Sealing body to footwell on new MK3 & other teething issues

[Scottmillhouse]

Just recently got my VIN and am working through troubleshooting and fixing the issues. Getting a plate is not possible with the DMV closed so just local shakedown runs. Just got the speedometer talking to the transmission so I’m guessing about 50 miles to date. Alabama is getting warm and my car is hot. The sealing strip FFR had you put around the driver’s footwell to the body did nothing. There is an inch or two gap. The hot engine air from driver’s side rather than going out the body vent runs freely into the driver through the body gap along the door hinge area. How have other’s sealed? I’m thinking spray insulation foam like used for household gaps. Concern is mess and expansion pressure to body.

Also looking for good information on carburetor modifications especially for demon. My engine is a new stock 1993 302 that has the GT-40 heads. Carb is a 650 CFM double pumper with vacuum secondary. Was way rich. Rebuilt carb after initial extremely rich runs and dropped main jets from #70 to #65 and secondary from #75 to #70 but did nothing else. Runs great steady state and mid range but severely balks and hesitates upon acceleration. Thinking I’m flooding the engine with either fuel or air. I’m not sure how to tell difference. Plugs have black base and light brown electrode as pulled. After the stumbles it then takes off like hell.

I’ll load pictures one I figure out how to rotate.

[Scottmillhouse]

Try for rotation. Upside down on iPad so it should work. That did not work so try from album. That does not work either way on albums and neither does editing the photos for rotation and size. What am I missing? They look great on IPAD, Iphone and viewing on computer or TV.
Rotating phone may be a solution but that does not work for existing pictures and would be a hack solution.
https://thefactoryfiveforum.com/attachment.php?attachmentid=125532&d=1585922011

https://thefactoryfiveforum.com/attachment.php?attachmentid=125533&d=1585922057

[Jeff Kleiner]

I use 2 1/4" window air conditioner insulating foam from the hardware store, Lowes, HD, etc.

https://thefactoryfiveforum.com/attachment.php?attachmentid=125530&d=1585919775

I apply it to the footbox sides as shown before installing the bodies. I realize that it's too late for you to do that but the stuff is pliable enough that you can squeeze it down and push into the gap between the body and footboxes just ahead of the doors. When it springs back it doesn't apply enough pressure to affect the body shape.

https://thefactoryfiveforum.com/attachment.php?attachmentid=125529&d=1585919721

https://thefactoryfiveforum.com/attachment.php?attachmentid=125531&d=1585919806

Hope that helps!

Jeff


125529
125530
125531

[Railroad]

Scott,
Many use the foam swimming pool noodles. The are pushed between the foot box and the body. If you like you can consider, pipe insulation. It might be a little softer, less body bulge, but more difficult to get in place.

On the carb, I would first look at the accel pump squirters. With the breather and engine off, look into the primary side of the carb, may have to prop choke open. At any movement of the throttle, you should see fuel come out of the discharge nozzles. If not, try adjusting the bolt on arm. With the throttle wide open, you want to have .020" of lever movement left.

I am betting you are lean, but someone running beside you should be able to tell if you get some black smoke on accel.

An extreme lean condition can causing popping back at the carb.
On Holley type carbs there are 2 pump cam positions. Just taking one screw out and putting in the other hole.
I will let you read up on this, it is a pump timing adjustment. You can try, without trying to get educated, no bad consequence and put back, if no improvement.

Being a stock engine, I doubt your power valve is not right. You can take a manifold vacuum reading, at idle and see how it compares to what you have in the stock carb.

Ign timing can cause hesitation also. Might want to double check it.

Car looks really sharp, good job.

[edwardb]

Scott,
Many use the foam swimming pool noodles. The are pushed between the foot box and the body. If you like you can consider, pipe insulation. It might be a little softer, less body bulge, but more difficult to get in place.

On the carb, I would first look at the accel pump squirters. With the breather and engine off, look into the primary side of the carb, may have to prop choke open. At any movement of the throttle, you should see fuel come out of the discharge nozzles. If not, try adjusting the bolt on arm. With the throttle wide open, you want to have .020" of lever movement left.

I am betting you are lean, but someone running beside you should be able to tell if you get some black smoke on accel.

An extreme lean condition can causing popping back at the carb.
On Holley type carbs there are 2 pump cam positions. Just taking one screw out and putting in the other hole.
I will let you read up on this, it is a pump timing adjustment. You can try, without trying to get educated, no bad consequence and put back, if no improvement.

Being a stock engine, I doubt your power valve is not right. You can take a manifold vacuum reading, at idle and see how it compares to what you have in the stock carb.

Ign timing can cause hesitation also. Might want to double check it.

Car looks really sharp, good job.

All good suggestions. And then there's that vacuum secondary carb. Had a Holley and never could get it to run right. Just not ideal for these cars.

X2 on that sealing foam Jeff described and pictured. I have it in my 20th Anniversary build and it's sealed tight. Of course I didn't put in before the body was on. :( But easy enough to add afterwards. I found it best to push in from the front, e.g. with the splash guards removed. Used a stick to get it properly positioned. Much easier I think than trying to get it past the hinges and body lip on the back side.

[Scottmillhouse]

X2 on that sealing foam Jeff described and pictured. I have it in my 20th Anniversary build and it's sealed tight. Of course I didn't put in before the body was on. :( But easy enough to add afterwards. I found it best to push in from the front, e.g. with the splash guards removed. Used a stick to get it properly positioned. Much easier I think than trying to get it past the hinges and body lip on the back side.
More challenging with the MK3 since the footwell comes nowhere near filling the body. It tapers severely to the top inward more like a triangle so there is a huge irregular shaped gap. Also splash guards permanently installed and brake/clutch lines and fluid obstructing access. May try low expansion sealant foam.

[edwardb]

More challenging with the MK3 since the footwell comes nowhere near filling the body. It tapers severely to the top inward more like a triangle so there is a huge irregular shaped gap. Also splash guards permanently installed and brake/clutch lines and fluid obstructing access. May try low expansion sealant foam.

Your choice. Just use low expansion foam and be careful. Have heard some harrowing stories. For the record, the area where the foam (or pool noodles, or whatever) goes is right behind the door hinges and isn't that different between a Mk3 and Mk4. Been there. Done both. Also, you can still reach behind with the splash guards. Just makes it easier with them out of the way. Or put something in from the hinge side. Lots of ways to tackle this thing. Just shared what worked for me.

[Papa]

Flipped your pics for you...

https://thefactoryfiveforum.com/attachment.php?attachmentid=125572&d=1585945696

https://thefactoryfiveforum.com/attachment.php?attachmentid=125573&d=1585945704

Great looking car!

[rich grsc]

I use 2 1/4" window air conditioner insulating foam from the hardware store, Lowes, HD, etc.

https://thefactoryfiveforum.com/attachment.php?attachmentid=125530&d=1585919775

I apply it to the footbox sides as shown before installing the bodies. I realize that it's too late for you to do that but the stuff is pliable enough that you can squeeze it down and push into the gap between the body and footboxes just ahead of the doors. When it springs back it doesn't apply enough pressure to affect the body shape.

https://thefactoryfiveforum.com/attachment.php?attachmentid=125529&d=1585919721

https://thefactoryfiveforum.com/attachment.php?attachmentid=125531&d=1585919806

Hope that helps!

Jeff

Follow Jeff's advice, this is the easiest stuff to use. You can use a paint stick and work it in from the door hinge side without too much trouble, way easier to manipulate than a rigid pool noodle. I would never use spray foam, in the future when the body needs to be removed you will regret it. How are you going to get the body and frame separated?

[D Stand]

I would defiantly NOT use expanding foam. A buddy in high school decided to insulate an old work van by attaching 1/8” plywood to the interior ribbing and filling the void with the foam. The sheet metal on the outside was all pushed out between every rib, I wish I got a picture��! I would take Jeff Kleiner’s advice for sure.

[Railroad]

Not to encourage the use of spray foam, but using a plastic bag inside the void to contain the foam keeps the foam from gluing everything together.
You still have a ship in a bottle, you cannot remove without chopping it up.

[Scottmillhouse]

Thanks all. I will try the air conditioning seal foam. Still fighting with carb. Thinking previous owner may have modified it for racing for a larger modified engine on a different car. Carb setup details show air inlet jets on top and these appear drilled and then there are all the passages from the float side that could have been modified too. About to give up and buy a new carb appropriate for a stock 302 since we are now in state wide lock down. I can not keep trying and driving. Would like to match fuel inlets and throttle interface if possible. Any suggestions for street use.

As an update, that foam works well and took care of the worst of the heat. Have gone over the carb many times and it did have some issues. Had a sealing plug gone from a vacuum passage on base casting. Tapped it and sealed with screw and locktite. Then car was then too lean so went back to stock jets. Runs well with some secondary lag at lower rpm acceleration but with high idle. Decided idle circuit was modified to provide more fuel for a cammed engine since all throttle plates fully closed and you can not lower. Dropped timing a little and set idle mixtures. Down to 1000-1200 so good for now. On to other issues.

[FFR 3099]

FYI-LIke everyone else I pondered the problem and tried few different things to fill the gap. I have posted this before but I found that memory foam works very well. I went to WAL-Mart and bought a memory foam pillow. I split the pillow vertically, as needed to push into the gap. Memory foam compresses very tight to fill gaps but doesn't press the body so hard it causes problems. It can be installed before or after the body is on, obviously easier with the body off.

[hugo-k]

Do you have photos?