I know you've all seen these.

(Funny thing...engine with smallest CID has the biggest Rods)

Attached Thumbnails

 

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'84 300SD sold
124.128

And now you know why I drive a Dodge truck...........when not driving a Mercedes car.

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daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
Cluster Needles Paint
New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

why is does the dodge rod have an angled cap? is that a cummins rod?

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'Have to ask the Engineers @ Cummins ?
(It may have something to do with angles of rotation and Max. exerted force)

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'84 300SD sold
124.128

Id rank rod size in order of which Id buy first. Dodge, Ford, Chevy. I wonder if there is a connection?

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1981 300 SD 213k miles "Stock for now"
1999 Super Duty 7.3L 113k miles
1981 300 SD 180k miles "Heavily modified" SOLD

The Ford's rod appears thin.

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1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)

The angled rod cap allows a bigger bearing in a given cylinder bore, (it is a matter of fitting through the cylinder bore) also featured in the old Ferrari 250 ,motor from the fifties and a ford flathead 60 that I happen to know of.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I also drive a Dodge Cummins when not driving my Mercedes.

yeah... I gotta agree, the PS rod looks mealy next to the chebby rod... GOD that Cummins Rod (can't call it a dodge, I just can't...) I have 4 Detroit Diesel (chevy) in my yard... I drive one daily, and love it... just can't stand the stinking transmission.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Yes, I think this is the primary reason. I have certainly heard the other reason given (fitting through the bore). The MGA and MGB engines are examples of the two designs being used with essentially the same bore diameter and rod journal diameter. The non-angled version survived to be used in the later 5-main engines. It is pretty interesting when you can follow developmental trends in an engine design over decades.

I think the angled rods would be optimal with low rpm engines. In high rpm engines the fasteners would come under greater shear forces and the design has inherent stress raisers. Note how the Dodge/Cummins rod is heavily reinforced on the beam section next to the parting line with the upper fastener -- not an accident. This is a common point of failure in the angled MGA/MGB rods under competition use.

it has the smallest CID, but two fewer cyllinders, so it has the MOST stress on each rod of the three.
I think MB could sure use those rods in their 3.5L inline six...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

The only problem with the Dodge is the truck they put around that wonderful engine. Of course, the 24v is a downgrade from the 12.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

When talking about the Cummins, you have to remember that the engine was not originally designed for automotive applications, but for industrial and off-road. Thus the engine is overbuilt for pickup applications.

That by relying on the slanted surface, it is kinda like sloped armour on a tank giving extra thickness for strength?

Regards

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1983 300SD - SPARKY THE DIESEL
2004 Audi TT 3.2 Quattro Roadster
1999 SLK - aka - LIL RED
1956 Chevy Nomad - aka - REAL MAD
1940 Ford dbl dr. Deluxe - aka - ORANGE U GLAD
1998 Kawasaki Nomad bike --

I agree to disagree... I have had the other 2 (GM and Ford brand new). When I bought mine in 2002 I went through numerous nightmares with Ford and Chevy. With the Chevy it was a never ending GM/Isuzu/Duramax "injector" problem. With the Ford it was the transmission. But the "24 valve" Dodge with the 6 speed does the job and does it easily. The other trucks (3500 dually's) struggled pulling the weight. Ford and GM had me waiting for my truck to be repaired and had me in numerous "waiting rooms".

I do agree about the trucks. I love the Ford interior. Plus the sheet metal on both GM and Ford was much better than the Dodge IMO... The Dodge sheet metal dings so easily? Weird... Not sure about the newer ones.

People are very uninformed about the early 24 valve Cummins. All you need to do is fix the lift pump problem, install a fuel pressure gauge and your done. I drive by my EGT gauge when pulling... But that is a different story. If you are refering to the "53 block" problem... Even some of the later 12 valvers were stuck with that mess. Research is involved with buying any new or used vehicle.

We all know the 12 Valve Cummins can make tons of power. But, it is not "where you need it when you need it" like the computer controlled 24 valve. Plus the fuel economy "sucks out loud" when pulling a heavy load. I do miss my 12 valve.... But, I'll stick with the 24 valve.

Edit: I almost forgot... That picture above is VERY misleading! Those pics are of the older GM and Ford rods. The newer Ford rod looks almost like the Cummins and the Duramax rod is even beefier in other locations. There is a newer picture somewhere. The one above is "really old".....

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AJ

1985 300D (SOLD)