Holiday ride of shame

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Glen Getchell
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Re: Holiday ride of shame

#31 Post by Glen Getchell » Thu Oct 10, 2019 11:53 pm

Vic asked
"Glen; were these AA P&Cs used in your race engine? What rpm ?"

No, this was on Rudy my street C coupe. Generally revs rarely exceed 5K RPM's, but we make long trips (10hrs at a stretch at 70-75 mph with an occasional blast as needed to what ever is needed) so 4K+ RPM for many hours at a time.

from the little bit I remember, the car ran great than started to ping and use oil simultaniously. I had already R&R the #2 cylinder after just a month. AA worked with me at the time (I have recently put their bearings in my race car) so I don't have a problem with AA. But I do question the quality of the cast Big Bore kit. It just seemed like there was constant trouble with it. I have another set, but I don't believe I would ever put them in a car that I plan to pound miles on. The final failure caught me at just the right time when I was flush and willing to bite the bullet and splurge on the the Shasta Kit. In approx. the same miles running similar timing I have not noticed any change over nearly 15K miles in oil usage or pinging. I also have one of Vic's cam's in this car. I don't know how the AA forged kit is, but I use this car a lot, and it is used for almost all long trips. Right now I have 100% confindence that I could drive the car anywhere without concern (In fact we are trying to figure out how to get it to Germany for the next International 356 event). It is glorious and easily the best driving car I own. But sometimes life dictates you just have to go the economical way. When it comes to the AA cast Big Bore Kit, I would say it's great for garage queens, or a stop gap. Figure you might get 20K miles. Hell even in a higher mileage 356 that can buy you 5 years. But if you can afford it, and you use the car, I would bit the bullet, have a few stiff drinks, then give your credit card number to one of the suppliers of the higher end forged kits with modern rings.

As to the race engine. Vic you should know by now that I blow that thing up in the dozens to the the hundred's of miles, not tens of thousands of miles.:-)

Glen
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neilbardsley
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Re: Holiday ride of shame

#32 Post by neilbardsley » Fri Oct 11, 2019 9:58 am

I get conflicted when I read posts like this because I have no direct experience of either sets. Howeever, I have talked to builders that have used AA sets that are happily used in none garage queen cars. As a garage numpty it seems to be most of the problems, apart from the solved wrist pins issues, are build issues with engine from inexperience people getting too close to the boundaries Mike H suggestions?

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Re: Holiday ride of shame

#33 Post by Dan Epperly » Fri Oct 11, 2019 10:07 am

neilbardsley wrote:
Fri Oct 11, 2019 9:58 am
I get conflicted when I read posts like this because I have no direct experience of either sets. Howeever, I have talked to builders that have used AA sets that are happily used in none garage queen cars. As a garage numpty it seems to be most of the problems, apart from the solved wrist pins issues, are build issues with engine from inexperience people getting too close to the boundaries Mike H suggestions?
I'm open to the idea of operator error, and I sort of hope it is something I did becuase I have AA kits in several engines.
My friend came by yesterday with his high end dial in timing light and we checked it and the timing was spot on.
I also checked the mileage and the engine has 10k on it. I'm thinking operator error would have surfaced long ago but we will see.

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Re: Holiday ride of shame

#34 Post by C J Murray » Fri Oct 11, 2019 10:28 am

I have used AAs in street applications without problems but I won't be using them in the future. I was never impressed with the quality of their cast pistons. Look at the original Mahle pistons or any cast piston from any Japanese motorcycle. No comparison. The wrist pin failures and the poor company response was it for me. I like sleeping at night. Honestly, skimping on a highly stressed part in an expensive engine is a bit foolish. It would be nice if a quality company like ART of Japan would make cast pistons for our engines. There are some advantages to cast pistons but no advantage to crap pistons.
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Re: Holiday ride of shame

#35 Post by Martin Benade » Fri Oct 11, 2019 10:47 am

CJ does AA have forged pistons that you trust more?

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Re: Holiday ride of shame

#36 Post by C J Murray » Fri Oct 11, 2019 11:14 am

Martin Benade wrote:
Fri Oct 11, 2019 10:47 am
CJ does AA have forged pistons that you trust more?
Don't they also sell JE pistons? But did somebody tell me their JEs use flat circlips? Round section clips with beveled wrist pins are much better.

I would buy Shasta or LN.
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Re: Holiday ride of shame

#37 Post by David Jones » Fri Oct 11, 2019 11:28 am

I am using AA sets in 2 cars and I have used them in a few more and so far no issues. One engine I have run to 7K rpm but no more, now I keep it below 6K. What about NPR sets or were they good because there was no alternative when they were being sold?
If I had known I would live this long I would have pushed the envelope a little harder.
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Al Zim
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Re: Holiday ride of shame

#38 Post by Al Zim » Fri Oct 11, 2019 2:43 pm

The factory always used cast pistons in the 356 engines. At first they were 3 rig later engines these had 4 rings with one below the piston pin. This kept the piston from rocking as much at top dead center as well as giving exc3llent oil control. It was not unusual for the factory engines to last over 100 thousand miles with frequent oil changes, normal service and driving that was not stupid. Now we must have forged pistons higher compression ratios or less expensive piston and cylinder sets that usually do not meet factory specifications. After each engine is assembled it is run on a dynomometer for an out put check. Those that did not pass were taken apart and the situation corrected. Every part installed was measured before assembly and checked after. One of our vendors has stated that anyone with a set of hand tools can rebuild a 356 engine. How can you measure the bore in the crankcase without an expensive tri-micrometer? How do you check the camshaft configuration or the radius of the lifters? Do you have tool with a read out that tells you the clearance between the small end of the rod and the piston bore to make sure the clearance to the piston pin is correct. Your Craftsman tool set cannot help you do this. The originator of this post is now looking at another rebuild. Martin, many times information on the talk list is well meaning but may not be factual al zim
 

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Re: Holiday ride of shame

#39 Post by Dan Epperly » Fri Oct 11, 2019 4:03 pm

Al Zim wrote:
Fri Oct 11, 2019 2:43 pm
The factory always used cast pistons in the 356 engines. At first they were 3 rig later engines these had 4 rings with one below the piston pin. This kept the piston from rocking as much at top dead center as well as giving exc3llent oil control. It was not unusual for the factory engines to last over 100 thousand miles with frequent oil changes, normal service and driving that was not stupid. Now we must have forged pistons higher compression ratios or less expensive piston and cylinder sets that usually do not meet factory specifications. After each engine is assembled it is run on a dynomometer for an out put check. Those that did not pass were taken apart and the situation corrected. Every part installed was measured before assembly and checked after. One of our vendors has stated that anyone with a set of hand tools can rebuild a 356 engine. How can you measure the bore in the crankcase without an expensive tri-micrometer? How do you check the camshaft configuration or the radius of the lifters? Do you have tool with a read out that tells you the clearance between the small end of the rod and the piston bore to make sure the clearance to the piston pin is correct. Your Craftsman tool set cannot help you do this. The originator of this post is now looking at another rebuild. Martin, many times information on the talk list is well meaning but may not be factual al zim
I think the point is that you don't need a lot of complicated set of tools to assemble an engine. My machinist does all the measuring and balancing, etc work that requires special tools.
What we are all dependent upon, whether pro or amateur, is the quality of the parts we purchase from vendors and they are dependent of course upon the manufacturers. I suppose that is why pros insist on spending their customer money on top of the line parts because they are likely to be more reliable than sketchy cheaper stuff we hobbyists might use.
A friend of mine has a VW restoration business and when he builds an engine for a customer he insist on all new parts, including a new case, to reduce the chance of having to redo his work from failed used parts. Even then, I have heard plenty of stories from him of new parts that have failed.
In summation a mechanics work in the end is only going to be as good as the parts he puts into it.

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Re: Holiday ride of shame

#40 Post by Glen Getchell » Tue Oct 15, 2019 1:09 am

I can't believe I forgot about this, especially considering the 912 culprit lump is sitting right in front of my face every time I walk into my garage. I think I know what has happened.

Several years ago we took our Roadster with a stock unmolested 912 engine to a car show. When we left it suddenly sounded terrible and loud like a really bad exaust gasket. But it was also down on power and clearly on three cylinders. We drove the car home making the racket. Luckily we had no problem climbing the 75ft mountain we had to go up to get home here in FL.

At first I could not figure out what was going on. It was clearly #2 cylinder but nothing seemed wrong visually or with the valve train. I took the sheet metal off and started the engine. BINGO, problem found in a HUGE way! The freaking #2 jug had cracked. I could literally watch the piston moving and see the spark while the engine was running. It was like one of those visible V8 models we all got for Xmas but never built.

I pulled the head off and found in my pile of parts a matching jug. I was not interested in re-building the engine, I just wanted it back on the road with the least work and expense. Perfection was not on my mind, I had other broken cars that were a priority. But that quick temporary repair would never take place (which is why that engine is sitting in my garage). What happened is that the the cracked jug worked like a plasma cutter cutting a slot in the mating surface on the head. So the head now either needs significant repair or replacement. It was quicker and cheaper to put the A Super that the car originally came with back in. The damaged 912 now helps hold down the garage floor and sometimes supplies nuts and bolts that I drop and seem to be swallowed up by that same garage floor (meaning I will need a bunch of nuts and bolts when I eventually fix the engine :? ).

Anyway, check your jugs for cracks!

Glen
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Re: Holiday ride of shame

#41 Post by Mike Horton » Tue Oct 15, 2019 12:22 pm

Glen, I think you have given us 2 different engine problems, with which to help, with the post damage analysis;
A) your C coupe, with AA P/C
B) your Roadster, with "unmolested" 912 engine

Sadly, back a few years, I was involved in 2 AA equipped engine damage situations, one involving a distinguished member of this forum, who has a T6 Cab, and the other, a long time 912 Registry BBS member, who has a '67 912, both involving recent engine overhauls, using the AA cast iron cylinders, and their hypereutectic pistons. In my investigation, with AA, it was discovered that the root cause of these failures, was the too thin piston pin issue, discovered in the early days of eth availability of these AA sets, and corrected in all later sets. There were threads on the issue both here, and on the 912 BBS. What was uncovered in both these instances, was that both owners, had sourced the AA P/C sets, from vendors, who had NOS AA sets on the shelf, which were dated, prior to the pin resolution. The AA fix, was to change the wall thickness, to a greater thickness, and IIRC, the later pins, were measured at .165", thicker than an old stock pin I measured, typical overkill, for a manufacturer, with such a dimensional issue. In both situations, AA furnished new parts to both owners, for their repairs, with the later same configuration sets. AA gave me the date of the kits which had the later, improved pins, and I posted it on the 912 Registry BBS, as AA had also offered back then, to furnish the later pins, to anyone who had not installed their NOS sets, dated before the pin resolution.

Glen, was the failed cylinder from the "unmolested" 912 engine, one of the factory original Biral cylinders, which were noted for going out of round, if significantly overheated, like Duane Spencer wrote of, in his 356, & 912 books? Also, recall, the cast pistons, which these 912, and later SCs were delivered with, had the thinner top ring width, and with high mileage, also, were noted to break earlier. Please check this, and let us know, as a knowledgeable and reasonable solution, needs to be based on fact, and not our "advancing" age memories (I'm 73, and completely understand).

It seems that in fact, we have two completely different issues, in these two examples...

Did anyone in these failed AA situations, measure the pin wall thicknesses?

It seems to me, that we've touched lightly, on many issues here, but we still have a significant problem, for the original poster, Dan, and many others here, who have run these AA PC sets, or like myself, have such a set in afresh engine build, not yet run, and placed in service. I chose the AA cast iron cylinder (my personal choice, due to the historical service, shape stability, and oil consumption in use), and hypereutectic aluminum pistons, obviously CNC machined, and this newish alloy, and more consistent machining method, have proven themselves in many modern production autos.

My choice of the AA set, had to do with the ever present issue of the combustion chamber angle in the "through 356B" cars production head angles, as my '62 S90, came to me with factory Mahle (good sets) "C" pistons, stock 82.5mm bore, and 5 or so copper base shims, to prevent the 30* pistons, from hitting the 22* heads. Oh, one of those really low time in service C pistons, on the post in-service forensics, had already been replaced, from the original set. AA's newer offering, of their 22* head angle shaped 86mm NPR cloned pistons, with the correct 22* head angle for my B heads, was the simplest answer to the matching of the factory otherwise pristine S90 heads, at a reasonable cost point, for an old codger touring engine, otherwise stock. It suits my need.

Vic, does not your C use these AA P/C? Inquiring minds...?

Several years ago, in this forum, and IIRC, later published in Volume 2, of the Technical and Restoration Guide, starting on Pg, 236, there is a reprint of the Big Bore pistons and cylinders, by several of the noted builders, and parts sellers, of the day, discussing pros and cons of the 86mm kits, and on page 240, Both the late Harry Pellow, the defender of the NPR, and other Japanese big bores, and Tim Berardelli, suggest, that keeping the static compression ratio under 9:1, will yield, with frequent oil changes and other routine maintenance, and more moderate driving, approximately 100,000 miles life. Harry, often referred to 8.8:1, as a longer life expectancy from these cast piston kits. David, seems to agree.

Yes, cast pistons, do have advantages, in some instances, per C.J., … but HARD use, may not be one of them.

Glen, if those original 912 cylinders are the "Birals", with the trough cast into the cooling fins, on top, contact me off line, and I'll send you a tech article I wrote for the 912 Registry, back in about '13, and on the Biral cylinders, I agree with Duane Spencer on those, based on my aircraft engine experience, with the Mahle Birals, used on the Teledyne Continental Tiara engines, of which I did factory warranty rework, replacing both pistons, and cylinders, on 28 of these 6 cylinder, geared engines, and a few of them, twice,
Mike

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Re: Holiday ride of shame

#42 Post by C J Murray » Tue Oct 15, 2019 2:06 pm

These are complicated issues that result in either overkill or doubt. Make your choice and pay your money.

Cylinders: I now only use LN or Durabar(Shasta is a reliable source). You can call it overkill but it frees me of doubt. LN and Shasta have owners that know what they are doing and have excellent business ethics. LN is really expensive but good luck trying to wear them out! They offer the ultimate technology and stand behind their product. In some ways they may be the cheaper option. Shasta is a close second at a better price and for those who worry about distortion of an aluminum cylinder they address that issue. I run LNs on my race engines and my 2133 160hp street engine without any significant oil consumption.

Pistons: The best commonly available piston has been the JE forged piston. Now LN is also supplying Mahle pistons as a choice for more money. I haven't seen or used any but I imagine they are less crude than the JE. JE is very good at producing a super strong piston on a special order basis from standard blanks and this sometimes means they are a little thick and heavy but they are otherwise a bullet proof product. There are companies that charge much much more for fabulously beautiful purpose forged pistons like Cosworth but that is not needed for a 6000rpm engine.

It has only been in recent years that ultra high performance Japanese sport bikes have begun to use forged pistons. The cast pistons they had been using were works of ART(company name, pun!). They were very light and temperature stable and never failed. Some metallurgy and forging improvements have allowed forged pistons to have some of the benefits that used to demand cast pistons so now sport bikes have the best of both worlds with the new forged pistons.

As for cheapo cast pistons, failure is common and they are not meant for sporting use. If ART made cast pistons for our cars they would last forever.
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Re: Holiday ride of shame

#43 Post by Dan Epperly » Tue Oct 15, 2019 3:29 pm

I am betting on a cracked cylinder in my case but it's going to be another week before I get to it.
Be prepared for amassive photo dump.
I'm sort of hoping it's something stupid I did otherwise there's going to a be a lot of people losing sleep over this. AAs are pretty ubiquitous.

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Re: Holiday ride of shame

#44 Post by Glen Getchell » Tue Oct 15, 2019 10:05 pm

Mike, the 912 engine was box stock and looked / s like it has never been opened up. It had never over heated during my ownership. However, with that said. Some of these parts are older than I am, and that is one of the reasons that I am so pissed off about not remembering things.

Dr. sent me for a brain scan. They found nothing (shut up everybody). I actually forgot I went for the scan. And I rarely forget spending large sums of money uselessly. But things are a little better now with less work stress.

As to the AA Big Bore. My problem always seemed to be related to the rings and the jugs. Of course wear of the lands on the pistons could have caused the rings to fail. But I would have expected more mileage out of them. None of the issues I had with AA P/C sets would explain Dan's problems sudden problem. But my 912 issue would. Granted totally different jugs, but similar symptoms.

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Re: Holiday ride of shame

#45 Post by Vic Skirmants » Wed Oct 16, 2019 8:12 am

Mike Horton: Yes, I use AA P&Cs in our 65 coupe, as well as many street rebuilds (when I was still doing those). Never had a problem that I heard of.
For the race engines, I used stock cast iron cylinders, machined to 83.5mm by a local friend. He gave me the best, straightest, round cylinders I have ever seen, Unfortunately he passed away a few years ago, so now I use the Shasta iron cylinders with pistons made to my design by JE. No, I do not stock any street P&C sets.

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