Ultimate Backdating Thread

[ERH]

Originally Posted by Tangie

Hey guys! I'm a newbie!! I really love this forum and have been reading it for over a year. I'm glad I finally joined. Anyway, I'm building my seventh or eigth Porsche 911 now and this time it's going to be really over the top.

The only 964 to 73 backdate I've seen is that white C4 to RSR backdate. Anyone else have any pics of such a car? Also, I don't want it to be an exact RS replica, so I'm thinking of deleting the silver trim. What do you guys think?

Some good pictures of the front end changes required:

zuffenhaus C2 to '72 RSR project...

[Tangie]

Originally Posted by ERH

Some good pictures of the front end changes required:

zuffenhaus C2 to '72 RSR project...

Oooh, thanks! Yeah lots of welding

[drb930]

Subscribed!

[PcarPhil]

In a different backdating thread someone was asking about mounting the front bumper. This is how I did it:

1. I reshaped some stock fender extension brackets and attached them to the front bumper shock mounting points. Making the brackets is a slow process - getting the bends and mounting holes correct to allow the bumper to sit where it needs to be. The bottom of the bracket attaches to the fiberglass bumper. I didn't cut the chassis at all in the front.

Passenger side:


Drivers side:


2. I bolted the sides of the bumper (near the fender opening) to the fenders. One bolt per side.



Here's some pics of the rear bumper mounting points:

1. This is the stock rear fender extension bracket reshaped to fit my wide rear bumper.



2. In the back corners I have more reshaped brackets. These are simply a press fit against the bumper. One day I may attach a bolt through the back corners but I can say the bumper isn't going anywhere. You may also notice some mods I did to a M&K 1 in 1 out SC/Carrera muffler to get it to fit behind the early bumper (cutting, rewelding, a few bangs here and there with a BFH!).





While I'm thinking about it - I left the metal to allow the stock rear engine lid seal to be used. Some people cut this off to use an early style seal but the stock later seal works fine:



And finally a side shot of the front and rear bumpers:





I hope these pics help!

[Pascal]

subscribed

[Joeaksa]

Very nice work!

[Zeke]

Tell me more about the air dam.

+1, Joe.

[PcarPhil]

Originally Posted by milt

Tell me more about the air dam.

+1, Joe.

Ahh...the infamous air dam. That's a $6 piece of lawn edging from the home improvement store. Eventually I'll be replacing it with a slightly deeper $50 version from McMaster-Carr.

One thing I noticed was the '74-'89 front valance is a good inch or two deeper than the early S front bumper/valance, even without the later rubber lower front spoiler lip. I had a few pieces of lawn edging left over from previous sports cars so I added one to the S front bumper. Then filled in the center section of the bumper with black racers tape. I notice the front end feels slightly more stable with it vs. without, plus I like the look.

Eventually I'm going to get some conveyor belt material (similar to what Ruf used on the Yellowbird) and cut it lengthwise to fit the bumper and also fill in the gap in the center of the bumper. This way I can do away with the racers tape and get the front lower edge down where the bottom of the rubber front spoiler lip is on the '74-'89 cars.

[whiteSC59]

getting ready for body and paint. subscribed...great thread..

trying now to decide on going rs or rsr since I have all the parts for either...

[PcarPhil]

Originally Posted by milt

Tell me more about the air dam.

+1, Joe.

Milt,

I was looking through some pics over on the Early S board and came across this one. It appears Kremer was doing similar mods to the S style front bumper. Note the filler piece...

[88911coupe]

Red964...any details on your car? That is stunning...what year model was it based on? Is there a thread somewhere that talks about it?
TIA

[techweenie]

This thread is a great asset.

I'm following a slightly different route with the front bumper backdate on my '85 Carrera.

I left the bumper shock mounts in place, notching them for the fenders, which I prefer not to modify -- a pair of nice '69-73 fenders are the most expensive component of the backdate process.



I chose to hang the front bumper from under the top edge in front. Here is one of the brackets, freshly welded.



The Carrera has mounting "arches" that are in the exact spot where the rearward front bumper mounting tabs are. I notched those structures and will work out a way to attach the bumper there this weekend. I'll also use the original mounting points of the front bumper (in this case they are oriented for SWB mounts) to complete the conversion.

I used the TRE hood so that I could retain the Carrera hood release mechanism.

[Jeroen]

Is there any info on backdating the front center panel (or latch panel or whaddayacallit panel) or did I miss it?
Would you need the center panel only, or do the fronts of the inner fenders need modification too?

[techweenie]

Originally Posted by Jeroen

Is there any info on backdating the front center panel (or latch panel or whaddayacallit panel) or did I miss it?
Would you need the center panel only, or do the fronts of the inner fenders need modification too?

The front of the older tub is extended beyond the shorthood cars, so the best thing is to find a decent longhood nose and cut it and section it in. I would rather see such a part go to restoring a longhood car, so I chose to keep the later latch panel. I believe there are other threads showing, but perhaps not in detail, the process of patching on the earlier pieces.

[Tim K]

Are the latch support panels available new from Porsche?

Restoration Design offers them ($495). Anyone with direct experience with the RD part?

Tim K

[rattlsnak]

Tech, I'm doing a backdate on my 84 right now and am going the route of keeping my existing fenders and adding the turn signal housing fiberglass kit onto the bottom. Much cheaper this way. I haven't got to the bumper bracket issue yet but I am using the hood kit also.

[techweenie]

Originally Posted by Tim K

Are the latch support panels available new from Porsche?

Restoration Design offers them ($495). Anyone with direct experience with the RD part?

Tim K

Tim, I heard from a restoration expert last week that RD sells Porsche OE panels along with the ones they make, so you can probably buy everything from RD. That's a company that's very effectively turned its reputation around with new owners and a responsive attitude.

Rattlesnak:
I bought the fender extensions, and had planned to try them, but stumbled on an exceptional deal on '73 fenders. If you document what you're doing as you add the extensions, I suspect many people will want to follow.

Not sure how I'll do the side mounting tabs on the bumper. The bumper I bought isn't "deep" enough to bolt to the fender flange as I had intended. Whatever I come up with, I'll post here.

[porschenut]

Here are a couple of pics of the latch panel that was welded onto my '86 tub. This is a brand new panel and I'm almost certain it came from Restoration Design, though I couldn't swear to it. It works perfectly.

[Jeroen]

My main question is: did you need to lenghten the front inner fenders?
Or do you only need the front panel?

[Tim K]

Originally Posted by techweenie

Tim, I heard from a restoration expert last week that RD sells Porsche OE panels along with the ones they make, so you can probably buy everything from RD. That's a company that's very effectively turned its reputation around with new owners and a responsive attitude...

That's great news! I was hoping to find an alternative to RD because of the supply/communication issues.

Originally Posted by porschenut

Here are a couple of pics of the latch panel that was welded onto my '86 tub. This is a brand new panel and I'm almost certain it came from Restoration Design, though I couldn't swear to it. It works perfectly.

I was concerned about the fit so that's also great news.

Originally Posted by Jeroen

My main question is: did you need to lenghten the front inner fenders?
Or do you only need the front panel?

I don't think so (hopefully someone will chime in). But I am confused about where the forward most hole in the fender is needed.

Tim K