Many Crankshaft Questions

[Joe Camper]

Hello I'm looking for a source for either a NEW FORGED crank or a rotating assembly with a forged crank and up to now all I get is " currently out of stock"

not interested in stroker stuff

This leads me to my next question.

First Some background here. I have 3 LA small blocks. 1 is a number's matching 318, and 4 speed in 69 Barracuda Fastback.

I have also acquired a 1968 340 engine that I know the history of. It came out of a 68 dart. GTS. Although It has had A solid lifter cam and a set of adjustable rockers off a 273 put on and the intake is not original the heads have never been off and the bottom end has never been taken apart.

so both of these engines have forged crankshafts but they're different.

i know this because I also have
a few other parts that include
a forged crank from a 318 and a forged crank from a 340 (pre 70). Some of the journals on1 crank r hollow the other journals r all solid.

it's also my understanding the 318 forged crank is ballanced different and based on what I'm seeing with these pieces I. Assume that to be the case.


what is the correct harmonic balancer. And how do you identify it for a pre1970 318 with a forged crank that is externally ballanced.

also, when an engine is externally balanced, is it all done with the ballancer or is a flywheel or torque converter also involved in balance????

Also where is a good supplier or source for ballancers.

I purchased the car with all the original numbers matching stuff. However, it was rebuilt by I don't know who. It sounded amazing, ran, really healthy.
No oil consumption no smoke. I've owned it for over a year. Have done a lot shaking gremlins out of it, drive it every day, if it's not snowing. I never took it over 5000 R. PM, I'm a retired truck driver. I like to hammer it low in the rpms. And besides that I knew right out of the box. Although it sounded really good, it wasn't right. It just didn't have it and I didn't want to hurt it. It would pull like a freight train to about 4000 but struggle from there up very odd. On one such jount, it spun a rod bearing and I can't help but wonder what the crank shaft it has and what balancer it has. I haven't taken it apart yet and I'm trying to educate myself and get my ducks in line for eventually in the Spring when I do. I think possibly the crank shaft that's in It is not mated to the correct harbonnic balancer???
But that's a pure guess on my part.

the image is my 68 motor this spring after I remove the 318 and repair it the 340 is going in and the 318 will go in preservation.

sorry for the long-winded post. But does anybody know if there is a difference in the volume that flows between the pre1970 cast waterpumps and the newer style aluminum pumps. The guy who built the 318 changed it to the newer style and I I'm changing everything back the way. It should be the time in cover the water pump the radiator. Right now it never even comes close to overheating. Or getting hot even on a hot day in traffic. And it would be really disappointing to find out that those older style water pumps aren't as good. Or r they.

thanks for anybody who took the time to read all this. Pershe8chall.

 

[Demonic]

Welcome to the forum.

I'd pull it apart and see what you have for damage. The timing tab looks far away from the balancer in your pic. If your other cranks are good, not rusty; spray them with Fluid Film and bag them to prevent rust.

 

[4eighteener]

Welcome Joe Camper!
In answer to your 1st question of where to get a crankshaft, perhaps member @PROSTOCKTOM can help.

With regards to the others questions of balancers and balancing, and water pumps there are more qualified people than myself to chime in.

In an off the cuff remark, that early thicker bore 318 has the potential to bore out to a 4" bore, perhaps even 340 size if checked.
Just saying...

 

[Joe Camper]

The 68 engine on the stand has been disassembled painted, properly prepped for new gaskets and a set of arp bolts. Good eyes on the ballancer but it's just pushed on slightly. The only gaskets on that engine right now r the head gaskets. It's got the correct valve covers correct timing cover and water pump. It's also the correct color 1 yr only 68 340 were born Chrysler industrial red they were only orange in 69 70. Numbscull who rebuilt my 318 got that wrong painted it hemi orange. 69 318 came Chrysler red too. Very handsome in red if u ask me. Orange clashes with my paint, green

I'm also curious what would the result be if a guy had a cast crank and ran it with a ballancer for a forged one. Is it something a guy would notice or it would kill itself without indication?

 

[Oldmanmopar]

The reason the LA340 forged cranks have the hole drilled in the journal is they are the same crank as the early LA318 that had the lighter narrow rods. When they made the 340 using these cranks they drilled the hole to balance the 340 with the wider heavier rods and pistons.
It was cheaper to drill the hole in the journal then to add heavy metal to the counter weight to use the heavier stronger rod and larger piston in 68-72 forge crank 340 engines

73 and newer LA small blocks all had the wider heavier rods but from then on they never had a forged crank.

The heavier the rotating assembly gives more inertia and is great for pulling out with a stick shift truck.

The lighter it is the more torque you get in gear. If you use light weight rods and pistons and cut the counter weights on a crank they spin up like an electric motor and have the torque of a Diesel.

Lightening up or making the spinning weight narrow to what ever is spinning from the front of the crank to the end of the rear axle and you'll see the torque numbers just keep going up . But the inertia will be lost for pulling out easy with a standard shift car or truck.

All the engines I have tore down over the years I have saw that all the auto cars came with a hollowed damper in the back and the 4 speed cars were always solid.

 

[Joe Camper]

I went looked at prostocktom he was here earlier maybe he will see this and be able to help with some answers.

I have a forged crank from a sixty seven barracuda with a 273 out of an engine I disassembled with only normal wear, journals all very flat smooth I can use on the 318 if nessessary depending on what I learn it terms of correct compatibility with components combined on what I find when I take it apart. That said I would still like to find a source on NEW forged cranks with stock stroke.

 

[Joe Camper]

Old man Mopar, thank you for clearing that up. I couldn't remember which crank with the hollow journals was which crank they are tagged and hanging in my garage.
But i'm not there right now your parts are way shinier. Then my parts very nice

 

[66fs]

Just going through all this with a 273 and 69 340. All internal balanced engines, forged or cast, can use the same balancer. There were different balancers for manual and automatic transmissions from 1962-1967. After 1967 they were the same till 1970 when the drivers side timing marks started with the aluminum water pump. It changed again in 1972 when the crank pulley bolt pattern changed to a symmetrical pattern. I'm not considering any external balanced engines.

The cranks for a 340 are different with the hollow throws, mainly due to the heavier pistons and to a lesser degree slightly heavier rods. 273 and 318 cranks are interchangeable forged or cast, do to the same reciprocating weights.

I have never had any cooling problems with any engine, cast iron or aluminum water pumps. The cast iron small block water pump is about 3/4 of an inch shorter than the aluminum water pump along with the corresponding timing cover and balancer. But I also always run original radiators with a 3 row core and an original fan. Typically I do not run a shroud.

 

[Professor Fate]

what is the correct harmonic balancer. And how do you identify it for a pre1970 318 with a forged crank that is externally ballanced.

First off, there are NO 318s that are externally balanced, either forged or cast crank. they are ALL internally balanced.

also, when an engine is externally balanced, is it all done with the ballancer or is a flywheel or torque converter also involved in balance????

An externally balanced engine is balanced with the convertor/flywheel and special weighted harmonic balancer. The ONLY externally balanced small blocks were late '72-'73 340s, all LA 360s, and Magnum 5.9s (360). However, even though all are externally balanced, they all use a different balance weight and parts are not interchangeable.
318/340 forged balancer:

Late '72 and up 340:

La360 balancer:

Magnum 5.9/360 balancer:

Also where is a good supplier or source for ballancers.

Many suppliers out there, just be aware that the timing marks on the balancer will vary according to the type of water pump used- the early iron water pump has the timing tab on the passenger side of the engine, the later aluminum pump has the timing tab on the driver's side- therefore the timing mark on the balancer is indexed differently between the two.

But does anybody know if there is a difference in the volume that flows between the pre1970 cast waterpumps and the newer style aluminum pumps.

The difference between the two factory pumps is negligible. A difference in each is more related to whether the car was originally AC equipped or not. Different vanes and pulley speeds were used depending on original application. There are aftermarket high flow pumps available also.

Just trying to clear up some misconceptions here.

 

[Oldmanmopar]

Eagle sells the standard 3.312 forged cranks for $913.99. I have some used standard cranks for less money if needed.

 

[Joe Camper]

Thank u everyone for clearing these things up. Eagle when u click on the forged stuff it says out of stock.

I'm still curious if u put the incorrect balancer on, say with a mild cam, do u think k it would be something u would notice seat of the pants and would it destroy a street motor that is driven only moderately aggressively. Anybody done or heard of this mistake?

 

[Professor Fate]

I'm still curious if u put the incorrect balancer on, say with a mild cam, do u think k it would be something u would notice seat of the pants and would it destroy a street motor that is driven only moderately aggressively. Anybody done or heard of this mistake?

Yes, yes and yes.

 

[Joe Camper]

Interesting u mention the shroud. I found a date coded radiator with both hoses drivers side like it should be but the shroud it's got is very odd putting it mildly. The shroud on the rad that's in the car now with the newer water pump lower hose pass side. Is so lame I bet if it were removed it wouldn't matter much. R the correct shrouds for the pre 70a body's all odd or do I have the wrong g stuff I am not sure.

Also was a 69 318 4 speed from the factory equipped with a duel point distributor I think it might have been. Everything ive read says manual transmission cars had duel point. It hasn't any influince on what I'm going to run im just curious and if it's in the Vin or fender tag what's the code.

When I pull the original 318 for a 340 and it goes into preservation I want all the correct stuff on it as it sits on the stand. I've got the silencer air cleaner with the 318 emblem the correct valve covers with the plug wire stays mount nicer, the right timing cover and water pump i found a set of original exhaust manifolds. Got a date coded intake and I'd like to put the correct distributor in it. I have an extra bell housing and flywheel. Eventually I'd like to be able to run it along with a couple hit miss engines I have and exercise them all togeather.

A 318 was also available with a 3 speed manual trans in 69 what about those lol no way the put a duel point in beasts like that.

Im also curious as to if the 8&3/4 was the sandard rear axle for a 318 4speed or not.

 

[Professor Fate]

The only LA engines that got dual point distributors were 340s and 273 Commando/Charger 4 bbl. engines. No 318s. There is even some debate as to whether all automatic equipped 340s got a dual point in '68-'69.
As far as the radiator shroud goes, what is "very odd"? A picture would go a long way there.

 

[Joe Camper]

Thank u. The shroud pic will need to wait until till it warms up slightly where it hibernates and I go to greet it this spring.

Last unknown is what was the cars standard rear axle. What was it born with with a 318 4 speed driveline? Is it in the fender tag and what's the code? I'm guessing the standard ratio was 2.72.

 

[cudamark]

Thank u. The shroud pic will need to wait until till it warms up slightly where it hibernates and I go to greet it this spring.

Last unknown is what was the cars standard rear axle. What was it born with with a 318 4 speed driveline? Is it in the fender tag and what's the code? I'm guessing the standard ratio was 2.72.

More likely a 3.23 ratio, and yes, it was an option to get an 8 3/4 rear end in that car.

 

[cudamark]

I went looked at prostocktom he was here earlier maybe he will see this and be able to help with some answers.

I have a forged crank from a sixty seven barracuda with a 273 out of an engine I disassembled with only normal wear, journals all very flat smooth I can use on the 318 if nessessary depending on what I learn it terms of correct compatibility with components combined on what I find when I take it apart. That said I would still like to find a source on NEW forged cranks with stock stroke.

A couple of notes on the 273 to 318 or 340 swap....first, if it's going in a manual trans car, look to see if the crank has been machined for a pilot bushing before ordering the bushing. Most automatic cranks didn't get that final machine work done, so, you need to get an aftermarket pilot BEARING to install in the converter register, or machine the crank for the bushing. The '64-7 273 crank has a smaller diameter register than the 318/340/360, so, the Magnum bearing won't fit. Same problem with using an automatic behind that 273 crank. You either have to make a custom converter, or, change the front pump assembly to the earlier 273 converter (with a 904 trans). With a 727, a custom converter is about the only way to go short of machining the end of the crank for the larger diameter converter hub.