Hi All, I have my doors apart on my 70 914/4 and while im in there I want to repair both door stops.

I recall an article on repairing the "T" shaped piece by welding on new "bumps". There was even a picture of what the finished shape should be.

Does anyone know where I can find this article? I thought it was in a magazine? Like Panorama or the Mid-Engine-Views?

Thanks in Advance.

Mark
MG911Guy

Are your bumps completely gone? Performance Products sells new aluminum rollers that cured most of the problems I've seen with door stops. Got any pictures of yours?

McMark

Thanks for the reply. Yes, they are almost gone. I have attached a photo.

Mark..

Yeeargghh... mine are worse than that...

How can we get new bars and rollers?

Wow. Thanks for the picture.

Sourcing good used ones would be my recommended course of action, as well as the roller replacement kit if yours are worn out.

PerfProd Roller Kit

Yeah, I found a 74 at Pick a Part last Sunday and forgot to check. I got the rear calipers though.

I just remember an article that had a life size drawing showing shape of both bumps. I have the welder ready to go. If I can find that article. I am searching through my magazines. I will let you know if I find it and maybe post a pic...

Thanks again Mark..

QUOTE (mg911guy @ Oct 1 2005, 03:32 PM)

Yeah, I found a 74 at Pick a Part last Sunday and forgot to check. I got the rear calipers though.

Ooh, which pick-a-part? What's left on the 74?

The Pick a Part in Sun Valley (SFV).
It still had the engine and tranny. No intake. 1.8L.
Side shift linkage was gone.
Front and Rear bumpers, doors, Trashed interior.
Head light assy's were gone no front trunk lid. But the rear was there.
Front Bilsteins were there w rotors and calipers.
No Sway Bars.
Gas tank was gone.
Engine lid was ripped out.
No muffler but the exchangers were there.
All fenders were there.
Windshield was there.
I cant remember if the rear glass was there.

Hope this helps.
Mark...

Cool, thanks. It'll be a bit before I'm down south, but I'll check it out if I can.. sounds like there are some good parts left.

QUOTE (McMark @ Oct 1 2005, 05:28 PM)

PerfProd Roller Kit

Just fix the rollers with some washers. Its easy and cheap, and the steel will never break. While your in there I would also suggest fixed the bolt pivot if it out of line at all. I'd suggest doing this while its out, cause its a b*tch to got back in.

Before:

After with steel replacement.

Steel washers rubbing against an aluminum piece doesn't sound like a recipe for longevity.

When I found that the door detent cams were NLA, I had a few reproductions machined. They differ in only two ways from the OE piece:
1. They don't have the tiny grooved serations along the "bumpy" side of the cam. Presumably, Porsche added these to provide some damping when plastic roller ran against them. The serations were worn completely away on the driver's side cam, and were only barely visible on the passenger cam. In any case, their presence or absence doesn't materially affect the primary purpose of the cam.
2. The repro cams have a second hole at the "head" of the cam, added for ease of machining. It doesn't affect the function of the piece and isn't visible when the door is assembled.

I've been considering having a production run of these made, assuming there is enough interest. What do you think?

QUOTE (davesprinkle @ Oct 3 2005, 07:09 PM)

When I found that the door detent cams were NLA, I had a few reproductions machined. They differ in only two ways from the OE piece: 1. They don't have the tiny grooved serations along the "bumpy" side of the cam. Presumably, Porsche added these to provide some damping when plastic roller ran against them. The serations were worn completely away on the driver's side cam, and were only barely visible on the passenger cam. In any case, their presence or absence doesn't materially affect the primary purpose of the cam. 2. The repro cams have a second hole at the "head" of the cam, added for ease of machining. It doesn't affect the function of the piece and isn't visible when the door is assembled. I've been considering having a production run of these made, assuming there is enough interest. What do you think?

How much do you think?

Ditto : How much ?


I think there would be some demand just for a replacement set of door stops that isn't made out of brittle pot metal. As long as the price is reasonable, say $15-20.

I think you could sell those!

OK. I'll pursue a quote on a small production run of the door detent cams. Stay tuned; I should have an answer in about a week or so. I'm not dodging the cost question; I just can't commit to a price until I know what my vendor will charge.

What about rollers? Anyone interested in replacements machined out of a proper hard plastic like Delrin?

I've just Stripped &cleaned up mine. I need a set.

I could use a set myself.

I could use a set too.

I'm interested in the detent and the plastic rollers. the only rollers available aftermarket are aluminum and I'd prefer plastic.

SS - else you have to plate.

M

I'm pursuing quotes on a small production run of the detent cams. However, the cam isn't the only problem with the door detent mechanism. The reason the cams wear out is that the plastic rollers wear far enough to allow the cam to run against the steel roller shaft. Merely replacing the cam won't completely repair the mechanism unless you also replace the damaged rollers.

I'm aware that PP sells replacement rollers machined out of aluminum. However, when I pulled my detent mechanism apart, I found that each mechanism already had 1 Al roller and 1 plastic roller. This makes me wonder if my car's PO has already replaced the rollers with PP's parts. Can someone please verify for me the OE roller material? 2 plastic rollers? 1 Al & 1 plastic?

Thanks for the input.

QUOTE (davesprinkle @ Oct 7 2005, 08:06 AM)

I'm pursuing quotes on a small production run of the detent cams. However, the cam isn't the only problem with the door detent mechanism. The reason the cams wear out is that the plastic rollers wear far enough to allow the cam to run against the steel roller shaft. Merely replacing the cam won't completely repair the mechanism unless you also replace the damaged rollers. I'm aware that PP sells replacement rollers machined out of aluminum. However, when I pulled my detent mechanism apart, I found that each mechanism already had 1 Al roller and 1 plastic roller. This makes me wonder if my car's PO has already replaced the rollers with PP's parts. Can someone please verify for me the OE roller material? 2 plastic rollers? 1 Al & 1 plastic? Thanks for the input.

When I removed and repaired mine ('75), they had one aluminum and one plastic roller each. I machined new one's of each. I straight knurled the aluminum roller, and re-created the worn grooves in the cams by hand using a small chisel. Seems the pin's were worn as well, so I machine some of those as well. At least that's how I remember it. I'll have to check my bagged parts. I recall that getting those springs back on was not easy.

Andys

I've seen how these things work out...... "I'll see about a small production run"....... 3 weeks later, topic is dropped and forgot about.... just like the engine seals .................but if it does happen, I'll take a set

The last post on this topic was a couple of weeks ago, when grasshopper lamented that most reproduction efforts never move from forum topic to physical reality. Well, grasshopper, I'll concede that there is still opportunity for this to fail, but I haven't yet abandoned the effort. Keep the faith.

Meanwhile, a brief update on progress: I have quotes for the detent cam from several vendors with a variety of manufacturing processes. Although the original detent cam was stamped, I suspect that sales volumes won't warrant tooling up a stamping die for the reproduction cam. So, for you concours weinies looking for an identical part, let me state up front that you might consider passing this one up and continue waiting for that dusty NOS part to appear on Ebay some day. But for those of you who are interested in a functional if not identical part, this will perform perfectly.

My experience with the 914 detent mechanism is that the plastic roller first fails and then the cam wears by running against the steel pin. So merely replacing the cam won't resolve the worn roller issue. I'm aware that replacement rollers are available from PP and other vendors, but I have some reservations about replacing the plastic roller with an aluminum version. Quite frankly, the roller needs to be softer than the cam, to avoid flattening the bump by high point loads that exceed the cam material's yield strength. To that end, I've also investigated a replacement plastic roller, machined from Delrin.

My plan is to offer the roller and the cam as a repair kit. My question is this: Do I also need to offer replacement roller pins? What about a replacement aluminum roller for the backside of the cam? I only have limited experience (one relatively low-mileage 914), so I appreciate any feedback from 914 enthusiasts who have more experience with the failure modes of this mechanism.

Sorry for the delay, guys and girls; this has taken longer than I anticipated. Schedule issues aside, I have completed a production run of the 914 door detent cams, cut from 3/16" 6061-T6 aluminum plate. I have also completed a run of Delrin rollers, intended to replace the factory pieces that rapidly get worn through. I am selling both pieces for $34.87 plus actual shipping.

Thanks,

David Sprinkle

Here is an image of the production cam and roller.

doesn't engman already make these?

b

Hello, Is that $34.87 for 1 strap & 1 roller?

QUOTE (mg911guy @ Oct 1 2005, 03:28 PM)

The Pick a Part in Sun Valley (SFV). It still had the engine and tranny. No intake. 1.8L. Side shift linkage was gone. Front and Rear bumpers, doors, Trashed interior. Head light assy's were gone no front trunk lid. But the rear was there. Front Bilsteins were there w rotors and calipers. No Sway Bars. Gas tank was gone. Engine lid was ripped out. No muffler but the exchangers were there. All fenders were there. Windshield was there. I cant remember if the rear glass was there. Hope this helps. Mark...

holy crap f'reals i was at the one in el monte/monrovia and there was a white one that was rear-ended all that was good to source was the driver-side front quarter panel, targa bar, rear trailing arms, and two red doors. the 14 was practically stripped. hmm i wonder if the 14 will still be at the one in sun valley. was it located in the back where the bugs are at? or more toward the middle?

Just realized this was posted back in October

Engman makes the arms from SS steel, high quality. You will need to source or make the rollers.

David

QUOTE

Hello, Is that $34.87 for 1 strap & 1 roller?

Yes, $34.87 includes 1 detent cam and 1 plastic roller. $60.00 for 2 of each. (Plus actual shipping.)

Daniel yeah that was in Oct. But I went back in Nov. There was a 72 there I got the small window channel rollers. But the eng/trans was gone.

That pAp turns over inventory fast. I have found a 66 911, 924s, 944's and lots and lots of BMWs and Mercedes

Maybe we could have a thread that lists the Porsche finds in the pAp yards?

Davesprinkle, Nice Straps. I ended up getting mine from PerfProd. Are you selling the rollers seperate? I could use a set of those.

Mark

QUOTE (mg911guy @ Dec 22 2005, 10:35 AM)

Davesprinkle, Nice Straps. I ended up getting mine from PerfProd. Are you selling the rollers seperate? I could use a set of those.

Hi Mark,

Yes, I will sell the plastic rollers separately. $15.26/each or 2 for $27.74. (Plus actual shipping)

Regards.

David Sprinkle

On advice from McMark, I have added a metal roller to the kit, so that it now includes ALL of the typically worn components in the 914 door stop mechanism: the aluminum door stay, the plastic roller, and the metal roller. (The metal roller was originally aluminum from the factory; you'll note that I've made it from brass. More on that below.)

A brief description of the pieces:
1. The door stay is machined from 6061-T6 aluminum plate, 3/16" thick. This alloy is stronger and harder than that of the OE door stay.
2. The plastic roller is plastic for 1 reason -- to minimize noise. I originally machined a metal replacement and I found that the metal roller was superb at passing the sound of the mechanism into the resonating door skin. The plastic roller, on the other hand, damps the creaking of the springs when the door is opened and closed. Much quieter. Believe me, you want the plastic.
3. The metal roller is machined from brass. The factory originally made this part from aluminum, apparently overlooking the galling problem that occurs when 2 aluminum parts are in loaded contact. Galling is one of the wear mechanisms of the factory part. The brass roller has similar hardness and corrosion resistance to the original aluminum and eliminates the galling problem.

Price for a kit of all 3 pieces is $43.27. Pretty cheap price to save the door-dings in the wife's driver. I have them in stock.

missed the pic last post, oops

Dave, sorry I didn't PM you earlier.

I've got a set of these and installed them last week. Super nice with the rollers. Beats the Performance Products roller replacement kit hands down. This is obviously a well thought out replacement, far far far above just a "should be fine" replacement (like the PP kit is). It's great to have the whole package, ready to roll.

Nice work Dave. Did you start a thread in the Parts forum?

Yeah, Mark, thanks for pointing out that the Parts forum is the proper place for this thread. Shoulda done that from the outset. Oops. Only 40 posts to my credit and already I'm about to see the dark side of the BAMFH.