RE: 325ci Cobra small block

[pbf777]

    I doubt it's necessary to try and make the "325" moniker a perfect physical dimensional match in the bore & stroke guessing game as manufactures have been assigning implications of such in their labeling for decades. 

    As an example: In 1963 with the introduction of the Pontiac "326" cu. in V8 it was actually "336" cu. in.; but apparently due to GM's capacity restrictions "labeling" it as being something under "330" cu. in. meant that it would be applicable for installations in more chassis.

    And then the other story is that since GM's "flagship" vehicle, the Corvette, would have Chevy's 327 cu. in. engine example, Pontiac was "informed" that the "336" just wasn't going to fly! 

    For 1964 the "326" actually became something closer to just that!   

    Scott.

[slither]

Interesting tidbit, pb!

[kranky]

The 1965 Shelby De Tomaso P70 designed by Peter Brock was scheduled to also be powered by the 325 engine with a future engine size increase to a 7-liter engine as of early August 1965.

[pbf777]

    It really would be interesting to know what it seems may have been the "reliability" problems that the "325" had been experiencing; that as of the past few decades the 3.4" stroker-crank packages have proven to be really "no problem".   

    And of course, even if it were accurate in the notion that there 'were' reliability problems, we also don't know if such was actually related to the engines capacity increase or whether caused by some other deviation from the 289 package?   

    This thread seems to be one with more questions than answers; but at least someone is asking!   

    Scott. 

[98SVT - was 06GT]

..... that there 'were' reliability problems, we also don't know if such was actually related to the engines capacity increase or whether caused by some other deviation....

Let's not forget the Ford edict that CS swap his engines in the 65 GT40s for ones built by Ford the night before LeMans - ALL failed. The Tunnel Port is another one. Shelby won the Daytona 24 hour 4th overall behind 3 prototype Porsches and 64 laps ahead of the 2nd place TA car. Then Ford required the engines be run as received and not even opened to check things like valve lash - multiple DNFs were  the result. Titus had one of those fail on the pace lap. The tattle tale was at 4,200 RPM.
Ford has a weird internal culture/mindset where they hire outside help to get the job done but then go out of their way to make it appear their inhouse guys did it and are the best in the world and know what they are doing.
Here's a little insight - https://www.youtube.com/watch?v=paEQCZxclPQ

[pbf777]

     

Ford has a weird internal culture/mindset where they hire outside help to get the job done but then go out of their way to make it appear their in house guys did it and are the best in the world and know what they are doing.

      It's not really "weird", it's just the bureaucratic mindset of incapable individuals, justifying the curb-stops out in the parking lot with their names on them!   

      Scott.

[pbf777]

The Tunnel Port is another one. Shelby won the Daytona 24 hour 4th overall behind 3 prototype Porsches and 64 laps ahead of the 2nd place TA car. Then Ford required the engines be run as received and . . . . multiple DNFs were  the result.

    And yes, the "Tunnel-Port" engine 'is' another one, that although there is a greater sum of information on, still leaves one wondering just what actually happened? 

    Scott.

[98SVT - was 06GT]

The Tunnel Port is another one. Shelby won the Daytona 24 hour 4th overall behind 3 prototype Porsches and 64 laps ahead of the 2nd place TA car. Then Ford required the engines be run as received and . . . . multiple DNFs were  the result.

    And yes, the "Tunnel-Port" engine 'is' another one, that although there is a greater sum of information on, still leaves one wondering just what actually happened? 

    Scott.

Street car engine builders using out of the bin parts for race engines. The 65 LeMans failure was due to head bolts failing. Grade 8 would have lasted and Ford would have won a year earlier. SA tore down one of the first TP failures and found casting sand still in the engine.

[pbf777]

The 65 LeMans failure was due to head bolts failing.

    I have a bad habit of not accepting statements at their face value, and this presents as possibly a good example of the difficulty, for anyone at this point in time, of being able to determine the "actual" cause(s) in the failures of this era. As unless one actually has access to evidence and/or technical inspections/testing as done by true experts on the subject matter, the rest of even the in period testimony or remembrances in later periods, just ends up as generalized perspectives provided by those whom really probably shouldn't comment in absolutes.   

    To explore further, here, "head bolt failure"?  Well, I'm guessing the bolts didn't just unexpectedly snap-off and cylinder heads just fell onto the ground?  So probably the problem was "head gasket failure" which led to overheating, which put the car(s) out of contention, which was then attributed to "bolt failure"?  The perspective issue here might be that generally in this sort of engine configuration and with "proper" type of gasket, surface preparation, etc., if the clamp load can be maintained on the gasket, it most likely isn't going anywhere, and it's generally accepted that the weakest link are the fasteners and that "lifting" of the cylinder head is often the accepted cause of a "blown head gasket" (but not always  ).  Attempting to address this issue is what has made ARP Fasteners who they are today! 

    So, were the head bolts truly "defective"?  Or rather as intended, just "not capable" by design?   

    And then, perhaps the bolts "were" capable, under the intended application and environmental conditions, but there was just to much cylinder pressure (say, ignition timing and/or running compression) and/or heat (was the cooling system capable?) for the octane capability of the fuel, and if not, did a potential detonation scenario lead to the chain of events that became addressed as "head bolt failure"?   

    B.T.W.  The Ford O.E.M. head bolts as utilized here are of a grade greater than "8", though not having been graded as such, it's generally accepted as say a Grade "9".  If you take a set of 1/2" x 13t grade 8 fasteners of the same lengths as the O.E.M. Ford units, pull them to the 95-105 ft. lbs. torque specification, if you have any "feel" for such (if they just don't snap-off!  ) you'll know their not as capable.   

    Scott.

       

[pbf777]

SA tore down one of the first TP failures and found casting sand still in the engine.

  Not disputing this statement, but I "think", I remember that it was after one of these engine failures, that upon tear-down at S.A., it was blasting media that was found in the oil pan and it was determined that it was residue as from the standard cleaning process adopted at S.A. of the oil pans, which was abruptly changed thereafter to not. 

  Now I said, I only sorta remember, something like that, so it's O.K. to blast me out of the water, and tell the "correct" story! 

  Scott.

[98SVT - was 06GT]

The 65 LeMans failure was due to head bolts failing.

    I have a bad habit of not accepting statements at their face value,
       

CS interview stated - Head bolts streched.

[98SVT - was 06GT]

SA tore down one of the first TP failures and found casting sand still in the engine.

  Not disputing this statement, but I "think", I remember that it was after one of these engine failures, that upon tear-down at S.A., it was blasting media that was found in the oil pan and it was determined that it was residue as from the standard cleaning process adopted at S.A. of the oil pans, which was abruptly changed thereafter to not. 

  Now I said, I only sorta remember, something like that, so it's O.K. to blast me out of the water, and tell the "correct" story! 

  Scott.

Engine torn down was one sent from Ford. Titus' kid told me it  was casting sand. He also told me that a Ford engineer accused his dad of over revving an engine on the pace lap and causing a failure. Titus grabbed the guy by the neck and shoved his head in the car to see the tach at 4,200.

[pbf777]

CS interview stated - Head bolts stretched.

    Carroll Shelby's statement isn't to be ignored and may be quite legitimate.  But the question is how accurate and truly revealing is it and how do 'you' interpret it?  Not to beg the question, and probably why I'll never be chosen to sit as a juror, at least not by those whom shoulder the burden of "proof", but this statement doesn't address any of the possibilities or questions I posed; rather it plays right into the scenario that I find makes for question.    

    Even we we choose to accept it at face value, is it that the head bolts were "defective" and just stretched, this after being put into operational service?  Or was this due to "improper installation" (aka. over-torqued) and stretched?  Or rather, an indication of "inadequate engineering execution" in the sum of and/or size of, aka., just not capable; and/or that of the supporting structure that they engage proved insufficient in rigidity?       
   
    Then, maybe the overall failure was just simply attributed to the known fact that the head bolts stretch (spring) in the operational functioning of the engine, just a little, this within the "elastic" limits of the fastener and isn't generally a problem until it becomes excessive (eg. due to detonation) and then the necessary clamping load requirements for gasket retention is potential lost, if only momentarily.  But this would rarely enter into the "plastic" range of the fastener where there would be retained elongation that could actually be physically measurable and warrant the label of as being "stretched".  And often, even if the bolt had stretched, it perhaps was inevitable and the true "fault" may prove due to the actions of other events involving other componentry encompassing the engineering endeavor as a hole?   

     The sum of these considerations or any others, prove as unanswered in the simple statement, because as stated previously, it is generally just accepted that in most instances if the head gasket blows it's because the clamping load which holds it in place was lost, and this in simplistic views this is solely the responsibility of the fastener; but in reality such events generally involve more than one aspect, as rarely is a failure the result of a singular action.   

    Besides, wasn't in some interview where C.S. was being asked something technical about the cars and his response was something amounting to:  Hell, I don't work on the cars, I hire other people to do that!   

    But in the end, I surely don't know . . . . . but I wonder . . . . . .?   

    Scott.       
   

[98SVT - was 06GT]

Besides, wasn't in some interview where C.S. was being asked something technical about the cars and his response was something amounting to:  Hell, I don't work on the cars, I hire other people to that!   

    But in the end, I surely don't know . . . . . but I wonder . . . . . .?   

True CS was no wrench - or engineer. But he did put a winning team of wrenches together that also knew the ins and outs of extracting the max out of engines and that street car production parts would not get the job done. Chuck Beck (Porsche 550 Spyder kit, etc) was a fabricator at SA. The GT40 originally had a small gel cell aircraft battery. Ford demanded that the whole area be rebuilt and modified to accept a big Motorcraft wet cell battery. I wonder how many of those died from the added vibrations and G forces in the racing environment.
In the end none of us will truly know. Unlike Enzo who enshrined his failed parts so his engineers didn't make the same mistake twice Ford's corporate structure assured that problems were swept under the carpet and the blame moved down the employee chain to protect your job.

Enzo's "room of mistakes"