[Formulas]

Tom in the engineering world what exactly constitutes a cycle?

Is it when any give part sees 90-100% of rated load? Something like that is what iam after

.

[SRR]

Given a choice between a set of conn. rods out of Grandma's 350 or a 455 you know had the crap kicked out of it which ones would you rather use if you insist on using factory cast rods?

[PunchT37]

Is Pontiac the only one with a "design flaw"? There are a lot of engines with design flaws. What defines a design flaw? Not being able to handle over a certain hp?

I can name a few blocks that are risky above about 500 hp. Ford small block. They have a closed lifter valley for the most part. Iv`e seen many cracked from the front to the rear lifter valley after being beat on. Ford Cleveland? Weak cyl. walls. At one time, I believe no one made a 060 over forged piston for them. Same for the Chrysler 340.

I`m sure other blocks have "design flaws" too. Like oiling systems. Buick comes to mind. They did last and performed like the engineers` stated purpose. So, what is a design flaw and is Pontiac the only trash engine?

[Formulas]

The chevy 348 / 409 wasn't a grand slam

[TAQuest]

Originally Posted by Formulas

Tom in the engineering world what exactly constitutes a cycle?

Is it when any give part sees 90-100% of rated load? Something like that is what iam after

.

Even if it's less than a cycle there still would be cumulative metal fatigue.

Cycles are just a way to try and quantify it.

[Tom Vaught]

For the engineering durability testing we were doing, (test to the point of failure), we would run the following cycle, (I have posted this in the past).

Some slight variations depending on what we were looking at.

1) Fire the engine up after checking the oil level and the dyno water tower for proper coolant at the correct level.

2) Warm up the engine for 15 minutes at a idle condition. Check for any audible issues as well as monitor the Dyno Operator computer read-outs on the multiple screen displays. If all is good go to step #3.

3) Bring the engine up to the Maximum Torque Point (after determining that point on the specific engine). Run the engine there for 6 hours of steady state running.
Say the number is 4200 rpm. These are smaller engines for the most part.

4) Bring the engine back down to idle rpm for 15 minutes. Listen for issues.
Shut off the engine. Walk into the Dyno Cell and inspect all of the components on the engine visually. Look for water, oil, and fuel leaks.

Typically shift change by then. Afternoon Dyno Guy comes on and gets a briefing on where we are in the testing sequence.

Afternoon Dyno Guy moves to the next step in the sequence. Say it is the Max Torque PLUS 10% higher rpm point.

He repeats the steps above except he does it at the 10% higher rpm point.
Still the engine runs at that point for 6 hours, unless there is an issue.

Morning Dyno guy talks to the Engineer and reads the info from the Afternoon Guys testing. He does not talk to a Midnight Dyno Operator unless it is a Hot Program and we run 24 hours in the day. So Days and Afternoon testing.

The Afternoon Guy comes in, does the same steps again, except he runs 6 hours of Max HP for the engine once he identifies that point for the specific engine.

Day Shift guy comes in and repeats the steps above except now he runs 6 hours of Max HP at a now identified rpm point PLUS 10 PERCENT MORE RPM ADDED.
Obviously the HP point may remain close to the Max HP rpm point or drop with the additional engine rpm. Each engine is different based on the components.
Boosted engines seem to carry the rpm more evenly across the rpm points.

So now you have had 5 Engine Modes on the Dyno:
Idle Rpm, Max Torque Point, Max Torque Point plus 10% additional rpm, Max HP Point, and Max HP Point plus 10% rpm. That is one cycle. Hope that helps.

We have a similar test which is called a 300 HR FIE test. Both of these are ENGINE DYNO TESTS

Some years ago Ford di a little Advertising to prove out the durability of the 3.5L ECOBOOST engine. Videos were made.

Several Marketing Videos were made.
Pull logs up a Logging Camp Trail.
Run the Baja 1000 race.
Pull two vehicles on a single trailer for 24 hours on a NASCAR Track, and then do a tear-down on the same engine which was used in each of the videos.

Not what we did at all. Marketing is different from Test to Failure Dyno Testing.

Marketing Video links are on the web if you look for them.
An example https://news.pickuptrucks.com/2011/0...ooks-like.html

Your question was what is a cycle of testing. We have run engines 2800 hours on the dyno before failure.

Hope I answered that question for you. (usually the poor connecting rods would finally take out the engine.)

Tom V.

[Formulas]

Tom. .. Was looking for a simpler answer really and maybe there is none


No car parts no running assemblies take a length of rod simple steel say 4 inch long let's say you put tension on it and it elongates and breaks at 10,000 lbs after you establish that,

Let's say at 8,000 lbs there is no permanent elongation call that a max working load ?
Iam sure if you take it repeatedly to 7,999 lbs each time that would be a fatigue cycle

Now in the extreme other direction you put 10 grams of pull on it is that a cycle? I wouldn't think so.

At which point in applying force could you chalk it up as a cycle?


.

[Tom Vaught]

A cycle is a period of load testing at a given test condition (in my example).

A combustion cycle would be TWO rod cycles: Intake and compression on one rod cycle and combustion and exhaust on the second rod cycle. Depending on the rpm these cycles change in duration vs the time (a minute) involved. (If I have my wording correct now).

The people from the University of Toledo (Toledo, Ohio) do a nice job of explaining it here. What things we are looking for.

https://pdfs.semanticscholar.org/1ab...93b59eb742.pdf

Tom V.

You can have all kinds of computer analysis performed but at some point you need to verify that the models are correct vs actual dyno testing.

[Douglas Willinger]

How many people encountered a Pontiac V-8 with broken lifter bosses, prior to encountering Pontiac's style, etc.?

[maxpowerta]

Originally Posted by 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.

There was Finnigans firebird episode as well, which i think he has now sold to his brother.

[Tom Vaught]

Originally Posted by Douglas Willinger

How many people encountered a Pontiac V-8 with broken lifter bosses, prior to encountering Pontiac's style, etc.?

If I understand your question correctly, I started playing with Pontiacs in 1965.

I first encountered a Broken Lifter Boss with Jim Brady, (a former Pontiac 64 GTO Racer) when he decided to get aggressive on the camshaft .200 lift vs duration specs on his Roller Camshaft.

Prior to that he had a Roy McKenny selected Comp Cams profile and the engine made great power with durability.
He put this other camshaft in at the recommendation of one of the Tech Guys and broke the lifter boss off the block shortly after the installation.

He got another block and had the Butler Lifter Bore "Plates" brazed into the block. No more issues after that work was done. Different Camshaft and lifter profile though. LOL!

Tom V.

[Sirrotica]

When I worked at the local Pontiac dealer in 1970 there was a RA IV block in the warranty pile that had a broken lifter bore in it. What I don't know is if the bore broke out with the hydraulic camshaft in it, or if it had the cam changed before the bore broke out of the block, and then they put the OEM cam and lifters back in to get it warrantied.

The guy that changed the fitted block out said it had the factory cam in it when it came in on the hook.

They had already put a sledge hammer through the water jacket, so it was completely scrap when I saw it. For anyone that isn't familiar with GM warranty, all warranty engines at that time were smacked with a sledge hammer while the factory rep was present to make certain the engine couldn't be used or sold after GM paid the warranty claim on it. In that case it was redundant with the lifter bore broken already.

Since seeing that lifter bore broken I have never seen another one broken, even though I used a solid roller cam in a few of my own engines without any bracing. Two 400s and a 455. The advertised spec on the cam was 320 degrees, by .525 lift, surely a mild cam by todays standards, but when I bought it used I was told the engine it came out of was a 60s era FED. I have no idea if there was any truth to that, or not. The 320 degrees advertised duration put the power band way up there, and it came with a rev kit.

Later I had it re-ground by Crower, somewhere in the 280 degree range, where it was much more streetable, especially behind a T400 with 4.33 gears. The first car it was in with 320 degrees of duration was a 65 GTO, 4 speed with a 3.90 axle. It would run 6500 no problem, until a keeper split and dropped a valve.

[tom s]

Since 1962 I have ever broken a lifter bore BUT never ran a cam with 200 duration at 200 lift or more.Tom

[Sirrotica]

Tom, I have no idea of what the lift was at .050. Back then all we worried about was advertised duration at the base circle of the cam. The cam cards are long gone so it would only be a educated guess to what Crower ground back then.

I still remember the grind number, it was 100R, but it's gone from the Crower online info now. I suppose if I called them they might still have the specs available. I do know it pretty lazy until you hit 3000 RPM, and then it pulled like a freight train.

[Dick Boneske]

I've read most of the 93 posts on this thread. I didn't see anything about the most obvious design flaw of the Pontiac V8, the timing chain. Beginning with my '64 GTO purchased new, jumped a tooth and needed changing after 60,000 miles. I've had a total of five timing chain failures with my Pontiacs. I can remember three of them failed while driving and wee changed along the roadway. Those three were 400's in a '69 Executive wagon, '73 Grand Safari wagon, and a '76 Grand Safari wagon, all stock. Failures occurred between 50,000 and 70,000 miles. Most of the engines were lubed with conventional oil, but at least two, the '73 and '76 used Amsoil..

Of the other 20+ Pontiac engines I've owned, no other timing chains failed, but I replaced them soon after 50,000 miles as a preventive measure.

The other common design problem with Pontiac V8's is the rear main seal. I've had leakage on every Pontiac I've owned except my '67 Firebird 400 which I sold with 6,000 miles on it. The BOP lip seal works much better than the factory rope seal, from my experience. .

I've owned two Buick Roadmaster Wagons with 350 SBC's. One went 185,000 miles before engine replacement due to bearing noise, the current one, a '95 LT1, is at 175,000 miles with no timing chain or rear main leaks.

For anyone who cares, here is a list of cars I've owned. The only ones purchased new were the '64 GTO, '67 Firebird, 2000 Bonneville, 2004 GTO, 2007 GP GXP, 2009 Buick Enclave, and 2014 Chev SS:

1957 Olds Super 88--J2 three carbs--fun! Bought from parents 1962
1964 GTO Tripower 389--lots of drag racing--12.70, 109.75 mph
1964 GTO Tripower My current GTO. Restoration 04-1987 to 07-2011.
1964 GTO w/o engine. Never restored it.
1963 Volkswagon Beetle--a serious mistake POS car
1967 Firebird--400 V8
1968 Firebird--400 V8 Ram Air II—had correct block, but heads had been swapped for #16 heads—Should have kept and found heads
1962 Bonneville coupe--great cruiser and tow car for the GTO
1962 Grand Prix--factory air, Tripower--favorite all time car
1962 Grand Prix--daily driver---bought it for options transferred to the other '62 (said to be Vince Lombardi’s when new)
1963 Bonneville Convertible—removed am/fm and junked
1969 Pontiac Executive Wagon
1969 GTO—Repo bought from credit union. Painted & sold
1970 GTO--455 factory V8-TH400
1970 Firebird Formula 350 engine and hood scoops
1973 Pontiac Grand Safari Wagon
1973 Grand Safari Convertible---fun until I sold it
1973 Grandville. 455 went into my ’76 and ’77 wagons.
1976 Pontiac Grand Safari Wagon—Replaced tired 400 with ’73 455
1977 Pontiac Grand Safari-Big Red!! Swapped a ’73 455 from my ’76 wagon. 245,000 miles!
1979 Bonneville Coupe—301 good mileage, but POS engine
1988 GMC 2500 Conversion Van
1988 Pontiac Sunbird Convertible
1988 Pontiac Grand Safari Wagon
1993 Buick Roadmaster Wagon- 25 mpg! Sold 1/13 w/235,000 miles
1997 Pontiac Bonneville
2000 Pontiac Bonneville SSei--loved the power and heads-up display
2004 Pontiac GTO---Best GTO
2007 Grand Prix GXP--V8 28 mpg!!
2009 Enclave SUV—bought new—quietest vehicle I’ve owned.
1995 Buick Roadmaster Wagon LT-1 bought 10/2012 w/78,000 miles
1996 Buick Roadmaster Wagon bought with 34,000 miles in 2014—sold at $15,000
2014 Chevrolet SS Sedan---First Chevrolet ever. Fastest car I’ve owned, best handling car I’ve owned. 25 mpg, but not drivable in winter.
2008 Grand Prix GXP---Our winter beater bought in 2017. Fun car!

[Skip Fix]

Originally Posted by Formulas

The chevy 348 / 409 wasn't a grand slam

Hey now!

[TCSGTO]

Just caught the newest episode where they rescue a 71 T-37 with a 1970 400/4barrel that hadn’t run since the 80’s from a scrap yard in Idaho and road trip it to The Snake River canyon.
Frieburger even said it was the best rescue car they ever had. Very Pontiac friendly show. They even have a HEMI cut down at the end.

[Formulas]

I would like to make a prediction

The flawed Pontiac engine will be here longer than Friedbugger and his show

.

[Marv]

Freiburger has worked in automotive media since 1991. He isn't going anywhere any time soon.

[Tom Vaught]

Freiburger's time as a magazine writer is small potatoes compared to a Pontiac Guy like Don Keefe.

Tom V.