The Resurrection of Foam Car - 63 T6B

[Phil Planck]

Continuing my hood latch assessment, today I took a look at the striker/latch alignment on the PreA. Turns out the striker does have the same nut welded in at an angle on the retaining plate. With this latch design, it appears to be critical that the striker be very perpendicular to that latch, particularly fore/aft. There was a significant angle difference fore/aft so I ended up shimming the back of the latch quite a bit to get the latch square to the striker. You can see the two pieces of sheet metal that I placed at the rear of the latch to raise it up:



The striker was off left to right so I put a shim(washer) under one side to get it much closer to square.



Next was getting the striker pin re-aligned with the hole in the latch. This process has been well documented so will not go into that. After these two adjustments I could tell a significant difference in how the hood latched up - much better and easier. Prior to squaring up the striker pin the hood was much harder to close and often needed several slammings. Thank the Porsche gods that my hood has never popped open in some 40,000 miles.

I also called an old friend from GM who is a real expert on latches. He has several of his more than 50 patents related to hood latches. I am emailing him pictures and hopefully he will give me his assessment of this latch. What he did say is that it was always a design no-no to have two detents or catches as it is very difficult to manufacture and adjust the accuracy needed when this is done.

Phil

[tperazzo]

Hi Phil,
I found an extra C latch today and took a few pictures for your entertainment. Three pictures show the latch in the various states, a) no tension, b) minimum required tension to lock, c) full tension to open.









Cheers,
Tom

[Phil Planck]

Tom
Thanks for posting the C latch pictures. This latch operates like every other pin type hood latch that I have seen - that is with just one catch. Interesting that after at least 8 years using the prior latch design(1955 - 1963) that Porsche changed to this design for the last 2 years. Now it would be interesting to know how often C hoods flew open compared to PreC cars. Hey, if we can call 356s PreAs then we should be able to use the term PreC, right.

I suppose the main feature of this latch was that if the cable broke you could open the hood? What was wrong with the old method of getting it open if the cable broke? If a C cable breaks or slips while you are driving - oops.
Phil

[Jack Staggs]

...it was always a design no-no to have two detents or catches as it is very difficult to manufacture and adjust the accuracy needed when this is done.
Phil

This is an interesting subject to me, as nearly every early car that comes through our shop with latch difficulties shows angular irregularities. I have ground welds, housing parts, made shims, re-bent brackets, re-welded, and even bent the post bolt, in an attempt to correct the problem, usually without requiring paint work. It's interesting that your GM friend said that a double blade is a no-no. I wonder what is the difference between a single blade latch, and a double blade that only latches on one blade, acting like a single blade. I know that the angle of approach of the blade to the post relief is critical. Perhaps you could ask him. Also of note is that the C models ( and 911/912) use a single blade, and have difficulties as well.
Thanks

[Phil Planck]

Jack
Glad you are interested, as you have tons more experience with 356s than most. I think the no-no is that with only one internal detent(on a fork bolt type latch), or one "catch" as I am calling it on the pin type latch, you know it is fully latched(it's either fully latched or fully unlatched). With more than one, things can happen where only one catches. But stay tuned, as I need to study some more old pin type latches, all so far with only one "catch".

Also, at the upcoming ECH I will be scrutinizing and photographing all 356s with their hoods open.

[JR]

Guys,
To prevent not getting the front lid open 'IF' the cable breaks I have run a 1/16 inch cable, that I had left over from my sailboat, from the striker plate arm to the left hand wheel well.
I put a loop in the cable in the wheel well by swageing it, and ran a piece of plastic tubing in the loop so I wouldn't grab a handful of head light wires by mistake.
I'll take pics later if anyone is interested.
I'm sure that it would work on 'C' cars as well as 'PRE Cs', but that just my 2 cents!

Dick

[JR]

FOAMCAR,
I should be at the ECH 'IF' we get a trailer for my Roadster and a Speedster from Richmond.
Come on by and I'll pop the front lid for you.
We won't get there until Friday evening
Dick

[bbspdstr]

The type of insight and interest on topics like this that morph in and out of a general 'topic' are very gratifying to those of us who have been involved in such things for a long time. I speak for myself, but am sure Jack will agree.

I am especially pleased to see more people getting involved. Interest in the technical aspects, pride in workmanship...wow! All with good attitudes, too! I read this stuff before and after doing this all day....and I get energized seeing the DIY guys being so careful to get their 356 as 'right' as possible. Thanks! Makes me feel good.

Justin, you have done a very good thing by hosting such a wide cross section of topics that let us 356 kids have a show-n-tell place to play, learn and share. Thank you again!

-Bruce
P.S. I've seen 'a few' 356s over the years and have been trying to remember a C that I've seen or worked on with evidence of it's hood 'blowing up' and I can't. The most prevalent victims have been T-6 B cars. My guess from that is that like most (not all) changes Porsche made were to solve a problem. Note that in it's brief time as a separate model, the C went from the plain mount for the lower front latch to a stronger embossed mount for the same Bomoro latch, and Porsche didn't do or change ANYTHING without a reason.

[JR]

OK here are some pics of the Roadster's front lid emergency release cable.
It is attached to the the release plate mechanisim and routed to the left wheel well. I made a loop with a piece of plastic tubing to be able to identify it in the dark if needed.
Dick

[Phil Planck]

Dick
Thanks for posting those pictures. Nice solution. Turns out T6Bs had an emergency cable standard. You can see parts of still attached to the latch. At first I thought someone just added this, but have found several articles that refer to it as used on the T6B. Ruetters on color and Karmanns a different color.

Today was supposed to be spent prepping the 55 coupe for trip to ECH. Did get the front end lubed and brakes adjusted. Back end is in the air with wheels off. But, I just had to do some more investigation on hood latches. Have not had a response yet from my expert friend. At this point I think the PreC latch will work okay as long as it is square to the striker in both planes and the striker is square to the hood pivot. I re-installed the striker and guesstimated where the hinge pivot was and it appears to be at a right angle to a line from the hinge pivot to the striker. That is why the retaining nut is welded in at an angle on the striker attaching plate.

I took a picture of the PreA(55) latch mounting bracket:


The PreA bracket is a more rigid design, having more flanges welded to the inner nose and also being fully boxed in. The T6B bracket has two shorter side flanges(due to a redesigned inner nose to accommodate spare tire) and is 18 ga. metal. The PreA bracket is thicker metal, but hard to measure. The safety catch on the PreA is also stronger(12 ga.) vs 14 ga. on the T6B. And as Jack had noted earlier, the PreA catch does not have the openings at each end. Both secondary strikers are 11 ga.

With that analysis in mind I decided to cut out Foam Cars latch bracket. On both the PreA and T6B, the weld at the top is very thin as it is dressed down for appearance. Earlier I posted a picture showing where this weld was beginning to fail. So it did not take a lot of grinding to break the top of the bracket loose. On the lower side flanges I cut through just before the weld. Here is the bracket on my shop stool:


Here is one side that has been deformed:


I decided to make a new bracket out of 16 ga. and to extend the side flanges down another 1/4" for a little more strength. I will also box it in with a separate piece ala my PreA. Here is the start of a template:


I will also make a new safety(secondary catch out of heavier metal and make it like the PreA design. Since I am planning to remove the center nose section, I can repair the inner nose and while I have the bad metal cut out I can determine an accurate angle for the latch pad on the bracket. The striker pin has M10x1.5 threads, so I will buy a long bolt and weld a plate on the bolt shank. Attach my magnetic angle gauge and with the hood in the closed position I can measure the angle.

Phil

[JR]

Hey Phil,
I see that your located in NE Michigan.
Where?
I am originally from MI, but left in September 1957 to start USN Flight Training.
Dick

[Phil Planck]

Dick
I'm about 20 miles south of Alpena.
Phil

[JR]

WHOA Phil,
Your up in COLD country!
We moved to Lake Odessa in Ionia County when I was 15 about 1949 from the CHI area.
Both my wife and I went to Western MI (me College-her UN) 1956 and 57.
My e-mail address, if you like, is jrpitman@juno.com so we don't garbage up the website.
This weekend I am planning on taking the Roadster to Classics On The Green which is a European Car Show at a Winery here in the Richmond, VA area.
The Marque this year is Ferrari.
There usually is 250 to 300 European cars on display!
The WX forecast is not looking good with some rain so if it is really wet the Roadster will not go. I'll take the 1984 Targa in its place. That will confuse the heck out of the organizers.

Dick

[JTR70]

Great idea Phil, your new heavy duty latch base void of all the later described relief shortcomings will definitely help you sleep better at night.

Appreciate it that Bruce, But its all due to the great group of guys we have here that make it an interesting place to visit. So my thanks to you all! Justin

[Phil Planck]

Made some progress on the latch base:


Can't do any more with it until I repair the inner nose piece as the flanges that weld to the nose control the angle of the latch. I did make a "fixture" to measure the angle of the striker with the hood almost closed. Just a 10mm x 1.5 threaded rod with 2 nuts to attach the magnetic angle gauge to:


With the hood almost closed but ajar enough to shine a flashlight in on the gauge it read 75 degrees, which means the latch plate should be at 15 degrees. I measured the shimmed latch on the PreA and it was 11.5 degrees. If any of you have one of these gauges, I would be interested to see what reading you get, particularly with the latch removed. But with the latch on it should still measure pretty close to the base plate. Remember there is weld holding the front of the latch up higher that it should be.
Phil