Late 74' up to Early 69'-73' fender conversion thread

[Bobboloo]

Part I

Time to share my experience converting late 74' - 89' fenders into early 69' - 73' style fenders. This is the approach I took but of course there are other ways to do it each having their pluses and minuses.

First I started with the turn signal area of an early fender.
I trimmed it back because I didn't want to try welding a seam all the way around the front of the fender.



While welding all the way around would have worked it would have been very labor intensive to get it looking right. Compound curves like the ones around the base of the headlight can be very difficult to finish and get looking right after welding.

I decided I would rather do a little more work at this stage prepping and welding as opposed to more body work grinding, filling and sanding later so I kept the weld bead to a minimum.

Here's the difference of the front lip between the early and later fenders.


The later fender edge wraps around a ~30 degree angle. The early fender makes only a 90 degree bend on the edge followed by another 90 degree bend back.



I started by wire brushing off the paint over the spot welds to prepare to remove the extra piece welded to the late fender.


Next I test fit the donor piece to the later fender to mark where I needed to trim the later fender.



Trimming the late fender.


Drilled out spot welds and removed the extra bracing on the late fender.


Filling the holes left from drilling out the spot welds. This surface will be part of the area that the seal for the turn signal lays up against.

[Bobboloo]

Part II

Next I needed to change the angle of the edge bend from 30 degrees to about 90 degrees( I ended up more like 80 degrees). It's very important to go slow and bend just a little at a time. Also, I was very careful to pull upward away from the fender with the pliers (with the fender upside down below me) as I was bending because I didn't want to cause a contrary bend on the flat surface above the turn signal. I know it's probably hard to grasp what I just said but I think if your doing this you'll get it.

Here I flipped the fender upright so you can see the progress from bending the flange. The flat surface below the headlight bucket is the area you don't want to disturb.


I followed up with a little hammer and dolly action.


Well we've got one 90 degree flange. Now we need the 90 degree flange going back. I cut a 1/2 inch strip of sheet metal and started welding the next flange 5mm from the edge of the fender lip..



Next I trimmed the welded flange to 5mm to give me a pair of 90 degree flanges.




It's important to check fit before you start welding so I clamped the donor piece to the fender to check the fit of a turn signal box and horn grill. I've found that the fit varies greatly on these handmade cars. When you've got the time to do it right you can improve upon the fit. In measuring a few different fenders I found how the tolerance was very wide. Couple that wide tolerance along with being tolerant yourself can yield less than desirable fit. So this is the time to take it really slow check, double check, and find the best compromise.

I ended up drilling out the spot welds on one of the donor pieces and re-fitting the lower bracket to it's donor sheet metal piece.




Time to get ready to weld on the donor piece. It's really best to have a pair of early fenders to stencile the placement. Eye balling is less than ideal. I tried that the first time and had to cut off and do it over. I stenciled the edge of the headlight mount, wheel lip, and turn signal cut out. Edit: Oops please ignore that this is the passenger side. We've been working on the drivers side.


Now that I had placement I tack welded and then checked fit one last time.

[Bobboloo]

Part III

Almost finished welding. I like to weld from the backside so less grinding needed to dress the weld.


Before:


After:
Finished product.

[dean]

Nice job

[felix_browne]

really really nice. is this for a backdate or are you going to swap the headlight buckets and use this for a restoration?

[Bobboloo]

I just did it for fun. I had the donor early parts from an old project from years ago and finally decided to do something with them.

[PcarPhil]

Bobby,

That's really cool. Great job!

[Deschodt]

Wow.... I bought a set of so-so early fenders with the idea of doing the same thing to my "better" late fenders (for a backdate), but after seing all that is involved, I wonder if I would not be better off just fixing the old fenders instead... I thought it was a straight cut/weld, it's clearly a lot more involved !!!

[John Schaefer]

Good for you! Very cool and way smart.

[wesayso]

Printed and saved for future reference (planning to backdate my SC)

To bad nobody makes/reproduces that lower part of the early fenders....

[Jays72T]

Nice work, looks great.

[Bobboloo]

Originally Posted by Deschodt

Wow.... I bought a set of so-so early fenders with the idea of doing the same thing to my "better" late fenders (for a backdate), but after seing all that is involved, I wonder if I would not be better off just fixing the old fenders instead... I thought it was a straight cut/weld, it's clearly a lot more involved !!!

If your early fenders are fixable then by all means save them. The donor fenders for the early parts I used were goners. They had rot in the usual bottom rocker area and had also been in a collision which crunched the headlight buckets.

There are other routes to doing this conversion. I just picked the one that I thought would require the least amount of finishing work. In my personal experience the finishing work (body filler and sanding) is the most time consuming part of body work. Welding goes quickly in comparison.

You could actually do a cut and weld of the whole lower area that includes the front lip but you'll have a lot more finishing work on an area that will be difficult to get right. The compound curves under the headlight bucket are a b*tch. I contained the finishing work to a smaller mainly flat area. The toughest part finishing was the flare edge.

[Bobboloo]

Originally Posted by wesayso

Printed and saved for future reference (planning to backdate my SC)

To bad nobody makes/reproduces that lower part of the early fenders....

I thought about this. Maybe a fiberglass conversion piece would be the way to go. Something that could be bolted on to the lower part of the later fender so that it would add the flange for the turn signal seal. Then you would just need to epoxy, fill and sand the meeting area along the side.

[jester911]

I have thought about doing a backdate on my car. I would consider using an add on piece like that to do it since serviceable fenders are really not in my price range.

[ulrichd]

I remember this pic from the ultimate backdating thread. Can't remember the guy's name but I think the name of the shop was "Series 900" or something like that. I think this would be a popular kit.

[Deschodt]

The above piece is a good idea in theory, but it does look kinda bad in practice, that gap between the metal and the fiberglass cannot be made to go away...

Hey, since this is the perfect thread for my "project", let me ask your enlightened opinion here... I can't weld so I'll have to farm this out... Given that unfortunate lack of skills, and the parts below, what would you do in my shoes ?

I have:

a) a perfect set of 911 SC fenders

b) A set of gnarly early fenders cut out



That's ebay for you, they didn't look quite that bad online, but the part I need is not too bad and can be bent back into shape


c) A set of decent and complete early fenders, but that need repair in the circled areas



Which is gonna be more economical for the best result ?

Splice the bottom of the white ones onto the SC ?
Splice the bottom of the red ones onto the SC and throw away the rest ?
Repair the red ones completely ?

Thanks guys... Trying to get an idea of the best way to go about this before talking to the body guy...
Again, $$$ is the factor here, and I would not resell my SC fenders or the red ones anyway so exclude resale
from your opinions (I have a 912 that may need repair one day when those are unobtainium, and the Sc
fenders are a dime a dozen on ebay, so there is no need to preserve them either..)

[Bobboloo]

Originally Posted by ulrichd

I remember this pic from the ultimate backdating thread. Can't remember the guy's name but I think the name of the shop was "Series 900" or something like that. I think this would be a popular kit.

Gosh, I never saw those. I didn't know Damon had done this already. I wonder how many he has sold/used. Definitely a quick solution to back dating. Just epoxy and then fill. Nice.

[Bobboloo]

Originally Posted by Deschodt

Hey, since this is the perfect thread for my "project", let me ask your enlightened opinion here... I can't weld so I'll have to farm this out... Given that unfortunate lack of skills, and the parts below, what would you do in my shoes ?

I have:

a) a perfect set of 911 SC fenders

b) A set of gnarly early fenders cut out

c) A set of decent and complete early fenders, but that need repair in the circled areas

Which is gonna be more economical for the best result ?

Splice the bottom of the white ones onto the SC ?
Splice the bottom of the red ones onto the SC and throw away the rest ?
Repair the red ones completely ?

Looks to me like your best bet would be to repair the red early fenders. They don't look too bad to me in the pictures. I like that the repairs are basically only needed in places that are not exposed to view. That's ideal from a time saving standpoint. The fender that needs repair to the mounting flange would just need welding and then a little grinding of the weld bead before you paint. No filling or sanding for hours on end.

I can only speak for myself but the thing that takes the most of my time time is after the welding is done. Prepping the surface for paint takes gobs of time.

The other fender is a fairly easy repair. If you can keep the flare/edge of the wheel cut out then it should go quickly. The curve of the flare/edge is a hard area to make look right when welded on.

Your white donor pieces are definitely could candidates for backdating the SC fenders. That bracket can be hammered out.

I still think your fastest, easiest, cheapest and even best looking route would be to repair the red fenders.

Backdating the fenders the way I did will take more time/money and a keen eye can see the difference. Particularly the leading edge above the turn signal is more rounded than on an OEM early fender. This is because the later fenders were bent all the way around to a ~30 degree angle which made for a more rounded edge. The early fenders were stamped at a 90 degree angle and have a sharper edge.

Some people backdate by taking the complete turn signal area upper lip/flange and all and welding it to the new fender. This means the welding part of the job goes quicker but then you'll have more paint prep work.

Believe it or not even doing it the way I did I still spent more time on the paint prep than I did on the welding.

[wesayso]

Originally Posted by ulrichd

I remember this pic from the ultimate backdating thread. Can't remember the guy's name but I think the name of the shop was "Series 900" or something like that. I think this would be a popular kit.

Are these parts still available? I've seen them on cars but never for sale. It would work for a while while searching for / (re)building real fenders.

[Deschodt]

Thanks Bobby,

I'll investigate repairing the complete fenders first then... You are correct, it's not a very visible area that needs to be repaired...