Bumpers and Body Grommets

[SCFFR]

After working about a year on the chassis, I finally got the body back on this past weekend and now busy getting everything fitted. When I purchased my MkIV basic kit, I also bought the complete front and rear bumper/overrider kit. Currently fitting the front and rear bumpers to get the ends of the body aligned and that is working well. I had purchased a set of the rubber body grommets from ********** and trying to get them installed also. I had planned on using the stainless spacers that came with the quick jack lifts but noticed they have a 5/8" o.d. where the grommets have a 3/4" i.d. so there would be a space.

Fort those of you who have installed the bumpers AND the body grommets, did you use a different spacer that more matched the i.d. of the grommet?

Would appreciate any feedback and pics you could provide.

Many thanks,

Ron

[jlfernan]

The ********** grommets are intended for MK 3.1's and older. On the older roadsters the the bolts for the quickjacks did not support the body, they simply passed thru the holes to the frame and two screws in the front brake vents secured the body. I bought thicker washers from Lowes. It took some time, but I ovaled the holes in them so they would sit flush to the body. I also bought some large, flat rubber washers to cushion the metal washer against the body. I had the metal washers chromed then glued the rubber ones to them and installed them.


http://img193.imageshack.us/img193/2561/jorgec.jpg (http://thefactoryfiveforum.com/private.php?do=newpm&u=111)

[edwardb]

Jorge is exactly right. I don't know how you would use the ********** grommets for a Mk4. The grommets are designed for the QJ tube to pass through the body. On the Mk4, the front QJ mounts hold the body in place, same as the rear mounts have been all along.

[SCFFR]

Thanks guys. I guess I will have to go to Plan B...............as soon as I figure out what that is!

Ron

[Paula Alibrandi]

Hi guys,
A few guys have used the grommets on the MK 4 so far.

I just saw a post from a builder on another site and he described how he replaced the cut tubes with an unlength cut of tube. He said it held up well nose well and he preferred it over pinching.

I just had a call from another customer that told me he did some kind of little body work to make his work but I don't remember exactly what he did. If I get more info I'll let you know.

Paula
Finish Line www.cobraaccessories.com

[SCFFR]

Thanks Paula. Will also check the posts on the other forum to see what the builders did there.

Ron

[Blue MK3]

I recently purchased a Mk 3.1 that had rear QJ's mounted but none on the front. I ordered a front set from FFR and mounted them with front grommets from Finish Line. The tubes supplied by FFR are a tad larger than 5/8" OD (0.63"). I would think this is what is being supplied on current Mk 4's. Even if the hole on the FL grommets is 3/4", that leaves a gap of less than 1/16". I prefer to have a bit of clearance between the tubes and the body/grommet in case I get a bump on the nose. Too tight and the body gets damaged instead of transferring the impact to the frame where the tubes are mounted. Besides, these cars aren't made to drive in the rain, so why worry about a waterproof seal? The gap between the tubes on my car and the grommets is invisible unless I get down on my knees and look closely.

[edwardb]

I recently purchased a Mk 3.1 that had rear QJ's mounted but none on the front. I ordered a front set from FFR and mounted them with front grommets from Finish Line. The tubes supplied by FFR are a tad larger than 5/8" OD (0.63"). I would think this is what is being supplied on current Mk 4's. Even if the hole on the FL grommets is 3/4", that leaves a gap of less than 1/16". I prefer to have a bit of clearance between the tubes and the body/grommet in case I get a bump on the nose. Too tight and the body gets damaged instead of transferring the impact to the frame where the tubes are mounted. Besides, these cars aren't made to drive in the rain, so why worry about a waterproof seal? The gap between the tubes on my car and the grommets is invisible unless I get down on my knees and look closely.

The OP's question was about a Mk4, which has a different front QJ setup than the Mk3. So in theory the pass-through design of the QJ tubes and the ********** grommets won't work. On the Mk4, the QJ tubes are in two pieces, and the body is captured between the two pieces. The mounting bolts in the brake ducts are eliminated. It's been suggested in the other forum that the Mk4 could be changed to this style, e.g. enlarge the hole so that the grommet fits, then use the one piece QJ tubes. Supposedly this holds the nose down OK. Interesting, and something I might think about on my Mk4 build. Not sure though...

But to your points for a Mk3 -- There is no concern about being waterproof. And I'm not sure I get what you're saying about impact. With a rubber grommet I don't think there would be any difference if there is a gap or not. In the end, it's all about appearance. The grommet looks more finished than the standard FFR cutout in the fiberglass. So a lot of guys use the ********** part to give the cutout a more finished look. The smaller tube going through the 3/4 inch hole is noticeable not only because of the gap but also because it looks a little skinny. The full 3/4 inch tube just looks more substantial. It's a good look and what I did with my Mk3.

This picture shows the ********** grommets and 3/4 inch SS tubes installed on my Mk3. I used 7/16 threaded rod and chrome acorn nuts from McMaster. The two bolts showing in the brake cooling inlet are deleted on the Mk4.

http://i867.photobucket.com/albums/ab234/edwardb123/Factory%20Five%20Mark%203%20Roadster%20Build/Questions/IMG_1527_cropped_reduced.jpg

[Blue MK3]

Edward said "On the Mk4, the QJ tubes are in two pieces, and the body is captured between the two pieces." That's interesting because the tubes FFR sent me a couple of weeks ago are one piece, going from the back side of the QJ, through the body and grommet, all the way to the bracket on the frame. I didn't tell them I had a Mk 3 when I ordered them. Looking back, I think I like the idea of the tube going through the body and grommet rather than the body being captured between two sections of tube.

[SCFFR]

The QJ tubes I received with my MkIV are two piece and are designed to "pinch" the body opening using the rubber coated washers.

I see that ********** carries the 3/4" polished stainless tubes that match the grommets they sell so I'm going to get a set for the front and rear. My body is sitting firmly on the hood tubes, firewall, rear bulkhead, trunk crosspiece and trunk side panels. Once the side flanges are bolted to the 2" square chassis tube under the car, it's just not going anywhere. The bumper/QJ bolts/threaded rod should hold the ends of the body in place. When you cut the larger holes for the grommets, as long as they are exactly centered around the bolts/threaded rod, everything would work fine. Anyway, that's my plan.

[carlewms]

I just received the kit a week ago. I have not removed the body yet but there appears to be rubber grommets installed. See pictures below:
13087

[carlewms]

I just received the kit a week ago. I have not removed the body yet but there appears to be rubber grommets installed. See pictures below:
13087

[edwardb]

I just received the kit a week ago. I have not removed the body yet but there appears to be rubber grommets installed. See pictures below:
13087

You're looking at washers with rubber gaskets bonded on the back against the body. When you disassemble, you'll find the hole in the body is roughly the size of the bolt (7/16 inch). There's a piece of SS tubing on the outside (pictured) and another piece on the inside bolted against the frame. This is the Mk4 setup several of us have described. No grommet in this standard FFR setup.

[j.miller]

It was me in the other post using Finish Line grommets. If you got the special or ordered the bumper kit (not quick jacks) then you should already have the uncut tubes. If you did not, then you can order them from finish line with the grommets. We have done 14 MK4s and I had fought the split tubes every time. They need to be exact so they don't crack the body and even then I worried about them over time with vibration or something bumping the Q/J. We started using the grommets and I like them much better. With all four tubes installed they offer a great deal of support without stress on the body. You do need to be careful when you open the holes ( I like to use a Dremmil with a barrel sander) for the grommets. The sides of the hood opening should not be resting on the square tubing, should be floating about 1/2-3/4 inch above in the most forward near the hood hinges. If you pull the nose down to where the hood opening is resting on the tubes you will never get the hood to close because of the forward hinge arm hitting the upper radiator support. da Bat