[TAQuest]

Originally Posted by RocktimusPryme

By most reports the 2nd gens are just built a little better, less of a rattle trap. Now Im sure part of that with mine is I just started with a rough car. So the windows out out of alignment etc etc. But yeah, if I could take my motor and put it in a 70-73 I would. I don't hate my car, I just think I would like the other better. More head room, more likely to be disc braked, more exhaust options, more interior options.

I was where you are with your thinking at one point in my life.
My first car was a 69 Camaro.
Always liked the 70 TA looks.
Then I bought one.
When sitting in it the feel was wrong. The doors are big and heavy. The whole front end seems whopping and heavy.
There was more head room and leg room.
Then I got a 68 Bird and it was just right.
Not cheap like a Chevy.
Not heavy like a second gen.
A 1st gen Firebird has always been an exact fit for me.
Like a glove.

[MarkS57]

Originally Posted by Will

For the vast majority of Pontiyakkers, this "design flaw" is of no concern whatsoever. Honestly, how many people are building engines over 600 HP? How many are over 500 HP?

Exactly right so why was it necessary to throw it out there?

Unless his idea is everything need to be 1K horsepower or bust? Sheesh!

[242177P]

Design flaw? Warranty department must've been swamped. Even the SR blocks have it! Madness!

[SRR]

I have owned a 70 Barracuda 383 and a 67 Dodge R/T 440. Talk about design flaws! Crappy brakes, unibodies, very rust prone and crappy transmissions. I can't even watch "Graveyard cars" anymore because if I hear him say "Mopar or no car one more time... lol. Like mentioned every engine has "flaws" I have rebuilt most of them. Buick 455 needs the oil pump mod if you want it to live. If Pontiac had a design flaw it was those cast rods. Put a Chevy guy behind the wheel and pop goes the rods. Ever see the oil pump drive in an Ford "FE" engine? 1/4" shaft. Had one snap when the nylon timing gear managed to get a piece into the oil pump. I do like those Engine master vids on youtube. Very informative.

[Mister Pontiac]

Originally Posted by SRR

I do like those Engine master vids on youtube. Very informative.

X2

I've learned to leave their opinions behind, and just watch the shows for the technical value & fun! I admire there approach to all things automotive.

[MarkS57]

Originally Posted by SRR

If Pontiac had a design flaw it was those cast rods

Most forget about the rods as there are so many forged options out there today. Still, for what they were most didn't end up through the block wall. Really, the bolts gave way before the rod itself. Like the heads, wasn't too much of an issue with the low end torque of the stock engines. A good install of ARP's makes the those cast rods live good enough for most 400 apps these days.

[Half-Inch Stud]

Originally Posted by KEN CROCIE

Getting back to "design flaw".
The design flaw is that the engineers who designed the Pontiac engine in or about 1953 did not anticipate a roller cam would be installed, 60 years later, that had so much lift and duration that the lifter bores would snap off as a result.
Could it be the open design of the lifter valley was used to promote and ensure lifter lubrication?

The PMD-cast M/T Hemi block shows a fully filled Valley; is evidence the PMD Engineers knew for sure that the valley could be filled with iron for stability & strength.

Im certain that Production pressures cause castings to be thin wall, so a qualified vat can make to most parts. Even the machined shavings went to remelt huh.

[77 TRASHCAN]

Originally Posted by Will

For the vast majority of Pontiyakkers, this "design flaw" is of no concern whatsoever. Honestly, how many people are building engines over 600 HP? How many are over 500 HP?

Smokey Yunick sometimes in his book talked about cars as machines made for surface transportation, or something close. Thinking along that line the open valley blocks that made up the majority of almost all Pontiac engines, were likely, mostly only thought of as family and grocery haulers. Engineering may have been NOT centered around the very best way to design something, but in making tuff that's good enough.
Many conversations about Pontiacs weaknesses. Yes, cast rods have limits, but the block has been hashed here, severely too. Man the 2 aftermarket blocks both have lifter valleys, done correctly!!!

500 hp is easy to do with a 455, but from my reading here, much past that, you are gambling....
All the gyrations, parts moving inside an engine, it's a wonder any engine has longevity....

[moontower69]

To echo other earlier comments, I very much respect Roadkill (Roadkill Garage is my favorite and also Engine Masters) and it's the ONLY car show I can constantly watch. Why, because I can relate to them and it's not "canned" feeling like other shows.

Dave, Finnegan and Dulcich are pretty down to earth and don't fake it. It does pain me when they get a cool junkyard car running and just abuse it till it breaks/overheats. (Somebody could be very happy with an old motor like that and take care of it.)

Just drive it and go. And always a good BURNOUT at the end!!

I can't stand it when folks make videos of their cars and it's obvious that they're utterly afraid/terrified of spinning a tire or getting on it. They baby it instead of getting on it. Heck man, that's what these cars were designed for - burning rubber and having some fun. I'll NEVER understand what the point is of having a muscle car if you're afraid to use the muscle (safely and within some reason of course!).

Dig the Roadkill guys. Just wish they'd give Pontiacs more of a chance. But like someone said, Dodge is their sponsor and Pontiac is no longer a going concern.

[TCSGTO]

They’ve had 3 Pontiac episodes on Roadkill/Roadkill Garage. They bought a Catalina in Texas for a couple hundred and drove/beat it back to California in one.

Dulcich’s 67 Bonneville wagon has been in 2 episodes. They drove it to the Bonne salt flats in one and thrashed it at an airport against a Chrysler wagon in another. They have probably put more miles on old Pontiacs in the last few years than some on this board.

And yes the lifter valley in Pontiac blocks is a major flaw, at least is was for me since I’ve got a broken one sitting on my garage floor.

They are Mopar guys, Dulcich used to and may still edit Mopar Muscle, but they don’t discriminate and feature a variety of “garbage” on their shows.

[J.C.you]

The major performance flaw (back in the day)of the engine was not the block but the cast rods. Before the Chinese stuff became available a factory sd forged rod would bring big bucs and be out of the question.
When we were budget shoe stringing a performance motor together it would be 3 old beater blocks tear down time. Usually about half the big ends on the cast rods would be egged and at least a couple thousands out. That alone has made many guys sour on ponchos go brand x when they popped a "performance" poncho motor.

[Sirrotica]

Originally Posted by J.C.you

The major performance flaw (back in the day)of the engine was not the block but the cast rods. Before the Chinese stuff became available a factory sd forged rod would bring big bucs and be out of the question.
When we were budget shoe stringing a performance motor together it would be 3 old beater blocks tear down time. Usually about half the big ends on the cast rods would be egged and at least a couple thousands out. That alone has made many guys sour on ponchos go brand x when they popped a "performance" poncho motor.

This is entirely true that the rods were the largest limiting factor, (I struggled with them in oval track cars for years). As better rods became available the blocks were the next weak link as well as the cast cranks. Both have been addressed now, and the engines have went on to produce power with many other marques.

Great Post JC....

[Tom Vaught]

Originally Posted by Half-Inch Stud

The PMD-cast M/T Hemi block shows a fully filled Valley; is evidence the PMD Engineers knew for sure that the valley could be filled with iron for stability & strength.

Im certain that Production pressures cause castings to be thin wall, so a qualified vat can make to most parts. Even the machined shavings went to remelt huh.

True statement, in my way of thinking.

Example, the 64 Heater plumbing worked fine. No robbing of the coolant flow by the heater core from the passenger head. BUT Pontiac changed the design (for a few pennies of savings on every foot of Heater Hose eliminated by the shorter hose system.

Imagine the $$ saving in all of that cast iron over millions of blocks (for Pontiac over the years) of production. All about the $$$ in my mind.

They would not have put the lifter boss support struts on the RA-V type blocks if there was not a need (when used with a racing camshaft).

Thankfully the aftermarket blocks have that built into their design.

Tom V.

[track73]

Originally Posted by MarkS57

Most forget about the rods as there are so many forged options out there today. Still, for what they were most didn't end up through the block wall. Really, the bolts gave way before the rod itself. Like the heads, wasn't too much of an issue with the low end torque of the stock engines. A good install of ARP's makes the those cast rods live good enough for most 400 apps these days.

Years ago asked Nunzi about installing ARP bolts on Pontiac rods and he said. "did you ever see Pontiac rod bolts break?"

[Buford T. JuSStice]

I'm sure it has been said, but the open valley doesn't have to necessarily be a huge disadvantage. When you're building your block, right at the very beginning you can reduce the chances for failure significantly by shaving down the casting flash yourself, and getting rid of as many sharp edges around the area as possible. Make sure to clean up the area very very thoroughly before going any further. It may even be a good idea to do this before bringing the block to a professional machine shop, and if you aren't confident in your abilities, they would be happy to take your money and do it for you. I'm sure if you're still afraid of things falling down into the valley area, you can have mesh inserts inserted similarly to how you can put a mesh insert into the corners of a SBC's valley area. Make sure to use an very tough, inflexible, finely woven stainless steel mesh, and epoxy it in place, making sure NOT to place it anywhere that it would be in the way of other moving parts!

[ta man]

Originally Posted by Buford T. JuSStice

I'm sure it has been said, but the open valley doesn't have to necessarily be a huge disadvantage. When you're building your block, right at the very beginning you can reduce the chances for failure significantly by shaving down the casting flash yourself, and getting rid of as many sharp edges around the area as possible. Make sure to clean up the area very very thoroughly before going any further. It may even be a good idea to do this before bringing the block to a professional machine shop, and if you aren't confident in your abilities, they would be happy to take your money and do it for you. I'm sure if you're still afraid of things falling down into the valley area, you can have mesh inserts inserted similarly to how you can put a mesh insert into the corners of a SBC's valley area. Make sure to use an very tough, inflexible, finely woven stainless steel mesh, and epoxy it in place, making sure NOT to place it anywhere that it would be in the way of other moving parts!

Much like this.

[Buford T. JuSStice]

Originally Posted by ta man

Much like this.

Very clean! And yes, that does look very good. Reducing stress points by shaving off casting flash and sharp edges is the cheapest, and easiest way to increase the life expectancy of your engine block, and the simplest thing you can do to increase it's ability to handle more power safely!

[ta man]

My shortblock can handle up to 900 hp and 7500 rpm. I'm nowhere close to that.

[TAQuest]

Oh no, say it aint so!

QUOTE: "Metals which are subjected to repeated or fluctuating loads, such as alternating between tension and compression, can break after a large number of loading cycles even though the maximum stress was well below the static strength of the metal. This type of fracture is called a fatigue failure, although the rate of load application or the length of time over which the cycles occur are not significant. The occurrence of a fatigue crack is directly influenced by the maximum unit stress and the cumulative number of times it is applied.
A fatigue crack starts in an area of high stress concentration after a large number of loading cycles. It is always a brittle type of fracture even when occurring in ductile metals. As the crack progresses, it increases the stress concentration, and the rate of propagation under the cyclic loading increases. When the cross section of the remaining metal becomes insufficient to support the maximum load, complete failure occurs as it would under an excessive steady stress. "

[Tom Vaught]

Fatigue failures will happen on any part if it runs enough cycles. No matter how good the part is.

So how many cycles would an expert (like you on this subject) assume before a GOOD connecting rod failure for example? Post up a number

Tom V.