[WARPed]

The cat 5140 (and their derivatives) is the way to go with any kind of performance in mind over the stock rods. With that said they should be given a once over (like any part) to make sure everything is, as it should.


And as stated above the Asia products are EVERYWHERE in our American lives.

Chinese Naysayers Should Read This Post

[azbirds]

WARPed, that doesn't mean we have to like it. :-} Those darned Unions made it to expensive to do anything in this country.

[Goat4three]

that's an interesting sentiment. i think (i could be wrong) my GTO was built by union labor.

[Z Code 400]

There is a lot of debate on this topic and I believe the stock rods get blamed for a lot of operator/machinist error(s) overall.

I have seen several 400's and 455's with Eagle, Crower and SD Rods blown through the pan and we are talking street motors without nitrous. The historical Pontiac problem of spinning rod bearings has a deeper cause than the material the connecting rods are made out of.

A former business partner of mine has a 455 SD Firebird and the engine was built by a very well know firm, not Fulper either, but you would immediately recognize the name. He put 11,000 miles on the car when it developed a knock. He shipped the engine back to the builder who told him he has lost the #1 and #2 rod bearings.

The builder told him he would need to upgrade to Crower rods since this was a 'common problem' with stock rods. That statement is utterly ridiculous. The 'problem' in this case is poor assembly/machine work.

When I built my 400, I went through several sets of stock cast rods until I found 8 of them that weighed almost exactly the same. I then polished the beams, cut the beams/caps, installed new rod bolts, balanced them all to the weight of the lightest rod and honed them to the low side of the tolerance.

Total investment: $50.00 for a set of aftermarket rod bolts. I do ALL my own machine work.

Based on my observations of many Pontiac blocks, I have found the biggest weakness is the block's ability to maintain cocentrcity of the mian bearing bores.

First of all, the main caps are quite thin (narrow) for such a large journal diameter and the front of the crank is unsupported. This is why so many Pontiac blocks I see have out-of-round main bearing bores, especially the #1 journal.

If the journal bore is out-of-round, it will act to 'pinch off' the oil supply to the rods. This is why the 3/4 groove main bearings are so effective as they 'extend' the period of time the rods are exposed to oil pressure.

While a Crower, SD or Eagle Rod is a nice piece, I have seen 389's spun well past 6000 for years with no problems, so the Armasteel Rods are doing their jobs.

I have also listened to the ridiculous theory that the #1 and #2 rod bearings fail because they are "the last ones to get oil pressure." Obviously, this person is unfamiliar with Pascal's Law. No point in a pressurized passage will receive pressure until all points are pressurized. However, the flow of a fluid can be interupted by restriction(s) which can result in bearing failure.

In my opinion and assuming you have a competent machinist, stock rods are fine to 6000 rpm in a 'detonation-free' engine...Robert

[firechicken]

Well said Robert and I totally agree.

[P@blo]

I would agree.......Guy's reving these motors past the intended RPM usage is I bet what contributed to alot of the bad rap on the Pontiac rods......

[Bad Karma]

Originally Posted by azbirds

WARPed, that doesn't mean we have to like it. :-} Those darned Unions made it to expensive to do anything in this country.

Aint the union's its the greedy corporations that ruined our economy. They are the ones who go outside the country for labor and materials thus further degenerating our economic status.
Res Ipsa loquitur!

[P@blo]

Nice signature Karma.......

[form406]

like a mentioned in my earlier post my buddy had a butler 455 with stock rods that he ran juice on up to 6500rpm's with no problems...

[WARIARGTO]

I posted this pic a few years ago, but I think it's appropriate. This is what happened the last time I used cast rods. These were resized inside a balanced motor with good bolts. Through the traps at 110MPH I got a shudder in the drivetrain...FWIW, I would recommend a good set of AMERICAN made rods- Crower or Childs and Albert. I'd leave the chinese stuff on the table. You may pay a little more, but at least you're doing the right thing supporting your country instead of the chinese economy.

[WARIARGTO]

Although, re-reading your original post, if all you're doing is a stock rebuild on a 400, maybe just go with the cast rods resized with good bolts. As long as you're under 5K rpm and not making any real power(<400HP) you shoudn't have any problems. I do have a stock cast rod 455 tripower in my other 65 GTO that was dragstrip thrashed for several years while in my blue 65 making just 400HP and not taking it past 5K.

[Cliff Ruggles]

Stock cast rods are incredibly strong and stable parts....right up to the point where they BREAK! This happens without warning and usually takes the whole engine with it. Ya, ya, I know, scores of folks running 10's with well prepared cast rods, here it all the time. Some things to ponder on:

About 15 years ago we encountered another racer at a local track. He had a beautiful early GTO, Nash 5 speed, RAIV heads and used an old solid cam. The car ran well into the 10's and he spun the engine well past 6000rpm's. At the time I was amazed, so we got on the discussion of engine durabilty.

He said that they shot peened, magged, polished, resized and installed new bolts in factory cast rods.....they snapped like twigs on the very FIRST run!

The next effort involved rebuilding an early set of SD forged rods with correct heat treating, etc, etc, bent them into "S's" on the FIRST run!

Ordered custom Crower billet rods and they ran season after season without any issues. At the time the only real trouble he was having was keeping a rope seal in the 400 engine.

For what it's worth, back in the 70's when I was in high school lots of us had "Muscle Cars", mostly Mopar's and Chevy's. The few who ran Pontiac's were constantly scouring the salvage yards for spare engines. We catagorized the Pontiac engines for having "soft" internals, so we avoided them at all costs.

30 years later, I have no doubt that the cast rods were the death sentence of so many of these engines. Of course non of us back then even looked at the tach when doing "donuts" in the high school parking lot at FULL throttle or during grudge races on the street. One very close friend of mine went through about a half dozen Pontiac 400 engines in less than two years....he was a barbarian behind the wheel and his foot was constantly pushing a hole in the floor board!

For what it's worth and my opinion, complete waste of time to bead blast, shot peen, polish, resize, good bolts, balance, etc a set of cast rods these days when you can buy good forged rods at reasonable prices that are many times than the cast rods would ever be after all the time/expense. If nothing else you will sleep better at night and have much less of a "pucker" factor when you spin your big Injun to past 6000 rpm's if a good set of forged rods are in place!......Cliff

[form406]

hahaha..."pucker"...that what i do when i go over 5300 rpms on my my 406 with 35 year stock old rods ...when you buy asian imports you are supporting our american economy as well cause we are the ones selling them and making the bigger profit...

[Mr. P-Body]

Cliff's assessment is among the more accurate. For every "success" story with cast rods, there are 50 Pontiac engines with air-conditioned pans.

We DO build stock engines with cast rods. Only when the customer won't authorize good ones. Consider that none of these cast rods are under 27 years old, regardless of where they came from. Most are far older. Most have a bazillion up/down cycles and heat/cool cycles on them. Fatigue IS an issue.
As another said, shot-piening and polishing a cast part is a waste of time. Installing new bolts insures the bolts are new. Nothing else.

One guy says he went through "several sets" of cast rods to find a "matched" set. He then sized them himself. They only cost him $50. That is, if his time is worthless. And that had to be a while back, because even stock replacement bolts are higher than $50 for a set (SPS, Pioneer). ARPs are higher, yet.

One of the primary reasons we hear why people cut this corner (don't be fooled, that IS what you're doing) is money. The average rebuild for a performance Pontiac (not "race") runs in the $3-3.5K-plus range. I submit that 10% of that cost going to the weakest link in the chain is money well spent. For a high revver, even 20% would be good. NOTE: Contrary to popular belief, we (engine builders) make MORE money rebuilding your stock rods than we do selling you new steel rods. This is not an opinion, and every professional on this site will agree with that. Of the $200 it costs to do a quality rebuild on the rods, we get to keep $150 or so. Of the $700 a set of Crower Sportsmans or Eagle Pontiacs cost, we get to keep about $120 of that. Do the math. Why would ALL of us recommend steel rods over the stockers, even if it cuts into profit? Because you NEED them, that's why. Cast rods are a failure in process. When and where is all that's left to be determined.

I agree, it isn't the rod material that causes the failure. Bearing trouble causes it. Cast rods are much less "forgiving" than forged rods. A bearing failure with cast rods is a sure explosion. It'll "knock" for a while with a forged rod, giving you warning. Same is true of crankshafts, which is why Chevy guys can't run cast cranks and make any serious power. The Pontiac crank is a whole lot bigger, making it much stronger.

And the SD rods? Great stuff! The 421 units are a tad stronger than the 455s, no matter what they LOOK like (4340 steel is tougher than 5140). Tough to find... in both cases. Unless you already have them, don't plan a "build" around them.

This topic has been beat to death 42 times. These cars are a hobby for most. Hobbies aren't for "saving money". Try to stay focused...

Jim

[Z Code 400]

Just across town, there is a 455 on the stand with a set of Crower I-Beam Rods. It spun the #1 and #2 main bearings and destroyed the crankshaft. We are seeing a lot of this on the local Pontiac scene and it has nothing to do with rod material.

I would not suggest spending more on a set of stock rods than you could buy a new set of Crower's for. That would be ridiculous. In my case, I do my own work, so the stock rods are cheap.

Almost everytime I have seen a rod failure, there was evidence to support a detonation condition, poor/improper assembly, oiling issues or overrevving.

Never, ever saw a problem with a 389 Pontiac. I have built several of those engines over the years (stock restorations) where the owners drove the hell out of them. Never saw a rod failure.

I built one 389 in particular for a gentleman. It was a 1965 GTO body-off restoration done by our shop. When it was done, he really abused this car. About 2 years after delivery, he complained about 1/4 mile performance. I drove down to Bakersfield Raceway and went for a ride with him.

Every shift, he revved the 389 until it would rev no more...the front end of the car would just lay down...and he was burrying the tach. I asked him why he was doing this as I felt the 389 was over and done with past 5300. He felt he was 'getting every last drop' out of the engine and had been driving it like this for two years.

I made a few passes shifting at 5500 and the 1/4 mile times immediately improved.

That engine, built in 1986, is still running and being taken to the drags on a regular basis.

I think a Chinese rod is OK as long as you bake them in an industrial oven for 8 hours at 400°F to stress relieve them. Smokey Yunick used to do this to SBC rods and it is detailed in a few publications. We started doing it on Flathead Ford V8's when I was working for the family business in high school.

Immediately after cooling them natuarlly, I would resize them to the low side of the tolerance.

The answer depends on how much you have to spend and what you intend on doing with the engine. That's just my take on the subject...Robert

[Z Code 400]

Originally Posted by Mr. P-Body

One guy says he went through "several sets" of cast rods to find a "matched" set. He then sized them himself. They only cost him $50. That is, if his time is worthless. And that had to be a while back, because even stock replacement bolts are higher than $50 for a set (SPS, Pioneer). ARPs are higher, yet.

Jim

That 'guy' is me and that's what I did on my 413. I bought a set of Pioneer Performance Rod Bolts from Ken at Re-Power Warehouse here in Visalia for $49.95. We still get a pretty good deal from Ken.

Time??? you must be joking. There is no way you could ever figure in the cost of labor, realistically, on a hobby car. I spent weeks porting and polishing the cylinder heads. My labor is free to me.

I picked (8) rods from several sets to find a group that all weighed nearly the same before balancing. We have done this for years and it works. It makes balancing much easier.

If you have ever balanced anything personally, you will know that sometimes you get a heavy rod that you just cannot bring into spec. Grouping rods into classes by weight is the best approach when you have enough cores.

I have never told anyone in this forum their time or effort was 'worthless' in any way...Robert

[74t/a]

I'm not touching this topic with a ten foot keyboard.

[Jack Gifford]

I've got a ten-foot pole, if you want to "not touch it" with that; it's left over from my last skunk-in-a-trap encounter!

[JSchmitz]

Originally Posted by Cliff Ruggles

. he spun the engine well past 6000rpm's. ......Cliff

There you go. Damn factory rods!

I normally agree with Cliff, Mr.P., etc. I will have to disagree on this one. This guy is buiding a "stock 400". If he plans on spinning it to sane RPM's, I say resize the factory rods with good bolts. They will live a long happy life. Unless, of course, you are going to some cheap dumna$$ engine builder (and there are plenty) who doesn't know how to build a Pontiac. Then maybe you should go with the aftermarket rods.

Originally Posted by Cliff Ruggles

.At the time the only real trouble he was having was keeping a rope seal in the 400 engine.......Cliff

If he couldn't install a rope seal, why would you expect him to keep rods in the pan?

[PONTIAC DUDE]

Originally Posted by 74t/a

I'm not touching this topic with a ten foot keyboard.

Bwhahahahahahahahahahahahahahahahahahahahahahahaha ha.

Awwwwwwwwwwwwwwwwwwwwwwww, come on. LOL.