Chevy powdered metal rods

[Casper393W]

I know this is a little off topic.... But I have always been heavily involved in racing Ford's modular engines... I have seen there PM rod progress over the years... Back in the late '90's if you pushed the rods over 450rwhp you were living on borrowed time!! (They would snap mid beam) I was surprised to see how much they would actually bend! I had one customer who made close to 700 but it was a Dyno Queen and it had a super conservative tune and he never "Got on it" The newer rods offered in the 5.0 coyote engine are much stronger! People are pushing 800+ to the wheels with Boss 302 rods...

My point for all of this... newer PM rods will take some serious abuse! I also like them due to how consistent the weight is between them. I think the PM rods have a good future ahead of them.. just my 2 cents....

[mag2555]

Smacking a powered metal rod on its side in a vise with a big hammer is introduceing a force into the rod that it will never see unless the Crank and or a cylinder wall gives out first!

[GARY C]

Smacking a powered metal rod on its side in a vise with a big hammer is introduceing a force into the rod that it will never see unless the Crank and or a cylinder wall gives out first!

Yes thats kind of like running an F1 car into the wall to prove how weak their carbon fiber suspension is.

[pdq67]

Maybe a little off topic but years ago when I was a GTO owner and Pontiac fan the Pontiac 389 and 400 motors had what most thought an "ideal" rod/stroke ratio of 1.8.  Don't know how that claim came from but for some reason the Pontiac 389/400 motors where designed with long rods.  Cadillacs where even longer though I can't recall those lengths and would have to look them up.  Some more trivia is those long rods where cast iron.  Yes cast iron - not forged.  And what the major cause for rod failure in the Pontiac was the weak stock rod bolt - not the rod.  Again I don't know the how they got that information on rods but Peterson and Johnny Angles wrote about it.  Well forged Pontiac rods where pretty expensive in those days so the common practice was to recondition the cast rod but install better bolts.  All that left me with the impression its not worth the experience in street motor to spend for fancy forged rods.

If not mistaken, Pontiac called it,"Armasteel".

From this... https://www.thefreelibrary.com/Q+What+i ... 0175286114

" However, confusion about the nature of this material has recently emerged in the casting community. Much of this results from GM's marketing efforts to apply a certain mystique to standard engineering materials. First, Armasteel is not steel but a GM trade name for a grade of pearlitic malleable cast iron. As a 1982 GM brochure explains, it is a ferrous alloy with temper carbon in a matrix of tempered pearlite or tempered martensite. It was produced at the GM Central Foundry Saginaw Malleable Iron plant (SMI), which was closed in mid-2007. "

pdq67

[PackardV8]

Positive features of powdered metal rods is they're all the same center-to-center length and all the big ends are round and they all weigh the same.

Pull a set of well-used rods from a '60s-'90s SBC. They'll most likely have eight different C/C lengths and the big ends aren't round and on size. To get them back in spec top-to-bottom of the big end bore, the parting lines will then be off. Then to balance them there will usually be grinding on both top and bottom to get them within one gram.

[pdq67]

Smacking a powered metal rod on its side in a vise with a big hammer is introduceing a force into the rod that it will never see unless the Crank and or a cylinder wall gives out first!

It is only indicative of rod material, "Toughness"! And right, it is not a true engine part test!

But it sure illustrates if a rod will bend or break, imho. And I know PM rods have come a long way but I will install forged rods.

pdq67

[rfoll]

The reason I asked in my first post was to determine what parts would be in an engine I was considering. Turned out the guy didn't really know what year he had, same old mid 70"s junk. I have a set of rods and pistons from a low mile Vortec 350 I am going to use in my current build. When I dropped rod and piston assemblies on the scale, the differences high to low are less than 2 grams. This build is going to clear a bunch of junk from the shelves. I had a low mile block that only need a hone. I am using a pair of 305 boat motor screw port heads with 1.84 valves and 58 cc chambers. Static CR comes out to 9.27:1. The cam is the 204/214 rv grind I have had for over 10 years. As this is a low rpm application, (2.73 gears), I am going to use the SP-2P manifold I have no other use for. The out of pocket cost is the set of 1.5 mm piston rings. It should make all the power I need, hopefully it will get decent economy.

[Krooser]

I love low $$$ builds from on the shelf parts... It's how most of us started before we knew "better"...

[rfoll]

This engine goes into a 79 El Camino. The rebuilt 3.8 Buick V6 had been mis-tuned, and beat up the valves. It was salvageable, actually in nice shape but for 3 exhaust valves, but when I measured the deck the pistons were .080" in the hole. It makes me wonder if the pistons were for a short deck 3800 or something like that. I gave it up.

[Carnut1]

I would not use the spdp manifold for anything.

[Tuner]

This engine goes into a 79 El Camino. The rebuilt 3.8 Buick V6 had been mis-tuned, and beat up the valves. It was salvageable, actually in nice shape but for 3 exhaust valves, but when I measured the deck the pistons were .080" in the hole. It makes me wonder if the pistons were for a short deck 3800 or something like that. I gave it up.

If the three valves were in the same cylinder head the distributor has the wrong magnetic pickup for the timing of the crank (even fire, odd fire, semi-even fire, semi-odd fire, arrrrgh) or the plug wires were on the wrong terminal in the cap. Either scenario advances the timing on the 2-4-6 side of the engine the amount of the crank pin offset. Plug wires on the wrong cap terminal advances spark timing 30 deg in 2-4-6 in a 90 deg. V-6.

[Tuner]

The reason I asked in my first post was to determine what parts would be in an engine I was considering. Turned out the guy didn't really know what year he had, same old mid 70"s junk. I have a set of rods and pistons from a low mile Vortec 350 I am going to use in my current build. When I dropped rod and piston assemblies on the scale, the differences high to low are less than 2 grams. This build is going to clear a bunch of junk from the shelves. I had a low mile block that only need a hone. I am using a pair of 305 boat motor screw port heads with 1.84 valves and 58 cc chambers. Static CR comes out to 9.27:1. The cam is the 204/214 rv grind I have had for over 10 years. As this is a low rpm application, (2.73 gears), I am going to use the SP-2P manifold I have no other use for. The out of pocket cost is the set of 1.5 mm piston rings. It should make all the power I need, hopefully it will get decent economy.

The screw port heads use no more than 25 deg. total timing but still need the same initial as "normal" for the cam timing, so you need to have a short mechanical advance curve. With the 204/214, 12 initial, start 1000 RPM, total 25 at 2500~~3000 or so. The screw heads are really-really-really "fast burn" heads and will not tolerate more than 25.

The SP-2P intake will work OK but if you play with the carb jetting will you will find the jet size may fall outside the "normal" range for the carb you are using. The unusual carb jetting may be why some people had bad experiences with them. I recall tuning a stock 350 with one on it that required a jet and metering rod combination in the QJet that would have been ridiculously rich on the stock intake. Another one with a 600 Holley, small cam and headers, went the other way, unusually small jet size. Go figure. Ain't we lucky jets are threaded.

[rfoll]

The 3.8 had ridiculously advanced timing, something in excess of 30 degrees initial, we could only see that far, plus mechanical and vacuum. It would hardly crank over. Also, the exhaust from the drivers side crosses under the engine and joins up with the passenger side in the right side manifold. The rod bearings were pretty beat up also. Thanks for the tip on the screw port timing, I don't want it to detonate. The QJ I was planning to use was rich enough that I had to bottom out the APT screw to get it to 14:1 on my truck, so maybe it will be the right one. I will weld an O2 bung into the collector just in case.

[Truckedup]

Screw port head? what's the casting number

[rfoll]

14102187. The date code comes out to Nov '86, one of the earliest versions. They are a heavy casting with center bolt valve covers and 72 degree bolt angle on the center 2 intake side.