Advice on Filling in gaps around front mounted Oil cooler : Race car

[Geneman]

Hi Peeps. My 74 911 RSR vintage race car has a front mounted oil cooler. its mounted , of course, to the chassis and the exhaust is directed downward in the rear. its about 5-6 inches from the front screen and I have aluminum flashing on top and bottom to channel the air at the cooler. however, there are big gaps on the sides because the bumper is so irregular, you cannot shape any metal to fit it properly. I am told you lose alot of air flow thru the cooler if there are easier paths for it to follow: so it does not setup a good boundary layer. my car tends to run hot anyway so concerned about this ( and of course global warming is upon us...).

One idea I had was to squirt that expandable foam from a rattle can in the gaps. it then hardens and it pretty airtight. likely makes a mess when you have to remove the bumper but that's another issue.

any thoughts on this approach or others? or am I just overthinking this.,..

thank you as always..frank

[3literpwr]

I’d jump on McMaster carr and order some soft foam tubes. I got a few for my rally car and was able to stuff them into the crack between bulkhead and engine. Might be a better solution then great stuff.

[stownsen914]

Hey Frank - for gaps up to 3/4", use that foam insulation tape like you get at Home Depot. It fills gaps and conforms to irregular shapes very nicely. If the gaps are larger, riveted pieces of aluminum flashing should do the trick. You can also use aluminum insulation tape to close small gaps. The spray stuff would work too, just might be a bit messy.

On my racecar I lowered oil temps by 20 degrees doing the above.

I see Peter in the background in that pic!

[Geneman]

thanks liter. great idea

st.. thanks. good ideas.. are you talking about that tape for weatherstripping and sealing window cracks? or something else? problem with the flashing is that there is no room to get the rivet gun in there. even the manual one. the aluminum. tape might work for small stuff but I bet would not hold up to much air pressure..

yes classic Peter with the cigar at lime rock!

[Bill Verburg]

I've used those foam pipe insulation tubes, they come is multiple widths,

very easy to work w/

[Geneman]

thanks liter. great idea

st.. thanks. good ideas.. are you talking about that tape for weatherstripping and sealing window cracks? or something else? problem with the flashing is that there is no room to get the rivet gun in there. even the manual one. the aluminum. tape might work for small stuff but I bet would not hold up to much air pressure..

yes classic Peter with the cigar at lime rock!

[stownsen914]

Yep, weatherstripping tape. It's convenient that it has the tape built in to secure.

If the spot is hard to get to, stuffing foam in there should do the trick though.

[Geneman]

Bill V./liter. this is just that brown dense foamy stuff that is split down the middle you wrap pipes with? ? so you just cram it into the gaps and glue/tape or something to hold it? thanks. frank

[911obgyn]

2” wide aluminum duct tape, get the thickest aluminum. It should hold up to air pressure, self adhesive peel and stick.

[Mahler9th]

Not sure I understand:

"...you cannot shape any metal to fit it properly."

Do you have or can you take pictures?

[Bill Verburg]

Originally Posted by Geneman

Bill V./liter. this is just that brown dense foamy stuff that is split down the middle you wrap pipes with? ? so you just cram it into the gaps and glue/tape or something to hold it? thanks. frank

yes, w/ the right size just cram it in and it will stay put. It is pretty compressible and bendable

[Jeff Higgins]

I like the foam rubber pipe insulation tubes available at any home improvement store. I believe they have been the go-to for this application for as long as any of us can remember.

I like the stuff that has the "stickum" on both sides of the seam where it is split. There is a cellophane peel-off protectant strip on each side so they don't stick together. Get the surfaces to which you would like these to stick as clean as possible, cut to length, peel the cellophane, and stick in place. So cheap it might as well be free, and it stays in place for a good long time.

[Geneman]

THANk you EVERYONE superb advice. as usual from the brain trust. cheers. frank

[Trackrash]

I have resorted to that spray foam crack sealant.

Never could get that stick on foam weather stripping to stay put. Kind of embarrassing when you have it dragging under the car.

[Cory M]

The stick on foam that is used as a gasket under 911 fuel tanks works good for this purpose. The adhesive is really sticky and the foam conforms well, as long as it's thick enough for your application.

[Geneman]

Thanks Cory. thats an excellent suggestion. Indeed its REALLY sticky !