMC manual in the on-line library - page V-11 shows the shields they recommend to separate top and bottom. Those should be combined with a suitable firewall "splash apron" and weatherstrip material as needed to seal off the engine compartment. I used 3/8" thick rubber floor mat material (Home Depot or Lowes) and attached it to the firewall with adhesive and hood liner mushrooms (from NAPA) in such a way that it pushes up against the engine tin (on the flywheel end) and then used a couple of pieces of 2" aluminum angle to attach the firewall piece to the lower engine insert. The CMC manual implies that you should also add a collar (page IV-18) to the firewall apron to act like a tunnel to the air intake, but I was afraid that, should it work loose it would get sucked into the fan and cause all kinds of hell so I deleted it with no apparant ill effects. Besides, having that hole in the firewall is better than original Beetles and they seemed to survive OK........
I made the engine compartment inserts from HVAC sheetmetal and attached them to the CMC frame with 10-32 screws so I can remove them to get the engine in and out. The CMC manual shows four inserts, while I made only two (upper and lower) and then used door weather stripping (frost king from Home Depot) to seal all the edges. It all came out looking professional and it seals really well.
Take a look at nichols1 in the files section and there are three pictures of my shield set-up. Let me know if you need more info.
gn
Yes, you should separate and seal the bottom of the engine from the top......that's why original VW's had all those shrouds and seals to seal up the engine compartment and keep the hot air from below (from the heads and exhaust pipes) away from the cool air intake. VW Beetles got all of their cooling air from the engine cover louvers, hence a lot of folks used spacer hinges at the top of the rear hood to push the hood up and get more cooling air in there, especially in hotter climates.
Take a look at the 1984 CMC manual in the on-line library - page V-11 shows the shields they recommend to separate top and bottom. Those should be combined with a suitable firewall "splash apron" and weatherstrip material as needed to seal off the engine compartment. I used 3/8" thick rubber floor mat material (Home Depot or Lowes) and attached it to the firewall with adhesive and hood liner mushrooms (from NAPA) in such a way that it pushes up against the engine tin (on the flywheel end) and then used a couple of pieces of 2" aluminum angle to attach the firewall piece to the lower engine insert. The CMC manual implies that you should also add a collar (page IV-18) to the firewall apron to act like a tunnel to the air intake, but I was afraid that, should it work loose it would get sucked into the fan and cause all kinds of hell so I deleted it with no apparant ill effects. Besides, having that hole in the firewall is better than original Beetles and they seemed to survive OK........
I made the engine compartment inserts from HVAC sheetmetal and attached them to the CMC frame with 10-32 screws so I can remove them to get the engine in and out. The CMC manual shows four inserts, while I made only two (upper and lower) and then used door weather stripping (frost king from Home Depot) to seal all the edges. It all came out looking professional and it seals really well.
Take a look at nichols1 in the files section and there are three pictures of my shield set-up. Let me know if you need more info.
gn
Thank's Gordon. I have the manual but the pages mentioned in this thread seem to be missing. I will look at the online one and review it. My kit semms to have come with rubber to seal around the engine once you make panels. Mine actually came with a fiberglass piece for the rear of the engine as well. I will also take a look at yours as I will have to fabricate the side peices at the least.
Thanks
Thanks
After reviewing the files it all makes sense now! I am working on completeing my pan now. Wanted to get this stuff straight before I start on the body. Lokks like the "top of the rear apron on the original VW tin is even with the bottom of the frame horn, is tyhis so?
Thanks again,
Ben
Thanks again,
Ben