GT4 Nosejob - "Euro/US" bumper mod.

Since getting my '79 308GT4, I have been envious of the more streamlined "Euro" bumpers...so decided to take the plunge and modify the profile -- both nose and tail.

Conceptually, this is an easy modification (a few notes to the contrary follow the summary). Concept: Remove the bumpers from the mounts/shock absorbers. Drill a hole to drain out the hydraulic fluid. Compress the bumper mounts. (I used piece of 1 x 3, and a scissor-jack against the side concrete wall of my garage. Not pretty, but effective). Re-drill a new hole while mounts compressed. Tap and insert metric set screw to hold in place. I drilled and tapped in both the original position, and in the compressed position, should I ever want to regain the original US Spec look.

Overall, I am very pleased with the result, although it tool a bit more work than I anticipated. I was able to remove about 3" from the front bumper (full compression) leaving about 1" extended remaining. It fits nicely with the curve of the bumper skin, and looks really nice in my opinion.

The rear, for reasons I will go into below, was reduced by just over 1-1.5"", with about 2.5 inches remaining extended. Just about in line with the indentation in the bumper. Not as dramatic a reduction, but a tremendous improvement from the 'diving platform' look that was there previously.

Learning experiences:
1) Drill into the shock units VERY SLOWLY. They are under pressure, and filled with hydraulic fluid. If you don't let the pressure off really slowly, they will blast you with a fog-like spray, and make a nice mess. The nice thing is that you only make that mistake once.
2) Drill the side of the shock unit, versus the bottom. Not a major concern, but the underside drill out gets more of the fluid out initially, but does continue to weep a bit if the car is parked at the right angle. The side drill out probably leaves more fluid behind, but doesnt weep. Either way, a problem that a paper towel will solve over a week or so.
3) Dry fit the bumpers to make sure that you have not compressed too far -- this is important for being able to put the front grill back on. Its mostly a matter of tight spaces in the front, but I was able to compress the full amount, and get the grill back on without major issue.
4) Deal with the rear bumper heat shield on later models. Earlier GT4's, without the thermonuclear reactor cats/muffler set up, don't have a form fitting rear hear shield attached to the bumper. Given how the shield was in place, it not only restricted your access to the rear bumper mounting bolts initially, but severely restricted the amount that you could move the bumper in before you hit up against the shield. It was a real game of take it on, take it off to figure out the maximum compression allowable....
The big issue besides the reduced compression room was that with the heat shield in place, you could not reach the bolts from under the bumper as in the front bumper, or I assume on earlier GT4's. Secondly, apart from access itself, compressing the bumper about an inch and a half left little or no room to reach in from the side, thread the nut on the bottom mounting bolt, let alone try to get some sort of a wrench in there. I really contemplated cutting the heatshield into sections, or cutting a hole to fit a wrench from underneath...but resisted. What a PITA. Multiple hours spent maneuvering, etc.
(Truthfully, I resorted to cranking down on the top nuts, and handtighten/locktite the bottoms for the rear bumper. Future "mod" to come when I figure out a better way. For now, its tight enough, and everything is good to go).

Take a look at the progress photo's, and I think you'll agree that despite the frustration on the rear, the 'surgery' was a success. Much more streamlined look, and I think well worth it.

Not too bad for my first F-Car mod. Now onto the 308 Air-box restrictor mod.
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Wow, Jim. No one has ever even mentioned "my name" and "tech article" in the same paragraph, let alone the same sentence.

I guess this is one of the benefits of F-Car ownership. You are motivated to tinker a bit, even if you are not a techie. I am having great fun with the projects, so far.

John

 

Perfusion - Please post a few photo's of yours. I am interested in how much you were able to get the rear bumper to compress, and whether or not you had to deal with the heat shield limitation on the back bumper.

Also, FYI everyone. I continue to be amazed at the seemingly frequent inconsistencies between model years, US Spec. If I look at the following thread on FCHAT for GT4 photos...you will clearly see later model Series II GT4's with the very extended bumpers. Probably just a bit more extension than Series I's.

http://www.ferrarichat.com/forum/showthread.php?t=118740&highlight=GT4+Series+photos

I started to say that as I looked at Dave Stacy's 75 in Photo#1. Then I looked through the other photos in the thread, and it seems like some 75's have bumper extensions that look very close to my '79. Dave, did yours have the bumpers moved in? or are my eyes off in comparison to Dom's, Alex L's or probably most visible in Peter's black 1975.

Seemingly odd. But not out of the ordinary.

Someone tell me if I am out to lunch here. Do Series I US bumpers typically extend out like Series II/III?

 

Ah, yes. So it is confirmed. Series I US bumpers are as damned ugly as Series II US bumpers.
<smile>

 

See the update to the rear bumper mod above. I went back in tonight and re-did it the right way. All bolts tightened as they should be, and bumper back in place and locked down with the set screws.

 

Saw the 308 bumper brackets for sale this weekend, and DinoGT4Guys question about the potential for GT4's. The tubes could be the same, but the bumper mod is really easy to do with drill and set screws. You can leave in two positions for "original" and "modified".

 

http://www.ferrarichat.com/forum/showthread.php?t=151119&highlight=gt4+nosejob