A Sad Tale

356 Porsche-related discussions and questions.
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Martin Benade
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Re: A Sad Tale

#16 Post by Martin Benade » Sun Jan 09, 2022 11:33 am

Harlan’s
Cleveland Ohio
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Vic Skirmants
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Re: A Sad Tale

#17 Post by Vic Skirmants » Sun Jan 09, 2022 11:57 am

Martin Benade wrote:
Sun Jan 09, 2022 11:33 am
Harlan’s
He didn't actually recommend that, did he?

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Al Zim
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Re: A Sad Tale

#18 Post by Al Zim » Sun Jan 09, 2022 1:52 pm

We saved loads of rods and even weigh them. Now what we have is a bunch of old rods that do not match. As far as I can tell rods may have been matched when they were manufactured but none of the rods show any metal removal to balance them..an obvious situation regarding balancing. For just a few hundreds of dollars more you can purchase new rods from the after market guys which have close to no discrepancy in the weights of each end of the rod. It takes special a very accurate inch pound torque wrench to properly install the rods.
Your next situation is what happened to the engine when the rod bent. A STRONG FORCE was present. In your assembly it is vitally important to have the proper clearance on the #1 main bearing...it is a tight clearance. Also have the crank magnafluxed
Check your tolerance on the rod and compare them to the aftermarket rods. The factory allows 5 grams difference. Is this on the big end or small end or both NOT specified in the shop manual. Usually we find that the aftermarket rods are less than 2 tenths of a gram difference location of the weight and the total weight. And sized correctly
Last edited by Al Zim on Wed Jan 12, 2022 3:29 pm, edited 1 time in total.
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Martin Benade
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Re: A Sad Tale

#19 Post by Martin Benade » Sun Jan 09, 2022 2:32 pm

I believe that was at least a semi serious recommendation. I actually think it would be fine but I couldn’t bring myself to do it.
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Mike Horton
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Re: A Sad Tale

#20 Post by Mike Horton » Sun Jan 09, 2022 3:30 pm

I've put together rod sets, from my "orphans", a term I borrowed from Tim Berardelli, and these days often done in well equipped shops, by highly experienced 616 engine builders, but when done in such a retail shop, at today's labor rates, to which Al alluded, the customer cost difference between correctly matched, and rebuilt old rods, and the new ones, gets closer. The first set of rods I self balanced, on shop made fixtures, and an old paint mixing shadowgraph, weighing down to grains, took me a little over 8 hours, a belt sander, a lot of patience, and attention to detail, the value to me, was the education I learned. As I now only build road engines for myself, I use an electric digital scale, and another holding fixture I made, and used more realistic weight limits, than in that learning exercise.

As Vic, or anyone else who have done this, not only is it time consuming, but... there is, in spite of Magnaflux, and utmost care, in the other needed processes, no guarantee.

For those of us who attempt these challenges, one needs to assess how hard you choose to use your engine, what are your long term goals for the engine, or just going through the excersize, to maintain one's mental and physical accuities, and the sense of accomplishment one receives, when we cruise down the byways...

(I have such a created matched rod set in my hybrid '62 S90. When I disassembled it, that engine contained 2 each "00" rods, and 2 each "01" rods", and not only could I Not live with that, but inspected every other piece carefully in that engine, as I went through it!) If I'd had to compare how many hours I spent on the overhaul, to what a customer would be willing to pay, I'm sure I'd have lost my "shirt"... but I am happy with it now,

(keep the "middle" shops are put in today, in working on these 50+ YO engines and parts in mind, before criticizing those still willing to do such needed service !)
Mike

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Patrick Ertel
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Re: A Sad Tale

#21 Post by Patrick Ertel » Sun Jan 09, 2022 4:45 pm

Al Zim wrote:
Sun Jan 09, 2022 1:52 pm
As far as I can tell rods may have been matched when they were manufactured but none of the rods show any metal removal to balance them..an obvious situation regarding balancing.
I agree the rods in the engine were probably not balanced at the factory, just matched by weight. After 40 years I don't recall whether any of these rods had grinding marks on them when I took them out or not, but after having them balanced only two came back with any material taken off the big end, three had material taken off the small end, and one was untouched.
Patrick Ertel

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Larry Coreth
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Re: A Sad Tale

#22 Post by Larry Coreth » Sun Jan 09, 2022 6:10 pm

Does no-one turn the petcock to "Zu" when parking a 356, any longer, especially for any length of time ? I was taught, back in the '60's, that "this was what was done". Not till later I understood the basis for this procedure, i.e. leaky needle & seat valves filling up the cylinder with fuel, and resultant hydro-lock. Since the carbs are directly over the intake valves, this is what you get if either carb leaks fuel.
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Patrick Ertel
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Re: A Sad Tale

#23 Post by Patrick Ertel » Tue Feb 08, 2022 4:07 pm

I'm making progress on bringing the "engine to last a lifetime" back to life - with a few hickups. My friend George Montgomery ("Ohio George" for any of you who were into drag racing in the '60s) offered to do the machine shop work. We became friends while I was writing a book about him and he offered to do the work for free, but his health isn't the greatest and I didn't feel like pushing him. It's a shame, because I would have been honored to have a car that "Ohio George" worked on.
I found a set of used .00 rods that were truly a set - within a gram of each other in weight. They went to the next best machine shop in the area, along with the crankshaft and case. Both the rods and crank magnafluxed clean and measured straight. They polished the crank and refurbished and balanced the rods. The rods balanced to within a half a gram between them and end to end with minimal polishing. The case bores measured right on the edge of OK, so I'm using it as is. I'm not going to race it and I'll probably not put more than 1000 miles per year on it over the rest of my lifetime.
Attachments
rods.jpg
A fellow Registry member fixed me up with a nice set of .00 rods
rods.jpg (497.96 KiB) Viewed 446 times
crank.jpg
The "C" crank polished up nicely, still well within the -.25 -.25 spec
crank.jpg (250.53 KiB) Viewed 447 times
case1.jpg
case1.jpg (303.67 KiB) Viewed 447 times
case2.jpg
#3 bearing bore
case2.jpg (270.1 KiB) Viewed 447 times
case3.jpg
The bearings that came out of my case
case3.jpg (276.87 KiB) Viewed 447 times
Last edited by Patrick Ertel on Tue Jul 05, 2022 4:46 pm, edited 1 time in total.
Patrick Ertel

Dick Weiss
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Re: A Sad Tale

#24 Post by Dick Weiss » Thu Feb 10, 2022 12:09 am

Patrick,

Years agoI had a set of conrods during a rebuild years ago which 1-of them
was heavier than the others which were w/in weight tolerance.

Notice the small end of the bent rod has more metal forged around the
wrist pin's bushing OD and I remachined the excess material on my special
tool grinder w/the pin zeroed in the locked chuck and the rod rotated on the
pin to grind the excess concentrick to the pin's diameter. Result--the conrod's
weight matched the other 3 w/in specs and the rod's small end matched the
diameter of the forgings.

I don't recall which version of conrods exsisted (-00 or -01) during the rebuild,
but it was recorded in my work writeup.

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Martin Benade
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Re: A Sad Tale

#25 Post by Martin Benade » Thu Feb 10, 2022 12:33 am

We’re they all in balance end for end too?
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Re: A Sad Tale

#26 Post by Dick Weiss » Thu Feb 10, 2022 12:49 am

Only the big end; The small end wasn't necessary. (my opinion)

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Don Gale
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Re: A Sad Tale

#27 Post by Don Gale » Thu Feb 10, 2022 1:30 am

Doing a static weight balance of the big end and small end is only part of the story. Some 50 odd years ago in my ME317 Vibrations Lab class, the instructor had us go thru an exercise to dynamically balance rods. As I recall, we hung the rod on a knife edge on the small end and measured the period of a pendulum swing, repeated it when suspended on a knife edge on the big end saddle, weighed the rod, calculated the CG, and went thru another series of calcs to determine the center of percussion. When correctly balanced, any lateral movement of the wrist pin i.e. knock or piston slap, resulted in only pure rotation around the crank journal and not impart sideways wear. Likewise, lateral knock/shock on the crank end resulted on only rotation on the wrist pin and not push the piston sideways in the bore. Mopar rods in the day had "nubs" or bumps on both ends which provided material to remove to achieve dynamic balance. Perhaps 356 rods were correctly designed to incorporate inherent dynamic balance? or by their smaller size, was less important? How do Pauter and Carrillo do it?

Mopar rod:
mopar_rod.jpg
mopar_rod.jpg (47.89 KiB) Viewed 385 times
The VW book for the Complete Idiot shows suggested locations to remove rod material, as well as where to remove material from a piston skirt, which would be somewhat similar for a 356/912:
vw_rod.jpg
vw_rod.jpg (74.82 KiB) Viewed 385 times
1958 356A 1600 Super Sunroof Coupe
former 1966 Euro 912 Sunroof
former 1978 Intermeccanica Speedster w/'68 912
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Mike Horton
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Re: A Sad Tale

#28 Post by Mike Horton » Thu Feb 10, 2022 9:55 am

Patrick Ertel wrote:
Tue Feb 08, 2022 4:07 pm
I'm making progress on bringing the "engine to last a lifetime" back to life - with a few hickups. My friend George Montgomery ("Ohio George" for any of you who were into drag racing in the '60s) offered to do the machine shop work. We became friends while I was writing a book about him and he offered to do the work for free, but his health isn't the greatest and I didn't feel like pushing him. It's a shame, because I would have been honored to have a car that "Ohio George" worked on.
I found a set of used .00 rods that were truly a set - within a gram of each other in weight. They went to the next best machine shop in the area, along with the crankshaft and case. Both the rods and crank magnafluxed clean and measured straight. They polished the crank and refurbished and balanced the rods. The rods balanced to within a half a gram between them and end to end with minimal polishing. The case bores measured right on the edge of OK, so I'm using it as is. I'm not going to race it and I'll probably not put more than 1000 miles per year on it over the rest of my lifetime.
Like Patric, the "00" factory set of the rods from my old '61 titled (very late in '60 buid) Normal engine, when checked, we're amazingly close, and well under book weight tolerance.
Last edited by Mike Horton on Thu Feb 10, 2022 12:07 pm, edited 1 time in total.
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Vic Skirmants
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Re: A Sad Tale

#29 Post by Vic Skirmants » Thu Feb 10, 2022 10:04 am

I have found that "early" rods were very close on weight. By the time of the 912 engines, weights were pretty inconsistent.
Also, the CC number stamped in the heads seemed to only match one of the chambers, with the other one as much as one or more CCs off.

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Al Zim
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Re: A Sad Tale

#30 Post by Al Zim » Thu Feb 10, 2022 10:50 am

Patrick: already this morning I have explained to a European email that it takes more than just a camshaft to increase the horsepower and longevity of a 57++ year old engine. Take a look at shops (you are retired) and it will be obvious (and expensive) who can do your work.
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