early Dodge poly/hemi crankshaft breakage ?

I've heard from quite a few people that the early 241-270 low deck Dodge hemis and poly engines, were prone to crankshaft breakage. There is one old timer who used to race a Dodge D-500 here locally, who said the tall deck Dodge 315-325 was also prone to cranks breaking. Well today I saw it myself, a 325 Dodge Super Red Ram poly engine, vintage 1957, with the crank snout sticking out of front of timing cover at an angle. I haven't pulled the timing cover/oil pan yet, ran out of time, but will tomorrow- I'm expecting it to be broken between #1 and #2 main bearing- because if it was broken further back past #2, the crank snout would not be crooked up front- the front 2 mains would hold it straight.

Anyway, is this a trait of ALL the early Dodge engines 241-325 ? Just wondering if anyone else had this problem.

 

The early Dodge hemis and polys are prone to cracking and breakage due to the lack of a harmonic balancer. Chrysler and DeSoto used balancers but Dodge being the redheaded stepchild within the corporate family got the short end of the stick.

 

Your not alone with this Problem !!

DeSoto's are prone to it also, I understand the reason for it is the Fillit area where the Rod Bearing suface meets the throw is at a sharp angle & they tend to crack.

Some are small & dont detract from the strength, But they also crack in a Circle at the Fillit and those are the ones to watch for.

Just had a 330 DeSoto checked & it was cracke in 2 spots, Have had a cople others the same.. & my Old Race 291 had 7 cracks

 

I broke the crank in a later model LA 318 once. Was a lot of fun just before it made that funny noise and through the fan belt off. Pulled to the side of the road and could slip the belt back on just by lifting on the end of the crank. Ooops! Gene

 

ouch- looks like I'm going to cross early Dodge and DeSoto motors off my "to do" list- and stick with the early Chrysler hemis 331-354-392

thanks for info guys

 

Balancer? Internally balanced. Some did have a torsion damper though. Forged steel crank and rolled fillets on the journals ,same deal with the bigger brothers. Oiling?

 

The way I understand it: the generic term is "harmonic balancer" but it's really there to absorb harmonics first/foremost- not to balance the engine. Some OEM's had external balancing, meaning the harmonic damper and flexplate/flywheel had weight offsets to balance the rotator and contriibute to total engine balance, like crank counterweights do. Other dampers are "zero balanced" meaning they don't contribute to engine balance at all, just absorb harmonics- i.e. engine is then "internally balanced" as you stated.

Breaking a crankshaft is a real bummer- can a larger damper be retrofitted on the Dodge V-8, from another engine ?

 

HH has them!

 

Hot Heads has a retrofit balancer for Dodge poly/hemi V-8 ?

well that's good news

now, who has a 325 crankshaft that's not bent, cracked, or broken ?

I got a SECOND 325 and the crank won't turn, I think it's bent.

 

SCROUNGER:

I know where two or three 57 325 poly's are in a yard... if they are not crushed by now. Cost is $250 per engine, but they are about 175 miles away... PM me if you are interested. Where are you located at? The yard owner won't disassemble them but I could since I am on good terms with him.

 

Anyone got a junk/broken/scrap 241/270/315/325/291/330/341/345/301/331/354/392 crank available for free? I am after the eight-bolt flywheel end to make a fixture out of instead of starting completely from scratch... Located near the Midwest is a plus.

 

Fixture? I've free hand tapped my cranks w/o a problem.

 

hmmm...by the time I buy the crank and ship it, it would cost me $350, a bit high- I may scrap the project first, and just build a Chrysler early hemi instead

 

Do you want to make a fixture so all can be tapped with one shot? I would make a drill template from a plate bolted to a flywheel. Enlarge the holes and tap away. All should be done on a mill.

 

you can have this one for shipping cost plus $10 for box/time/tape/label/marker/gas/paypal fee if you want it

some engineer went to 6 years of mechanical engineering school, to help design this engine, and put a forged crank/rods in a Dodge V-8...

just so someone else could decide, to leave out the f-ing balancer, to save costs...

what a stupid thing to do, frigged up a really good motor design

 

It's odd that this information has not hit the internet boards in force before. I found this on Allpar, which goes along with what you are saying. Gut intuition tells me, the reason most Dodge polys/hemis were in the junkyard, was because they have a bent, broken, or cracked crankshaft- come to think of it, I never saw any early Dodge poly/hemi cars running around, compared to Olds-Chevy-Ford-Pontiac-Buick. There's very few running Red Rams or Super Red Rams around, actually I can't ever remember seeing a single one at a car show ! And I've only seen ONE poly, a 1955 Red Ram 270, that actually runs, and it's a low mileage car w/70,000 on clock. This may explain why.

Anyone else have anything to add to this, i.e. had one break on them ?

http://www.allpar.com/mopar/redram.html

"The weakest part of the V8 engine is the crankshaft. Even though the cranks are forgings, they are prone to breakage. Mine broke between the number four main bearing journal and the number seven and eight connecting rod journal. I know of at least seven other 55 Dodge owners who have experienced similar problems. My car, however, gave me a warning of impending trouble with low oil pressure. There were no "funny" noises until it cut loose, and then there were plenty of new audio sensations. So watch that oil pressure gauge and believe what it says. The crank looks structurally sound; I believe that the trouble is in the Dodge bearing materials. A good aftermarket bearing should be used during a rebuild. The cranks can be welded back together and made into interesting lamps."

 

I've also read that the sharp angle is main reason for these cranks to fail. The 241/270 is reputed to be more fragile. The recommended preventative measure is to weld the fillit and then turn the crank. This is particularly applicable to performance applications.
However as you read in the Allpar article they can fail under normal conditions although that author believes that bearing materials are responsible. That's easily remedied. Faithful attention to oil cleanliness and pressure is important. I'd be interested to know if chamfering the oil holes helps as well as any recommendations to improve oil galleys.

I just spun a bearing on a 315 and will be interested in what I find when I get it apart.

 

I have my doubts about the bearing material explanation- yes I've read that on the net elsewhere too. If a bearing is soft, it will simply wear faster and oil pressure will drop, then it will start making noise, i.e. bearing knock. I've disassemlbed/rebuilt Ford small blocks that had bearings that were down to the copper, with 3 lbs. oil pressure. The engines still ran fine and didn't break cranks or crack cranks, but they had balancers OEM. The early Dodge engine not having a harmonic balancer seems to be the main culprit- remove the balancer from any engine and drive it long enough, the crankshaft will break. What was Dodge thinking ?

Your 315-best have that crank shot peened/magged and looked at very closely for cracks. I did a search for 315/325 cranks for sale, not a single one on the entire net to be found- so far. Methinks they are all grenaded !

Do you have a spare 315/325 crankshaft you want to part with ? I either have to find one fast, or scrap the Dodge project, and concentrate only on the early Chrysler.

 

Thanks, everyone. Need to add this warning to my future booklet update!!
Anyone know of damper interchanges from other Mopars that fit the Dodge and DeSoto engines?
Do all poly "A" engines (277, 318, etc.) have dampers, and if not can the later 318 poly fit?
If I use this info you will be credited as the source.

 

I have a 241 in my roadster with 100,000 plus on it. Rebuilt it in 84. No balancer but I have one I am going to put on it. The 318 balancers fit except for the key. I believe someone (triwaters?)makes a stepped key to solve the problem.

 

Apparently the 318 Poly just uses a hub instead of a damper.

 

318 Polys had no balancers up to 61. From 62 on they had balancers and aluminium 727's.Correct me if I am wrong but I think that balancers from the later LA engines will fit on the earlier 318's and they may require the stepped key for other models.

 

Correct. Just use a late balancer and work out the key problem

 

hey Panic, instead of combing message boards to glean information from guys like us, who actually take these engines apart and rebuild them, why don't you f-ing TAKE ONE APART yourself, and build it for once ? Your POLY book is a POS, IMHO. All you did was take Tex Smith's book, and copy it over again, then extrapolate as to what you "weren't sure of". Your POLY "performance book" is a useless piece of toilet paper, IMO. There nearly nothing in it, to justify the $25 cost, and Tex Smith's book now costs even less than yours, and is about 20 times thicker and professionally done, with step by step engine builds.

All YOUR book has, it pictures you LIFTED off other books and the net, and stuck in there. If I see the broken crank picture I took and posted in your book, rest assured, my lawyers will be crawling all over you, like a swarm of killer bees.

i.e., NO, you do NOT have my permission, to include any pictures or posts I put in this thread, in your f-ing book, and if I see it in your book I'll sue your lousy ass.

SECOND, and more terminally, you listed Dodge Hemi heads on Ebay, then kept adjusting the price UPWARDS every time someone emailed you about them, or bid on them. It's guys like you that are a pimple on the ass of hot rodding progress.

 

which 318 balancer fits, the "A" or "LA" ?? or is there no difference ?

I did manage to find an intact 325 crankshaft, the one I thought was bent, in fact had one stuck piston at BDC of bore, making the crank climb out of main saddles like a bent crank would. The other 7 slugs pushed right out with ease, bores looked good, but this one piston somehow had corrosion all around top 2 rings and stuck. Had to destroy piston to get it out, after cleaning main bearings and crank, dropped crank on bearings, it spun like greased lightning.

this engine was in amazing good shape, can't believe someone junked it like this, it looks like it was rebuilt at one time, this one came out of a '57 Desoto, block code KD5 325 CID

 

This is the master engineer who asked me "is the Desoto hemi and Dodge hemi the same block?" (and much other high school level stuff) before getting the booklet - but now he "already knew all that".
He was a mechanic for 12 years?
Me, too - in 1974. That was a while ago - I do more complex things now.
What have you done since? You... sell used Ford steering columns. Perhaps that's the best you can do, keeps you from ruining someone's motor.

"Practically everything else in your book, is online for free"
Would you mind showing us exactly where the information is already available?
Not Wikipedia - except the stuff I wrote for them.
Not All-Par - they still haven't corrected the material they have to include my data.
The huge number of errors in the Tex Smith book (and absolutely no speed parts for the poly - the 318 chapter is Smith watching someone else rebuild a stock engine) was what caused me to write the booklet in the first place. But, of course, you already knew that...
He declined my offer to return the booklet for a full refund, and instead offered me a choice: either give him some of the money back, or he would (falsely) claim a charge-back on his credit card which would cost me lots of money.
What a nice guy! Perhaps that's why he already has lawyers?
After I didn't respond, he favored me with 15 long, withering personal attacks by e-mail (much like here) loudly proclaiming his ignorance of how engines function. Towards the end, he let the reason slip: he made me a low-ball offer for a set of heads I had for sale. I declined, and sold them off-line.

For those age 12 and under: here's how commerce works:
1. I describe the product
2. you read the description
3. if you want this information, you buy it
4. if not, you don't
5. if you want to know more, you ask
6. if you don't ask, but buy it hoping that it contains information that I do not claim, and then complain that I cheated you - you're an idiot.

 

Want to know WHY those cranks broke sometimes?

It is called TORSIONAL VIBRATION. Torsional vibrations are a rotational vibration that at most times cannot be felt. Think of a shaft rotating in a jerky motion instead of rotating at a smooth, even speed. Not to be confused with linear vibrations that we can sometimes see and the human body is good at feeling. Sometimes the effects of torsional vibrations can be heard though - sometimes as "gear rattle", and sometimes as a "ringing" sound. For example - put a stick-shift vehicle in high gear at 750RPM and you might be able to cause (and hear) gear rattle at full throttle - the sound I am referring to is clearly not engine pinging, but rather sounds as if the driveshaft is "ringing". Torsional vibrations are greatest at certain speeds and are dependant on the system's mass elastic characteristics (i.e. torsional "stiffness"). At other speeds, torsional vibrations may be negligible. Most torsional vibrations are caused by the engine's firing pulses, but they can be from other sources as well. The engine's flywheel mass helps to dampen torsional vibrations after the engine (transmission, driveshaft, axle, etc), but not within the engine crankshaft. Torque converters are also good for absorbing them without passing them on down the line. Torsional vibrations can cause otherwise unexplainable failures in components, as some parts get "wound up" and "unwound" many times per revolution. Whether parts fail or not depends on whether or not the system spent enough time at those critical speeds, as the number of fatigue cylces can add up unbelievably quick.

The aggrivating part is that Chrysler Corp engineering already knew all about torsional vibrations 30 years earlier when he (Walter P. Chrysler) started in 1928. He immediately hired the three engineers Zeder, Breer and Skelton who worked the bugs out of the 6-cylinder engine their previous employer (Studebaker) was producing - including loud "ringing" sounds (from the engine crankshaft) at certain speeds and unexplainable crankshaft and bearing failures. That was sometime around 1916-1918. When Walter P. hired those guys and charged them with building a new 6-cylinder engine for Chrysler, it was by no accident their engine was better from day one... They applied all of their experience learned at Studebaker. If you get a chance, read the book "The Birth of Chrysler Corporation and Its Engineering Legacy" it is extremely interesting.

Why Dodge engines did not get a damper is beyond me. I speculate it was omitted to save cost. Keep in mind Dodge was lower priced than Chrysler or Desoto.

My $.02 ...

 

Excellent description. I agree - they spent a lot of money to down-scale the hemi to make the 241, and I would guess that the accountants over-rode the engineers to save $10. on a damper - and they ate the damage.

I'm surprised that the Dodge 315/325 and small DeSotos are also prone to this - all the reports I've seen attributed the 241/259/270 failures to small rod journals (which I took to mean lack of crank stiffness - which increases vibration damage). The 241 rod journal is smaller than any comparable V8 at 1.9375" and it's the only one I can find that small (everything else begins at 2.00", the DeSoto 276/291 is 2.0625"; both high deck motors are 2.25" - big even by modern standards for such low power).

In addition to (obvious) Magnaflux etc. of a used crank, I would consider cryo treatment to try to normalize any stress built up through mileage.
I would guess that any damper that can be made to fit (even if not Chrysler) is better than none, and one from another V8 will be "tuned" for similar range of vibration (different from an in-line 6) and RPM range.
If adapting one, it should be as close to the front cap as possible to minimize overhang. Far easier to make up offset pulleys than re-manufacture a damper.

 

Here are three photos of a 330 Desoto crank.

 

That's some scary shite - when you consider that's one of the engines where the crank got no prep whatever to run the salt on nitro "back in the day".
Any chance that it's a fillet radius problem (sharp corner) confined to only a certain time period or forging number?